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LostInPhysics
I suggest that

Absolute Time (in arbitrary units) is equal to the total number of past entropic states of the observed system but then after that i know it really should be affected somehow by the speed of light and the relative motion of the observed system but i don't seem to be able to formulate this into an equation...

thoughts?

And if your merely going to reply to tell me why i am an idiot, don't bother replying, because i believe this thread actually says in the description that it is for new theories that may sound weird, but hey, quantum theory was weird enough and look how that turned out!
Robittybob1
If you are going to make something equal to the past states you are never going to solve anything for we only experience the "NOW".
Your measurement must be in the "NOW".
LostInPhysics
Surely though, we do not experience the perfect now as light moves at a finite speed and our experience is relative to the speed of light? i.e no matter how quickly we see something, we are still not seeing it in the same state as it is due to the infinitesimally small amount of "time" it takes for the light to hit the object, bounce back and be processed by our brains...

But in any sense, i am referring to the concept of absolute time, i.e how long has it been since the start of the universe, now in one sense you could say X number of years, but according to several lectures i attended during the british science festival as we go back in time the universe shrinks, as it does this the matter in it is compressed.

As we compress the universe time slows down eventually slowing to a point where it seems time has stopped all together.

I am afraid i am not very good at explaining myself but what i am trying to say is that could it be that time slows down as you condense a system because the total number of possible states of disorder (or entropy) have been reduced. Therefore could this not explain why time moves slower when under the influence of a stronger field of gravity...

By this i mean, the gravity on earth is stronger than the gravity in low earth orbit because it is nearer to the source of the gravity, since the strength of a gravitational field is proportional to the mass of the object creating it, could we not say that a higher density object has less states of entropy that it can exist in, therefore time moves slower, where as in low earth orbit, the system has more states of entropy that are possible increasing the rate of time.

waitedavid137
QUOTE (LostInPhysics+Apr 11 2012, 09:58 AM)
Absolute Time (in arbitrary units) is ....of the observed system ...

Aside from the stuff that doesn't have a real meaning what you have left here is a statement that the proper time for something between the events of its creation and the event where its observation takes place is an invariant.
niels
I think it is an interesting and puzling question about how long time it takes to make an observation.

Physical show inertia (delay) and a physical observation cannot IMO be of instantaneous nature.

Another, and just as puzling, question is about how long time it takes to create (express) an event.

Any observation is IMO an act of interference between object (event) and observer, and time is being involved, if we assume that instantaneous is no option.

Now the OP says *could we not say that a higher density object has less states of entropy that it can exist in, therefore time moves slower, where as in low earth orbit, the system has more states of entropy that are possible increasing the rate of time*

IMO it is a vaguely formulated but right question. Time cannot move, time has no dimension, but time can be characterized by its rate, the TICK of time, which is the rate by which one event is being followed by the next event. Time IS change, and I am not trying here and now to further define CHANGE.

An event can be anything from the smallest thinkable physical existence that can be expressed within the shortest thinkable period of time, and vice versa with increasingly more complex events.

My premise is (I admit it is highly speculative and not part of officially and generally accepted physics and therefore can be put forward in this tread dealing with speculative and weired ideas) that physics IS dimensional, physics involve 3D, physics cannot exist without having a metric. My premise is also that it takes a metric to get a metric, iow a metric cannot be constructed out from something which inherently is dimensionless. Zero dimension is not physical. From this it logically follows that a physical event takes a dimension, and the smaller the event the smaller the dimension and vice versa, and (again my premise) there is a relationship between event and time period needed in order to express said event. And there is a relationship between *size, dimension* of event and the time it takes to observe said event. From this it logically follows that small events are more rapidly being expressed (configured) and they show a smaller dimension, so the speed by which such an event can be propagated through space is *re configuration time x dimension*. Speed of light is the *re configuration time of PHOTON x dimension PHOTON* and any physical expressions less complex than photon is being re configured within a shorter time period, and therefore with a higher frequency, but at the same time exhibit smaller dimension, so the resulting speed or propagation in spacetime is no faster. Speed of light is a universal constant and reflects the propagation of information in spacetime.

Last year there was some hype about the observation that speed of light was being measured as being slightly slower than the speed of neutrino, with a delay of 60 nanoseconds over a distance of about one km.

I have suggested that this time dealy of the arrival of light as compared to neutrino flight, is a reflecion of how long time it takes to OBSERVE the passing of the line, and NOT reflecting a difference in propagational speed in space. If this is a correct assumption then a repetition of the experiment with variable distances would show exactly the same delay irrespective of flight distance, namely this 60 nanoseconds.

niels
correction

line 4

Any *physical phenomena*

niels
rpenner
QUOTE (niels+Apr 11 2012, 09:07 PM)
this 60 nanoseconds.

Two general categories of self-delusional pseudo-science exist: Cargo-Cult pseudo-science and Tooth Fairy pseudo-science.

Cargo-Cult pseudo-science apes the form of science to try to get the authority and benefits of science. This is why actors wear lab coats to tell us about shampoo or caffeinated drinks with dubious health benefits, because it gives the ad a "sciency" feel that would inspire more trust than "Please buy our expensive product -- it smells nice and probably won't kill you horribly."

Tooth-Fairy pseudo-science spends time trying to model phenomena not shown to exist. Lots of things exist in human heads without objective reality. Famously, N-Rays and Piltdown man were driven by nationalism and confirmation bias.

The current trend in cheaply filmed paranormal-chasing television shows appear to be mixtures of both.

The Gran Sasso researchers did not fall into these traps, but instead appear to have put publicity (important for funding) ahead of truth. They, with much fanfare in 2011 put forward a result from a very complicated timing experiment. They weren't racing light and neutrinos, but were attempting to compare the actual time-of-flight of neutrinos with the expected time-of-flight of light. Lots of things could have gone wrong, but they said "we looked at those." They had a huge press announcement and the story went around the Earth.

No scientist believed their experimental results. Some of them compared the results to other neutrino properties. The Gran Sasso/OPERA organization basically said that they didn't care if the result made no sense, they pushed the button and this was the number.

Then in February of this year, their confidence fell apart. They had a small press release that basically said: "Oops. Stay tuned."

In March, a second group showed time-of-flight of the same neutrinos was not faster than light. It was clear than a loose fiber optic cable was not getting enough light to an electronic circuit to quickly trigger the timing circuit. So the timing circuit was getting triggered late, which mean that the time of the neutrinos only appeared to be 60 ns early when the clock was 60 ns late. The lead scientist who signed off on the high-publicity route resigned after a vote of no confidence.

http://profmattstrassler.com/articles-and-...hat-went-wrong/

But trying to explain FTL neutrinos when there is no observation of FTL neutrinos is Tooth Fairy pseudo-science. Its like trying to explain how to distinguish drafts from ghostly cold spots.
Confused1
QUOTE (rpenner+)
The Gran Sasso/OPERA organization basically said that they didn't care if the result made no sense, they pushed the button and this was the number.
The first report I read :
http://www.bbc.co.uk/news/science-environment-15017484
QUOTE
"We tried to find all possible explanations for this," the report's author Antonio Ereditato of the Opera collaboration told BBC News on Thursday evening.

"We wanted to find a mistake - trivial mistakes, more complicated mistakes, or nasty effects - and we didn't.

"When you don't find anything, then you say 'well, now I'm forced to go out and ask the community to scrutinise this'."

Friday's meeting was designed to begin this process, with hopes that other scientists will find inconsistencies in the measurements and, hopefully, repeat the experiment elsewhere.
..
"We look forward to independent measurement from other experiments."

-C2.

rpenner
Timeline: http://www.dipity.com/kahoakes/Faster-than-light-neutrinos/
http://blogs.scientificamerican.com/basic-...nos-a-timeline/

2011-09-22 -- News story broke at a press conference at CERN by the OPERA (Gran Sasso) lead scientist before paper put on arXiv or reviewed by the CERN scientists "Particles found to break speed of light"
QUOTE
Antonio Ereditato, spokesman for the researchers, told Reuters that measurements taken over three years showed neutrinos pumped from CERN near Geneva to Gran Sasso in Italy had arrived 60 nanoseconds quicker than light would have done.

"We have high confidence in our results. We have checked and rechecked for anything that could have distorted our measurements but we found nothing," he said. "We now want colleagues to check them independently."

And then this had a high-profile tweet, a counter-wave of scientifically educated strong skepticism and finally The first preprint of OPERA-1

2011-09-23 Then CERN hears about what OPERA has said (video)

2011-10-22 A month later, ICARUS reports that physical consequences of FTL neutrinos predicted by Glashow were not observed in the lab, another group weighs in similarly for cosmic rays.

2011-11-17 OPERA does a high-level review and reruns the experiment, updating the paper. But ICARUS doesn't think so.

2012-02-22 After months of doing high-level reviews of the calculations, OPERA discovers a loose fiber optic cable that would retard the time base of the Gran Sasso receivers and lead to the illusion that everything happens 60 ns faster in Italy.

2012-03-15: ICARUS measures the time with their equipment: no FTL neutrinos

2012-03-30: OPERA proves it was the loose fiber optic cable, effectively retracting the physics content of their papers. http://profmattstrassler.com/2012/03/30/op...ssue-confirmed/
And Ereditato resigns after a vote of no-confidence.

Confused1
The BBC[Antonio_Ereditato] seems to be a lot more modest than the Reuters[Antonio_Ereditato]. If Antonio_Ereditato==Antonio_Ereditato then BBC<>Reuters. In matters of fair and honest reporting it is possible BBC > Reuters though I admit, being British, I may be biassed.
-C2.

Edit.. I hope the (probable) technician responsible has been given the option of a blindfold.
Edit2.. IMHO Antonio_Ereditatos should not have let the story get out of hand which (clearly) it did - if he'd stuck to the BBC[Antonio_Ereditato] story he might have got away with it.
mik
LostinPhysics:
QUOTE
As we compress the universe time slows down eventually slowing to a point where it seems time has stopped all together.
....
Surely though, we do not experience the perfect now as light moves at a finite speed and our experience is relative to the speed of light? i.e no matter how quickly we see something, we are still not seeing it in the same state as it is due to the infinitesimally small amount of "time" it takes for the light to hit the object, bounce back and be processed by our brains...

The first statement is an example of the basic fallacy of reification of time, "making something of it" beyond the *concept* of elapsed time (duration) as things move.

For instance, if "things" move more slowly, like oscillations of a clock "ticking" more slowly at higher velocities, the above fallacy claims that "time dilates" or "time slows down." What we empirically observe is that clocks "tick" more slowly.

Regarding the second statement:
The fact that light and information travels from an object/ event to an observer at a constant speed limit does not mean that "now here" is a different now than "now on the sun," for instance. Now IS now everywhere, not limited by delayed information about what IS happening elsewhere. Of course we will not get information about the simultaneous now on the sun (say a specific solar flair) for 8+ minutes... the signal delay.

rpenner
That's just solipsism and denial of physics, not a physics argument.

Your claim that the other person's clock doesn't slow down ignores that half the time you are the "other person" oblivious to the fact that your clocks are running slow. This is solipsism in that by treating you and your clock alone as real, all other clocks are just wrong instead of there being some great principle at work.

QUOTE (rpenner+ 2010-05-12)
Inability to comprehend relativity is the inability to put oneself intellectually into the shoes of another and working out the consequences. It seems to me that this belongs on the non-clinical side of a spectrum of sociopathic disorders. http://www.squidoo.com/the-sociopath-next-door

http://www.sciforums.com/showpost.php?p=2540723&postcount=22

Your claim that "now is now everywhere" ignores the lessons learned from electromagnetism and the study of high-speed phenomena -- it's an intuitionist assumption antique after 1859, incompatible with physical theory after 1862, and replaced with better assumptions in 1905.
mik
rpenner:
"Your claim that the other person's clock doesn't slow down..."

Just a quick pass through here. I don't remember making that claim. Please specify.

My "claim" was that time is not 'something' that slows down as we observe clocks slowing down.

And "Now" IS the present. It doesn't depend on who sees what and when at whatever distance from the source of light/info and travel time for info about it.
rpenner
It's not a clock -- it's all clocks, be they based on electromagnetism, weak force, strong force or gravity. Therefore the laws of physics look the same to the moving laboratory with its definitions of space and time as to the stationary laboratory with its definitions of space and time. Therefore space and time are not absolute, but observer-based conventions and physical theories can be written in terms of motion-independent invariants if physics is to mean anything at all.

Maxwell's equations, written in terms of potentials defined in the Lorentz gauge, is a particularly good example of this.

"Now" defines a slice through space-time where all events have the same t-coordinate. Maxwell's equations written in the standard set of four equations in E and B fields use such a coordinate system, but for a relatively moving laboratory describing the same electromagnetism results, it is necessary to use the correct relative definition of "now." Galilean relativity (which says the "now" is the same) doesn't work. Special relativity ( which has the well-documented "relativity of simultaneity" does work ).

I'm not arguing that a universe couldn't exist if "now" was "now everywhere" -- I'm using evidence and over 150 years of observation to say such a universe is not the one we inhabit.
mik
rpenner,

My point about time dilation was simply, empirically, that what we *observe* is clocks slowing down in rate of oscillation when they are traveling at higher speeds (or in stronger gravity fields.)

It is a leap beyond empirical observation to claim that time is *something* that slows down, which clocks somehow detect, which makes them slow down.

As for "now," we all know that it takes 8+ minutes for sunlight to reach earth. So, a flair happening *now* will not be seen for 8 min. Yet the *now* in which the flair erupted was the same now on earth, regardless of travel time delay for us to see that light/info.

The relativity of simultaneity has not debunked presentism. And it leads to "eternalism" which claims a "block universe" in which everything that ever existed or will ever exist somehow exists now, in some frame of reference somewhere.

synthsin75
QUOTE (mik+Apr 15 2012, 06:40 PM)
rpenner,

My point about time dilation was simply, empirically, that what we *observe* is clocks slowing down in rate of oscillation when they are traveling at higher speeds (or in stronger gravity fields.)

...

As for "now," we all know that it takes 8+ minutes for sunlight to reach earth. So, a flair happening *now* will not be seen for 8 min. Yet the *now* in which the flair erupted was the same now on earth, regardless of travel time delay for us to see that light/info.

The relativity of simultaneity has not debunked presentism. And it leads to "eternalism" which claims a "block universe" in which everything that ever existed or will ever exist somehow exists now, in some frame of reference somewhere.

You need to define which frame you are talking about. The clock of a relatively faster frame is only observed to slow from the frame it is moving relative to, but the "faster" moving frame observes that other frame to be the one moving with its clock being observed to run slower.

Blanket statements like "traveling at higher speeds" are only ever relative, with a reciprocal relationship with the frame it is wrt.

The relativity of simultaneity has nothing to do with the signal delay of the finite speed of light. As you say, we are completely aware of that fact, and we can easily account for it. When we do, events observed as simultaneous in one frame STILL aren't simultaneous in another.

Presentism is a philosophical doctrine that is not anywhere near as empirically rigorous as the relativity of simultaneity. Guess what, it is presentism that would bear the onus of debunking the RoS, not the other way around.
rpenner
Having received a gloss on the subject, presentism doesn't sound like it needs to be debunked.

If presentism is the source of mik's problems with Relativity, it is equally the source of his problems with History and Literature, and possibly Current Events.
QUOTE
Q: Who wrote Twelfth Night?
A: Presentism requires me to assert that no one actually wrote Twelfth Night for having wrote is to exist in the past and act and such things are inadmissible to my philosophy. Neither is there anyone writing Twelfth Night, therefore I conclude noone wrote Twelfth Night.

As stated, I believe that mik's problem is chauvinism and over-reliance on preconceptions, two traits I find distasteful in philosophers. I prefer philosophers engage in a reality with more than one person in it.

[Moderator: A full discussion of length contraction as a natural consequence of accepting the principle of relativity and the Poincaré transformation was made in a previous post. (Click Here). By order of the Moderator, mik and Mazulu are required to read this post, to understand the post, and to ask questions about what things mean if there is any doubt about understanding before any further discussion on the topic of relativity. The penalty for not fully understanding this post before continuing will be a complete loss of faith in your good intentions by the moderator.]
mik
QUOTE (rpenner+Apr 16 2012, 05:24 AM)
Having received a gloss on the subject, presentism doesn't sound like it needs to be debunked.

If presentism is the source of mik's problems with Relativity, it is equally the source of his problems with History and Literature, and possibly Current Events.

As stated, I believe that mik's problem is chauvinism and over-reliance on preconceptions, two traits I find distasteful in philosophers. I prefer philosophers engage in a reality with more than one person in it.

[Moderator: A full discussion of length contraction as a natural consequence of accepting the principle of relativity and the Poincaré transformation was made in a previous post. (Click Here). By order of the Moderator, mik and Mazulu are required to read this post, to understand the post, and to ask questions about what things mean if there is any doubt about understanding before any further discussion on the topic of relativity. The penalty for not fully understanding this post before continuing will be a complete loss of faith in your good intentions by the moderator.]

rpenner,

I read the required link/post (again.) I am not a mathematician but I am an avid philosopher of science, through which the numbers relate to meaningful concepts and to "the real world" to which those concepts refer.

You say:
QUOTE
"If presentism is the source of mik's problems with Relativity, it is equally the source of his problems with History and Literature, and possibly Current Events.

As stated, I believe that mik's problem is chauvinism and over-reliance on preconceptions, two traits I find distasteful in philosophers. I prefer philosophers engage in a reality with more than one person in it.

Here is a quick review of presentism as contrasted with eternalism and the Block Universe concept of 4-D relativity (starting with the basic ontology of time and review of your quotes on the subject):

me, 4/12:
My "claim" was that time is not 'something' that slows down as we observe clocks slowing down.
...
And "Now" IS the present. It doesn't depend on who sees what and when at whatever distance from the source of light/info and travel time for info about it. "

rpenner:
QUOTE (->
 QUOTE "If presentism is the source of mik's problems with Relativity, it is equally the source of his problems with History and Literature, and possibly Current Events. As stated, I believe that mik's problem is chauvinism and over-reliance on preconceptions, two traits I find distasteful in philosophers. I prefer philosophers engage in a reality with more than one person in it.

Here is a quick review of presentism as contrasted with eternalism and the Block Universe concept of 4-D relativity (starting with the basic ontology of time and review of your quotes on the subject):

me, 4/12:
My "claim" was that time is not 'something' that slows down as we observe clocks slowing down.
...
And "Now" IS the present. It doesn't depend on who sees what and when at whatever distance from the source of light/info and travel time for info about it. "

rpenner:
"Now" defines a slice through space-time where all events have the same t-coordinate. ...
but for a relatively moving laboratory describing the same electromagnetism results, it is necessary to use the correct relative definition of "now." Galilean relativity (which says the "now" is the same) doesn't work. Special relativity ( which has the well-documented "relativity of simultaneity" does work ).

I'm not arguing that a universe couldn't exist if "now" was "now everywhere" -- I'm using evidence and over 150 years of observation to say such a universe is not the one we inhabit.

QUOTE
Analogously, the sentence "is the world three-dimensional or four-dimensional?" is a canonical example of sloppy formulations. The answer depends on whether "the world" in the sentence means a "slice of spacetime" or the "spacetime" itself. Both concepts, the slice as well as the spacetime, "exist" in the space of concepts.

There are two competing theories of time, presentism and eternalism.. Presentist claim objects only exist in the present after emerging from the future and disappearing into the past. Eternalist, on the other hand, insist that objects continue to exist in the past, present and future. Intuitively, presentism appeals to common sense, However, it is inconsistent with Einsteins special theory of relativity as well as not explaining how things pop in and out of existence,

Eternalism, on the other hand, has become the favorite theory of time even though it is difficult to imagine. According to this theory, Aristotle and Abraham Lincoln still exist in four dimensional time. It also eliminates the mystery over the flow of time, According to eternalism, we live in a timeless block universe where time is a real dimension in the same way as the spatial dimensions.

Also, check out the “Presentism, Eternalism, and The Growing Universe Theory” subsection at the Stanford encyclopedia of Philosophy site, “Time” section.

Also Wikipedia on “four-dimensionalism.
QUOTE (->
 QUOTE Analogously, the sentence "is the world three-dimensional or four-dimensional?" is a canonical example of sloppy formulations. The answer depends on whether "the world" in the sentence means a "slice of spacetime" or the "spacetime" itself. Both concepts, the slice as well as the spacetime, "exist" in the space of concepts. There are two competing theories of time, presentism and eternalism.. Presentist claim objects only exist in the present after emerging from the future and disappearing into the past. Eternalist, on the other hand, insist that objects continue to exist in the past, present and future. Intuitively, presentism appeals to common sense, However, it is inconsistent with Einsteins special theory of relativity as well as not explaining how things pop in and out of existence,Eternalism, on the other hand, has become the favorite theory of time even though it is difficult to imagine. According to this theory, Aristotle and Abraham Lincoln still exist in four dimensional time. It also eliminates the mystery over the flow of time, According to eternalism, we live in a timeless block universe where time is a real dimension in the same way as the spatial dimensions.

Also, check out the “Presentism, Eternalism, and The Growing Universe Theory” subsection at the Stanford encyclopedia of Philosophy site, “Time” section.

Also Wikipedia on “four-dimensionalism.
”Eternalism is a philosophical approach to the ontological nature of time, according to which all points in time are equally "real", as opposed to the presentist idea that only the present is real.

So your four dimensional universe reifies time and space in a way that claims that everything that has ever existed or ever will exist are "equally real."

So "real and present"loses its meaning and the "concept" of "slices of spacetime" can contain past and future as "now present"... conceptually speaking if you ignore that future events are not yet present and past events are no longer present.

