Ok i was wondering why didnt all of the stars and stuff insinerate the planet stuff if it was all in one place at first?
Also all of the matter and energy and atoms, were did they come from?
Have they ever been able to triangulate the point in which everything blew from?
My understanding is that it was all star stuff at first... And the planet stuff was created when the first stars burned themselved out.
"We are stardust." - Joni Mitchell
"We are stardust." - Joni Mitchell
QUOTE (Your fellow human (yfh)+Nov 14 2005, 12:56 PM)
Ok i was wondering why didnt all of the stars and stuff insinerate the planet stuff if it was all in one place at first?
Also all of the matter and energy and atoms, were did they come from?
Have they ever been able to triangulate the point in which everything blew from?
It's my understanding...
All the "stuff" initially was all light elements (H, He...) the heavier elements came from the second and succeeding generations of stars dying and exploding, ejecting the heavier elements to be used by the planets at a later time. A circle of life type of thing.
The big bang does not deal with pre-bang only post-bang.
There is no "point" because universe did not exist pre-bang. The "point" can be thought of as occupying the entire universe. So the universe has no center and no edge. There is an observational limit defined by the time the universe has existed. You can't see 13B light-years in a universe that is only 12.5B years old.
Also all of the matter and energy and atoms, were did they come from?
Have they ever been able to triangulate the point in which everything blew from?
It's my understanding...
All the "stuff" initially was all light elements (H, He...) the heavier elements came from the second and succeeding generations of stars dying and exploding, ejecting the heavier elements to be used by the planets at a later time. A circle of life type of thing.
The big bang does not deal with pre-bang only post-bang.
There is no "point" because universe did not exist pre-bang. The "point" can be thought of as occupying the entire universe. So the universe has no center and no edge. There is an observational limit defined by the time the universe has existed. You can't see 13B light-years in a universe that is only 12.5B years old.
i thought that stars turned into black holes when they burned out and that they didnt turn into matter.
Thanks for replies so far buddies
Thanks for replies so far buddies
The Big bang is pretty complex and I'm sure others will correct me. I left a wee bit out.
At the very start there were no planets, stars, or even elements. It was a soup of energy and fundamental particles spreading outwards. As it spread out it cooled, allowing protons and then hydrogen and (helium?) to form. Eventually these were attracted to each other under gravity, forming stars. Some of the largest stars blew up in a supernova at the end of their life rather than quietly fade away. The supernova created all the heavier elements from which most planets are made of.
Some of the very very largest stars could form blackholes, but that is a rare occurance and requires unusual circumstances I believe.
I think krreagan is right, there is no "center" of the universe due to Einsteins general relativity. We are at the center of a sphere we can see, which is the radius of the speed of light times the age of the universe. Other matter exists outside that sphere but we can not see it.
As for the big bang itself, well nobody knows what it is, why, or how, so if some other being created it thats a philosophical question not a scientific one until a new theory sheds light on the big bang.
At the very start there were no planets, stars, or even elements. It was a soup of energy and fundamental particles spreading outwards. As it spread out it cooled, allowing protons and then hydrogen and (helium?) to form. Eventually these were attracted to each other under gravity, forming stars. Some of the largest stars blew up in a supernova at the end of their life rather than quietly fade away. The supernova created all the heavier elements from which most planets are made of.
Some of the very very largest stars could form blackholes, but that is a rare occurance and requires unusual circumstances I believe.
I think krreagan is right, there is no "center" of the universe due to Einsteins general relativity. We are at the center of a sphere we can see, which is the radius of the speed of light times the age of the universe. Other matter exists outside that sphere but we can not see it.
As for the big bang itself, well nobody knows what it is, why, or how, so if some other being created it thats a philosophical question not a scientific one until a new theory sheds light on the big bang.
QUOTE (Your fellow human (yfh)+Nov 14 2005, 05:08 PM)
i thought that stars turned into black holes when they burned out and that they didnt turn into matter.
Thanks for replies so far buddies
If memory serves...
