References: I haven't googled any
But seriously, if dark energy is going to rip apart all mattter, can the universe expand at light speed?
One equation E=mc^2
References: I haven't googled any
But seriously, if dark energy is going to rip apart all mattter, can the universe expand at light speed?
References: I haven't googled any
But seriously, if dark energy is going to rip apart all mattter, can the universe expand at light speed?
Well it made me laugh. At least it made a prediction...
Are you thinking of this BM?
In Einstein’s theory, gravity is as an attractive force so, in general relativity, the expansion should slow down depending on the density of matter and energy in spacetime. As it doesn't seem to do so, we will have to look at the possibility of other forms of energy producing a repulsive gravity.
Jack Sarfatti see that 'energy' as being 'dark energy', this apparently is allowed by General relativity, even though belonging to 'special cases'. To explain the effects of dark energy he then look at vacuum energy, as it seems mathematically equivalent to the 'cosmological constant' (Einstein 1917). The idea behind this is a so called “vacuum coherence” which then would be a inflation field in 'disguise'. And the idea behind that :) is then based on Dirac’s theory of the electron, and would then be a similar effect to how a normal metal becomes a superconductor.
http://arxiv.org/abs/gr-qc/0602022 (2006) and http://arxiv.org/abs/0902.0032 (2009)
Or is it those space bubbles of 'false vacuum' you are considering?
Those seems to hinge on if the Higgs field exists?
http://www.historyoftheuniverse.com/falsvacu.html
Oh, I'm so lucky that I don't believe in it yet :)
But for the rest of you...
Beware of bubbles.
----------
Awh Sh*
E = mc2
Mean, very mean my man :)
Sorry, I mean mean^2 ::))
-------
Kind of like that one.
I mean, it works...
I will present it to the Nobel comity.
Enjoy ::))
In Einstein’s theory, gravity is as an attractive force so, in general relativity, the expansion should slow down depending on the density of matter and energy in spacetime. As it doesn't seem to do so, we will have to look at the possibility of other forms of energy producing a repulsive gravity.
Jack Sarfatti see that 'energy' as being 'dark energy', this apparently is allowed by General relativity, even though belonging to 'special cases'. To explain the effects of dark energy he then look at vacuum energy, as it seems mathematically equivalent to the 'cosmological constant' (Einstein 1917). The idea behind this is a so called “vacuum coherence” which then would be a inflation field in 'disguise'. And the idea behind that :) is then based on Dirac’s theory of the electron, and would then be a similar effect to how a normal metal becomes a superconductor.
http://arxiv.org/abs/gr-qc/0602022 (2006) and http://arxiv.org/abs/0902.0032 (2009)
Or is it those space bubbles of 'false vacuum' you are considering?
Those seems to hinge on if the Higgs field exists?
http://www.historyoftheuniverse.com/falsvacu.html
Oh, I'm so lucky that I don't believe in it yet :)
But for the rest of you...
Beware of bubbles.
----------
Awh Sh*
E = mc2
Mean, very mean my man :)
Sorry, I mean mean^2 ::))
-------
Kind of like that one.
I mean, it works...
I will present it to the Nobel comity.
Enjoy ::))
You didn't answer my question: If all the matter in the universe is destroyed by the push of dark energy, will the universe then expand at light speed?
Why do you say it will be destroyed, pushed apart I can see, but gravity still seems to be able to hold the galaxies together? if dark energy would be shown to be something similar to 'virtual particles' perhaps it could act on spacetime without being 'here', as it then might be outside the hold of Heisenberg's Uncertainty principle (HUP) time wise?
I'm not sure why you expect it to destroy all matter though?
------
sorry, saw that i wrote BM up there, meant BW:)
I'm not sure why you expect it to destroy all matter though?
------
sorry, saw that i wrote BM up there, meant BW:)
QUOTE (yor_on+Mar 13 2009, 10:50 PM)
Why do you say it will be destroyed, pushed apart I can see, but gravity still seems to be able to hold the galaxies together? if dark energy would be shown to be something similar to 'virtual particles' perhaps it could act on spacetime without being 'here', as it then might be outside the hold of Heisenberg's Uncertainty principle (HUP) time wise?