Gotta go. Forgot a reference above (the "]Analogously...," quote. Will find it when I come back.
rpenner
QUOTE (mik+Apr 16 2012, 09:02 PM)
So your four dimensional universe reifies time and space in a way that claims that everything that has ever existed or ever will exist are "equally real."

So "real and present"loses its meaning and the "concept" of "slices of spacetime" can contain past and future as "now present"... conceptually speaking if you ignore that future events are not yet present and past events are no longer present.

That need not be my position. For example, I may describe things in my personal past light cone (including boundary) as equally real in that my present state can be formulated as a function of this personal past. Or I may treat my personal slice of simultaneity as real-to-me while allowing someone else may with equal validity treat their slice of simultaneity as real-to-them.

Both of these viewpoints are compatible with special relativity that says the meaningful-to-us portion of our past is bounded by our personal past light-cone and our future prospects are bounded by the our future light cone, and that which is outside of the light cones is presently beyond our ability to influence just as we are presently beyond its ability to influence us.

What is solipsism is to deny that the other person is real. What violates the principle of relativity is to claim that the other person is real and still deny that other persons reality is as real as your reality, all things being equal, mutatis mutandis.

Do you have any questions about the above linked post, its use of coordinate system S (with coordinates x and t) and S' (with coordinates x' and t'), on the relativity of simultaneity, the principle of relativity or what ties them all together? Was it clear that a Poincaré transform allows one to relate S and S' ?
rpenner
The main benefit of the methodology of science is that science is progressive -- it gets better over time as more things are added. It's the part of the human civilization that is learning.

QUOTE (Ethan Siegel+)
No matter who you are, no matter how smart you are, no matter how brilliantly you've drawn the conclusions you've drawn from the evidence you've gathered, there will come an instance where the evidence you encounter will be irreconcilable with the picture of reality you presently hold. And when that moment happens, your response will mean absolutely everything.

Because there is the possibility that your view of reality -- the way you make sense of things -- is flawed in some way. You have to open your self up to at least the possibility that you are wrong. It is a humbling admission, that you may be wrong, but it's also the most freeing thing in the world. Because if you can be wrong about something, then you can learn.

The discovery that planets move about the Sun in ellipses required exactly that; were it not for Kepler and his ability to accept that his earlier models were flawed, and then abandon them and create new and improved ones, physics and astronomy would likely have been set back an entire generation. And if you, yourself, can do this in your own life, you can find a better explanation for the phenomena you encounter in this world. You can bring your understanding of the world more closely in line with what reality actually is. In other words, you can do what all good scientists do, and in the end, learn something amazing.

But if you can't admit that you might be wrong, if your picture of reality is unchangeable despite any evidence to the contrary, if you refuse to assimilate new information and new knowledge and re-evaluate your prior stance on an issue, then you will never learn.

Anything.

http://scienceblogs.com/startswithabang/20...ing_im_wron.php

So when I evaluate claims that "The Big Bang is Wrong" or "Global Warming is Wrong" or "Evolution is Wrong" or "Time does not Exist" or "Maxwell's Equations are Wrong" or "Special Relativity is Wrong" or "I am not a plagiarist" I want to look at some items.
• Does the person show evidence that he fully understands the topic or are they arguing against some sort of straw-man?
• Does the person show evidence that they are making a fair evidence-based argument, or are they just promoting their gut feeling over evidence provided by observation of phenomena?
• Is the viewpoint objective and communicable or does it rely on ephemeral philosophical or semantic distinctions?
• Does the viewpoint lead to a predictive understanding of phenomena or is it just some outlier data that stands outside the collection of the best and most reliable observations?
It means nothing to me that a bunch of crackpots and science outsiders are willing to stand under a common umbrella to rally against the prevailing view. Their ideas must stand or fall on their own. And when they hold contrary positions it is clear that they cannot convince their fellow outsiders of their views, let alone the science-educated mainstream.

It appears that niels' suppositions don't begin to meet the minimum requirements for advancing human knowledge.

This post has been adapted from here for general educational benefit.
brucep
QUOTE (rpenner+Apr 17 2012, 11:04 PM)
The main benefit of the methodology of science is that science is progressive -- it gets better over time as more things are added. It's the part of the human civilization that is learning.

http://scienceblogs.com/startswithabang/20...ing_im_wron.php

So when I evaluate claims that "The Big Bang is Wrong" or "Global Warming is Wrong" or "Evolution is Wrong" or "Time does not Exist" or "Maxwell's Equations are Wrong" or "Special Relativity is Wrong" or "I am not a plagiarist" I want to look at some items.
• Does the person show evidence that he fully understands the topic or are they arguing against some sort of straw-man?
• Does the person show evidence that they are making a fair evidence-based argument, or are they just promoting their gut feeling over evidence provided by observation of phenomena?
• Is the viewpoint objective and communicable or does it rely on ephemeral philosophical or semantic distinctions?
• Does the viewpoint lead to a predictive understanding of phenomena or is it just some outlier data that stands outside the collection of the best and most reliable observations?
It means nothing to me that a bunch of crackpots and science outsiders are willing to stand under a common umbrella to rally against the prevailing view. Their ideas must stand or fall on their own. And when they hold contrary positions it is clear that they cannot convince their fellow outsiders of their views, let alone the science-educated mainstream.

It appears that niels' suppositions don't begin to meet the minimum requirements for advancing human knowledge.

This post has been adapted from here for general educational benefit.

Great post. Ethan's wisdom will fall on many 'hollow spheres with ears' at physforum.
mik
QUOTE (rpenner+Apr 16 2012, 10:14 PM)
That need not be my position. For example, I may describe things in my personal past light cone (including boundary) as equally real in that my present state can be formulated as a function of this personal past. Or I may treat my personal slice of simultaneity as real-to-me while allowing someone else may with equal validity treat their slice of simultaneity as real-to-them.

Both of these viewpoints are compatible with special relativity that says the meaningful-to-us portion of our past is bounded by our personal past light-cone and our future prospects are bounded by the our future light cone, and that which is outside of the light cones is presently beyond our ability to influence just as we are presently beyond its ability to influence us.

What is solipsism is to deny that the other person is real. What violates the principle of relativity is to claim that the other person is real and still deny that other persons reality is as real as your reality, all things being equal, mutatis mutandis.

Do you have any questions about the above linked post, its use of coordinate system S (with coordinates x and t) and S' (with coordinates x' and t'), on the relativity of simultaneity, the principle of relativity or what ties them all together? Was it clear that a Poincaré transform allows one to relate S and S' ?

rpenner,

Please respond to the Wiki quote on four-dimensionalism:

QUOTE
Eternalism is a philosophical approach to the ontological nature of time, according to which all points in time are equally "real", as opposed to the presentist idea that only the present is real.”...

and my comment:

"So your four dimensional universe reifies time and space in a way that claims that everything that has ever existed or ever will exist are 'equally real.' "

Are living dinosaurs and human colonies on Mars “real and present” in some “slice” of “four dimensional spacetime” (a concept) as seen from another frame of reference with each frame of reference having its own 'now' and its own reality?

QUOTE (->
 QUOTE Eternalism is a philosophical approach to the ontological nature of time, according to which all points in time are equally "real", as opposed to the presentist idea that only the present is real.”...

and my comment:

"So your four dimensional universe reifies time and space in a way that claims that everything that has ever existed or ever will exist are 'equally real.' "

Are living dinosaurs and human colonies on Mars “real and present” in some “slice” of “four dimensional spacetime” (a concept) as seen from another frame of reference with each frame of reference having its own 'now' and its own reality?

One of the consequences of special relativity is that time is not absolute. Not only do clocks in motion disagree on what the rate of time passing is, but inertial coordinate system disagree on what events have the same coordinate time if their positions are distinct from one another. This is called the relativity of simultaneity.

Regarding the first sentence, you have never addressed the ontological challenge to the reification of time, making “something” of it besides the obvious “elapsed time” as things move from one point in space to another.
We all know that clocks slow down relative to each other as above yet the challenge to time reification still stands unanswered. The physical process of oscillation slows down in clocks at higher speeds relative to those at lower speeds or in lower gravity fields (higher elevation.)
But what is "time," that "it" slows down?

You never commented on the quote above about “coordinate systems” like 4-D spacetime being in “conceptual space” as distinguished from actual objects moving through space as time passes. Rather, the conceptual coalescence of space and time are taken for granted.

I did not understand why you said, “Ignoring two dimensions of space, we can establish the inertial coordinate system S ...”

Why ignore two dimensions of space?
Space is three dimensional. Time elapses as things move. Call it a fourth dimension but "it" is not an entity combined with space (ontologically speaking.) Everything you wrote beyond the above quote was math. I already said that I am not a mathematician, but I do understand the difference between a coordinate system and the “real world” which it “maps.”

A couple of missing links from yesterday's post:

Stanford Encyclopedia of Philosophy on "Time":
http://plato.stanford.edu/entries/time/

The Reference Frame: Presentism vs Eternalism
http://motls.blogspot.com/2008/05/presenti...eternalism.html

Finally, "real to me" and "real to them" puts priority on frame of reference *as Reality.* Philosophically, beyond that dictum of relativity, things are as they are in the "real world" regardless of frame of reference. "Length contraction" (as per the other thread) is a good example. It is up to science to figure out whether, for instance, earth is a very oblate spheroid, as "seen" from very high speed, or nearly spherical as "seen" from living on it or from orbit around it.

"What is solipsism is to deny that the other person is real. What violates the principle of relativity is to claim that the other person is real and still deny that other persons reality is as real as your reality, all things being equal, mutatis mutandis."

The above statement about "the 'real world' regardless of frame of reference..." does not deny anyone's reality. It elevates "reality" beyond how it is *observed* from different frames of reference. This point has never been addressed here.

I put it to you as I did to synthsin75: Is the flattened earth "equally valid" with the spherical earth just because "another person" flying by at very high speed might see it that way... and we must 'respect his reality'? No.

The philosophy of science called realism says, as above, that the world IS as it IS, not as different frames of reference *see* it. Accordingly, IS means the Present, and the Present IS the Present everywhere, transcending relativity's reification of space, time and spacetime.

Again, please address presentism vs eternalism, the latter of which describes a "block universe" where past, present and future are somehow all Present (depending on frame of reference.) Do you actually believe that?
rpenner
QUOTE (mik+Apr 18 2012, 12:19 AM)
rpenner,

Please respond to the Wiki quote on four-dimensionalism:
QUOTE (Wikipedia+)
Eternalism is a philosophical approach to the ontological nature of time, according to which all points in time are equally "real", as opposed to the presentist idea that only the present is real.”...
and my comment:

"So your four dimensional universe reifies time and space in a way that claims that everything that has ever existed or ever will exist are 'equally real.' "

Classically, one should master logic and rhetoric before attempting philosophy. Your insistence that I respond makes little sense when I have already responded and called out that your oversimplification in terms of absolute presentism versus eternal block time is an example of the fallacy of false dilemma and I gave two other possible philosophical viewpoints on what is real. I quote this interaction for your benefit:
QUOTE (mik+Apr 16 2012, 09:02 PM)
So your four dimensional universe reifies time and space in a way that claims that everything that has ever existed or ever will exist are "equally real."

So "real and present"loses its meaning and the "concept" of "slices of spacetime" can contain past and future as "now present"... conceptually speaking if you ignore that future events are not yet present and past events are no longer present.

Gotta go. Forgot a reference above (the "]Analogously...," quote. Will find it when I come back.

QUOTE (rpenner+Apr 16 2012, 10:14 PM)
That need not be my position. For example, I may describe things in my personal past light cone (including boundary) as equally real in that my present state can be formulated as a function of this personal past. Or I may treat my personal slice of simultaneity as real-to-me while allowing someone else may with equal validity treat their slice of simultaneity as real-to-them.

Both of these viewpoints are compatible with special relativity that says the meaningful-to-us portion of our past is bounded by our personal past light-cone and our future prospects are bounded by the our future light cone, and that which is outside of the light cones is presently beyond our ability to influence just as we are presently beyond its ability to influence us.

And for pedagogical reasons, the text you quote appears to come from here: Wikipedia:Eternalism (philosophy of time)

Real is in scare quotes in this wiki page because the concept is only of metaphysical import. Contrastingly, personal-past-conism limits one to asserting as metaphysically real that which in principle one could discover or physically could influence one, while relativity-informed-presentism involves personal skew realities which are fully commensurable only when the individuals are in the same state of motion (and for the GR-eductation version, in the same place). These philosophies are metaphysical in that those that are compatible with relativity are not distinguishable by physical experiment. They are opinions about intangibles.

QUOTE (mik+Apr 18 2012, 12:19 AM)
Are living dinosaurs and human colonies on Mars “real and present” in some “slice” of  “four dimensional  spacetime” (a concept) as seen from another frame of reference with each frame of reference having its own 'now' and its own reality?
The postulated human colonies on Mars seem to require strong, possibly unphysical, assumptions about terrestrial economics. Even if I subscribed to the Wikipedia gloss on Eternalism, living dinosaurs are "knowable, real, and past" while human colonies are "unknowable, potentially real, and future." Both the light cone of physics and English tenses seem adequate to distinguish them from things that conventionally are "real and present."

QUOTE (mik+Apr 18 2012, 12:19 AM)
QUOTE (rpenner+Apr 13 2012, 10:19 PM)
One of the consequences of special relativity is that time is not absolute. Not only do clocks in motion disagree on what the rate of time passing is, but inertial coordinate system disagree on what events have the same coordinate time if their positions are distinct from one another. This is called the relativity of simultaneity.

http://www.physforum.com/index.php?showtop...ndpost&p=516338
QUOTE (mik+Apr 18 2012, 12:19 AM)
Regarding the first sentence, you have never addressed the ontological challenge to the reification of time, making “something” of it besides the obvious “elapsed time” as things move from one point in space to another.
Physics does not respect elapsed coordinate time as a fundamental and invariant observable to all observers. Physics does respect elapsed proper time and light cones as fundamental and invariant. From multiple light-cones a geometry of a 3+1 space-time emerges, and that requires a coordinate time to be distinguished if all hypothetical events are to be labelled. The Poincaré transform allows one to relate the labels of one coordinate system to another. Change T' if you want to talk about the coordinate system of "then", change X' if you want to talk about the coordinate system of "over there", change µ' if you want to talk about the coordinate system "passing you by" (omitted are angles required in the 3+1 system in the event the coordinate system is on its head). Empirically, coordinate time is part of models so we can relate measurements to proper time. See also http://www.physforum.com/index.php?showtop...ndpost&p=516449 for other examples of quantities more empirically justified as real than coordinate time.

QUOTE (mik+Apr 18 2012, 12:19 AM)
We all know that clocks slow down relative to each other as above yet the challenge to time reification still stands unanswered.
If coordinate systems S and S' are in relative motion, ( Δx=0, Δt=Δτ ) describes a motionless clock tick, while ( Δx'=vΔτ/√(1 − v²/c²), Δt'=Δτ/√(1 − v²/c²) ) describes the same tick with different clocks and rulers. But from both of these:
(cΔt)² − (Δx)² = c²(Δτ)² = (cΔt')² − (Δx')²
So the physical model of reality speaks to the reality of elapsed proper time even when all we have are the coordinates in which the clock is moving. Elapsed proper time is vital, non-removeable part of all fundamental physical theories.

S has the Δt of its unmoving clocks and S' has the Δt' of its unmoving clocks, but comparing Δt to Δt' is a case of apples and oranges when S likes apples precisely as much as S' likes oranges.

QUOTE (mik+Apr 18 2012, 12:19 AM)
The physical process of oscillation slows down in clocks at higher speeds relative to those at lower speeds or in lower gravity fields (higher elevation.)
"higher speeds" implies a physically distinguishable absolute standard of rest, which is neither evidenced nor argued for. And in GR it is clock which are lower in a gravity well that tick slower.
QUOTE (mik+Apr 18 2012, 12:19 AM)
But what is "time," that "it" slows down?
We are talking about the ratio of proper time to coordinate time, ∂τ/∂t, which is 1 in the above example for S, and √(1 − v²/c²) < 1, for S' where the clock has a relative motion of v.

QUOTE (mik+Apr 18 2012, 12:19 AM)
You never commented on the quote above about “coordinate systems” like 4-D spacetime being in “conceptual space” as distinguished from actual objects moving through space as time passes. Rather, the conceptual coalescence of space and time are taken for granted.
Coordinate systems are man-made systems for labeling sections of reality with respect to geometry. The physics that demands the real consequences of light-cones and their interrelations implies that such a geometry is real. It is not, however, Euclidean geometry but hyperbolic. I emphasized this in my April 13th post when I explicitly chose a inhomogeneous hyperbolic rotation with parameter µ'.

QUOTE (mik+Apr 18 2012, 12:19 AM)
I did not understand why you said, “Ignoring two dimensions of space, we can establish the inertial coordinate system S ...”

Why ignore two dimensions of space?
Space is three dimensional. Time elapses as things move. Call it a fourth dimension but "it" is not an entity combined with space (ontologically speaking.) Everything you wrote beyond the above quote was math. I already said that I am not a mathematician, but I do understand the difference between a coordinate system and the “real world” which it “maps.”
I skipped two dimensions because I only needed one time-like dimension and one space-like dimension to talk about velocity and relativity. Additional spatial dimensions would require me to include 5 angles and two more translation parameters to talk about the most general form of the Poincaré transform. This would seem to be a disservice to the reader.

Everything past that point was high school level algebra with all the heavy lifting done for you. I respected your lack of mathematical education.

Today's physical models are currently experimentally indistinguishable from observation. Therefore, on a economic basis where learning costs resources, knowledge of the map is superior to knowledge of the territory because the map describes the whole of the experimental record. While I deliberately used an antique physical model, it passes tests where the influence of gravity is negligible at the parts-per-trillion level. So even crippled by this forum's complete unsuitability to sketch how physically meaningful light cones requires the geometry of light cones to be reflected in reality, exposing you to 1+1 special relativity is a distillation of empirical observation for the case where the relative motion and the direction of length measurement are in the same direction.

QUOTE (mik+Apr 18 2012, 12:19 AM)
A couple of missing links from yesterday's post:

Stanford Encyclopedia of Philosophy on "Time":
http://plato.stanford.edu/entries/time/

The Reference Frame: Presentism vs Eternalism
http://motls.blogspot.com/2008/05/presenti...eternalism.html

QUOTE (mik+Apr 18 2012, 12:19 AM)
Finally, "real to me" and "real to them" puts priority on frame of reference *as Reality.* Philosophically, beyond that dictum of relativity, things are as they are in the "real world" regardless of frame of reference.p
Events that happen have an absolute reality that can't be denied just because someone has different clocks and rulers. The geometry of space-time and light cones at least reflects something that is real. Points in space time where nothing happens (also technically called events in SR) are therefore real because the geometry requires the midpoint to exist. The coordinate elapsed time or coordinate distance however are tied necessarily (so physics informs us) to a frame of reference.

QUOTE (mik+Apr 18 2012, 12:19 AM)
"Length contraction" (as per the other thread) is a good example. It is up to science to figure out whether, for instance, earth is a very oblate spheroid, as "seen" from very high speed, or nearly spherical as "seen" from living on it or from orbit around it.
Huh? A sphere is mathematical idealization. What something "really is" is also a mathematical idealization. In SR, a sphere at rest is congruent with a flattened sphere moving at high velocity. In that SR reflects the geometry of reality, it is not inconsistent to say the Earth is both an approximate sphere at rest and approximate pancake at high velocity.

QUOTE (mik+Apr 18 2012, 12:19 AM)
QUOTE (rpenner+Apr 16 2012, 10:14 PM)
What is solipsism is to deny that the other person is real. What violates the principle of relativity is to claim that the other person is real and still deny that other persons reality is as real as your reality, all things being equal, mutatis mutandis.

The above statement about "the 'real world' regardless of frame of reference..." does not deny anyone's reality. It elevates "reality" beyond how it is *observed* from different frames of reference. This point has never been addressed here.

I put it to you as I did to synthsin75: Is the flattened earth "equally valid" with the spherical earth just because "another person" flying by at very high speed might see it that way... and we must 'respect his reality'? No.
I disagree.

I believe that nothing you have said about Reality is actually informed of by observation of more than the most pedestrian and parochial kind. By studying physical law as modeled by physical theory, I believe that your Reality is more hubris than real.

QUOTE (mik+Apr 18 2012, 12:19 AM)
The philosophy of science called realism says,
I don't recognize the philosophy of science as other than methodological empiricism.
QUOTE (mik+Apr 18 2012, 12:19 AM)
as above, that the world IS as it IS, not as different frames of reference *see* it. Accordingly, IS means the Present, and the Present IS the Present everywhere, transcending relativity's reification of space, time and space-time.
Just because you capitalize Reality and the Present, doesn't mean the universe respects your opinion. Einstein went down the path of chasing what was beautiful to him, but in the last twenty years of his life contributed nothing close to important as the theories of his youth. His last hurrah was the EPR paradox -- a thought experiment intended to show that quantum physics was ridiculous; starting in the 1970s experiment and experiment showed that the actual universe was just as ridiculous as Einstein thought the mathematical model of quantum physics was. The universe if it respects reality is not local, and if it respects locality, it is not real.

QUOTE (mik+Apr 18 2012, 12:19 AM)
Again, please address presentism vs eternalism, the latter of which describes a "block universe" where past, present and future are somehow all Present (depending on frame of reference.)  Do you actually believe that?
Why are you insisting on this false dilemma?
Raphie Frank
QUOTE (rpenner+Apr 17 2012, 11:04 PM)
It means nothing to me that a bunch of crackpots and science outsiders are willing to stand under a common umbrella to rally against the prevailing view. Their ideas must stand or fall on their own. And when they hold contrary positions it is clear that they cannot convince their fellow outsiders of their views, let alone the science-educated mainstream.