Only very large stars turn into black holes due to their mass and the fact that eventually the nuclear forces from the star burning can no longer hold up the stars mass, so it collapses into a black hole. Smaller stars go through one of many possible life profiles, a couple of which end in the star blowing off most of the matter which has been "burned" into heavier elements and what remains is a neutron star (which is almost as weird as a black hole).
Krreagan
Thanks for replies so far buddies
If memory serves...
Only very large stars turn into black holes due to their mass and the fact that eventually the nuclear forces from the star burning can no longer hold up the stars mass, so it collapses into a black hole. Smaller stars go through one of many possible life profiles, a couple of which end in the star blowing off most of the matter which has been "burned" into heavier elements and what remains is a neutron star (which is almost as weird as a black hole).
Krreagan
Ok thanks for clerifications.
Now i know that theory atleast!
Weather someone wants to say things like that happened by themselves or
weather it was done by the all-mighty is a matter of opinion.
I naturaly guess that there iz a God above all things,
and hopefuly im right and he has some sort of good plans for the future.
I dunno though, we will see.
QUOTE
It was a soup of energy and fundamental particles spreading outwards.
Now i know that theory atleast!
Weather someone wants to say things like that happened by themselves or
weather it was done by the all-mighty is a matter of opinion.
I naturaly guess that there iz a God above all things,
and hopefuly im right and he has some sort of good plans for the future.
I dunno though, we will see.
it is very possible that the universe as we know it may have been here more than once,I also feel it is possible that there may be an outer border to it.
and beyond this border there is totally nothing,where not even the presents of time can exists.
it may be possible that the universe in general may be made up of more positive
energy than negative energy.thus causing the border affect.
and beyond the border the negative out ways the positive matter.
causing a Resistance to anything of positive form.
thus explaining the black hole thory..or adding to the theory
black holes may be a actual hole in the universe leading to the area beyond
the universe's outer dimension. a door to the outer universe or the Field of negativity,or total nothingness.
and beyond this border there is totally nothing,where not even the presents of time can exists.
it may be possible that the universe in general may be made up of more positive
energy than negative energy.thus causing the border affect.
and beyond the border the negative out ways the positive matter.
causing a Resistance to anything of positive form.
thus explaining the black hole thory..or adding to the theory
black holes may be a actual hole in the universe leading to the area beyond
the universe's outer dimension. a door to the outer universe or the Field of negativity,or total nothingness.
QUOTE
As for the big bang itself, well nobody knows what it is, why, or how, so if some other being created it thats a philosophical question not a scientific one until a new theory sheds light on the big bang.
Thats why the catholic church didn't take long to support the big bang theory. It is, in essence, a creationist theory, or at least leaves the door WIDE OPEN to be interpretted as a creationist theory.
QUOTE (->
| QUOTE |
| As for the big bang itself, well nobody knows what it is, why, or how, so if some other being created it thats a philosophical question not a scientific one until a new theory sheds light on the big bang. |
Thats why the catholic church didn't take long to support the big bang theory. It is, in essence, a creationist theory, or at least leaves the door WIDE OPEN to be interpretted as a creationist theory.
Weather someone wants to say things like that happened by themselves or
weather it was done by the all-mighty is a matter of opinion.
You got it right YFH, there are arguements for each side (god vs no god) but they are arguements, not evidence or proof.
About black holes. There is actually a lot of things scientists don't understand about black holes. Even recently, the neccessary mass of a star needed to form a black hole is not concrete knowledge.
Check out this link
SPACE.com
freemindman has asked some interesting questions. Mostly philosophical, but interesting. I have heard different things about the geometry of the universe (my favorite is the idea of a donut (torus) shaped universe). I think the most interesting idea I have hear centers around the concept that we might live in a finite, unbounded universe, and that it is actually much smaller than the 13.6 billion years old we think it is. That because we are unbounded, light from a star might make two loops around the universe and we would see it twice, thinking it is two different stars, at different distances away. For another look at this idea, imagine being an ant on a large spool of thread. You would think there were many pieces of string under your feet, but you would not know that they were all connected if you did not know the geometry of the spool.