I'm not sure why you expect it to destroy all matter though?
------
sorry, saw that i wrote BM up there, meant BW:)
I you deliberately trying to make of my theory?
I'm not sure why you expect it to destroy all matter though?
------
sorry, saw that i wrote BM up there, meant BW:)
I you deliberately trying to make of my theory?
QUOTE (Beer w/Straw+Mar 12 2009, 07:20 AM)
But seriously, if dark energy is going to rip apart all mattter, can the universe expand at light speed?
Yes.
The light speed restriction is that of the relative speed of two objects 'through space'. Two objects may have a relative separation speed of say, 1/2c, and be so far apart that the two points of space they occupy are moving apart at a speed greater than 1/2c, so that their apparent separation speed is greater than c.
In fact, I believe you can have two objects which are stationary relative to each other but still be apparently separating faster than c due to the expansion.
The 'c' limit is a limit 'through space'. The expansion can make objects appear to break this 'limit'.
Now, fingers crossed that I didn't make any silly errors and that made sense!!!
(I struck through the silly bit. In fact, Dark Energy is easily overcome by gravity at relatively small distances and has no effect on structures even as big as galaxies. Only the large spaces between them.)
Yes.
The light speed restriction is that of the relative speed of two objects 'through space'. Two objects may have a relative separation speed of say, 1/2c, and be so far apart that the two points of space they occupy are moving apart at a speed greater than 1/2c, so that their apparent separation speed is greater than c.
In fact, I believe you can have two objects which are stationary relative to each other but still be apparently separating faster than c due to the expansion.
The 'c' limit is a limit 'through space'. The expansion can make objects appear to break this 'limit'.
Now, fingers crossed that I didn't make any silly errors and that made sense!!!
(I struck through the silly bit. In fact, Dark Energy is easily overcome by gravity at relatively small distances and has no effect on structures even as big as galaxies. Only the large spaces between them.)
Yep, totally so BM :)
But there is one thing I wonder over there (Well many in fact:)
That is where the 'force' or 'energy' to be able to push Galaxies apart comes from?
We have a lot of mass invested in every galaxy, think of the energy it would take just to push the milky way a meter or two. I wouldn't want to try it. Either this mysterious expansion is a consequence of what we too call 'energy' and then I have to wonder just how much energy there is inside that vacuum, or 'energy' is the wrong concept here.
As far as I see it, as soon as some point in space have 'materialized' due to expansion it will be a part of it, but this 'pushing' of mass may happen before it is a defined point?? It's a very strange concept to me having something moving galaxies without needing to expend anything.
But there is one thing I wonder over there (Well many in fact:)
That is where the 'force' or 'energy' to be able to push Galaxies apart comes from?
We have a lot of mass invested in every galaxy, think of the energy it would take just to push the milky way a meter or two. I wouldn't want to try it. Either this mysterious expansion is a consequence of what we too call 'energy' and then I have to wonder just how much energy there is inside that vacuum, or 'energy' is the wrong concept here.
As far as I see it, as soon as some point in space have 'materialized' due to expansion it will be a part of it, but this 'pushing' of mass may happen before it is a defined point?? It's a very strange concept to me having something moving galaxies without needing to expend anything.
QUOTE (yor_on+Mar 14 2009, 01:39 PM)
That is where the 'force' or 'energy' to be able to push Galaxies apart comes from?
First, that is a very good question which would earn at least a Nobel with an answer, I would think!
*After writing the paragraph below I re-read it and realised that it is pure speculation on my part, I guess an assumption that I have held for no particular reason. It would be good to get it confirmed/shot down...* PROCEED WITH SCEPTICISM! lol
Secondly, and perhaps slightly pedantically, I would be careful about thinking of it as 'pushing' galaxies apart. Any pushing through space would be doing work (work done = force x distance). I don't think that the energy which is causing space to expand is actually doing work on the galaxies, I think it is working at a more fundamental level, acting only on space itself, not on the galaxies.
First, that is a very good question which would earn at least a Nobel with an answer, I would think!