RPenner, respectfully, I have, by way of analogy, taken the liberty of rewriting your remarks to reflect what a critic of cubism or post-impressionism or any of many artistic movements might have once have had to say...

-------------------------------------------------------------------------------------
It means nothing to me that a bunch of Bohemian wackos and commercial artist outsiders are willing to stand under a common umbrella to rally against the prevailing artistic views. Their aesthetic notions must stand or fall on their own. And when they hold contrary positions it is clear that they cannot convince their fellow outsiders of the value of their work, let alone the art-educated mainstream.
-------------------------------------------------------------------------------------

It would have been a smart position to take, from the market-place standpoint, but would not have been the manner of position conducive to moving the arts forward. Mainstream scientists "consolidate" and propagate and, yes, even constructively advance the status quo IMHO. And they are far more often right than wrong until they are wrong -- all at once -- when a paradigm shift occurs. But no worries there because there is safety in numbers and there is little downside to being wrong when you have all that company in wrongness. [As opposed, for instance, to the guy who (or so I read) recently resigned after being wrong about faster than light neutrinos]

When did the cubists become popular? Was it before or after 1905? If after, does that mean there were no cubists before that point in time? The failed cubist of 1899, whoever he or she may have been, was the equivalent of a crackpot and scientific outsider.

In other words, what I am trying to gently get at here is that it is faulty logic IMHO to suggest that one's failure to convince others necessarily reflects a failure in one's understanding. It may also reflect a failure in the understanding of others.

One can argue probabilities here, but, without undue explanation, that's an argument that can cut more than one way.

- RF
Confused1
“Yes, it is true that sometimes unusually intelligent and sensitive children can appear to be stupid. But stupid children can sometimes appear to be stupid as well. I think that's something you might have to consider.”
― Douglas Adams, The Long Dark Tea-Time of the Soul
brucep
QUOTE (Raphie Frank+Apr 18 2012, 09:12 AM)
RPenner, respectfully, I have, by way of analogy, taken the liberty of rewriting your remarks to reflect what a critic of cubism or post-impressionism or any of many artistic movements might have once have had to say...

-------------------------------------------------------------------------------------
It means nothing to me that a bunch of Bohemian wackos and commercial artist outsiders are willing to stand under a common umbrella to rally against the prevailing artistic views. Their aesthetic notions must stand or fall on their own. And when they hold contrary positions it is clear that they cannot convince their fellow outsiders of the value of their work, let alone the art-educated mainstream.
-------------------------------------------------------------------------------------

It would have been a smart position to take, from the market-place standpoint, but would not have been the manner of position conducive to moving the arts forward. Mainstream scientists "consolidate" and propagate and, yes, even constructively advance the status quo IMHO. And they are far more often right than wrong until they are wrong -- all at once -- when a paradigm shift occurs. But no worries there because there is safety in numbers and there is little downside to being wrong when you have all that company in wrongness. [As opposed, for instance, to the guy who (or so I read) recently resigned after being wrong about faster than light neutrinos]

When did the cubists become popular? Was it before or after 1905? If after, does that mean there were no cubists before that point in time? The failed cubist of 1899, whoever he or she may have been, was the equivalent of a crackpot and scientific outsider.

In other words, what I am trying to gently get at here is that it is faulty logic IMHO to suggest that one's failure to convince others necessarily reflects a failure in one's understanding. It may also reflect a failure in the understanding of others.

One can argue probabilities here, but, without undue explanation, that's an argument that can cut more than one way.

- RF

Your analogy is wacko. You put scientific illiterates [crackpots and cranks] in the same group as skilled artists. Cubism wasn't bullshit. Everything the cranky crackpots tout IS useless bullshit. They're not being ignored for any reason other than they're full of crap.
mik
rpenner,
Seems you misunderstand what presentism has to say about the meaning of the reification of time in relativity, specifically how the latter is a case of eternalism in which things past and future are "real" in various frames of reference using the light cone *model.*

But, at this point, I would settle for clarification of the "real shape of earth" in which length contraction insists that a flattened earth is just as real as a nearly spherical one, given that "all frames are equally valid" and a near 'c' fly-by frame might "see"/measure it as a very oblate spheroid.

You said:
QUOTE
Huh? A sphere is mathematical idealization. What something "really is" is also a mathematical idealization. In SR, a sphere at rest is congruent with a flattened sphere moving at high velocity. In that SR reflects the geometry of reality, it is not inconsistent to say the Earth is both an approximate sphere at rest and approximate pancake at high velocity.

Earth *is* nearly spherical. Earth science knows exactly how much longer its diameter is through the equator than through the poles. Earth in the 'real world' does not in fact "flatten" because of mathematical/relativistic considerations.
me:
QUOTE (->
 QUOTE Huh? A sphere is mathematical idealization. What something "really is" is also a mathematical idealization. In SR, a sphere at rest is congruent with a flattened sphere moving at high velocity. In that SR reflects the geometry of reality, it is not inconsistent to say the Earth is both an approximate sphere at rest and approximate pancake at high velocity.

Earth *is* nearly spherical. Earth science knows exactly how much longer its diameter is through the equator than through the poles. Earth in the 'real world' does not in fact "flatten" because of mathematical/relativistic considerations.
me:
I put it to you as I did to synthsin75: Is the flattened earth "equally valid" with the spherical earth just because "another person" flying by at very high speed might see it that way... and we must 'respect his reality'? No.”

You disagreed. Because of the "no preferred frames" dictum, you believe that Earth *is* "both an approximate sphere... and approximate pancake" depending on frame of reference, whether at rest or at high velocity. So there is no natural reality to 'the world' independent of frames of reference. The latter create reality. Earth is both nearly flattened and nearly spherical... depending on your point of view. Some philosophy!** (See below)

You continued:
QUOTE
I believe that nothing you have said about Reality is actually informed of by observation of more than the most pedestrian and parochial kind. By studying physical law as modeled by physical theory, I believe that your Reality is more hubris than real.

Do you really think that insisting on the well documented, precisely observed and measured Earth described above as the accurate description is "pedestrian and parochial?"

You:
“The universe if it respects reality is not local, and if it respects locality, it is not real.”

Really? Earth is a real local part of the universe. No one is claiming that the universe *is local,* but each part of it is *real* independent of how it is observed/measured.

** It is easy to see how relativity came to endorse the philosophy that reality depends on observation and varies according to how it is observed.

From the Collected Papers of Albert Einstein, Edited by J.J. Stachel and Robert Schulmann
(Princeton Univiversity Press, 1987); Letter to Eduard Study from Albert Einstein
dated Sep 25, 1918:

QUOTE (->
 QUOTE I believe that nothing you have said about Reality is actually informed of by observation of more than the most pedestrian and parochial kind. By studying physical law as modeled by physical theory, I believe that your Reality is more hubris than real.

Do you really think that insisting on the well documented, precisely observed and measured Earth described above as the accurate description is "pedestrian and parochial?"

You:
“The universe if it respects reality is not local, and if it respects locality, it is not real.”

Really? Earth is a real local part of the universe. No one is claiming that the universe *is local,* but each part of it is *real* independent of how it is observed/measured.

** It is easy to see how relativity came to endorse the philosophy that reality depends on observation and varies according to how it is observed.

From the Collected Papers of Albert Einstein, Edited by J.J. Stachel and Robert Schulmann
(Princeton Univiversity Press, 1987); Letter to Eduard Study from Albert Einstein
dated Sep 25, 1918:

It appears to me that “real” is an empty meaningless category (drawer) whose
immense importance lies only in that I place certain things inside it and not
certain others.

And so modern relativity adopts the philosophy that there is no "real" world. Reality depends only on what we place in the metaphorical "drawer." We create our own reality.

Yet, if intelligent life never evolved 'the world' (universe and all its parts) would still exist and still have all its intrinsic properties, in and of themselves, without ever being observed or measured... or placed in whatever "drawer" we see fit to call meaningful.

rpenner
A sphere at rest is defined by a locus of world-lines with respect to it's center world-line so that for any two events, with one on the center world-line and the other on the sphere surface we have in the coordinate system S: u = 0, Δt = 0, (c Δt)²−(Δx)²−(Δy)²−(Δz)² = −R² where R is the proper radius of the sphere.

So we have a center world line:
x = x₀ + 0 t, y = y₀ + 0 t, z = z₀ + 0 t
and a two-parameter (two-dimensional) family of surface world-lines:
x = x₀ + R (cos φ) (cos θ) + 0 t, y = y₀ + R (cos φ) (sin θ) + 0 t, z = z₀ + R (sin φ) + 0 t
Leading to Δt = 0 ⇒ Δx = R (cos φ) (cos θ), Δy = R (cos φ) (sin θ), Δz = R (sin φ)
and (c Δt)²−(Δx)²−(Δy)²−(Δz)² = −R²

Limiting ourselves to motion in the x direction, the S' labels for the same physical system is:
Δz' = Δz = R (sin φ)
Δy' = Δy = R (cos φ) (sin θ)
Δx' = Δx cosh μ' + c Δt sinh μ' = R (cos φ) (cos θ) (cosh μ') + c Δt sinh μ'
Δt' = (1/c) Δx sinh μ' + Δt cosh μ' = (1/c) R (cos φ) (cos θ) (sinh μ') + Δt cosh μ'

Looking at the three-dimensional slices of this with Δt' = 0, we have the following result in the relativity of simultaneity:
v = c tanh μ
Δt = (−v R/c²) (cos φ) (cos θ)
Δt' = 0
Δx' = R (cos φ) (cos θ) √(1 − v²/c²)
Δy' = R (cos φ) (sin θ)
Δz' = R (sin φ)

And so the universal description of a sphere in special relativity is:
Δt = 0 ⇒ (Δx)²/(1 − v²/c²)+(Δy)²+(Δz)² = R²
where v is the motion of the sphere in the x-direction (possibly zero).

This same description describes an unmoving sphere as congruent to a highly flattened sphere moving at high velocity with the same proper radius.
brucep
QUOTE (mik+Apr 18 2012, 10:14 PM)
rpenner,
Seems you misunderstand what presentism has to say about the meaning of the reification of time in relativity, specifically how the latter is a case of eternalism in which things past and future are "real" in various frames of reference using the light cone *model.*

But, at this point, I would settle for clarification of the "real shape of earth" in which length contraction insists that a flattened earth is just as real as a nearly spherical one, given that "all frames are equally valid" and a near 'c' fly-by frame might "see"/measure it as a very oblate spheroid.

You said:

Earth *is* nearly spherical. Earth science knows exactly how much longer its diameter is through the equator than through the poles. Earth in the 'real world' does not in fact "flatten" because of mathematical/relativistic considerations.
me:

You disagreed. Because of the "no preferred frames" dictum, you believe that Earth *is* "both an approximate sphere... and approximate pancake" depending on frame of reference, whether at rest or at high velocity. So there is no natural reality to 'the world' independent of frames of reference. The latter create reality. Earth is both nearly flattened and nearly spherical... depending on your point of view. Some philosophy!** (See below)

You continued:

Do you really think that insisting on the well documented, precisely observed and measured Earth described above as the accurate description is "pedestrian and parochial?"

You:
“The universe if it respects reality is not local, and if it respects locality, it is not real.”

Really? Earth is a real local part of the universe. No one is claiming that the universe *is local,* but each part of it is *real* independent of how it is observed/measured.

** It is easy to see how relativity came to endorse the philosophy that reality depends on observation and varies according to how it is observed.

From the Collected Papers of Albert Einstein, Edited by J.J. Stachel and Robert Schulmann
(Princeton Univiversity Press, 1987); Letter to Eduard Study from Albert Einstein
dated Sep 25, 1918:

And so modern relativity adopts the philosophy that there is no "real" world. Reality depends only on what we place in the metaphorical "drawer." We create our own reality.

Yet, if intelligent life never evolved 'the world' (universe and all its parts) would still exist and still have all its intrinsic properties, in and of themselves, without ever being observed or measured... or placed in whatever "drawer" we see fit to call meaningful.

So you refuse to learn anything. Bring out the machete for all those who continuously disrespect or ignore the scientific literature.
mik
So... No comment on the utterly absurd assertion that Earth is both nearly spherical and nearly flattened, depending on how you look at it?

...Or on Einstein's philosophical influence on what relativity theory considers "real?",i.e., the term is meaningless and there is no "real Earth" independent of variations in how it is observed?

... or on the "thought experiment" challenge of a "world" with no intelligent life to "see" it this way or that way?

I guess everything would just disappear if no one were around to bestow "reality" on it by observing and measuring,... as its existence an properties depend on our omnipotent powers of observation and measurement.

Oh well. You all have a right to your opinions, even if you think Earth's shape depends on how you look at it.
Never mind.
Ps: I'm still not a mathematician, but I do know that neither math nor length contraction theory can make Earth flattened, i.e., "in reality", even if Einstein thought reality is just what we choose to stick in a theoretical "drawer"... no such thing as reality.
rpenner
QUOTE (rpenner+Apr 12 2012, 07:03 PM)
That's just solipsism and denial of physics, not a physics argument.

QUOTE (rpenner+ 2010-05-12)
Inability to comprehend relativity is the inability to put oneself intellectually into the shoes of another and working out the consequences. It seems to me that this belongs on the non-clinical side of a spectrum of sociopathic disorders. http://www.squidoo.com/the-sociopath-next-door
http://www.sciforums.com/showpost.php?p=2540723&postcount=22

Your claim that "now is now everywhere" ignores the lessons learned from electromagnetism and the study of high-speed phenomena -- it's an intuitionist assumption antique after 1859, incompatible with physical theory after 1862, and replaced with better assumptions in 1905.
http://www.physforum.com/index.php?showtop...ndpost&p=516234
QUOTE (rpenner+Apr 16 2012, 05:24 AM)
As stated, I believe that mik's problem is chauvinism and over-reliance on preconceptions, two traits I find distasteful in philosophers. I prefer philosophers engage in a reality with more than one person in it.
[Moderator: A full discussion of length contraction as a natural consequence of accepting the principle of relativity and the Poincaré transformation was made in a previous post. (Click Here). By order of the Moderator, mik and Mazulu are required to read this post, to understand the post, and to ask questions about what things mean if there is any doubt about understanding before any further discussion on the topic of relativity. The penalty for not fully understanding this post before continuing will be a complete loss of faith in your good intentions by the moderator.]
http://www.physforum.com/index.php?showtop...ndpost&p=516450
QUOTE (mik+Apr 16 2012, 09:02 PM)
So your four dimensional universe reifies time and space in a way that claims that everything that has ever existed or ever will exist are "equally real."

So "real and present"loses its meaning and the "concept" of "slices of spacetime" can contain past and future as "now present"... conceptually speaking if you ignore that future events are not yet present and past events are no longer present.
http://www.physforum.com/index.php?showtop...ndpost&p=516473
QUOTE (rpenner+Apr 16 2012, 10:14 PM)
That need not be my position. For example, I may describe things in my personal past light cone (including boundary) as equally real in that my present state can be formulated as a function of this personal past. Or I may treat my personal slice of simultaneity as real-to-me while allowing someone else may with equal validity treat their slice of simultaneity as real-to-them.

Both of these viewpoints are compatible with special relativity that says the meaningful-to-us portion of our past is bounded by our personal past light-cone and our future prospects are bounded by the our future light cone, and that which is outside of the light cones is presently beyond our ability to influence just as we are presently beyond its ability to influence us.

What is solipsism is to deny that the other person is real. What violates the principle of relativity is to claim that the other person is real and still deny that other persons reality is as real as your reality, all things being equal, mutatis mutandis.
http://www.physforum.com/index.php?showtop...ndpost&p=516476
QUOTE (mik+Apr 18 2012, 12:19 AM)
Please respond to the Wiki quote on four-dimensionalism: ... and my comment:

"So your four dimensional universe reifies time and space in a way that claims that everything that has ever existed or ever will exist are 'equally real.' "
http://www.physforum.com/index.php?showtop...ndpost&p=516541
QUOTE (rpenner+Apr 18 2012, 07:00 AM)
Classically, one should master logic and rhetoric before attempting philosophy.
And perhaps you should master Ethics before attempting debate on Epistemology.
QUOTE (rpenner+Apr 18 2012, 07:00 AM)
Your insistence that I respond makes little sense when I have already responded and called out that your oversimplification in terms of absolute presentism versus eternal block time is an example of the fallacy of false dilemma and I gave two other possible philosophical viewpoints on what is real.

...

In SR, a sphere at rest is congruent with a flattened sphere moving at high velocity. In that SR reflects the geometry of reality, it is not inconsistent to say the Earth is both an approximate sphere at rest and approximate pancake at high velocity.
http://www.physforum.com/index.php?showtop...ndpost&p=516551
QUOTE (mik+Apr 18 2012, 10:14 PM)
at this point, I would settle for clarification of the "real shape of earth" in which length contraction insists that a flattened earth is just as real as a nearly spherical one, given that "all frames are equally valid" and a near 'c' fly-by frame might "see"/measure it as a very oblate spheroid.
http://www.physforum.com/index.php?showtop...ndpost&p=516571
So is this claim true?
QUOTE (rpenner+Apr 18 2012, 11:00 PM)
And so the universal description of a sphere in special relativity is:
Δt = 0 ⇒ (Δx)²/(1 − v²/c²)+(Δy)²+(Δz)² = R²
where v is the motion of the sphere in the x-direction (possibly zero).

This same description describes an unmoving sphere as congruent to a highly flattened sphere moving at high velocity with the same proper radius.
http://www.physforum.com/index.php?showtop...ndpost&p=516572
This appears to complete the demonstration that a sphere at rest is congruent to a flattened sphere moving at non-zero velocity. What say you?
QUOTE (mik+Apr 19 2012, 09:44 PM)
So... No comment on the utterly absurd assertion that Earth is both nearly spherical and nearly flattened, depending on how you look at it?
http://www.physforum.com/index.php?showtop...ndpost&p=516623
"No comment"? Really? .... Really?

If this is the patently dishonest tactic you wish to take to maintain your position built on uninformed preconceptions in the face of evidence and logic and experience, then as a moderator and a decent human being, I guess I will have to respect that. But by no means do I have to respect any alleged right to post in this forum.
synthsin75
QUOTE (mik+Apr 19 2012, 03:44 PM)
So... No comment on the utterly absurd assertion that Earth is both nearly spherical and nearly flattened, depending on how you look at it?

...Or on Einstein's philosophical influence on what relativity theory considers "real?",i.e., the term is meaningless and there is no "real Earth" independent of variations in how it is observed?

... or on the "thought experiment" challenge of a "world" with no intelligent life to "see" it this way or that way?

I guess everything would just disappear if no one were around to bestow "reality" on it by observing and measuring,... as its existence an properties depend on our omnipotent powers of observation and measurement.

Oh well. You all have a right to your opinions, even if you think Earth's shape depends on how you look at it.
Never mind.
Ps: I'm still not a mathematician, but I do know that neither math nor length contraction theory can make Earth flattened, i.e., "in reality", even if Einstein thought reality is just what we choose to stick in a theoretical "drawer"... no such thing as reality.

You've been told about proper length umpteen times now, and how coordinate measurements have a physical effect on the observer using that coordinate system. You should really try to learn some physics instead of hunting up new philosophical terms to support your strictly intuitive cognitive bias.

Every one here has tried to explain this countless times now, to no avail. You must be willing to learn before you ever will.
Raphie Frank
QUOTE (mik+Apr 19 2012, 09:44 PM)
So... No comment on the utterly absurd assertion that Earth is both nearly spherical and nearly flattened, depending on how you look at it?

What is absurd, mlk, is that you believe this to be absurd. Draw a circle on a piece of paper. Look at it straight on. It looks like a circle. Now rotate the paper 90 degrees towards you. It looks like a line segment.

What you see and what you perceive as "reality" depends upon your reference frame.

It's neither brain surgery nor "absurd."

Moreover, in philosophical vein, wars get started by dumba** leaders who think that if he/she sees a circle, then so too should the other guy/gal; and if he/she says he/she doesn't see a circle then he/she must either be a liar or dangerously psychotic and delusional.

- RF
mik
QUOTE (rpenner+Apr 19 2012, 10:22 PM)
http://www.sciforums.com/showpost.php?p=2540723&postcount=22

Your claim that "now is now everywhere" ignores the lessons learned ...

So is this claim true?
This appears to complete the demonstration that a sphere at rest is congruent to a flattened sphere moving at non-zero velocity. What say you?
"No comment"? Really? .... Really?

If this is the patently dishonest tactic you wish to take to maintain your position built on uninformed preconceptions in the face of evidence and logic and experience, then as a moderator and a decent human being, I guess I will have to respect that. But by no means do I have to respect any alleged right to post in this forum.

rpenner:
"Your claim that "now is now everywhere" ignores the lessons learned ..."

No, it just disagrees with the assumption of relativity that "everything is relative" and that reality depends on the frames of reference from which it is observed and measured.

In the philosophical sense transcending those locally descriptive assumptions (i.e., in the universal sense) the present *is now* without the limits of location assumed by relativity.

My local example was clear on this point. To elaborate, a flair happening now on the sun will not be seen on earth for over 8 minutes, but that lack information (seeing it) doesn't mean that it is not now happening. Throw in an earth event like a bomb exploding in the atmosphere (in violation of the treaty) at the same time as the above flair erupting. The sun's frame will not see the explosion for eight more minutes either, though both events happened at the same time, the same universal now.

"So is this claim true?"
(Confused as to which claim... linked above or below the questions.)
I will assume it was my claim that you never addressed the nearly flattened earth as equally valid from a different frame, as the issue of focus here.

You said:
"This appears to complete the demonstration that a sphere at rest is congruent to a flattened sphere moving at non-zero velocity. What say you?"