Steveo,
I picked this idea up recently, after reading "A Brief History of Time" - but it didn't mention the latter part, regarding the possibly younger age of the universe.
I've never formally studied physics (apart from some stuff on motion and electricity, which I didn't understand, at high school), so correct me if I'm wrong here ... but all the stars we see undergo red-shift, i.e. they are moving away from us. If we saw the light twice in one direction, i.e. it goes past us, "loops round" to the other side, and meets us the next time round (if you get me ...), so we see it twice ... well, if we looked the other way, wouldn't we see the same star moving towards us? Er, I hope this makes sense. It seems logical to me, but there may well be a great reason for it to be wrong.
Cheers
Kaeroll
QUOTE
I think the most interesting idea I have hear centers around the concept that we might live in a finite, unbounded universe,
I picked this idea up recently, after reading "A Brief History of Time" - but it didn't mention the latter part, regarding the possibly younger age of the universe.
I've never formally studied physics (apart from some stuff on motion and electricity, which I didn't understand, at high school), so correct me if I'm wrong here ... but all the stars we see undergo red-shift, i.e. they are moving away from us. If we saw the light twice in one direction, i.e. it goes past us, "loops round" to the other side, and meets us the next time round (if you get me ...), so we see it twice ... well, if we looked the other way, wouldn't we see the same star moving towards us? Er, I hope this makes sense. It seems logical to me, but there may well be a great reason for it to be wrong.
Cheers
Kaeroll
Hi Kaeroll.
I am impressed! Very impressed indeed! But not surprised. I have had occasion to mention before elsewhere that a layperson's/non-professional's perspective often yields insights far more to the point than many a 'professional expert'-----in many a field!
Thank you for providing the latest proof of the validity of my view that 'layperson/non-professional' involvement plus Occam's Razor plus Frequent 'Reality Checks' are CRUCIAL to the proper development of ANY theory/model.
Your surmise/observation is indeed correct; and very telling for all those finite-yet-unbounded-Universe scenarios. The receding stars' light that shines AWAY from the observer would indeed (according to that f-y-u-U scenario) then be constrained to come around and 'hit' that observer from 'behind'...and since (as you observe) the star is receding in the AWAY direction, then that 'looped-trajectory' light hitting the observer from behind should be BLUE-SHIFTED because the receding star would, in effect, be moving in the same direction as that AWAY-directed light that hits us from 'behind'!
So if all the distant galaxies are receding from us, they should be red-shifted AND blue-shifted SIMULTANEOUSLY....and the only way we could reconcile that, would be if what we observe ALL AROUND at a distance is actually an 'averaged-out' shift. But of course, that would mean the light frequencies/wavelengths we ascribe to distant astronomical body elements/constituents, and to the same elements/constituents in our laboratories, should ALL be 'consistently' DIFFERENT.
For someone professing ignorance of physics, you (like many other 'laypersons' I've encountered in these fora) certainly seem to have the wherewithal to find the crucial point of the matters you DO ponder!
You've made my day, Kaeroll! Thanks.
RealityCheck.
.
I am impressed! Very impressed indeed! But not surprised. I have had occasion to mention before elsewhere that a layperson's/non-professional's perspective often yields insights far more to the point than many a 'professional expert'-----in many a field!
Thank you for providing the latest proof of the validity of my view that 'layperson/non-professional' involvement plus Occam's Razor plus Frequent 'Reality Checks' are CRUCIAL to the proper development of ANY theory/model.
Your surmise/observation is indeed correct; and very telling for all those finite-yet-unbounded-Universe scenarios. The receding stars' light that shines AWAY from the observer would indeed (according to that f-y-u-U scenario) then be constrained to come around and 'hit' that observer from 'behind'...and since (as you observe) the star is receding in the AWAY direction, then that 'looped-trajectory' light hitting the observer from behind should be BLUE-SHIFTED because the receding star would, in effect, be moving in the same direction as that AWAY-directed light that hits us from 'behind'!