*After writing the paragraph below I re-read it and realised that it is pure speculation on my part, I guess an assumption that I have held for no particular reason. It would be good to get it confirmed/shot down...* PROCEED WITH SCEPTICISM! lol
Secondly, and perhaps slightly pedantically, I would be careful about thinking of it as 'pushing' galaxies apart. Any pushing through space would be doing work (work done = force x distance). I don't think that the energy which is causing space to expand is actually doing work on the galaxies, I think it is working at a more fundamental level, acting only on space itself, not on the galaxies.
So which one is it?
to Work or not to Work as Hamlet said:)
Can there be anything existing for a measurable time inside spacetime that won't follow work done = force x distance while creating a distance?
to Work or not to Work as Hamlet said:)
Can there be anything existing for a measurable time inside spacetime that won't follow work done = force x distance while creating a distance?
QUOTE (yor_on+Mar 14 2009, 04:20 PM)
So which one is it?
to Work or not to Work as Hamlet said:)
Can there be anything existing for a measurable time inside spacetime that won't follow work done = force x distance while creating a distance?
Ok, I'll try to be more precise, but I thin I'm pushing my boundaries again now.
work done = force applied in direction of motion x distance moved by applied force
My point is, if Dark Energy somehow moves 'points' of space further apart without imparting a force on the objects occupying that space (which I believe is the case), then no energy is being transferred to those objects. This is why I think that 'pushing galaxies' is a bad way to describe how Dark Energy works.
Unfortunately though, so little is known about Dark Energy (I even think that assuming it is is 'energy' in the sense that we use the word would be a mistake) that I think any conversation about this is pure speculation and metaphysics. If I'm wrong though I would love to learn more!
to Work or not to Work as Hamlet said:)
Can there be anything existing for a measurable time inside spacetime that won't follow work done = force x distance while creating a distance?
Ok, I'll try to be more precise, but I thin I'm pushing my boundaries again now.
work done = force applied in direction of motion x distance moved by applied force
My point is, if Dark Energy somehow moves 'points' of space further apart without imparting a force on the objects occupying that space (which I believe is the case), then no energy is being transferred to those objects. This is why I think that 'pushing galaxies' is a bad way to describe how Dark Energy works.
Unfortunately though, so little is known about Dark Energy (I even think that assuming it is is 'energy' in the sense that we use the word would be a mistake) that I think any conversation about this is pure speculation and metaphysics. If I'm wrong though I would love to learn more!
QUOTE (bm1957+Mar 14 2009, 10:15 AM)
...Dark Energy is easily overcome by gravity at relatively small distances and has no effect on structures even as big as galaxies. Only the large spaces between them.)
The exploration of dark energy was one reason alone to keep the Hubble space telescope in operation. WMAP, however, may do a better job of discerning dark energy. So NASA can feel free to crash the telescope on Farsight's head.
Dark energy is an enigma. A refreshing one for me from the constant idea of the Big Crunch theory. I can't say for certain if dark enrgy is really an 'energy.' To imagine an enrgy that powerful is... well scary.
I actually forget why I'm commenting...
What is wrong with my theory? It could happen you know!
The exploration of dark energy was one reason alone to keep the Hubble space telescope in operation. WMAP, however, may do a better job of discerning dark energy. So NASA can feel free to crash the telescope on Farsight's head.
Dark energy is an enigma. A refreshing one for me from the constant idea of the Big Crunch theory. I can't say for certain if dark enrgy is really an 'energy.' To imagine an enrgy that powerful is... well scary.
I actually forget why I'm commenting...
What is wrong with my theory? It could happen you know!
Ok :)
My point of view then. A vacuum is defined as consisting of 'nothing'. If you imagine a box wherein you create a vacuum, how would you do to add some more? Yep, you would try to 'pump out' what 'density' there might be left. Would that add a 'distance' to the inside of your box?
It wouldn't.