I say that "is congruent to" in above context does not address the question "what is the true shape of earth?"... maintaining instead that it *is* flattened when seen that way from relativistic velocities and that it *is* spherical when seen from a a frame at rest with earth.
Philosophically, this denies that earth has a shape of its own, intrinsic and independent of observation... as per my thought experiment above (no intelligent life to measure things), also not yet addressed.

" 'No comment'? Really? .... Really?"

Really, as just explained, and there were no comments on the several other points on that post.

"If this is the patently dishonest tactic you wish to take to maintain your position built on uninformed preconceptions in the face of evidence and logic and experience, then as a moderator and a decent human being, I guess I will have to respect that. But by no means do I have to respect any alleged right to post in this forum."

It is not at all dishonest, uninformed or preconceived to challenge the absurdity of a flattened earth or one that is "both" flattened and spherical, depending on how you look at it. I have always been honest and sincere here. It is a reasonable philosophy that grants "the world" a reality of its own which does not fluctuate with the frame of reference from which it is observed. As I've said, it is clear that the at- rest frame with earth (the present issue) yields the accurate measurement, while the frame moving relative to earth must use the Lorentz transform coordinate system/ math to find the correct measurement and resulting shape.

If this honest and sincere challenge gets me banned, as per the above threat, so be it.

mik
QUOTE (Raphie Frank+Apr 20 2012, 09:02 AM)
What is absurd, mlk, is that you believe this to be absurd. Draw a circle on a piece of paper. Look at it straight on. It looks like a circle. Now rotate the paper 90 degrees towards you. It looks like a line segment.

What you see and what you perceive as "reality" depends upon your reference frame.

It's neither brain surgery nor "absurd."

Moreover, in philosophical vein, wars get started by dumba** leaders who think that if he/she sees a circle, then so too should the other guy/gal; and if he/she says he/she doesn't see a circle then he/she must either be a liar or dangerously psychotic and delusional.

- RF

me:
QUOTE
So... No comment on the utterly absurd assertion that Earth is both nearly spherical and nearly flattened, depending on how you look at it?

QUOTE (->
 QUOTE So... No comment on the utterly absurd assertion that Earth is both nearly spherical and nearly flattened, depending on how you look at it?

Draw a circle on a piece of paper. Look at it straight on. It looks like a circle. Now rotate the paper 90 degrees towards you. It looks like a line segment.

What you see and what you perceive as "reality" depends upon your reference frame.

Earth is not a circle on a piece of paper. It is in fact a very nearly spherical semi-rigid (not radically morphing) planet. It looks about same from the space station as we orbit and it rotates.
It never ever flattens into a severely oblate spheroid, no matter how you look at it. If you think that it does, you must believe that extremes of observational frame creates extremes in the natural "world" as if reality depended on how we see it. That is an extreme philosophical position.
Raphie Frank
QUOTE (mik+Apr 21 2012, 12:17 AM)
Earth is not a circle on a piece of paper. It is in fact a very nearly spherical semi-rigid (not radically morphing) planet. It looks about same from the space station as we orbit and it rotates.
It never ever flattens into a severely oblate spheroid, no matter how you look at it. If you think that it does, you must believe that extremes of observational frame creates extremes in the natural "world" as if reality depended on how we see it. That is an extreme philosophical position.

No, it's an extreme physical proposition, since, in order for the earth to appear to "pancake" from the reference frame of an external observer, extremely high velocity, relatively speaking, would be required.
mik
QUOTE (Raphie Frank+Apr 21 2012, 08:56 AM)
No, it's an extreme physical proposition, since, in order for the earth to appear to "pancake" from the reference frame of an external observer, extremely high velocity, relatively speaking, would be required.

"...an extreme physical proposition?" Yes, quite extreme to assert that earth does actually, physically flatten.

But then you contradict that assertion, saying:

"...in order for the earth to appear to "pancake" from the reference frame of an external observer, extremely high velocity, relatively speaking, would be required."

I am not arguing against the probability that earth might *appear* to "pancake," as you said.
I am arguing that it doesn't "physically flatten," as per the assertion that both descriptions are equally valid, since "there are no preferred frames of reference.

So in that case, either it changes shape with how we look at it (which it does not) or we can't know its "true shape" because it doesn't have an intrinsic shape independent of observation.

The latter is the assumed philosophy of relativity, that reality depends on how it is observed and measured (no reality independent of observation.) This fits with Einstein's philosophy, which I quoted above, that there is no "reality" but what we choose to "place in the drawer" of observation. Some of us don't agree with that. Again, what would the reality of "the world" be without any observers? If observers create reality... that is an extreme philosophy if not a new religion with relativity theorists as the "creators."

Btw... relativity does a great job of predicting many things. No argument there. Yet I stand by my specific criticisms as posted in this forum.
rpenner
Likewise, I stand by my general criticisms of underinformed philosophical musings having low value when compared to parsimonious, precise predictive theories winnowed by hundreds of years of observation and experiments designed to produce a confrontation between theory and experiment.

I stand by by specific criticisms of those that seek a mathematical equivalence as a foundation for enlightenment and when presented with that congruence only shut their eyes tighter.

I question the motives that brought you to this forum, when no amount of discussion changes the foundation of experiments and observations that special relativity relies upon. Neither did you argue for your viewpoint on intangibles to support the case that they made sense in some intangible way not directly contradicted by experiment and observation. The only foreseeable outcome of your public embrace of presentism was a challenge to that viewpoint and yet no support came.

Instead, what we got was a claim that the only possible alternative to presentism was eternalism. Such a tactic was bound to run face-to-face with the fallacy of false dilemma.
brucep
QUOTE (mik+Apr 24 2012, 08:26 PM)
"...an extreme physical proposition?" Yes, quite extreme to assert that earth does actually, physically flatten.

But then you contradict that assertion, saying:

"...in order for the earth to appear to "pancake" from the reference frame of an external observer, extremely high velocity, relatively speaking, would be required."

I am not arguing against the probability that earth might *appear* to "pancake," as you said.
I am arguing that it doesn't "physically flatten," as per the assertion that both descriptions are equally valid, since "there are no preferred frames of reference.

So in that case, either it changes shape with how we look at it (which it does not) or we can't know its "true shape" because it doesn't have an intrinsic shape independent of observation.

The latter is the assumed philosophy of relativity, that reality depends on how it is observed and measured (no reality independent of observation.) This fits with Einstein's philosophy, which I quoted above, that there is no "reality" but what we choose to "place in the drawer" of observation. Some of us don't agree with that. Again, what would the reality of "the world" be without any observers? If observers create reality... that is an extreme philosophy if not a new religion with relativity theorists as the "creators."

Btw... relativity does a great job of predicting many things. No argument there. Yet I stand by my specific criticisms as posted in this forum.

You don't have a valid criticism because you don't have a clue what you're criticizing. Learn some physics. Your continual confusion about 'measurement' and 'frame of reference' is stupid when you could learn something about the physics instead. The literature is available for our use. That includes folks critical of 'stuff' they don't understand. You just keep spouting nonsense and call it argument. As rpenner said " ...... underinformed philosophical musings having low value when compared to parsimonious, precise predictive theories winnowed by hundreds of years of observation and experiments designed to produce a confrontation between theory and experiment." That's the literature I was talking about. This part ".... precise predictive theories winnowed by hundreds of years of observation and experiments designed to produce a confrontation between theory and experiment."
mik
QUOTE (brucep+Apr 24 2012, 10:45 PM)
You don't have a valid criticism because you don't have a clue what you're criticizing. Learn some physics. Your continual confusion about 'measurement' and 'frame of reference' is stupid when you could learn something about the physics instead. The literature is available for our use. That includes folks critical of 'stuff' they don't understand. You just keep spouting nonsense and call it argument. As rpenner said " ...... underinformed philosophical musings having low value when compared to parsimonious, precise predictive theories winnowed by hundreds of years of observation and experiments designed to produce a confrontation between theory and experiment." That's the literature I was talking about. This part ".... precise predictive theories winnowed by hundreds of years of observation and experiments designed to produce a confrontation between theory and experiment."

I'll be brief. What shape does science tell us that the earth *is*, as distinguished from how it might *appear* to an extreme velocity frame of reference?
mik
QUOTE (rpenner+Apr 25 2012, 12:35 AM)
The "shape of the Earth" is a question of geometry. In the geometry natural to the laws of physics, the shape of the surface of the Earth is a bundle of co-moving world lines with approximately common proper distance of 6.37±0.02 Mm. about a central world-line. This is a four-dimensional analogue of a cylinder indefinitely extended in a time-dimension.

If you restrict the meaning of the "shape of the Earth" to just it's spatial extent during an instant of time, then such a definition requires that one account for a definition of "then" and "there" that applies over the whole of the Earth -- in short, the definition chosen here requires a choice of coordinate system. If you choose to work in a coordinate frame where the center of the earth is not in motion, then proper distance would be numerically equal to coordinate distance, but such a choice of coordinates is neither required by the physics of the universe nor preferred from any universal viewpoint. Only the parochial viewpoint on someone who thinks the Earth is the center of the universe would prefer the viewpoint of a unmoving Earth. (This is the actual engineering viewpoint of the GPS system, which explains why the military and commerce on Earth use it so well.) For someone on Mars asking the shape of the Earth using their parochial viewpoint (or a person on Earth asking the question of Mars, mutatis mutandis), the choice of a coordinate system where the definition of "now" depends on the assumption that the target of inquiry is not moving makes no sense. So the most universal answer of the "shape of the Earth" should work generally no matter what the natural coordinate system of the day says the velocity of the Earth is -- and the description of that shape is an approximate spheroid of proper radius 6.37±0.02 Mm length-contracted by the factor of √(1 − v²/c²) in the direction of movement where v is the coordinate velocity of the Earth in any inertial system of coordinates where inertial motion is represented as a straight line through space-time.

All of that did not address my question: "What shape does science tell us that the earth *is*, as distinguished from how it might *appear* to an extreme velocity frame of reference?"

In the natural world, the shape of things does not depend on how we see and measure them or on what conceptual/mathematical model we use to describe them.

Clearly the length contraction aspect of relativity theory is consistent with the Einstein quote I shared earlier, i.e., that there is no "reality" independent of what we "place in the drawer" for observation and investigation.

I keep hammering on the difference between how things might *appear* from extreme frames of reference (i.e., the "flattened earth"... It is not flattened) and how things *are,* independent of observation, and how best to investigate the latter (i.e., from "at rest" with the object of observation.)

You say:
QUOTE
... the shape of the surface of the Earth is a bundle of co-moving world lines with approximately common proper distance of 6.37±0.02 Mm. about a central world-line.

I have no doubt that this is an accurate application of the "the geometry natural to the laws of physics." But planet Earth itself (and all of its intrinsic, naturally occurring properties like the shape of its surface and its somewhat varying diameters) is not " a bundle of co-moving world lines..." The latter describes the geometric "map," not the actual planet itself, which is, in fact, nearly spherical (with its polar diameter a bit shorter than its equatorial diameter, as you well know.) Time is not a factor in its actual physical shape (except over eons as it will probably continue to bulge at the equator with age (like a lot of us humans.) The 4-D spacetime coordinate system is an undeniably useful tool, but it does not make the earth either change shape or *be* as it might *appear* from other frames of reference.

You wrote:
QUOTE (->
 QUOTE ... the shape of the surface of the Earth is a bundle of co-moving world lines with approximately common proper distance of 6.37±0.02 Mm. about a central world-line.

I have no doubt that this is an accurate application of the "the geometry natural to the laws of physics." But planet Earth itself (and all of its intrinsic, naturally occurring properties like the shape of its surface and its somewhat varying diameters) is not " a bundle of co-moving world lines..." The latter describes the geometric "map," not the actual planet itself, which is, in fact, nearly spherical (with its polar diameter a bit shorter than its equatorial diameter, as you well know.) Time is not a factor in its actual physical shape (except over eons as it will probably continue to bulge at the equator with age (like a lot of us humans.) The 4-D spacetime coordinate system is an undeniably useful tool, but it does not make the earth either change shape or *be* as it might *appear* from other frames of reference.

You wrote:
Only the parochial viewpoint on someone who thinks the Earth is the center of the universe would prefer the viewpoint of a unmoving Earth.

You totally misrepresent me as having such a ridiculous viewpoint. I have never even implied any such thing. We all know that everything is moving relative to everything else (except those things "at rest" with each other), from local to cosmic scales. That doesn't make earth's shape either morph to a "pancake" or become unknowable just because other frames would measure its diameter differently (and be "equally valid.")
rpenner
QUOTE (mik+Apr 25 2012, 07:55 PM)
You totally misrepresent me as having such a ridiculous viewpoint. I have never even implied any such thing. We all know that everything is moving relative to everything else (except those things "at rest" with each other), from local to cosmic scales.

"Shape" is not native and intuitionist -- "Shape" is mathematical abstraction from geometry. In Euclidean geometry, shapes are congruences of objects preserved by continuous transforms like rotations and translations and discrete transforms like mirror images.

http://www.learner.org/teacherslab/math/geometry/
http://plus.maths.org/content/imaging-math...de-klein-bottle
http://en.wikipedia.org/wiki/Geometry

Knowing that the Earth is not naturally defined as at rest requires you to accept the principle of relativity, as did Galileo even before Newton codified his laws of motion. However, Galilean relativity, where "shape" and velocity are independent of each other is disallowed by physical experiment and observation. Only a Lorentz-covariant description of shape in terms of a locus of co-moving world-lines or in terms of a three-dimensional spatial slice taken at an instant in someones definition of time and parameterized by the velocity of the rigidly moving object for that person make sense.

Your viewpoint is not ridiculous, but it is resting on, perhaps, a more parochial intuition than you realize.

That's because to a population of slow-moving folks, Lorentzian hyperbolic geometry looks a lot like Euclidean geometry. Here's just one example about how one might be fooled.

QUOTE (rpenner+Apr 24 2012, 04:40 AM)
All [free] particles in special relativity obey these relations:

E v = c² p
E² = (m c²)² + (p c)²

Where E = coordinate-based energy, p = coordinate-based momentum, v = coordinate velocity, m = invariant mass, c = invariant velocity characteristic of special relativity.

So if m > 0, E > 0, p > 0, |v| < c we have these exact relationships:

p c/E = v/c = β
E² = (m c²)² + v² E²/c²
E² = (m c²)² / ( 1 − v²/c² )
p² = (m c)² [ 1/ ( 1 − v²/c² ) − 1 ] = m² v² / ( 1 − v²/c² )

dE/dv = m v / ( √( 1 − v²/c² ) )³
dp/dv = m / ( √( 1 − v²/c² ) )³

Which give these low-velocity approximate relationships:

lim (v->0) E = mc² + (1/2) m v² [ 1 + (3/4)β² + (5/8)β⁴+ (35/64)β⁶ + (63/128)β⁸ + ... ]
lim (v->0) p = 0 + mv [ 1 + (1/2)β² + (3/8)β⁴+ (5/16)β⁶ + (35/128)β⁸ + ... ]

And so when |v| << c, β² << 1 and this is experimentally indistinguishable from pre-1905 assumptions that KE = (1/2) m v² and p = m v.
rpenner
So in short, mik has a Platonic/essentialist conception of rigid objects having a proper shape defined in a co-moving coordinate system, and so the GEOmetric shape of Earth is to be defined by Earthlings and Earthlings alone -- which is the very definition of a parochial viewpoint.

As I embrace the principle of relativity and an experimental record which rejects Galilean relativity, I cannot be content with Euclidean geometry defined in reference to the object.Instead, I work in a geometry of physical absolutes like proper-lengths and when I relate a statement of shape to coordinates, I make sure that the statement is Lorentz-covariant so that it is physically meaningful regardless of choice of coordinates.

This is not my free choice -- it is a choice I feel constrained to adopt if what I say is going to matter to the physics of this universe. A covariant description of shape is not a description of the illusion or mere appearance of shape, but a recognition that the geometry of space time is not Galilean or Euclidean and that the most generally useful definition of a particular length or angle has to be covariantly described.

While I have reasons for the choices I make, mik leaves it up to me to argue for his position, which being unphysical seems underinformed, poorly thought-out, and parochial. The whole point of the field of philosophy is to have rational discussions about how one should think about things. mik does himself no favors by naked insistence on his preconceived ideas.
mik
QUOTE (synthsin75+Apr 25 2012, 11:33 PM)

QUOTE (mik+)
All of that did not address my question: "What shape does science tell us that the earth *is*, as distinguished from how it might *appear* to an extreme velocity frame of reference?"

You keep framing your question with unsupported philosophical preconceptions. What "*is*" is what has a physical effect. What "*appears*" is that which is observed without a corresponding effect.

Have you even tried to contrast Terrell rotation with length contraction? Have you even read up on them? Terrell rotation is the appearance which has no effect on the physical reality and consequences of length contraction.

My challenge is not and has never been addressed to changes in *appearance* as exemplified in Terrell rotation. My challenge has focused on the length contraction claim that (signature example) earth does not just *appear* flattened but *is* flattened as observed from frames not at rest with it, as in "pancaked" as seen from a relativistic, near 'c' fly-by frame.
So far you continue to dodge this challenge.

If the claim were true, then either earth drastically morphs into different shapes (which it clearly does not) or science can not know its "true shape" because there is no such thing as "true shape", given that "length is not invariant" and reality (like earth's shape/diameter) all depends on observation and it (reality) changes with different frames of reference.
I continue to call "nonsense!"

ps: "Have you even read up on them?"
Yes. My challenge is an informed disagreement with the claim that the reality of the "real world"changes with how you look at it, but that may be too philosophical for you. I told you up front that my passion is not math but philosophy of science. I refuse to divulge my credentials in that field, as i have very good reason to maintain a degree of anonymity.
rpenner
QUOTE (mik+Apr 26 2012, 07:58 PM)
My challenge is not and has never been addressed to changes in *appearance* as exemplified  in Terrell rotation.
Your "challenge" has never been defined and argued for -- it has merely been asserted. Your terms are left undefined, apparently because you have never actually thought about them. If you insist on talking past all the experimentally-informed points then there is no dialogue and you might as well move on to a blog or a street corner.

For you to make the above-quoted distinction, you must acknowledge that Terrell rotation concerns appearance, and is distinct in predictions from length contraction which was explicitly calculated for you as a consequence of the experimental equivalence between hyperbolic rotations of time and space with a change of coordinates into a system where the spatial origin is moving with respect to the original coordinate system. If neither system is preferred then the essential description of a rigid "shape" must be valid in both coordinate systems and that essential description must be written in terms that are described in the coordinate system yet covariant so that we ultimately are talking about the same "shape" so that the meaning of rigid is preserved.

QUOTE (mik+Apr 26 2012, 07:58 PM)
My challenge has focused on the length contraction claim that (signature example) earth does not just *appear* flattened but *is* flattened as observed from frames not at rest with it, as in "pancaked" as seen from a relativistic, near 'c' fly-by frame.
So far you continue to dodge this challenge.
Twice now, I have directly answered this question. Here is attempt three to get you to engage in dialogue. "Shape" is a geometrical concept, geometry is a field of math originally inspired by practical use surveying fields and thus is a mathematical model based on empirical utility. If experiment says the geometry of the universe is not Euclidean, then it is an error to cling to only a Euclidean concept of "shape."

Here I give you two alternatives to the shape of a rigid object:
1) Congruent (by operations of spatial rotation, translation and space-time hyperbolic rotation) to a locus of time-like world lines that are parallel.
2) A three-dimensional slice of the above, parametrized by the coordinate velocity of any of the world-lines, by a hypersurface of all points with the same t-coordinate in an admissible coordinate system.
Definition 1 is four-dimensional; definition 2 is 3-dimensional but parametrized.

Either of these definitions of shape obeys the definition of an equivalence relationship, in that: 1) all shapes are congruent to themselves, 2) if shape A is congruent to shape B it follows that shape B is congruent to shape A, and 3) if shape A is congruent to B, and B is congruent to C, then A is congruent to C.

Either of these definitions say a shape at rest is congruent to the same itself at high speed, which justifies the term "rigid" even if this results in different physical consequences than the Galilean relativity version of "rigid".

Thus a pencil of all world lines separated by constant proper length from a central, inertial world-line is a the shape of a sphere in definition 1, while a spheroid flattened in the direction of motion by factor √(1 − v²/c²) is the shape of a rigid, ponderable body which is naturally described as a sphere to itself. in definition 2. Since to different admissible coordinate systems, the velocity of the same object is different yet the assumption of rigidity and self-congruence hold, either of these two definitions of shape satisfy all requirements.

Coordinate systems are man-made mathematical imaginings. They model the natural geometry of space and time and give rise to coordinates for events in space-time. The existence of a coordinate system in which the Earth is moving at 0.99c does nothing physical to the Earth, and yet, unambiguously in such a coordinate system the Earth is highly-flattened. The resolution is that, in so far as the Earth can be said to have a shape, that shape is flattened in the direction of motion of travel. This is a concept of shape in Lorentzian space-time.

For a two-dimensional Euclidean analogue, consider an unnatural definition of shape that distinguished V from Λ. An admissible rotation of the coordinate system shows the two shapes are congruent in Euclidean geometry even if the writing system treats them as unrelated symbols. In the same way, a natural definition of shape for congruence in hyperbolic geometry requires that one allow hyperbolic rotations of time and space.

QUOTE (mik+Apr 26 2012, 07:58 PM)
If the claim were true, then either earth drastically morphs into different shapes (which it clearly does not) or science can not know its "true shape" because there is no such thing as "true shape", given that "length is not invariant" and reality (like earth's shape/diameter) all depends on observation and it (reality) changes with different frames of reference.
No one has ever claimed that a man on Mars applying their coordinate system to describe the shape of the Earth causes the Earth to morph. What was claimed was that that description of the shape is only congruent with the shape of the Earth at rest if the definition of shape is one that makes sense in the natural geometry of the universe. The concept of "true shape" requires that one uses the "true geometry" and not just rely on some parochial intuitions derived from bronze-age Egyptian field surveyors.