So if all the distant galaxies are receding from us, they should be red-shifted AND blue-shifted SIMULTANEOUSLY....and the only way we could reconcile that, would be if what we observe ALL AROUND at a distance is actually an 'averaged-out' shift. But of course, that would mean the light frequencies/wavelengths we ascribe to distant astronomical body elements/constituents, and to the same elements/constituents in our laboratories, should ALL be 'consistently' DIFFERENT.
For someone professing ignorance of physics, you (like many other 'laypersons' I've encountered in these fora) certainly seem to have the wherewithal to find the crucial point of the matters you DO ponder!
You've made my day, Kaeroll! Thanks.
RealityCheck.
.
QUOTE
For someone professing ignorance of physics, you (like many other 'laypersons' I've encountered in these fora) certainly seem to have the wherewithal to find the crucial point of the matters you DO ponder!
You've made my day, Kaeroll! Thanks.
You've made my day, Kaeroll! Thanks.
I think its a good physical common sense. Many 'handymen' are like this even if they couldn't do the math if their life depended on it. And them many 'analytical experts' in real life couldn't make an estimate to do it right if their life depended on it. Kind of funny I think....and I have often made the claim that NFL QB's are the fastest physicists in the world haha.
QUOTE (->
| QUOTE |
| For someone professing ignorance of physics, you (like many other 'laypersons' I've encountered in these fora) certainly seem to have the wherewithal to find the crucial point of the matters you DO ponder! You've made my day, Kaeroll! Thanks. |
I think its a good physical common sense. Many 'handymen' are like this even if they couldn't do the math if their life depended on it. And them many 'analytical experts' in real life couldn't make an estimate to do it right if their life depended on it. Kind of funny I think....and I have often made the claim that NFL QB's are the fastest physicists in the world haha.
I've never formally studied physics (apart from some stuff on motion and electricity, which I didn't understand, at high school), so correct me if I'm wrong here ... but all the stars we see undergo red-shift, i.e. they are moving away from us. If we saw the light twice in one direction, i.e. it goes past us, "loops round" to the other side, and meets us the next time round (if you get me ...), so we see it twice ... well, if we looked the other way, wouldn't we see the same star moving towards us? Er, I hope this makes sense. It seems logical to me, but there may well be a great reason for it to be wrong.
Unlike reality check I do think your wrong, although its a very fair question. I never really thought about this until now, but I think I have a good analogy to properly explain why it would still be a redshift in all directions.
Think of me and you sitting on opposite sides of a barely inflated balloon. Now, the balloon gets inflated (ie. the universe is expanding). The distance between you and I (on the surface) increases in both directions. So in either direction I look at you you appear to be getting farther and farther away from me. This would also explain why the second loop around you viewed the star it would be even more red shifted because the light would have to travel twice around, but the second time would be extra expansion to 'fight through'.
I am not an expert on cosmology, and I doubt that this idea is any leading candidate for the geometry of the universe, but I enjoy pondering this idea more than others. It would also be very difficult to determine if two stars, or galaxies or whatever were the same, even though on appeared to be much farther away.
Realitycheck, I also hope this clears things up for you too.
Hi Steveo!
You are correct, I was wrong. I think I made one too many assumptions when placing 'boundary conditions' to the scenario Kaeroll (and I) was contemplating. I'll explain the insights Kaeroll's observations elicited, which I should also have explained and didn't.
(1) In the case where 'you' and 'me' are placed DIAMETRICALLY OPPOSITE each other on your inflating balloon, the light on its INITIAL trip from 'you' to 'me' along the surface of that balloon is identically 'shifted' IN ALL DIRECTIONS in relation to 'me'----seeing as how 'your' position on the balloon surface is exactly opposite mine just as on the earth 'globe' surface the 'north pole' is diametrically opposite 'south pole'. So, you see, just as the ‘great-circle’ lines radiate and converge from one pole to the other on a globe, so would there be a virtually INFINITE number of IDENTICAL 'images' of 'you' arriving where 'me' is. In fact, such a scenario would result in 'your' image-lines of light 'washing' into my positions from all directions to form one infinitely 'bloated' and all-encompassing image of 'you' EVERYWHERE I LOOKED; practically ‘engulfed’ by an all-pervading image of ‘you’. Since we don't see every galaxy's infinitely-bloated images washing over us, then a 'finite but bounded' universe cannot be in reality what we are experiencing. You see?