Here we are discussing just that phenomena, to somehow add a 'distance' to a existing vacuum that we call space. So how can that be? We probably (?) agree on that there is a 'distance' to what we see in space, and that it's mostly consisting of vacuum. But then again, we also agree on that the definition for 'distance' more seems a description of a relation between density, velocity, motion and acceleration, than a 'goldstandard' of its own:) As for the 'push' that I like to see it as, that also seems a problem of definition. I call that 'space' that comes into being(?) somehow, as belonging to our spacetime as soon as it has 'materialized'. That to me means that it has to obey all the 'laws' of spacetime, same as everything else. To be able to create that 'distance' vacuum must have some sort of 'force' it seems, as it can 'expand' a vacuum? As for the question of 'virtual particles' and the 'inherent energy' vacuum seems to hide, that goes hand in hand with this question it seems.
Yeah BW, in Einstein’s theory gravity is as an attractive force so in general relativity the expansion should slow down depending on the density of matter and energy in spacetime. As it doesn't seem to do that, we look at the possibility of other forms of energy producing a repulsive gravity. Jack Sarfatti, for example, sees that 'energy' as being 'dark energy', this apparently is allowed by General relativity, even though belonging to 'special cases'. To explain the effects of dark energy he then look at vacuum energy, as it seems mathematically equivalent to the 'cosmological constant' (Einstein 1917). The idea behind this is a so called “vacuum coherence” which then would be a inflation field in 'disguise'. And the idea behind that :) is then based on Dirac’s theory of the electron, and would then be a similar effect to how a normal metal becomes a superconductor.
Two pdf:s (2006) and (2009) ...
Here and here.
My point of view then. A vacuum is defined as consisting of 'nothing'. If you imagine a box wherein you create a vacuum, how would you do to add some more? Yep, you would try to 'pump out' what 'density' there might be left. Would that add a 'distance' to the inside of your box?
It wouldn't.
Here we are discussing just that phenomena, to somehow add a 'distance' to a existing vacuum that we call space. So how can that be? We probably (?) agree on that there is a 'distance' to what we see in space, and that it's mostly consisting of vacuum. But then again, we also agree on that the definition for 'distance' more seems a description of a relation between density, velocity, motion and acceleration, than a 'goldstandard' of its own:) As for the 'push' that I like to see it as, that also seems a problem of definition. I call that 'space' that comes into being(?) somehow, as belonging to our spacetime as soon as it has 'materialized'. That to me means that it has to obey all the 'laws' of spacetime, same as everything else. To be able to create that 'distance' vacuum must have some sort of 'force' it seems, as it can 'expand' a vacuum? As for the question of 'virtual particles' and the 'inherent energy' vacuum seems to hide, that goes hand in hand with this question it seems.
Yeah BW, in Einstein’s theory gravity is as an attractive force so in general relativity the expansion should slow down depending on the density of matter and energy in spacetime. As it doesn't seem to do that, we look at the possibility of other forms of energy producing a repulsive gravity. Jack Sarfatti, for example, sees that 'energy' as being 'dark energy', this apparently is allowed by General relativity, even though belonging to 'special cases'. To explain the effects of dark energy he then look at vacuum energy, as it seems mathematically equivalent to the 'cosmological constant' (Einstein 1917). The idea behind this is a so called “vacuum coherence” which then would be a inflation field in 'disguise'. And the idea behind that :) is then based on Dirac’s theory of the electron, and would then be a similar effect to how a normal metal becomes a superconductor.
Two pdf:s (2006) and (2009) ...
Here and here.
I didn't read those PDF's but could you tell me how they relate to my theory?
Added to my theory.
Since E=mc^2 and dark energy is going to rip apart all matter, it follows that it blows up entire galaxies. And blows up black holes at their centers like a huge atomic bomb.
How screwed up is that1
Since E=mc^2 and dark energy is going to rip apart all matter, it follows that it blows up entire galaxies. And blows up black holes at their centers like a huge atomic bomb.
How screwed up is that1
You haven't presented any 'theory' yet.
It sounds 'banging' though, whatever it might be.
It sounds 'banging' though, whatever it might be.
Baa!
I'm saving it for a PhD thesis: Zoom zoom universe with bigass explosions!
Sure it may be a gradual exploding of a galaxy, but black holes should go all at once - their stubborn
I'm saving it for a PhD thesis: Zoom zoom universe with bigass explosions!