Now coordinate length does actually depend on which coordinates one uses, while the proper length is a description of shape parametrized by the coordinate motion of the the rigid body. This is not the same thing as saying reality changes on the basis of coordinate systems, this is saying that reality disfavors Euclidean geometry and Galilean relativity.

QUOTE (mik+Apr 26 2012, 07:58 PM)
I continue to call "nonsense!"
Would that because you are feeling inarticulate?

QUOTE (mik+Apr 26 2012, 07:58 PM)
Yes. My challenge is an informed disagreement with the claim that the reality of the "real world"changes with how you look at it, but that may be too philosophical for you.
It does not seem very informed. Your "real world" doesn't seem to match my empirically vetted models of hundreds of years of observations of this actual world.

QUOTE (mik+Apr 26 2012, 07:58 PM)
I told you up front that my passion is not math but philosophy of science. I refuse to divulge my credentials in that field, as i have very good reason to maintain a degree of anonymity.
So... shall we assume you are an unpublished, home-schooled, parochial yutz who picks up a creationist screed on philosophy from Powell's Books and runs around asserting that he is the way, the truth and the light, but seems unable to argue in favor of the proposition?

I also don't know how you have an "informed disagreement" that "may be too philosophical" can coexist with credentialed anonymous person. Unpublished philosophical amateurs don't have informed positions on the philosophy of science because they have to be degree-worthy in both philosophy and science to have an informed opinion -- science and philosophy aren't things that one reads about but things that one does; you, on the other hand, haven't demonstrated sophomoric level of knowledge of either.
mik

rpenner:
QUOTE
Twice now, I have directly answered this question. Here is attempt three to get you to engage in dialogue. "Shape" is a geometrical concept, geometry is a field of math originally inspired by practical use surveying fields and thus is a mathematical model based on empirical utility. If experiment says the geometry of the universe is not Euclidean, then it is an error to cling to only a Euclidean concept of "shape."

If Earth has an intrinsic “shape”, then our concepts about it and geo-metry to describe it are secondary to its (clearly well verified) nearly spherical shape. Earth was here and clearly what it is before we evolved to attempt to describe it. Let's not mistake or descriptions for Reality.
And we do know what shape Earth is, independent of various observations.

More later as “time” permits. (A quick pass through for now.)
brucep
QUOTE (mik+Apr 27 2012, 12:24 AM)
rpenner:

If Earth has an intrinsic “shape”, then our concepts about it and geo-metry to describe it are secondary to its (clearly well verified) nearly spherical shape. Earth was here and clearly what it is before we evolved to attempt to describe it. Let's not mistake or descriptions for Reality.
And we do know what shape Earth is, independent of various observations.

More later as “time” permits. (A quick pass through for now.)

You should put a cork in it because you refuse to understand anything rpenner has said to you. Your world view is pretty screwed up and you must like it that way. Both you and Mazulu were told to learn something about relativistic physics but you refuse and just continue to make the same inane arguments.
synthsin75
QUOTE (mik+Apr 26 2012, 01:58 PM)
My challenge is not and has never been addressed to changes in *appearance* as exemplified in Terrell rotation. My challenge has focused on the length contraction claim that (signature example) earth does not just *appear* flattened but *is* flattened as observed from frames not at rest with it, as in "pancaked" as seen from a relativistic, near 'c' fly-by frame.
So far you continue to dodge this challenge.

No, your challenge is that length contraction is somehow merely apparent. I bring up Terrell rotation to specifically show you the difference between an observational artifact and a physical effect. I haven't dodged anything except unintentionally overestimating your comprehension and capacity to learn. If a subject you seek to understand is over your head, you have only yourself to hold responsible for not putting in the requisite study.

QUOTE
If the claim were true, then either earth drastically morphs into different shapes (which it clearly does not) or science can not know its "true shape" because there is no such thing as "true shape", given that "length is not invariant" and reality (like earth's shape/diameter) all depends on observation and it (reality) changes with different frames of reference.
I continue to call "nonsense!"

I've already told you, several times, that the coordinate observations of a remote observer do not change any proper observations of the local observer. Why don't you try looking up some of those terms and broaden your understanding of actual physics? Perhaps then you'd realize just how concisely and repeatedly your "challenges" have been answered.

Yet again, apparently ad infinitum, proper length is invariant. You continue to call "intuitive incredulity", nothing more.

QUOTE (->
 QUOTE If the claim were true, then either earth drastically morphs into different shapes (which it clearly does not) or science can not know its "true shape" because there is no such thing as "true shape", given that "length is not invariant" and reality (like earth's shape/diameter) all depends on observation and it (reality) changes with different frames of reference.I continue to call "nonsense!"

I've already told you, several times, that the coordinate observations of a remote observer do not change any proper observations of the local observer. Why don't you try looking up some of those terms and broaden your understanding of actual physics? Perhaps then you'd realize just how concisely and repeatedly your "challenges" have been answered.

Yet again, apparently ad infinitum, proper length is invariant. You continue to call "intuitive incredulity", nothing more.

ps: "Have you even read up on them?"
Yes. My challenge is an informed disagreement with the claim that the reality of the "real world"changes with how you look at it, but that may be too philosophical for you. I told you up front that my passion is not math but philosophy of science. I refuse to divulge my credentials in that field, as i have very good reason to maintain a degree of anonymity.

Really? "Yes"? Then why don't you seem capable of demonstrating that you have? Apparently reading doesn't equate to understanding, especially with a preconceived bias hard at work.

I don't believe for a second that you have any philosophical education, as you've never even demonstrated that you understand scientific realism.
rpenner
QUOTE (synthsin75+Apr 27 2012, 01:00 AM)
proper length is invariant.

At least for ordinary definitions of rigid objects moving inertially.
mik
QUOTE
My challenge is not and has never been addressed to changes in *appearance* as exemplified in Terrell rotation. My challenge has focused on the length contraction claim that (signature example) earth does not just *appear* flattened but *is* flattened as observed from frames not at rest with it, as in "pancaked" as seen from a relativistic, near 'c' fly-by frame.
So far you continue to dodge this challenge.

Synthsin:
QUOTE (->
 QUOTE My challenge is not and has never been addressed to changes in *appearance* as exemplified in Terrell rotation. My challenge has focused on the length contraction claim that (signature example) earth does not just *appear* flattened but *is* flattened as observed from frames not at rest with it, as in "pancaked" as seen from a relativistic, near 'c' fly-by frame.So far you continue to dodge this challenge.

Synthsin:
No, your challenge is that length contraction is somehow merely apparent. I bring up Terrell rotation to specifically show you the difference between an observational artifact and a physical effect.

If length contraction is more than “merely apparent”, i.e., a physical effect, then a length contracted earth diameter is actually shorter than the well known at rest polar or equatorial diameters. So earth is not physically nearly spherical when it is seen as severely oblate. It actually is very oblate as observed from a high speed frame. Is “proper length” the magic phrase that resolves this? If its “proper length” of diameter is around 8000 miles, then a (say)1000 mile contracted diameter is in fact in error and in need of the Lorentz transform application.

But this would violate the “all frames equal” dictum of relativity, so you will not admit that earth has the actual true shape well published in all of earth science.

You:
"I've already told you, several times, that the coordinate observations of a remote observer do not change any proper observations of the local observer."

Of course not. My challenge transcends the issue of what one observer sees as compared with what another observer sees or whether one observation effects another. It is about the true shape of earth and your denial of such a true shape. You insist that a flattened earth is a valid description *if* seen from a very high speed (relative to earth) frame of reference. You insist that earth is not spherical *as seen from* the latter frame... not *does not appear spherical* but *is not spherical.* This is where you seem blind to realism, and you just use “proper length” as a nod to what earth's true shape is as seen from at rest with it. So if "proper" equates to accurate or true, then the challenge is over. (And a flattened earth is neither accurate or true.)

You:
“Yet again, apparently ad infinitum, proper length is invariant.”

Does that or does that not mean that earth’s diameter does not change. If so, why do you keep insisting on the equal validity of the extreme frame description?

You:
QUOTE
“Really? "Yes"? Then why don't you seem capable of demonstrating that you have? Apparently reading doesn't equate to understanding, especially with a preconceived bias hard at work.

I don't believe for a second that you have any philosophical education, as you've never even demonstrated that you understand scientific realism.

I couldn't care less what you believe. More ad hominem attacks... It carries no weight whatsoever in this debate. You always equate disagreement with lack of understanding. Try answering the above challenge directly for a change.
rpenner
QUOTE (mik+Apr 27 2012, 10:16 PM)
But this would violate the “all frames equal” dictum of relativity,

First of all -- CITATION REQUIRED -- What is in quotes here is your misunderstanding of relativity, not a proper understanding of relativity at all.

The correct formulation would be "the fundamental laws of physics are the same in all admissible (i.e. inertial) frames."

How have you missed this? For frames in different states of motion:

• Still objects in one frame are moving in another

• Some moving objects in one frame are still in another

• Clocks which are synchronized in one frame are not synchronized in another

• With a bunch of clocks in different states of motion, the not-moving clock ticks at the fastest rate, but in another frame a different clock is the not-moving clock at it is the one that ticks at the fastest rate

• Some lengths and angles measured in one frame do not have the same value when measured in another frame.

This is trivial stuff -- around since 1905. All inertial frames are physically equivalent -- the laws of physics don't prefer one to another -- but equivalence is not equality.

Your understanding is regressing when you posted that your understanding was "all frames are equally valid." http://www.physforum.com/index.php?showtop...ndpost&p=516571

In English translation, Einstein wrote:
QUOTE
§ 2. On the Relativity of Lengths and Times

The following reflexions are based on the principle of relativity and on the principle of the constancy of the velocity of light. These two principles we define as follows:―

1. The laws by which the states of physical systems undergo change are not affected, whether these changes of state be referred to the one or the other of two systems of co-ordinates in uniform translatory motion.

2. Any ray of light moves in the "stationary" system of co-ordinates with the determined velocity c, whether the ray be emitted by a stationary or by a moving body.

which can be paraphrased as "1. Coordinate systems (frames) which differ only in uniform linear motion are equivalent for the purpose for physical law // 2. Physical law (as modeled by Maxwell, 1865) requires the coordinate speed of light (in vacuum) to be c"

English translation: http://wikilivres.info/wiki/On_the_Electro...ngths_and_Times http://www.physik.fu-berlin.de/~kleinert/f...ins_specrel.pdf
German: http://wikilivres.info/wiki/Zur_Elektrodyn...ngen_und_Zeiten. http://www.physik.fu-berlin.de/~kleinert/f..._17_891-921.pdf

The conclusion from the success of special relativity is that the laws of physics don't care about coordinate time or coordinate length -- proper time and proper length and light cones are a different matter.
synthsin75
QUOTE (mik+Apr 27 2012, 04:16 PM)
But this would violate the “all frames equal” dictum of relativity, so you will not admit that earth has the actual true shape well published in all of earth science.

No, it doesn't. All frames can be equally valid while not agreeing upon observations. Perhaps you should bring more than earth science to bear on the issue.

QUOTE
Of course not. My challenge transcends the issue of what one observer sees as compared with what another observer sees or whether one observation effects another. It is about the true shape of earth and your denial of such a true shape. You insist that a flattened earth is a valid description *if* seen from a very high speed (relative to earth) frame of reference. You insist that earth is not spherical *as seen from* the latter frame... not *does not appear spherical* but *is not spherical.* This is where you seem blind to realism, and you just use “proper length” as a nod to what earth's true shape is as seen from at rest with it. So if "proper" equates to accurate or true, then the challenge is over. (And a flattened earth is neither accurate or true.)

The "true shape" of Earth is completely dependent upon the observer's coordinate system. You don't seem to understanding how time and space are interchangeable within the spacetime interval. Perhaps this will help:

http://www.physicsoftheuniverse.com/topics..._spacetime.html

But I doubt it.

"Proper" doesn't equal "accurate or true", as this would directly imply that the fly-by observer is not, and thus that the Earth observer constitutes a preferred frame, which experiments contradict. If the proper length of the Earth were preferred in such a manor, we wouldn't get the results we find of muon lifetimes.

This not only seems but is most definitely demonstrated to be where you are blind to scientific realism. Seeing how you profess an interest in the philosophy of science, you should be very familiar with this.
brucep
QUOTE (mik+Apr 24 2012, 11:05 PM)
I'll be brief. What shape does science tell us that the earth *is*, as distinguished from how it might *appear* to an extreme velocity frame of reference?

You tell me. Like I said ' measurements' and 'frame of reference'. All measurements are valid. No measurement for 'appears'. Including 'appears' in a discussion of scientific measurements shows you haven't done what rpenner asked you to do. You're doing what he asked you not to do. Continue to obfuscate the argument with irrelevant terms such as 'appears' and display a huge disconnect with the subject matter. You won't get it until you learn the physics. You probably won't do that because it conflicts with your 'simpleton' world view.

It easy to predict the measurement you requested but you need to learn some physics so it won't fall on deaf ears. Because you refuse to learn the physics, while professing false expertise, your intellectual honesty is called into question.
Robittybob1
The logic is all wrong BruceP. It feels a bit overly inquisitional to imply accept it or else accept the burning at the stake. I can accept Terrell rotations when viewing objects at high velocities but in the examples of that I looked at it was more a matter of saying "this is how things would appear", rather than saying "this is how they are". The high velocity of the observer makes other objects viewed "change shape", but this in appearance only, for can the one object really have more than one actual shape? That seems rather illogical if you think this is so.

OK the internal aspects of the high velocity craft will still look normal to the occupant but that is because the measuring method contracts in the direction of motion. So if the dimensions are re-read, once the high velocity is achieved, the measuring device is contracted also. This might seem that I have contradicted myself, but I accept that the objects will appear normal, but in reality they are contracted in length.
Confused1
QUOTE (Robitty+)
OK the internal aspects of the high velocity craft will still look normal to the occupant but that is because the measuring method contracts in the direction of motion. So if the dimensions are re-read, once the high velocity is achieved, the measuring device is contracted also. This might seem that I have contradicted myself, but I accept that the objects will appear normal, but in reality they are contracted in length
You know that this is the pre-1905 (pre-Einstein and pre-Special Relativity) view don't you?
-C2.
Robittybob1
QUOTE (Confused1+Apr 28 2012, 08:11 AM)
QUOTE (Robitty+)
OK the internal aspects of the high velocity craft will still look normal to the occupant but that is because the measuring method contracts in the direction of motion. So if the dimensions are re-read, once the high velocity is achieved, the measuring device is contracted also. This might seem that I have contradicted myself, but I accept that the objects will appear normal, but in reality they are contracted in length
You know that this is the pre-1905 (pre-Einstein and pre-Special Relativity) view don't you?
-C2.

That is a surprise for I thought I was including length contraction in my explanation.
The moving one is length contracted, but each one sees the other as length contracted, but find they are still "normal" within their own frame at that time.

In fact I can not see why the moving one sees the non moving one length contracted, but rather length dilated. For since the measuring device has shortened. So when the meter ruler has shortened any object not contracted (off to the side) should in fact appear longer???

Confused1
All the planets twirl round the Sun
A spaceship has a velocity
v_Earth with respect to an observer on Earth
v_Mars with respect to an observer on Mars
v_Mercury with respect to an observer on Mercury
v_Jupiter with respect to an observer on Jupiter
etc.
As far as an observer on the spaceship is concerned
is his spaceship length contracted as a result of
his velocity with respect to an observer on Earth
his velocity with respect to an observer on Mars
his velocity with respect to an observer on Mercury
his velocity with respect to an observer on Jupiter
his velocity with respect to something else
his spaceship is not length contracted because his velocity with respect to the spaceship is zero
something else
-C2.
brucep
QUOTE (Robittybob1+Apr 28 2012, 05:57 AM)
The logic is all wrong BruceP. It feels a bit overly inquisitional to imply accept it or else accept the burning at the stake. I can accept Terrell rotations when viewing objects at high velocities but in the examples of that I looked at it was more a matter of saying "this is how things would appear", rather than saying "this is how they are". The high velocity of the observer makes other objects viewed "change shape", but this in appearance only, for can the one object really have more than one actual shape? That seems rather illogical if you think this is so.

OK the internal aspects of the high velocity craft will still look normal to the occupant but that is because the measuring method contracts in the direction of motion. So if the dimensions are re-read, once the high velocity is achieved, the measuring device is contracted also. This might seem that I have contradicted myself, but I accept that the objects will appear normal, but in reality they are contracted in length.

I really don't care whether you think it's logical or whether you and mik think empirical measurements are 'apparent' or real. The logical thing you and mik could do is learn how the theoretical model works. Then you and mik wouldn't be so confused. During the inquisition the self serving clergy persecuted everybody who knew their 'clergy world view' was bullshit. In this forum it's usually the other way around. The terminology you use to describe measurements is asinine. If you won't review the scientific literature and continue with the nonsense questions then take a hike. If you learn the basics of the theory then you'd understand why the questions in your post are irrelevant to the discussion.
Robittybob1
QUOTE (Confused1+Apr 28 2012, 10:09 AM)

his spaceship is not length contracted because his velocity with respect to the spaceship is zero
something else
-C2.

I don't see a problem with that as the velocity which length contraction occurs is approaching light speed which would mean that the velocity variation WRT the planets is minimal.
Confused1
We seem to be sinking deeper and deeper into the swamp.

The correct answer is that the observer on the spaceship sees no length contraction (of the ship) because there is NO LENGTH CONTRACTION.

QUOTE (Robitty+)
..velocity which length contraction occurs is approaching light speed..

The spaceship could just as well be stationary with respect to something travelling in the same direction .. the observer on the spaceship is doing exactly that.

-C2.

Edit .. you clearly have something in mind that is heading away from the spaceship at close to the speed of light - how could that affect the spaceship?
synthsin75
QUOTE (Robittybob1+Apr 27 2012, 11:57 PM)
The logic is all wrong BruceP. It feels a bit overly inquisitional to imply accept it or else accept the burning at the stake. I can accept Terrell rotations when viewing objects at high velocities but in the examples of that I looked at it was more a matter of saying "this is how things would appear", rather than saying "this is how they are". The high velocity of the observer makes other objects viewed "change shape", but this in appearance only, for can the one object really have more than one actual shape? That seems rather illogical if you think this is so.

Terrell rotation IS the apparent, observational artifact. This has no bearing on the physical length contraction, say, a muon experiences in the atmosphere. If you had read my above posts to mik, you'd see how I've already made this distinction.

QUOTE
OK the internal aspects of the high velocity craft will still look normal to the occupant but that is because the measuring method contracts in the direction of motion.  So if the dimensions are re-read, once the high velocity is achieved, the measuring device is contracted also.  This might seem that I have contradicted myself, but I accept that the objects will appear normal, but in reality they are contracted in length.

You have that backwards. Since the high speed craft would observe other things as length contracted, it must be stretched, if anything, in the direction of travel. If that observer were contracted, it would measure slower frames as being elongated.

Like mik, you seem to assume some preferred frame of "rest", from which all motion can be given absolute speeds.

QUOTE (->
 QUOTE OK the internal aspects of the high velocity craft will still look normal to the occupant but that is because the measuring method contracts in the direction of motion.  So if the dimensions are re-read, once the high velocity is achieved, the measuring device is contracted also.  This might seem that I have contradicted myself, but I accept that the objects will appear normal, but in reality they are contracted in length.

You have that backwards. Since the high speed craft would observe other things as length contracted, it must be stretched, if anything, in the direction of travel. If that observer were contracted, it would measure slower frames as being elongated.

Like mik, you seem to assume some preferred frame of "rest", from which all motion can be given absolute speeds.

I don't see a problem with that as the velocity which length contraction occurs is approaching light speed which would mean that the velocity variation WRT the planets is minimal.

What about planets near the edge of our visible universe, which are already moving at near c? These would measure our nearby planets at near c, and if the craft were moving toward these edge planets, they would measure its speed to be less than those of our local planets.
rpenner
QUOTE (Confused1+Apr 28 2012, 12:56 PM)
The correct answer is that the observer on the spaceship sees no length contraction (of the ship) because there is NO LENGTH CONTRACTION.

Or rather, there are no velocity effects related to the measurement of length of rigid objects in the coordinate system where the velocity is zero. That's why this (uncontracted length) is called the proper length of the rigid body.
Robittybob1
QUOTE (rpenner+Apr 28 2012, 02:27 PM)
Or rather, there are no velocity effects related to the measurement of length of rigid objects in the coordinate system where the velocity is zero. That's why this (uncontracted length) is called the proper length of the rigid body.

The velocity here I take it to be zero velocity with respect to (WRT) to the centre of mass of the inertial frame.
So I can accept that with an inertial frame things can move about without this affecting the over all velocity of the frame.
So I understand that a standardised meter rod would be unaffected by dilation when measuring objects in that frame as long as there is zero motion between the object and the device.
This is not saying that this frame is at rest WRT to any other frame.

So how do you @rpenner define "velocity is zero"?
rpenner

But now I have to reply.

QUOTE (Robittybob1+Apr 28 2012, 06:04 PM)
The velocity here I take it to be zero velocity with respect to (WRT) to the centre of mass of the inertial frame.