Sure it may be a gradual exploding of a galaxy, but black holes should go all at once - their stubborn
What the?
How weird does this thing get!
Cosmologists estimate that the acceleration began roughly 5 billion years ago. Before that, it is thought that the expansion was decelerating, due to the attractive influence of dark matter and baryons.
http://en.wikipedia.org/wiki/Dark_energy
How weird does this thing get!
Cosmologists estimate that the acceleration began roughly 5 billion years ago. Before that, it is thought that the expansion was decelerating, due to the attractive influence of dark matter and baryons.
http://en.wikipedia.org/wiki/Dark_energy
Well I am not sure I hit the right thread, but I wanted to share these thoughts:
Now is we really sit inside Cosmic Bacground Radiation... then:
I have been trying to read J.A.Wheeler's and R.Feynman's "Interaction with the absorber as the mechanism of radiation". Of course, it is a difficult text for me, but would it be wrong to say, and why, that CBR is - just as authors name it, Dirac's incident EM field, the difference between advanced and retarded absorber fields, in favour of advanced.
That is to say, CBR is the part of absorber ( placed far away) ADVANCED field (that is coming to us before our charges require it) which is not compensated by retarded field generated by accelerated charges. So in essence, CBR is and extra , uncompensated prereaction of absorber ( which is defined as something rather shperical that absorbs everything and is enough far away) to what may happen inside it, so to say advanced field not compensated by fields of accelerated charged particles inside absorber.
Now, Wheeler/Feynmann says that the characteristics of absorber does not lead to any extra incident advanced fields except if it is deformed, has gaps, and fields outside it.They say that if absorber is perfect, it does not have any EM fields outside it. The model they use for absorber is either slow moving or chaotically moving charges ( as far as I have been able to understand).
What would happen, though, if the charges in absorber move fast and not totally chaotically? Would they be able to create extra advanced incident EM field that we would monitor as CBR?
Secondly, would existence of such incident field mark the existance of arrow of time inside absorber since obviously movements of charges that compensate CBR and movements that increase its effect would be than happening in different directions relative to direction of time set by absorber.
Article can be read here:
http://authors.library.caltech.edu/11095/1/WHErmp45.pdf
rpenner: I am doing a little double posting here
Now is we really sit inside Cosmic Bacground Radiation... then:
I have been trying to read J.A.Wheeler's and R.Feynman's "Interaction with the absorber as the mechanism of radiation". Of course, it is a difficult text for me, but would it be wrong to say, and why, that CBR is - just as authors name it, Dirac's incident EM field, the difference between advanced and retarded absorber fields, in favour of advanced.
That is to say, CBR is the part of absorber ( placed far away) ADVANCED field (that is coming to us before our charges require it) which is not compensated by retarded field generated by accelerated charges. So in essence, CBR is and extra , uncompensated prereaction of absorber ( which is defined as something rather shperical that absorbs everything and is enough far away) to what may happen inside it, so to say advanced field not compensated by fields of accelerated charged particles inside absorber.
Now, Wheeler/Feynmann says that the characteristics of absorber does not lead to any extra incident advanced fields except if it is deformed, has gaps, and fields outside it.They say that if absorber is perfect, it does not have any EM fields outside it. The model they use for absorber is either slow moving or chaotically moving charges ( as far as I have been able to understand).
What would happen, though, if the charges in absorber move fast and not totally chaotically? Would they be able to create extra advanced incident EM field that we would monitor as CBR?
Secondly, would existence of such incident field mark the existance of arrow of time inside absorber since obviously movements of charges that compensate CBR and movements that increase its effect would be than happening in different directions relative to direction of time set by absorber.
Article can be read here:
http://authors.library.caltech.edu/11095/1/WHErmp45.pdf
rpenner: I am doing a little double posting here
Chandra doesn't like me 
Comparing X-ray observations of distant and nearby clusters of galaxies, astronomers say they have found new, independent evidence for the existence of dark energy, the mysterious entity that is accelerating cosmic expansion. By combining the new data with that from several other studies, the team finds that dark energy appears to have maintained the same density over time, resembling Einstein’s cosmological constant.
http://www.sciencenews.org/view/generic/id...stantly_with_us
But at least I had fun with the thread
Actually this is real news BTW, pretty recent too.
Comparing X-ray observations of distant and nearby clusters of galaxies, astronomers say they have found new, independent evidence for the existence of dark energy, the mysterious entity that is accelerating cosmic expansion. By combining the new data with that from several other studies, the team finds that dark energy appears to have maintained the same density over time, resembling Einstein’s cosmological constant.
http://www.sciencenews.org/view/generic/id...stantly_with_us
But at least I had fun with the thread
Actually this is real news BTW, pretty recent too.
QUOTE (Beer w/Straw+Mar 16 2009, 05:33 PM)
I'm saving it for a PhD thesis: Zoom zoom universe with bigass explosions!
Hey, stop stealing my thesis titles! Now I'm going to have to go with "String theory, W T F is it and why should I care?" !
Hey, stop stealing my thesis titles! Now I'm going to have to go with "String theory, W T F is it and why should I care?" !
A National Plan for Isolating Surplus Phosphorous from Public Houses: Illumination in the Urinal
Drat -- the title is mine, but this idea, like so many others, has been written up already.
Article on Peak Phosphorous
Drat -- the title is mine, but this idea, like so many others, has been written up already.
Article on Peak Phosphorous
This article that I posted was dated Jan 3 2009 - 3 months old.
http://www.sciencenews.org/view/generic/id...stantly_with_us
I had a chat with a Math Major taking astronomy telling me the things he was taught like WMAP's indications that dark energy is growing in strength. Which is at odds with the posted article.
Now it could be that I (meaning the article) is right and that dark energy is not increasing in strength but that the finding is so new that it has been widely recognized yet.
I'm wondering if there is any more evidence to say that dark energy is not increasing in strength.
The new space telescope, not scheduled for launch for quite some time, that is mainly going to study supernovae would probably yield the answers, but unitlill then, is the article (or chandra x-ray observatory) proposing the only evidence that dark energy is not increasing in strength?
http://www.sciencenews.org/view/generic/id...stantly_with_us
I had a chat with a Math Major taking astronomy telling me the things he was taught like WMAP's indications that dark energy is growing in strength. Which is at odds with the posted article.
Now it could be that I (meaning the article) is right and that dark energy is not increasing in strength but that the finding is so new that it has been widely recognized yet.
I'm wondering if there is any more evidence to say that dark energy is not increasing in strength.
The new space telescope, not scheduled for launch for quite some time, that is mainly going to study supernovae would probably yield the answers, but unitlill then, is the article (or chandra x-ray observatory) proposing the only evidence that dark energy is not increasing in strength?
I had a similar discussion with Quatermass a little while ago.
As far as I know, the evidence is that the expansion of the universe is accelerating. But as far as I can make out, this does not necessarily imply that Dark Energy is getting stronger. A uniform constant force would produce similar effects and until we have even a basic understanding of DE, it is pointless to speculate about how any force it produces changes... simply because we have no real idea about how it is distributed and exactly what it acts on.
But that's only my point of view; it would be good to get a more 'authoritative' perspective! (Oh, and I couldn't open the link from work, so I'm commenting blind on this one.)
As far as I know, the evidence is that the expansion of the universe is accelerating. But as far as I can make out, this does not necessarily imply that Dark Energy is getting stronger. A uniform constant force would produce similar effects and until we have even a basic understanding of DE, it is pointless to speculate about how any force it produces changes... simply because we have no real idea about how it is distributed and exactly what it acts on.
But that's only my point of view; it would be good to get a more 'authoritative' perspective! (Oh, and I couldn't open the link from work, so I'm commenting blind on this one.)
Thanks BM, but I think my question should be asked elsewhere
QUOTE (bm1957+Mar 14 2009, 09:43 PM)
Ok, I'll try to be more precise, but I thin I'm pushing my boundaries again now.
work done = force applied in direction of motion x distance moved by applied force
My point is, if Dark Energy somehow moves 'points' of space further apart without imparting a force on the objects occupying that space (which I believe is the case), then no energy is being transferred to those objects. This is why I think that 'pushing galaxies' is a bad way to describe how Dark Energy works.