This is a great error here. A coordinate system does not require a central mass or any mass at all.
Better: "The velocity here I take it to be zero velocity with respect to (WRT) to the spatial origin of the inertial coordinate system (frame)."
It doesn't matter if you call it a frame or a coordinate system -- it is not a real thing. It's just a particular system for assigning unique labels to events in space-time and the labels are collections of 4 numbers called coordinates. The coordinate systems that are the nicest for physics are inertial coordinate systems where the coordinate descriptions of a body in inertial motion is particularly simple.

QUOTE (Robittybob1+Apr 28 2012, 06:04 PM)
So I can accept that with an inertial frame things can move about without this affecting the over all velocity of the frame.
Real things need not have any affect on imaginary things, so I agree. That you raise this as an issue seems to indicate that you have some unstated assumptions about what a coordinate system is.
QUOTE (Robittybob1+Apr 28 2012, 06:04 PM)
So I understand that a standardised meter rod would be unaffected by dilation when measuring objects in that frame as long as there is zero motion between the object and the device.
Physical rulers and rigid physical objects which share the same state of motion share the same length contraction. Therefore a yard-stick is 3-times as long as a foot-ruler, if they are parallel and in parallel motion.
QUOTE (Robittybob1+Apr 28 2012, 06:04 PM)
This is not saying that this frame is at rest WRT to any other frame.

So how do you @rpenner define "velocity is  zero"?
I'm not sure why you are quoting just the part you are quoting. Generally "velocity is zero" and "the object is at rest" are equivalent ways of saying either the coordinate velocity is zero in a specific coordinate frame, or that the physical separation between the object and another is unchanging. Velocity is not a physical absolute, but is a function of choices in made for a standard of rest.

All ponderable objects (i.e. those that have non-zero mass) that move inertially are at rest with respect to themselves. In an Cartesian, Inertial coordinate system, their position is a simple (linear) function of time: x(t) = x₀ + u t . There exist (in the mathematical sense of the term) physically equivalent Cartesian, Inertial coordinate system where this motion is zero. In such a coordinate system, new position and time labels are given to events, and we have the equivalent description of the world-line of the object as: x'(t') = x'₀ + u' t' where u' = 0 and so for any two distinct times, Δx' = 0 or Δx'/Δt' = 0 or, more four-dimensionaly, c²(Δt')² − (Δx')² = c²(Δt')² = c² τ² . All of these say the velocity in the coordinate system S' is zero.

When I wrote: "in the coordinate system where the velocity is zero" because I was referring to a choice of coordinate system where the rigid body had zero coordinate velocity and so coordinate length of the body equalled its proper length. Above, I also demonstrated in the coordinate system where the velocity is zero, coordinate time differences equal elasped proper time differences along the world lines of non-moving objects.

You are directed to here for details about length contraction and alternate coordinate systems: http://www.physforum.com/index.php?showtop...ndpost&p=516338
Robittybob1
Thanks for your reply. Trouble for me at this stage is when the argument goes purely mathematical is I go to zero understanding.
I appreciate you have introduced ideas slowly and I nearly got to understand what you are saying.
Ill give you an example what I'd need is the maths to be expressed as an idea so I know how to read it.
"Thus for any time T, in coordinate system S, the distance between the simultaneous events of the world lines is
Δx = ( R + u t ) − ( L + u t ) = ( R − L ) + ( u t − u t ) = R − L"
Δx is clearly read as "the distance between the simultaneous events of the world lines", but what what does the rest mean?

So the problem is how to get up to speed with the maths?
rpenner
x and t are coordinates in the coordinate system S, like x and y in ordinary graphs.

x = R + u t describes a straight line in algebra, but if x is position and t is time, then this is the inertial motion of a particle which moves at velocity u and is at position x = R at time t = 0. This description is used to describe the Right edge of a (possibly) moving object.

x = L + u t is the same thing except for being the Left edge. Obviously at time t = 0, the left edge is at position x = L.

Both left sides and right sides move at the same speed, u. (The lines are parallel.) If u = 0 this object isn't moving at all. But no matter what u is, if you compare the positions of the right side, x_R = R + u t_R and the left side x_L = L + u t_L at the same time t_R = t_L, or Δt = 0, the separation between x_R and x_L is constant Δx = x_R − x_L = ( R + u t_R ) − ( L + u t_R ) = ( R − L ) + u ( t_R − t_L ) = ( R − L ) + u Δt = ( R − L ) + 0 = R − L

Got it?

QUOTE
Person: Yes, science is an open process in which a good idea can come from anybody.

Person: Yes, widely-believed theories are
on occasion
overturned by simple thought experiments.

Person: And yes, your philosophy degree equips you to ask interesting questions sometimes.

[[The person is talking to a philosopher with a goatee, who is sitting at a computer.]]
Person: But you did not just overturn special relativity, a subject you learned about an hour ago, with your &quot;racecar on a train&quot; idea.
Philosopher: You just don't like that I'm turning a rational eye to your dogma. Hey, what's the email for the president of physics?

{{Title text: I mean, what's more likely -- that I have uncovered fundamental flaws in this field that no one in it has ever thought about, or that I need to read a little more?  Hint: it's the one that involves less work.}}

http://xkcd.com/675/
Confused1
Robbitty's algebra query here seems to go back to this post (1) from rpenner:
http://www.physforum.com/index.php?showtop...ndpost&p=516338
QUOTE (rpenner+)
Ignoring two dimensions of space, we can establish the inertial coordinate system S with coordinates (x, t) for every event. We can establish an inertially-moving rigid object with left endpoint having the world-line of events x = L + u t , and a separate world-line for it's right endpoint x = R + u t. (Using the usual conventions, R > L.) Thus for any time T, in coordinate system S, the distance between the simultaneous events of the world lines is
Δx = ( R + u t ) − ( L + u t ) = ( R − L ) + ( u t − u t ) = R − L
I seek confirmation that Δx isn't the proper length of "the rigid object" or rod.
The above post (1) was further clarified by post(2) here:
http://www.physforum.com/index.php?showtop...ndpost&p=516422
To recover the proper length of the rod do (or don't) we need u'=-u to undo the 'hyperbolic rotation'* which was built in to the initial declaration of Δx?
-C2.
Edit.. * or time dilation and length contraction
rpenner
Δx is the coordinate length of the object, because it is a description of length (actually the difference in spatial coordinates at a single coordinate time) without reference to the coordinate velocity of the object.

The proper length of the object is the coordinate length Δx' in a system of coordinates S' where the object is not moving u' = 0.

In the context of [post 1], this requires S and S' to be related by a transformation with parameter μ' = arctanh (−u/c) = − arctanh (u/c)

In the context of [post 2], this requires S and S' to be related by a transformation based on velocity v = −u.

(The two posts have some parallelism and both refer to this special relationship between S and S' as "Case I").

So proper length is equal to the coordinate length in an inertial coordinate system where the rigid body is not in motion, Δx', which can be expressed in terms of values measured in any coordinate system, a description of length parameterized by coordinate velocity and coordinate length: Δx / √(1 − u²/c²)

Δx' = Δx cosh μ' = Δx cosh (− arctanh (u/c) ) = Δx cosh arctanh (u/c) = Δx / √(1 − u²/c²)
mik
From my post of 4/21:

QUOTE
Philosophically, this denies that earth has a shape of its own, intrinsic and independent of observation... as per my thought experiment above (no intelligent life to measure things), also not yet addressed. ...

It is a reasonable philosophy that grants "the world" a reality of its own which does not fluctuate with the frame of reference from which it is observed. ...

(Earth) never ever flattens into a severely oblate spheroid, no matter how you look at it.

From 4/25:
QUOTE (->
 QUOTE Philosophically, this denies that earth has a shape of its own, intrinsic and independent of observation... as per my thought experiment above (no intelligent life to measure things), also not yet addressed. ...It is a reasonable philosophy that grants "the world" a reality of its own which does not fluctuate with the frame of reference from which it is observed. ...(Earth) never ever flattens into a severely oblate spheroid, no matter how you look at it.

From 4/25:
In the natural world, the shape of things does not depend on how we see and measure them or on what conceptual/mathematical model we use to describe them. ...

rpenner:

QUOTE
Only the parochial viewpoint on someone who thinks the Earth is the center of the universe would prefer the viewpoint of a unmoving Earth.

Me:
QUOTE (->
 QUOTE Only the parochial viewpoint on someone who thinks the Earth is the center of the universe would prefer the viewpoint of a unmoving Earth.

Me:
You totally misrepresent me as having such a ridiculous viewpoint. I have never even implied any such thing. We all know that everything is moving relative to everything else (except those things "at rest" with each other), from local to cosmic scales. That doesn't make earth's shape either morph to a "pancake" or become unknowable just because other frames would measure its diameter differently (and be "equally valid.")

from 4/26:

QUOTE
If the claim (ed: of length contraction) were true, then either earth drastically morphs into different shapes (which it clearly does not) or science can not know its "true shape" because there is no such thing as "true shape", given that "length is not invariant" and reality (like earth's shape/diameter) all depends on observation and it (reality) changes with different frames of reference.

rpenner:
QUOTE (->
 QUOTE If the claim (ed: of length contraction) were true, then either earth drastically morphs into different shapes (which it clearly does not) or science can not know its "true shape" because there is no such thing as "true shape", given that "length is not invariant" and reality (like earth's shape/diameter) all depends on observation and it (reality) changes with different frames of reference.

rpenner:
Twice now, I have directly answered this question. Here is attempt three to get you to engage in dialogue. "Shape" is a geometrical concept, ...

My “engagement” with that assertion has been that the map is not the territory. Shape is more than a geometric concept. It is an actual physical property of actual physical objects. Earth’s shape is independent of any geometric description of it as seen from any of the variety of possible frames of reference.

But you say:
QUOTE
If experiment says the geometry of the universe is not Euclidean, then it is an error to cling to only a Euclidean concept of "shape."

Maybe you would find this paper interesting: Kelley Ross, The Ontology and Cosmology of Non-Euclidean Geometry. Synthsin75 did early on.... not that he endorsed it, but it does take a critical look at that transition rather than assuming there are no true shapes in nature, and that non-Euclidean geometry re-defines the natural world according to its concepts.

http://www.friesian.com/curved-1.htm

QUOTE (->
 QUOTE If experiment says the geometry of the universe is not Euclidean, then it is an error to cling to only a Euclidean concept of "shape."

Maybe you would find this paper interesting: Kelley Ross, The Ontology and Cosmology of Non-Euclidean Geometry. Synthsin75 did early on.... not that he endorsed it, but it does take a critical look at that transition rather than assuming there are no true shapes in nature, and that non-Euclidean geometry re-defines the natural world according to its concepts.

http://www.friesian.com/curved-1.htm

So... shall we assume you are an unpublished, home-schooled, parochial yutz who picks up a creationist screed on philosophy from Powell's Books and runs around asserting that he is the way, the truth and the light, but seems unable to argue in favor of the proposition?

Let’s not. Lets not assume that ad hominem arguments are legitimate either. Relativity has been a field of interest for me for a long time,(especially its philosophical assumptions) even though I am not a mathematician. See Ross's comments about about math elitism near his conclusion. If I'm to be continually dismissed as an ignoramus, must speak again in my own defense. My SBIS score was 170 and my WAIS score was 178. Do not continue to mistake disagreement for ignorance.

synthsin75
QUOTE (mik+Apr 29 2012, 05:46 PM)
Maybe you would find this paper interesting: Kelley Ross, The Ontology and Cosmology of Non-Euclidean Geometry. Synthsin75 did early on.... not that he endorsed it, but it does take a critical look at that transition rather than assuming there are no true shapes in nature, and that non-Euclidean geometry re-defines the natural world according to its concepts.

http://www.friesian.com/curved-1.htm

I did not find this philosophical farce of the science interesting. I actually told you that it rings with typical, uninformed, crank sentiment. Here's a prime example:

QUOTE
Now we actually have two competing ways of understanding gravity, either through Einstein's geometrical method or through the interaction of virtual particles in quantum mechanics.

We have nothing of the kind, as the graviton is still hypothetical while GR has weathered numerous tests unscathed.

QUOTE (->
 QUOTE Now we actually have two competing ways of understanding gravity, either through Einstein's geometrical method or through the interaction of virtual particles in quantum mechanics.

We have nothing of the kind, as the graviton is still hypothetical while GR has weathered numerous tests unscathed.

Let’s not. Lets not assume that ad hominem arguments are legitimate either. Relativity has been a field of interest for me for a long time,(especially its philosophical assumptions) even though I am not a mathematician. See Ross's comments about about math elitism near his conclusion. If I'm to be continually dismissed as an ignoramus, must speak again in my own defense. My SBIS score was 170 and my WAIS score was 178. Do not continue to mistake disagreement for ignorance.

There's nothing ad hominem about your gratuitously demonstrated naive and intuitive bias, nor your lack of demonstration of any understanding of the actual science or even some pretty basic concepts in philosophy. The power is completely your own to decide to quit refuting science with philosophical tripe and actually learn something. No amount of intelligence will help those who are determined not to learn.
Robittybob1
QUOTE (rpenner+Apr 29 2012, 05:48 PM)
Δx is the coordinate length of the object, because it is a description of length (actually the difference in spatial coordinates at a single coordinate time) without reference to the coordinate velocity of the object.

The proper length of the object is the coordinate length Δx' in a system of coordinates S' where the object is not moving u' = 0.

In the context of [post 1], this requires S and S' to be related by a transformation with parameter μ' = arctanh (−u/c) = − arctanh (u/c)

In the context of [post 2], this requires S and S' to be related by a transformation based on velocity v = −u.

(The two posts have some parallelism and both refer to this special relationship between S and S' as "Case I").

So proper length is equal to the coordinate length in an inertial coordinate system where the rigid body is not in motion, Δx', which can be expressed in terms of values measured in any coordinate system, a description of length parameterized by coordinate velocity and coordinate length: Δx / √(1 − u²/c²)

Δx' = Δx cosh μ' = Δx cosh (− arctanh (u/c) ) = Δx cosh arctanh (u/c) = Δx / √(1 − u²/c²)

So looking at the left and right sides of an object;
"Δx = x_R − x_L = ( R + u t_R ) − ( L + u t_R ) = ( R − L ) + u ( t_R − t_L ) = ( R − L ) + u Δt = ( R − L ) + 0 = R − L"

So when you say left and right that seems to suggest width to me.

Whereas Confused2 start talking of length, and with length you were introducing terms like a Lorentz transformation "Δx' = Δx cosh μ' = Δx cosh (− arctanh (u/c) ) = Δx cosh arctanh (u/c) = Δx / √(1 − u²/c²)"
No further mention of L or R.

So does an object moving at speed u contract to a new length
Δx' = Δx / √(1 − u²/c²); but the width still stays the same? As in "Δx = R − L"
rpenner
QUOTE (mik+Apr 29 2012, 11:46 PM)
My “engagement” with that assertion has been that the map is not the territory. Shape is more than a geometric concept. It is an actual physical property of actual physical objects.
This sounds like Platonic essentialism to me. I believe shape is exactly a geometric concept and challenge you to describe a shape without reference to geometry or objects; I challenge you to say the shape of two objects is the same without reference to geometry. I have never contested that actual objects have abstract descriptions called shapes. I have asserted that abstraction known as shape is developed in geometry as is "sphere" and "cube" and "cylinder" and if you want to talk about actual shapes then one is constrained to use actual or physical or natural geometry in time and space and acknowledge that an instantaneous sphere, a sphere that has no extent in time, is a horrible approximation of the four-dimensional shape of the Earth. A successful challenge would strip that assertion of any perceived merit of authority and experience. So given that the Earth is extended in space and time, the hyperbolic geometry of space and time requires us to distinguish its proper radius from its coordinate radius.

QUOTE (mik+Apr 29 2012, 11:46 PM)
Earth’s shape is independent of any geometric description of it as seen from any of the variety of possible frames of reference.
Earth's shape is its abstract geometric description in a manner that is neutral to choice of coordinates.

QUOTE (mik+Apr 29 2012, 11:46 PM)
But you say:
QUOTE
If experiment says the geometry of the universe is not Euclidean, then it is an error to cling to only a Euclidean concept of "shape."
I continue to support that position.

QUOTE (->
 QUOTE If experiment says the geometry of the universe is not Euclidean, then it is an error to cling to only a Euclidean concept of "shape."
I continue to support that position.

Maybe you would find this paper interesting: Kelley Ross, The Ontology and Cosmology of Non-Euclidean Geometry. Synthsin75 did early on.... not that he endorsed it, but it does take a critical look at that transition rather than assuming there are no true shapes in nature, and that non-Euclidean geometry re-defines the natural world according to its concepts.

http://www.friesian.com/curved-1.htm
The essay starts off poorly claiming quantum mechanics has been refuted as illogical with Schrodinger's Cat when in fact the issue was narrower about the role of measurement. Escher's "Circle Limit I" makes my point about shape -- the hyperbolic tiling works because the black and white shapes are congruent, but the model requires them to distorted to fit in the diagram. It's a mismatch between hyperbolic geometry and the Euclidean geometry of a flat diagram on a piece of paper. The definition of shape and whether the geodesics are curved or straight depends on the geometry being used, and for the tiles themselves there is no natural geometry other than hyperbolic. Use of a unevidenced external geometry is a violation of parsimony and is thus unscientific.

QUOTE (mik+Apr 29 2012, 11:46 PM)
Let’s not. Lets not assume that ad hominem arguments are legitimate either. Relativity has been a field of interest for me for a long time,(especially its philosophical assumptions) even though I am not a mathematician. See Ross's comments about about math elitism near his conclusion. If I'm to be continually dismissed as an ignoramus, must speak again in my own defense. My SBIS score was 170 and my WAIS score was 178. Do not continue to mistake disagreement for ignorance.

None of that quote was an ad hominem argument. I was not asserting that you were wrong on the basis of your ignorance or your home-schooling, I was asserting that your ignorance has led you hasty generalizations that have no utility in a wider universe. Geometry and mathematical foundations like "set" and "number" are abstraction and generalizations of real world observations about figures, collections and equivalence of collections. No one has the time in their finite lifetimes to make all the observations, all the abstractions and all the generalizations to replace the efforts of hundreds of years of the world-wide efforts of dedicated and self-correcting scholars. But instead of leveraging their efforts to "stand on the shoulders of giants" you stand at their feet, refusing to climb, and stating that the view doesn't look so good.

Claiming that you have a high Stanford-Binet Intelligence Scale score or a high Wechsler Adult Intelligence Scale score does nothing to weaken the claim that you are a "unpublished, home-schooled, parochial" ignoramus -- the charge is ignorance, certainty, lack of drive to improve and lack of usefulness not lack of intelligence. I believe the only "math elitism" in evidence is your claims of 170 and 178. Ross wrote: "Every physical theory has a mathematical component and a conceptual component, but these two are often confused" and your denial of the principle of relativity does violence to both. Ross wrote: "Philosophy usually does a poor job of preparing the way for science, but it never hurts to ask questions" and in this I agree with him, you should limit yourself to asking questions until you have mastered the physics and math of relativity and cease trying to impose your preconceived notions of shape and geometry upon us when you rely on nothing more than naked assertions.

// Edit: added underlined sections after last edit changed the meaning
rpenner
QUOTE (Robittybob1+Apr 30 2012, 02:10 AM)

No further mention of L or R.

So does an object moving at speed u contract to a new length
Δx' = Δx / √(1 − u²/c²); but the width still stays the same?  As in "Δx = R − L"

No further mention of L or R is needed because of the equals sign. Δx = R − L. Any unique properties of R and L individually are abstracted away by the definition of Δx.

Your conceptualization of length as something distinct from width is not part of the model. The model requires only the differences Δx, Δx' and the velocity u be parallel (in the same spatial direction). In [post 1] I made this explicit by working in (1+1) special relativity, removing for the purposes of discussion two spatial dimensions from (3+1) special relativity.

So R − L is "length as measured in the direction of (relative) motion" of a (conceptually) rigid body in the S coordinate system. This could be a "width" if that direction of motion is a direction you would association with the direction of "width" of the object.

But in the mathematical model, R means the +x direction and L means the −x direction which in the Western presentation of a horizontal number line means numbers further to the Right are larger than numbers further to the Left and so R > L > 0 and so R − L = | R − L | which is mathematically convenient. The labels R and L were supposed to evoke Right and Left on the number line and not necessarily apply to any physical right and left or a direction other than the direction of motion.

Any measure of the object in a direction orthogonal to the direction of motion remain unchanged in the coordinate system, S', where the object is not in motion.
This is discussed in Chapter 4 of the new pop science book:
Chad Orzel, How to Teach Relativity to Your Dog (2012), pp. 73-92

But you probably read the Introduction and chapters 1-3 first. Many of the common misunderstandings are addressed.
Robittybob1
OK I understood all that, so whatever happens to the "ship" also happens to the "crew". So at a high speed their lengths are contracted in the direction of motion only.
Now as person raised on biology I'm thinking if the crewman turns his head through 90 degrees first it is compressed front to back but when looking out the side window it is compressed ear to ear. What sort of effect does this have on brain function and will bone matter withstand these reshaping events?

Will the crewman see that the side window which used to be square is now physically shortened compared to the height of the window?
rpenner
The laws of quantum mechanics, electromagnetism, and similar have been shown to be completely compatible with special relativity. So the person on board this ship you introduced may indeed turn their head without anything untoward happening.

The physics of the situation on board the ship in the "stationary frame" is exactly the same as if the coordinates are changed to that of the "moving frame", the laws of physics applied to get a result, and then the result is translated back to the coordinates of the "stationary frame." This is part-and-parcel of the hundred-plus years of the testing of Lorentz invariance.
Robittybob1
QUOTE (rpenner+Apr 30 2012, 07:07 AM)
The laws of quantum mechanics, electromagnetism, and similar have been shown to be completely compatible with special relativity. So the person on board this ship you introduced may indeed turn their head without anything untoward happening.