Unfortunately though, so little is known about Dark Energy (I even think that assuming it is is 'energy' in the sense that we use the word would be a mistake) that I think any conversation about this is pure speculation and metaphysics. If I'm wrong though I would love to learn more!
Well. I guess you could see it as something not 'pushing' at all if you liked?
If you have a 'distance-less' field :) acting on SpaceTime in a one-way direction disallowing 'interactions' it may not need any 'force'. That is if what we deem to be forces only are being applicable inside Spacetime.
We use 'time' to measure about anything, with the possible exception of those 'one-dimensional' strings, right? And if you define something without a distance I doubt you will be able to define an arrow of time to it. And with no single arrow to it, as we see in a Feynman diagram, then what we see as causality chains might be easier understood as whole 'processes' emerging into Spacetime.
But what would that make of our concept of forces?
work done = force applied in direction of motion x distance moved by applied force
My point is, if Dark Energy somehow moves 'points' of space further apart without imparting a force on the objects occupying that space (which I believe is the case), then no energy is being transferred to those objects. This is why I think that 'pushing galaxies' is a bad way to describe how Dark Energy works.
Unfortunately though, so little is known about Dark Energy (I even think that assuming it is is 'energy' in the sense that we use the word would be a mistake) that I think any conversation about this is pure speculation and metaphysics. If I'm wrong though I would love to learn more!
Well. I guess you could see it as something not 'pushing' at all if you liked?
If you have a 'distance-less' field :) acting on SpaceTime in a one-way direction disallowing 'interactions' it may not need any 'force'. That is if what we deem to be forces only are being applicable inside Spacetime.
We use 'time' to measure about anything, with the possible exception of those 'one-dimensional' strings, right? And if you define something without a distance I doubt you will be able to define an arrow of time to it. And with no single arrow to it, as we see in a Feynman diagram, then what we see as causality chains might be easier understood as whole 'processes' emerging into Spacetime.
But what would that make of our concept of forces?
wow
QUOTE (Beer w/Straw+Oct 7 2009, 08:26 PM)
wow
You started it.
You started it.
QUOTE (Zebdraer+Oct 9 2009, 09:42 PM)
how the the equation mc2 derived ? I thought mass could not propagate ata the vilocity of light.
But what if there was no matter in the universe?
[Ben Ito, deleted again.]
But what if there was no matter in the universe?
[Ben Ito, deleted again.]
Where in the world did you get that dark energy does that? 
I have never heard that about dark energy.
EVER.
Q: Was this all meant as a joke?
I have never heard that about dark energy.
EVER.
Q: Was this all meant as a joke?
Btw, in relativity m is constant. c is constant and
therefore since:
(1 - v^2/c^2)/(1 - v^2/c^2) = 1/(1 - v^2/c^2) - (v^2/c^2)/(1 - v^2/c^2) = 1
then
1/(1 - v^2/c^2) = 1 + (v^2/c^2)/(1 - v^2/c^2)
then since m and c are constants
(mc^2)^2/(1 - v^2/c^2) = (mc^2)^2 + (mvc)^2/(1 - v^2/c^2)
or
(γmc^2)^2= (mc^2)^2 + (γmvc)^2
Or since E = γmc^2 and p = γmv
E^2= (mc^2)^2 + (pc)^2
Which shows E = mc^2 only when p (and therefore v) is zero.
Einstein figured out this relation from his initial description of the radiation, showing if that a atom gave off light in equal and opposite directions in its rest frame, then it would stay at rest but its mass must go down, and this must be consistent for all observers.
http://wien.cs.jhu.edu/AnnusMirabilis/AeRe...icles/e_mc2.pdf
therefore since:
(1 - v^2/c^2)/(1 - v^2/c^2) = 1/(1 - v^2/c^2) - (v^2/c^2)/(1 - v^2/c^2) = 1
then
1/(1 - v^2/c^2) = 1 + (v^2/c^2)/(1 - v^2/c^2)
then since m and c are constants
(mc^2)^2/(1 - v^2/c^2) = (mc^2)^2 + (mvc)^2/(1 - v^2/c^2)
or
(γmc^2)^2= (mc^2)^2 + (γmvc)^2
Or since E = γmc^2 and p = γmv
E^2= (mc^2)^2 + (pc)^2
Which shows E = mc^2 only when p (and therefore v) is zero.
Einstein figured out this relation from his initial description of the radiation, showing if that a atom gave off light in equal and opposite directions in its rest frame, then it would stay at rest but its mass must go down, and this must be consistent for all observers.
http://wien.cs.jhu.edu/AnnusMirabilis/AeRe...icles/e_mc2.pdf
In good keeping with my impulsiveness (as I have a kickass PC and video games to play.) I believe this in reference to the quote I made:
CODE
QUOTE (Zebdraer @ Oct 9 2009, 09:42 PM)
how the the equation mc2 derived ? I thought mass could not propagate ata the vilocity of light.
how the the equation mc2 derived ? I thought mass could not propagate ata the vilocity of light.
In which I avoided the first sentence and concentrated on the second. With the rule in mind that physical theories must make observable predictions...
At least I was able to entertain, as was a primary motive of this thread, with the thought that dark energy will rip apart matter even subatomic particles.
But I still don't know why you deleted his initial post and edited the posters name
QUOTE (bm1957+Mar 14 2009, 10:15 AM)
Yes.
The light speed restriction is that of the relative speed of two objects 'through space'. Two objects may have a relative separation speed of say, 1/2c, and be so far apart that the two points of space they occupy are moving apart at a speed greater than 1/2c, so that their apparent separation speed is greater than c.
In fact, I believe you can have two objects which are stationary relative to each other but still be apparently separating faster than c due to the expansion.
The 'c' limit is a limit 'through space'. The expansion can make objects appear to break this 'limit'.
Now, fingers crossed that I didn't make any silly errors and that made sense!!!
(I struck through the silly bit. In fact, Dark Energy is easily overcome by gravity at relatively small distances and has no effect on structures even as big as galaxies. Only the large spaces between them.)
Since no massive object can attain c, the separation speed can only be <2c.
It can certainly be bigger than c.
The light speed restriction is that of the relative speed of two objects 'through space'. Two objects may have a relative separation speed of say, 1/2c, and be so far apart that the two points of space they occupy are moving apart at a speed greater than 1/2c, so that their apparent separation speed is greater than c.
In fact, I believe you can have two objects which are stationary relative to each other but still be apparently separating faster than c due to the expansion.
The 'c' limit is a limit 'through space'. The expansion can make objects appear to break this 'limit'.
Now, fingers crossed that I didn't make any silly errors and that made sense!!!
(I struck through the silly bit. In fact, Dark Energy is easily overcome by gravity at relatively small distances and has no effect on structures even as big as galaxies. Only the large spaces between them.)
Since no massive object can attain c, the separation speed can only be <2c.
It can certainly be bigger than c.
QUOTE (Trout+Oct 14 2009, 01:52 PM)
Since no massive object can attain c, the separation speed can only be <2c.
It can certainly be bigget than c.
relative to what?
It can certainly be bigget than c.
relative to what?
QUOTE (buttershug+Oct 14 2009, 02:02 PM)
relative to what?
Relative to the frame where the speeds of the two separating objects are being measured.
Relative to the frame where the speeds of the two separating objects are being measured.
Exactly. For a symmetrical situation, the observer in the middle might see both receding at speed u, and thus a separation speed of 2u, which might figure into to some calculation. (A certain circular ring is measured to have the radius expand at 0.9c. By how much does its diameter grow after 1 second of growth?) But relativity says no information travels at that speed. And the the two separating endpoints, and observer there would calculate the separation speed at v = (2u)/(1 + u^2/c^2)
If using simple algebra, v = (2u)/(1 + u^2/c^2) = c - (c-u)^2/(c + u^2/c) which is slower than c if u is.
If using simple algebra, v = (2u)/(1 + u^2/c^2) = c - (c-u)^2/(c + u^2/c) which is slower than c if u is.
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