The physics of the situation on board the ship in the "stationary frame" is exactly the same as if the coordinates are changed to that of the "moving frame", the laws of physics applied to get a result, and then the result is translated back to the coordinates of the "stationary frame." This is part-and-parcel of the hundred-plus years of the testing of Lorentz invariance.

OK the crew can survive. But what will the side window look like? Will it look square when in fact it is contracted?
I think you will say that it will be square.

So when the crewman holds up a rod measure at arms length and compares it to an object out the side window why would it appear longer than it was before?
Maxila
QUOTE (Robittybob1+Apr 29 2012, 11:06 PM)
So at a high speed their lengths are contracted in the direction of motion only.

Rpenner answered you however I thought it might help to hear it from a different perspective.

QUOTE
Will the crewman see that the side window which used to be square is now physically shortened compared to the height of the window?

The length contraction appears only to an observer for which the ship has a relative velocity. The ship and its occupants do not observe a change in, any ship length, themselves, or anything inertial that is part of the ship frame.

QUOTE (->
 QUOTE Will the crewman see that the side window which used to be square is now physically shortened compared to the height of the window?

The length contraction appears only to an observer for which the ship has a relative velocity. The ship and its occupants do not observe a change in, any ship length, themselves, or anything inertial that is part of the ship frame.

I'm thinking if the crewman turns his head through 90 degrees first it is compressed front to back but when looking out the side window it is compressed ear to ear.

Your questions are only relevant to those observer's I mentioned. This next statement is NOT a part of SR, GR; however it may be helpful. All observations we are discussing are via light (any part of the EM spectrum not specifically visible light). Using visible light as an example, doesn't a fish look bigger through a fish bowl then from inside the bowl? When examining motion picture film, you see a number of still frames that usually differ a little from each other, run it through a projector and it appears as fluid motion.

The point I am trying to make is that in SR and GR anything that is part of an inertial frame in question never observes a change in length, or time, for anything that is part of that frame. It can only be from a different perspective length and time may appear to change. We accept that our observations are relative to our perspective in our every day experience, as in the film and fish bowl examples I mentioned. Don't get so caught up that those people's brains have to contract relative to the direction of motion of the ship, they never see or experience such a thing. Only an outside observer could see that and it may be just as an observation of a fish in a bowl or that piece of film, the outside observer sees something different from the nature of what is observed? SR and GR in fact tell us that from their own perspective the ship and the people on board don't change in length and their own time never appears to change.

I imagine it may not be easy, but if you can try to visual the light in motion the ship and the perspectives of the different frames (the inertial perspectives and the relative velocity perspectives), these relative observations makes sense.

Maxila
AlexG
QUOTE
Only an outside observer could see that and it may be just as an observation of a fish in a bowl or that piece of film, the outside observer sees something different from the nature of what is observed?

No, it's not just an optical illusion. It's the geometry of space/time. If the outside observer could somehow extend his fingers so he could feel the inside of the ship as it passes by, he would feel that everything is contracted in the direction of movement. If he had a ruler in those ghostly extened fingers, he would measure contraction.
Robittybob1
QUOTE (AlexG+Apr 30 2012, 07:00 PM)

No, it's not just an optical illusion.  It's the geometry of space/time.  If the outside observer could somehow extend his fingers so he could feel the inside of the ship as it passes by, he would feel that everything is contracted in the direction of movement.  If he had a ruler in those ghostly extened fingers, he would measure contraction.

Error happened somehow sorry.
Maxila
QUOTE (AlexG+Apr 30 2012, 02:00 PM)
If the outside observer could somehow extend his fingers so he could feel the inside of the ship as it passes by, he would feel that everything is contracted in the direction of movement.

SR and GR don't postulate what he would "feel", only what is observed via light and time. You would also see your hand or ruler appear larger if you placed it in the fish bowl, that doesn't mean your hand and the ruler actually got bigger; however I admit in that example time and the disagreeing size will not reconcile.

QUOTE
No, it's not just an optical illusion.  It's the geometry of space/time.

You're extending my statements more then you should, I said, "it may be just as an observation of a fish in a bowl or that piece of film, the outside observer sees something different from the nature of what is observed?" The postulates of SR are what is observed (light and time), my statements and yours are only speculative ponderings. I did say, "may", and put a question mark after my statement to indicate it was just a possible explanation, and I reiterated in the ships frame nothing is observed to change.

QUOTE (->
 QUOTE No, it's not just an optical illusion.  It's the geometry of space/time.

You're extending my statements more then you should, I said, "it may be just as an observation of a fish in a bowl or that piece of film, the outside observer sees something different from the nature of what is observed?" The postulates of SR are what is observed (light and time), my statements and yours are only speculative ponderings. I did say, "may", and put a question mark after my statement to indicate it was just a possible explanation, and I reiterated in the ships frame nothing is observed to change.

If he had a ruler in those ghostly extended fingers, he would measure contraction
.

It's still an observation via EM radiation and time. All this says is the observation is relative to ones clock, which we both already knew. It can only confirm length and time are relative to an "observer" and their frame.

Maxila
rpenner
QUOTE (Robittybob1+Apr 30 2012, 05:33 PM)
Will it look square when in fact it is contracted?
I think you will say that it will be square.

You have failed to understand the principle of relativity.

The Euclidean 3-dimensional shape of the window is contracted in the coordinates of the "stationary" frame, coordinate system S.

The Euclidean 3-dimensional shape of the same window if not contracted in the coordinates of the "moving" or "ship" frame, coordinate system S'.

The 3-dimensional, covariant shape of the window is a square contracted in the direction of motion by a factor of √(1 − v²/c²) where v is the motion of the window in the chosen coordinate frame.

The 4-dimensional, invariant shape of the window is a spatial square indefinitely extended in the time-direction.

The principle of relativity requires that we treat S and S' as equivalent for all purposes. So our corresponding definition of shape or geometry only makes sense if we require that we use invariant descriptions of shape that are equal in S and S' or covariant (parameterized) descriptions of shape that are equivalent.
synthsin75
QUOTE (Maxila+Apr 30 2012, 02:08 PM)
SR and GR don't postulate what he would "feel", only what is observed via light and time.

Time is not a factor in the measurement of contracted lengths, as such measurements are made of both ends simultaneously in the frame of the coordinate observer.
brucep
QUOTE (mik+Apr 29 2012, 11:46 PM)
From my post of 4/21:

From 4/25:

rpenner:

Me:

from 4/26:

rpenner:

My “engagement” with that assertion has been that the map is not the territory. Shape is more than a geometric concept. It is an actual physical property of actual physical objects. Earth’s shape is independent of any geometric description of it as seen from any of the variety of possible frames of reference.

But you say:

Maybe you would find this paper interesting: Kelley Ross, The Ontology and Cosmology of Non-Euclidean Geometry. Synthsin75 did early on.... not that he endorsed it, but it does take a critical look at that transition rather than assuming there are no true shapes in nature, and that non-Euclidean geometry re-defines the natural world according to its concepts.

http://www.friesian.com/curved-1.htm

Let’s not. Lets not assume that ad hominem arguments are legitimate either. Relativity has been a field of interest for me for a long time,(especially its philosophical assumptions) even though I am not a mathematician. See Ross's comments about about math elitism near his conclusion. If I'm to be continually dismissed as an ignoramus, must speak again in my own defense. My SBIS score was 170 and my WAIS score was 178. Do not continue to mistake disagreement for ignorance.

If relativity has been an interest of yours for a 'long time' then why haven't you become literate on the subject? Leads me to believe the scores are exaggerated.

WAIS 178. Internet bullshit. Most humans fall between 85-115.

Your problem is you don't understand relativity and feel it must be wrong since it doesn't fit your world view. You don't have a valid disagreement. Everything you present has been empirically round filed.

Robittybob1
QUOTE (rpenner+Apr 30 2012, 08:36 PM)
You have failed to understand the principle of relativity.

I have failed to understand the principle of relativity? Well that could be so for I determined to get a better understanding of it if at all possible.

QUOTE
The Euclidean 3-dimensional shape of the window is contracted in the coordinates of the "stationary" frame, coordinate system S.

So I take that to mean as we look up at the craft we see it shortened. And this is a real physical phenomena and it is not a result of optics or the speed of light.

QUOTE (->
 QUOTE The Euclidean 3-dimensional shape of the window is contracted in the coordinates of the "stationary" frame, coordinate system S.

So I take that to mean as we look up at the craft we see it shortened. And this is a real physical phenomena and it is not a result of optics or the speed of light.

The Euclidean 3-dimensional shape of the same window is not contracted in the coordinates of the "moving" or "ship" frame, coordinate system S'.

So I take that to mean on board all seems normal. They can't tell they are compressed, for every method to measure the dimensions are affected by the same phenomena. This comes about by the coordinates contracting as much as the objects. For how can we see it as contracted but those on board don't.

QUOTE
The 3-dimensional, covariant shape of the window is a square contracted in the direction of motion by a factor of  √(1 − v²/c²) where v is the motion of the window in the chosen coordinate frame.

My main issue here is can both know the speed? So the observer can say the window at rest is a square but now looks shortened by √(1 − v²/c²)"

But on board they say "it looks like a square but we know in reality it is shortened by √(1 − v²/c²)"

QUOTE (->
 QUOTE The 3-dimensional, covariant shape of the window is a square contracted in the direction of motion by a factor of  √(1 − v²/c²) where v is the motion of the window in the chosen coordinate frame.

My main issue here is can both know the speed? So the observer can say the window at rest is a square but now looks shortened by √(1 − v²/c²)"

But on board they say "it looks like a square but we know in reality it is shortened by √(1 − v²/c²)"

The 4-dimensional, invariant shape of the window is a spatial square indefinitely extended in the time-direction.

Interesting!

QUOTE
The principle of relativity requires that we treat S and S' as equivalent for all purposes. So our corresponding definition of shape or geometry only makes sense if we require that we use invariant descriptions of shape that are equal in S and S' or covariant (parameterized) descriptions of shape that are equivalent.

Interesting!
rpenner
QUOTE (Robittybob1+May 1 2012, 04:36 AM)
My main issue here is can both know the speed? So the observer can say the window at rest is a square but now looks shortened by √(1 − v²/c²)"

But on board they say "it looks like a square but we know in reality it is shortened by √(1 − v²/c²)"

You have failed to understand what covariant means. v has different values depending on what coordinate system is used to measure this coordinate velocity.

The coordinate velocity of the window in coordinate frame S is v = u, so √(1 − v²/c²) < 1

The coordinate velocity of the window in coordinate frame S' is v = u' = 0, so √(1 − v²/c²) = 1

So the proper length of the window in the direction of motion is invariant -- it doesn't change if the coordinate system changes.

Δx is the coordinate length of the window in the direction of motion in coordinate system S. It is not coordinate invariant, so for another coordinate system S' it may be the case that Δx ≠ Δx', which is the case if the ship is moving at speed u in S and speed u' = 0 in S'.

But there is a relationship between coordinate length and proper length:
Δx / √(1 − u²/c²) = Δx' / √(1 − u'²/c²)

And since (in our (1+1) special relativity) we can construct invariants from the coordinate length in ANY coordinate system Δx and the speed of the object in the same coordinate system, v, the expression Δx / √(1 − v²/c²) is an invariant constructed from two covariant quantities.
Robittybob1
QUOTE (rpenner+May 1 2012, 05:38 AM)
You have failed to understand what covariant means. v has different values depending on what coordinate system is used to measure this coordinate velocity.

The coordinate velocity of the window in coordinate frame S is v = u, so √(1 − v²/c²) < 1

The coordinate velocity of the window in coordinate frame S' is v = u' = 0, so √(1 − v²/c²) = 1

So the proper length of the window in the direction of motion is invariant -- it doesn't change if the coordinate system changes.

Δx is the coordinate length of the window in the direction of motion in coordinate system S. It is not coordinate invariant, so for another coordinate system S' it may be the case that Δx ≠ Δx', which is the case if the ship is moving at speed u in S and speed u' = 0 in S'.

But there is a relationship between coordinate length and proper length:
Δx / √(1 − u²/c²) = Δx' / √(1 − u'²/c²)

And since (in our (1+1) special relativity) we can construct invariants from the coordinate length in ANY coordinate system Δx and the speed of the object in the same coordinate system, v, the expression Δx / √(1 − v²/c²) is an invariant constructed from two covariant quantities.

You were right I hadn't looked up "covariant".

QUOTE
But there is a relationship between coordinate length and proper length:
Δx / √(1 − u²/c²) = Δx' / √(1 − u'²/c²)

So it is the length of the division in the coordinates change with coordinate system velocity?
How do you using words explain how the window is shortened in one S view but in the moving coordinate system it still looks a normal "square"?

Catch you tomorrow!
Confused1
QUOTE (Robitty+)
but in the moving coordinate system it still looks a normal "square"?
For a spaceman in the spaceship the window (also in the spaceship) isn't moving. BUT the Earth and just about everything else is moving relative to the spaceship .. hence the desire for a general description of the window seen from anywhere (not just by the spaceman inside the spaceship).
-C2.
synthsin75
QUOTE (Robittybob1+Apr 30 2012, 10:36 PM)
So I take that to mean on board all seems normal. They can't tell they are compressed, for every method to measure the dimensions are affected by the same phenomena. This comes about by the coordinates contracting as much as the objects. For how can we see it as contracted but those on board don't.

How many time must you be told? The remote observer on earth doesn't affect the coordinate system of the spacecraft, and it is only in the earth's coordinate system that the craft is contracted. Only the observer's own local coordinate system affects their measurements.
rpenner
So because choice of coordinate systems is artificial, thinking about shape in a way that is confined to just one coordinate system is artificial. Therefore one needs to embrace 4-dimensional hyperbolic geometry to say something about shape that is naturally meaningful in our universe.

If you don't get that choice of coordinate systems is artificial, then you need to start over at the principle of relativity.
Robittybob1
QUOTE (synthsin75+May 1 2012, 12:16 PM)
How many time must you be told? The remote observer on earth doesn't affect the coordinate system of the spacecraft, and it is only in the earth's coordinate system that the craft is contracted. Only the observer's own local coordinate system affects their measurements.

Well I think that is what I was saying. It is the coordinate system in motion which makes the divisions in its own coordinates change in the direction of motion. One meter in a moving coordinate system is not the same length meter as in the "stationary" system.

I am still amazed by the thought that this moving meter ruler changes length when rotated 90 degrees to the direction of travel when viewed by the stationary observer but appears unchanged by the crewmen in motion.

For that means the same thing is happening here on Earth too for we won't be absolutely stationary.
Robittybob1
QUOTE (rpenner+May 1 2012, 03:37 PM)
So because choice of coordinate systems is artificial, thinking about shape in a way that is confined to just one coordinate system is artificial. Therefore one needs to embrace 4-dimensional hyperbolic geometry to say something about shape that is naturally meaningful in our universe.

If you don't get that choice of coordinate systems is artificial, then you need to start over at the principle of relativity.

But what I have seen from our discussion is that a square is a square when measured in your own coordinate system. It is not a square when you look at it while it is moving past you. You can bring it back to a square when you do the Lorentz transformations.
mik
This nails the difference between the philosophy that “the world” exists and has intrinsic, objective properties independent of observation/measurement... and that there is no reality independent of the latter:
Me:
"My 'engagement' with that assertion has been that the map is not the territory. Shape is more than a geometric concept. It is an actual physical property of actual physical objects."

You:
"This sounds like Platonic essentialism to me."

“The shape of things” (and actual distances between them in the real world) does not depend on Platonic ideals.... or on relativity theory. Of course earth is not a perfect sphere, but rather nearly so. Nature’s properties are as they are. Nature doesn’t care about the theoretical distinction between "proper length" and "contracted length" or how it is measured... from at rest with a given object or from whatever extreme frames of reference. It stays as it is, independent of measurement and theory. Call that philos0phy whatever you like.

You: “...you rely on nothing more than naked assertions.”

Here is another “naked” one you have never addressed:
“The world” (including earth) was here long before mankind and his science, and will be here long after we are gone. it won’t change much during our brief occupation here. And it certainly doesn’t change with how we observe it, thought it clearly appears to change. Your philosophy to the contrary is extremely anthropomorphically centered. 'It is as we see it.'

For Brucep; re:
"In a normal distribution, the IQ range of one standard deviation above and below the mean (i.e., between 85 and 115) is where approximately 68% of all adults would fall."

Right. My 178, however has a “true rarity of occurance” of about one in a million, at the 99.9999th percentile. I get to question authority, not just regurgitate what I have been taught.
And, as in "Imagine,"... "I'm not the only one."

rpenner:

QUOTE
There's nothing ad hominem about your gratuitously demonstrated naive and intuitive bias, nor your lack of demonstration of any understanding of the actual science or even some pretty basic concepts in philosophy. The power is completely your own to decide to quit refuting science with philosophical tripe and actually learn something. No amount of intelligence will help those who are determined not to learn.

Could it be that "philosophical tripe" is just your opinion as a physicist with a very low opinion of philosophy of science and that your 'dissing' of the Ross paper simply confirms your physics/math elitism. You still mistake the map for the territory, apparently not philosophically astute enough to know the difference.
And are you “determined not to learn" anything from the volumes of papers published from the conferences held by the International Society for the Advanced Study of Spacetime?
Too much questioning of authority for you?
Maxila
QUOTE (synthsin75+Apr 30 2012, 05:51 PM)
Time is not a factor in the measurement of contracted lengths, as such measurements are made of both ends simultaneously in the frame of the coordinate observer.

You need to rethink that. This snippet I cut and paste from rpenners post should help you get on the right track.

Quote: rpenner - "the expression Δx / √(1 − v²/c²) is an invariant constructed from two covariant quantities."

hint: c is directly relative to t, remember in numerical units c is always per t, i.e. 299,792,458 meters per second, or 10 light years, etc. c would have no meaning stated without a relation to t.

Maxila
synthsin75
QUOTE (Maxila+May 1 2012, 03:09 PM)
You need to rethink that. This snippet I cut and paste from rpenners post should help you get on the right track.

Quote: rpenner - "the expression Δx / √(1 − v²/c²) is an invariant constructed from two covariant quantities."

hint: c is directly relative to t, remember in numerical units c is always per t, i.e. 299,792,458 meters per second, or 10 light years, etc. c would have no meaning stated without a relation to t.

Maxila

No, you simply don't understand what the transform you cut and paste is used for. This is not the measurement. The measurement is simply a simultaneous measurement of two ends of an object. Simultaneous means that there is no elapse of time, exactly as I told you.

And I believe it was me who was trying to hammer home to you that any motion is always with respect to time. Perhaps you've finally learned that much?

QUOTE (Robittybob1+)
I am still amazed by the thought that this moving meter ruler changes length when rotated 90 degrees to the direction of travel when viewed by the stationary observer but appears unchanged by the crewmen in motion.

QUOTE (mik+)
Could it be that "philosophical tripe" is just your opinion as a physicist with a very low opinion of philosophy of science and that your 'dissing' of the Ross paper simply confirms your physics/math elitism. You still mistake the map for the territory, apparently not philosophically astute enough to know the difference.
And are you “determined not to learn" anything from the volumes of papers published from the conferences held by the International Society for the Advanced Study of Spacetime?
Too much questioning of authority for you?

No, "philosophical tripe" is my opinion of someone who relies solely on philosophical arguments but can't even manage to demonstrate a basic understanding of the most relevant to philosophy of science, i.e. scientific realism. You can ignore me telling you that as many time as you like, but until you do demonstrate such understanding, of at least the relevant philosophy, your arguments are completely baseless.

Your reliance on that "Ross paper" only proves you aren't discerning enough to keep from being duped by cranks, and you quote all of the typical crank justifications to boot.
mik
QUOTE (synthsin75+May 2 2012, 03:50 AM)

No, "philosophical tripe" is my opinion of someone who relies solely on philosophical arguments but can't even manage to demonstrate a basic understanding of the most relevant to philosophy of science, i.e. scientific realism. You can ignore me telling you that as many time as you like, but until you do demonstrate such understanding, of at least the relevant philosophy, your arguments are completely baseless.

Your reliance on that "Ross paper" only proves you aren't discerning enough to keep from being duped by cranks, and you quote all of the typical crank justifications to boot.

Wiki on Naive Realism (my comments labeled as edits within text and emphasis added as *...*):
Naïve realism, also known as direct realism or common sense realism, is a philosophy of mind rooted in a theory of perception that claims that the senses provide us with direct awareness of the external world....

(My edit: Let’s include the sophisticated technology of science’s instruments as extended “senses” gathering empirical data.)

The realist view is that objects are composed of matter, occupy space and have properties, such as *size, shape, texture, smell, taste and colour, that are usually perceived correctly.* We perceive them as they really are. *Objects obey the laws of physics and retain all their properties whether or not there is anyone to observe them.*

The naïve realist theory may be characterized as the acceptance of the following five beliefs:

1. There exists a world of material objects.
2. Statements about these objects can be known to be true through sense-experience. (Edit: amended as above)
3. These objects exist not only when they are being perceived but *also when they are not perceived. The objects of perception are largely perception-independent.*
4. These objects are also able to retain properties of the types we perceive them as having, even when they are not being perceived. *Their properties are perception-independent.*
5. By means of our senses, we perceive the world directly, and pretty much as it is. In the main, our claims to have knowledge of it are justified.

Naïve realism is distinct from scientific realism, which states that the *universe contains just those properties that feature in a scientific description of it;...*

(Edit : Ergo, Nature is not “real” in and of itself, ”perception-independent.”
Before mankind and science arrived, there was no real world, nor will there be without continued perception of it. Yet "scientific realism" denies this as per *...* above.)

" [W]e have to give up the idea of realism to a far greater extent than most physicists believe today." (Anton Zeilinger)... By realism, he means the idea that objects have specific features and properties — that a ball is red, (Edit:...* that Earth is nearly spherical)* that a book contains the works of Shakespeare, or that an electron has a particular spin... for objects governed by the laws of quantum mechanics, like photons and electrons, it may make no sense to think of them as having well defined characteristics. Instead,* what we see may depend on how we look*...

(Edit: *...* above is a variation of idealism, though "scientific realism" denies the similarity.)

Realism in physics refers to the fact that any *physical system must have definite properties whether measured/observed or not.* Physics up to the 19th century was always implicitly and sometimes explicitly taken to be based on philosophical realism.

Scientific realism in classical physics has remained compatible with the naïve realism of everyday thinking on the whole but there is no known, consistent way to visualize the world underlying quantum theory in terms of ideas of the everyday world. "The general conclusion is that in quantum theory naïve realism, *although necessary at the level of observations, fails at the microscopic level."*[7] Experiments such as the Stern–Gerlach experiment and quantum phenomena such as complementarity lead quantum physicists to conclude that "*[w]e have no satisfactory reason for ascribing objective existence to physical quantities as distinguished from the numbers obtained when we make the measurements which we correlate with them.*

(Edit: The measurements and numbers are now real, but “physical quantities” [sizes, shapes,distances between objects] have no “objective existence” in and of themselves.)

A concluding question/challenge:
How does the failure of “naive” realism at the microscopic level (as per quantum physics) translate to the macro-scale, as per the discussion of the properties of planets (size/shape) and the distances between bodies in macro-space?
How is it that the description the depth/thickness of Earth’s atmosphere “for a muon” is "equally valid," as per length contraction, with its actual thickness as per at-rest within Earth’s frame of reference? Length contraction on large scale is bogus.

Maybe a unified field theory will someday unite the micro-world of quantum physics and the macro-world of large objects and distances between them. Until then the former does not adequately describe the latter.

Ps; Are you calling Ross a "crank?" How exactly is he wrong? Just by citing QM as having an alternative theory of gravity? How about the "intrinsic vs extrinsic" distinction so vital to non-Euclidean geometry and cosmology? How do parallel lines intersect in the real world,or is it just "in infinity" mathematically speaking. These are issues that have not been addressed here but have been addressed by Ross.
How is, "The map is not the territory" a "typical crank justification?"
synthsin75
Mik, I'm not responding to that mess until you clearly indicate what is a quote and what is your personal comments. You seem to have chosen to indicate both your own comments and emphasis of quoted material in the exact same way.

How that post is written, it could count as plagiarism.
brucep
QUOTE (mik+May 1 2012, 09:08 PM)
This nails the difference between the philosophy that “the world” exists and has intrinsic, objective properties independent of observation/measurement... and that there is no reality independent of the latter:
Me:
"My 'engagement' with that assertion has been that the map is not the territory. Shape is more than a geometric concept. It is an actual physical property of actual physical objects."

You:
"This sounds like Platonic essentialism to me."

“The shape of things” (and actual distances between them in the real world) does not depend on Platonic ideals.... or on relativity theory. Of course earth is not a perfect sphere, but rather nearly so. Nature’s properties are as they are. Nature doesn’t care about the theoretical distinction between "proper length" and "contracted length" or how it is measured... from at rest with a given object or from whatever extreme frames of reference. It stays as it is, independent of measurement and theory. Call that philos0phy whatever you like.

You: “...you rely on nothing more than naked assertions.”

Here is another “naked” one you have never addressed:
“The world” (including earth) was here long before mankind and his science, and will be here long after we are gone. it won’t change much during our brief occupation here. And it certainly doesn’t change with how we observe it, thought it clearly appears to change. Your philosophy to the contrary is extremely anthropomorphically centered. 'It is as we see it.'

For Brucep; re:
"In a normal distribution, the IQ range of one standard deviation above and below the mean (i.e., between 85 and 115) is where approximately 68% of all adults would fall."

Right. My 178, however has a “true rarity of occurance” of about one in a million, at the 99.9999th percentile. I get to question authority, not just regurgitate what I have been taught.
And, as in "Imagine,"... "I'm not the only one."

rpenner:

Could it be that "philosophical tripe" is just your opinion as a physicist with a very low opinion of philosophy of science and that your 'dissing' of the Ross paper simply confirms your physics/math elitism. You still mistake the map for the territory, apparently not philosophically astute enough to know the difference.
And are you “determined not to learn" anything from the volumes of papers published from the conferences held by the International Society for the Advanced Study of Spacetime?
Too much questioning of authority for you?

Liar. Your long interest in relativity has amounted to nothing. You're orbiting the dunce stool. You might change the subject to something you have the will to understand and can treat with intellectual honesty.
rpenner
QUOTE (Alfred Korzybski+1931)
If we consider an actual territory (a) say, Paris, Dresden, Warsaw, and build up a map (b​) in which the order of these cities would be represented as Dresden, Paris, Warsaw; to travel by such a map would be misguiding, wasteful of effort; In case of emergencies, it might be seriously harmful; We could say that such a map was 'not true'; or that the map had a structure not similar to the territory, structure to be defined in terms of relations and multidimensional order. We should notice that:
A)  A map may have a structure similar or dissimilar to the structure of the territory.
B​)  Two similar structures have similar 'logical' characteristics. Thus, if in a correct map, Dresden is given as between Paris and Warsaw, a similar relation is found in the actual territory.
C)  A map is not the territory.
D) An ideal map would contain the map of the map, the map of the map of the map ; endlessly. This characteristic was first discovered by Royce. We may call it self-reflexiveness.
Languages share with the map the above four characteristics.
...
C)  Words are not the things they represent.
...
The above unusually simple considerations lead to unexpectedly far-reaching consequences.
...
E)  From [above] - the only aim of 'knowledge' and science appears as the empirical search for, and verbal formulation of, structure.
F)  The only method for acquiring 'knowledge' is found in an empirical investigation of the potentially unknown structure of the world, ourselves included, only afterwards adjusting the structure of languages so that they would be similar, and so of maximum usefulness; instead of the delusional reversed order of ascribing to the world the structure of an inherited primitive language.
...
I) Mathematics appears as a very limited but the only language in existence, in the main similar in structure to the world around us and the nervous system.
J) From the study of mathematics, mathematical physics, and physics, we learn, and will continue to learn, the fundamentals of [multiordinal] structure. It is no mystery that all chemistry has become a branch of physics, all physics can be made a branch of geometry, all geometry a part of analysis, and all analysis a part of general semantics. The present work shows that the analysis of all human, problems of daily life or science becomes dependent on general semantics which on the verbal levels becomes generalized mathematics. Thus mathematics, mathematical physics, and physics become the most important disciplines from which we learn most about structure, - the only 'content of knowledge'.
Alfred Korzybski "A Non-Aristotelian System and its Necessity for Rigour in Mathematics and Physics," reprinted in Science and Sanity, pp. 747–761 (1933)

Thus, in context, "The map is not the territory" is a rejection of Platonic essentialism and embrace of empirical verification that the map matches the structure of the territory, that the language of the map is some form of mathematics, and to stop using bad maps.

QUOTE (William Goldman+1973)
"You keep using that word!" the Spaniard snapped. "I don't think it means what you think it does."

William Goldman, The Princess Bride (1973) [later a Major Motion Picture]

QUOTE (mik+May 1 2012, 09:08 PM)
This nails the difference between the philosophy that “the world” exists and has intrinsic, objective properties independent of observation/measurement... and that there is no reality independent of the latter:
Me:
QUOTE (mik+Apr 29 2012, 11:46 PM)
My “engagement” with that assertion has been that the map is not the territory. Shape is more than a geometric concept. It is an actual physical property of actual physical objects.
You:
QUOTE (rpenner+Apr 30 2012, 02:37 AM)
This sounds like Platonic essentialism to me.
“The shape of things” (and actual distances between them in the real world) does not depend on Platonic ideals.... or on relativity theory. Of course earth is not a perfect sphere, but rather nearly so. Nature’s properties are as they are. Nature doesn’t care about the theoretical distinction between "proper length" and "contracted length" or how it is measured... from at rest with a given object or from whatever extreme frames of reference. It stays as it is, independent of measurement and theory. Call that philos0phy whatever you like.
I think it is only you who have claimed my position is so ridiculous as to say "the world" does not exist and does not have objective properties. I have had very little to say of philosophical observers and measurements, when I prefer to refer to imaginary coordinate systems as systematic ways of labeling events in ways that the labels on the events (coordinates) make clear what is the structure (geometry) of the territory (space-time). Your embrace of presentism is not informed by the empirical rejection of Galilean relativity and thus its structure does not reflect the relativity of simultaneity and amounts to sterile solipsism where you don't care about the territory or the scouts making reports from parts unknown to you.

Platonic essentialism is anti-scientific. It leads to racial prejudice (in that it presupposes that there is an intrinsic, non-circumstantial expectation that X-people are different than Y-people) and claims that fish cannot evolve to non-fish (a classic case of the confusion of taxonomic labels for reality as emphasized in Neil Shubin's Your Inner Fish (2009) ) and that intuitive things are not necessary of study.

For example, the intuitive concept of "rigid" doesn't have a place in relativistic physics except as an abstraction when no acceleration is involved.

The geometric concept of "shape" that you are asserting as an Aristotelean primitive has been similarly demonstrated to be just a legend on a poor map. In Back to the Future, Part III (1990), Emmett "Doc" Brown puts his finger on your cognitive difficulty: "You're just not thinking fourth (sic) dimensionally!" Euclidean concepts of shape -- the square, the sphere, the line of fixed length -- these concepts don't map to the same four-dimensional concepts in Galilean relativity and special relativity. To the extent that Galilean relativity does not have the structure of the territory, we reject it and we reject the notion that a shorter length in motion must not be congruent to a longer length at rest.

In short, your use of "the map is not the territory" is shown to be sterile and empty sloganeering devoid of thoughtful consideration. You have disgraced yourself and your self-study of philosophy, math and physics. Start again.

QUOTE (mik+May 1 2012, 09:08 PM)
You:
QUOTE (rpenner+Apr 30 2012, 02:37 AM)
... you rely on nothing more than naked assertions.
Here is another “naked” one you have never addressed:
“The world” (including earth) was here long before mankind and his science, and will be here long after we are gone. it won’t change much during our brief occupation here. And it certainly doesn’t change with how we observe it, thought it clearly appears to change. Your philosophy to the contrary is extremely anthropomorphically centered. 'It is as we see it.'
Anthropogenic global warming and the extinction of the dodo are just two empirical facts that demonstrate that your assertion of about the inability of man to change the world is false. Extinction is forever. The assertion that the world changes because we observe it is your straw-man for my position that different coordinate systems give different labels to events and that the assumption of Galilean relativity where there is no relation between velocity and description of a rigid shape is empirically false. You have not, I need point out, not demonstrated that you have adopted the principle of relativity but you have not argued against it. Instead you have misunderstood it as an embrace of some weird philosophical position when it is the pragmatic observation that if the concept of absolute motion is either unknowable or meaningless then only relative motion is knowable and to the extent that physical laws are knowable they should only depend on relative motion. Yet we need coordinates to express these laws, so any inertial standard of rest is as good as any other. Therefore my yardstick may be moving at 200 km/s in one coordinate system AND in motion at 1000 km/s in another. In the first coordinate system it has a coordinate length short of a yard by 1/4500000 and in the other by 1/180000 but both are equally correct -- both descriptions of length AND movement are congruent.

QUOTE (mik+May 1 2012, 09:08 PM)
For Brucep; re:
QUOTE (Wikipedia+)
In a normal distribution, the IQ range of one standard deviation above and below the mean (i.e., between 85 and 115) is where approximately 68% of all adults would fall.
[from Wikipedia:Wechsler Adult Intelligence Scale (Standardization)]

Right. My 178, however has a “true rarity of occurance” of about one in a million, at the 99.9999th percentile. I get to question authority, not just regurgitate what I have been taught.
And, as in
QUOTE (John Lennon+1971)
Imagine, ...  I'm not the only one.
It's probably ill-advised to claim lack of facility with mathematics AND try to impress us with a particular unevidenced IQ score. It's probably ill-advised to get snippy with Bruce about the IQ score claim and misspell "occurrence" -- if you didn't get it for verbal or math skills, it doesn't seem very useful this "intelligence" of yours. It is definitely unwise to assume that the tails of the distribution are normally distributed out 5 sigmas. It's not clear at all how you get from 100 + 15 * 5.2 to where you are quoting "true rarity of occurance" from. It's more likely that you have been lied to and lack the faculties or inclination to find the truth on your own. http://www.ncbi.nlm.nih.gov/pubmed/19573277 http://askville.amazon.com/considered-smar...equestId=206618

Also, the authority of Aristotle and Plato held back Europe for a thousand years. Bacon, Newton, Darwin, Maxwell, Einstein, Korzybski, and myself are on the side that empiricism is the only authority in these matters. Some smart people elsewhere inform me that you aren't even doing philosophy here -- philosophy involves understanding, thinking and making persuasive arguments.

QUOTE (mik+May 1 2012, 09:08 PM)
rpenner:
QUOTE (synthsin75+Apr 30 2012, 12:02 AM)
There's nothing ad hominem about your gratuitously demonstrated naive and intuitive bias, nor your lack of demonstration of any understanding of the actual science or even some pretty basic concepts in philosophy. The power is completely your own to decide to quit refuting science with philosophical tripe and actually learn something. No amount of intelligence will help those who are determined not to learn.

Could it be that "philosophical tripe" is just your opinion as a physicist with a very low opinion of philosophy of science and that your 'dissing' of the Ross paper simply confirms your physics/math elitism. You still mistake the map for the territory, apparently not philosophically astute enough to know the difference.
And are you “determined not to learn" anything from the volumes of papers published from the conferences held by the International Society for the Advanced Study of Spacetime?
Too much questioning of authority for you?

Well 1) That wasn't me you were quoting.
2) You have done nothing to improve the standing of the philosophy of science. We know you aren't doing science and I am pretty sure that you aren't doing philosophy either.
3) Quoting a high IQ score is naked elitism and in this case abuse of math -- the IQ distribution at the high end is not normal.
4) Korzybski agrees more with me on the issue of whether the best meaning of "shape" is the intuitive one you cling to or the educated meaning I have explained.
5) You have sloganeered "the map is not the territory" and yet you seem ignorant of the content of Korzybski's paper or the meaning. Korzybski wanted people to learn the territory so that they might have better maps. Our special relativity maps are better than your Euclidean or Galilean maps.
6) I'm pretty sure that the International Society for the Advanced Study of Spacetime http://www.spacetimesociety.org/ was not introduced prior to your post and question why you bring them up as an example, when their front page is a paean to Minkowski's geometry of space-time.
7) You really aren't asking questions -- you are making unsupported claims.
brucep
QUOTE (rpenner+May 3 2012, 07:39 AM)
Alfred Korzybski "A Non-Aristotelian System and its Necessity for Rigour in Mathematics and Physics," reprinted in Science and Sanity, pp. 747–761 (1933)

Thus, in context, "The map is not the territory" is a rejection of Platonic essentialism and embrace of empirical verification that the map matches the structure of the territory, that the language of the map is some form of mathematics, and to stop using bad maps.

William Goldman, The Princess Bride (1973) [later a Major Motion Picture]

You: “The shape of things” (and actual distances between them in the real world) does not depend on Platonic ideals.... or on relativity theory. Of course earth is not a perfect sphere, but rather nearly so. Nature’s properties are as they are. Nature doesn’t care about the theoretical distinction between "proper length" and "contracted length" or how it is measured... from at rest with a given object or from whatever extreme frames of reference. It stays as it is, independent of measurement and theory. Call that philos0phy whatever you like.[/QUOTE] I think it is only you who have claimed my position is so ridiculous as to say "the world" does not exist and does not have objective properties. I have had very little to say of philosophical observers and measurements, when I prefer to refer to imaginary coordinate systems as systematic ways of labeling events in ways that the labels on the events (coordinates) make clear what is the structure (geometry) of the territory (space-time). Your embrace of presentism is not informed by the empirical rejection of Galilean relativity and thus its structure does not reflect the relativity of simultaneity and amounts to sterile solipsism where you don't care about the territory or the scouts making reports from parts unknown to you.

Platonic essentialism is anti-scientific. It leads to racial prejudice (in that it presupposes that there is an intrinsic, non-circumstantial expectation that X-people are different than Y-people) and claims that fish cannot evolve to non-fish (a classic case of the confusion of taxonomic labels for reality as emphasized in Neil Shubin's Your Inner Fish (2009) ) and that intuitive things are not necessary of study.

For example, the intuitive concept of "rigid" doesn't have a place in relativistic physics except as an abstraction when no acceleration is involved.

The geometric concept of "shape" that you are asserting as an Aristotelean primitive has been similarly demonstrated to be just a legend on a poor map. In Back to the Future, Part III (1990), Emmett "Doc" Brown puts his finger on your cognitive difficulty: "You're just not thinking fourth (sic) dimensionally!" Euclidean concepts of shape -- the square, the sphere, the line of fixed length -- these concepts don't map to the same four-dimensional concepts in Galilean relativity and special relativity. To the extent that Galilean relativity does not have the structure of the territory, we reject it and we reject the notion that a shorter length in motion must not be congruent to a longer length at rest.

In short, your use of "the map is not the territory" is shown to be sterile and empty sloganeering devoid of thoughtful consideration. You have disgraced yourself and your self-study of philosophy, math and physics. Start again.

Here is another “naked” one you have never addressed:
“The world” (including earth) was here long before mankind and his science, and will be here long after we are gone. it won’t change much during our brief occupation here. And it certainly doesn’t change with how we observe it, thought it clearly appears to change. Your philosophy to the contrary is extremely anthropomorphically centered. 'It is as we see it.'[/QUOTE]Anthropogenic global warming and the extinction of the dodo are just two empirical facts that demonstrate that your assertion of about the inability of man to change the world is false. Extinction is forever. The assertion that the world changes because we observe it is your straw-man for my position that different coordinate systems give different labels to events and that the assumption of Galilean relativity where there is no relation between velocity and description of a rigid shape is empirically false. You have not, I need point out, not demonstrated that you have adopted the principle of relativity but you have not argued against it. Instead you have misunderstood it as an embrace of some weird philosophical position when it is the pragmatic observation that if the concept of absolute motion is either unknowable or meaningless then only relative motion is knowable and to the extent that physical laws are knowable they should only depend on relative motion. Yet we need coordinates to express these laws, so any inertial standard of rest is as good as any other. Therefore my yardstick may be moving at 200 km/s in one coordinate system AND in motion at 1000 km/s in another. In the first coordinate system it has a coordinate length short of a yard by 1/4500000 and in the other by 1/180000 but both are equally correct -- both descriptions of length AND movement are congruent.

[from Wikipedia:Wechsler Adult Intelligence Scale (Standardization)]

Right. My 178, however has a “true rarity of occurance” of about one in a million, at the 99.9999th percentile. I get to question authority, not just regurgitate what I have been taught.
And, as in [/QUOTE] It's probably ill-advised to claim lack of facility with mathematics AND try to impress us with a particular unevidenced IQ score. It's probably ill-advised to get snippy with Bruce about the IQ score claim and misspell "occurrence" -- if you didn't get it for verbal or math skills, it doesn't seem very useful this "intelligence" of yours. It is definitely unwise to assume that the tails of the distribution are normally distributed out 5 sigmas. It's not clear at all how you get from 100 + 15 * 5.2 to where you are quoting "true rarity of occurance" from. It's more likely that you have been lied to and lack the faculties or inclination to find the truth on your own. http://www.ncbi.nlm.nih.gov/pubmed/19573277 http://askville.amazon.com/considered-smar...equestId=206618

Also, the authority of Aristotle and Plato held back Europe for a thousand years. Bacon, Newton, Darwin, Maxwell, Einstein, Korzybski, and myself are on the side that empiricism is the only authority in these matters. Some smart people elsewhere inform me that you aren't even doing philosophy here -- philosophy involves understanding, thinking and making persuasive arguments.

Could it be that "philosophical tripe" is just your opinion as a physicist with a very low opinion of philosophy of science and that your 'dissing' of the Ross paper simply confirms your physics/math elitism. You still mistake the map for the territory, apparently not philosophically astute enough to know the difference.
And are you “determined not to learn" anything from the volumes of papers published from the conferences held by the International Society for the Advanced Study of Spacetime?
Too much questioning of authority for you?[/QUOTE]
Well 1) That wasn't me you were quoting.
2) You have done nothing to improve the standing of the philosophy of science. We know you aren't doing science and I am pretty sure that you aren't doing philosophy either.
3) Quoting a high IQ score is naked elitism and in this case abuse of math -- the IQ distribution at the high end is not normal.
4) Korzybski agrees more with me on the issue of whether the best meaning of "shape" is the intuitive one you cling to or the educated meaning I have explained.
5) You have sloganeered "the map is not the territory" and yet you seem ignorant of the content of Korzybski's paper or the meaning. Korzybski wanted people to learn the territory so that they might have better maps. Our special relativity maps are better than your Euclidean or Galilean maps.
6) I'm pretty sure that the International Society for the Advanced Study of Spacetime http://www.spacetimesociety.org/ was not introduced prior to your post and question why you bring them up as an example, when their front page is a paean to Minkowski's geometry of space-time.
7) You really aren't asking questions -- you are making unsupported claims.

It's nice to have a 'real scholar' amongst us. Much appreciated.
Robittybob1
@BruceP - Others get told off for quoting long winded posts and not using it in your response.

It is truly remarkable the intensity that RPenner puts into his responses. An intensity that is beyond the rest of us.

In that state one would have to be careful not to burn-out. Take care.
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