(2) In the case where 'you' and 'me' are NOT diametrically opposite, then the situation would be that 'your' ACTUAL position would be 'closer' to 'me' in one direction (looking along the then SOLE 'great circle' line connecting us); and so be further away in the other direction (along that same 'great circle' line). In which case your RECESSION from me would be ASYMMETRICAL and so perceived 'differently-shifted' depending on which direction (along the great-circle line) 'me' was looking at 'you' (ie, 'me' looking front/behind along that line). Do you see?
I DO see what you tried to say about NOT seeing 'you' coming TOWARDS 'me' from the other direction. But if we COMBINE an A-SYMMETRIC RECESSION BALLOON MODEL, and then compare the two images in that case, they WOULD, as you say, STILL both be 'receding' and shifted', but DIFFERENTLY SO AGAIN from Kaerolls comparison of the single/twice-round 'image' in the SYMMETRIC RECESSION case. So I agree with what you said.
(3) In the case where a star was JUST MOVING away from Kaeroll in the ABSENCE OF SPACE EXPANSION, then the star's light hitting her from the other direction, after curving around ONCE in a 'finite but unbounded' universe, WOULD INDEED make the star appear to be APPROACHING from that direction while receding from the other direction. But again, that supposes a 'finite but unbounded' universe WITHOUT GLOBAL SPACE EXPANSION.
This is the sort of 'complication' that creeps in to such 'finite but unbounded' scenarios, ESPECIALLY WHEN COMBINED WITH RECESSION purporting to be GLOBAL rather than LOCAL (and possibly hence ACTUALLY ASYMMETRIC). But you see the aspect which Kaeroll was pondering was 'simplistic' yet 'profound' within the context, even though Kaeroll only mentioned the 'twice-around' bit.
Good luck to us all, I say! I think Kaeroll has just opened a little 'finite but unbounded' PANDORA'S BOX, hehehe. Thanks again, Kaeroll! And good 'reality check' there for me too, Steveo; thanks!
Your friend in science: RealityCheck.
.
You are correct, I was wrong. I think I made one too many assumptions when placing 'boundary conditions' to the scenario Kaeroll (and I) was contemplating. I'll explain the insights Kaeroll's observations elicited, which I should also have explained and didn't.
(1) In the case where 'you' and 'me' are placed DIAMETRICALLY OPPOSITE each other on your inflating balloon, the light on its INITIAL trip from 'you' to 'me' along the surface of that balloon is identically 'shifted' IN ALL DIRECTIONS in relation to 'me'----seeing as how 'your' position on the balloon surface is exactly opposite mine just as on the earth 'globe' surface the 'north pole' is diametrically opposite 'south pole'. So, you see, just as the ‘great-circle’ lines radiate and converge from one pole to the other on a globe, so would there be a virtually INFINITE number of IDENTICAL 'images' of 'you' arriving where 'me' is. In fact, such a scenario would result in 'your' image-lines of light 'washing' into my positions from all directions to form one infinitely 'bloated' and all-encompassing image of 'you' EVERYWHERE I LOOKED; practically ‘engulfed’ by an all-pervading image of ‘you’. Since we don't see every galaxy's infinitely-bloated images washing over us, then a 'finite but bounded' universe cannot be in reality what we are experiencing. You see?
(2) In the case where 'you' and 'me' are NOT diametrically opposite, then the situation would be that 'your' ACTUAL position would be 'closer' to 'me' in one direction (looking along the then SOLE 'great circle' line connecting us); and so be further away in the other direction (along that same 'great circle' line). In which case your RECESSION from me would be ASYMMETRICAL and so perceived 'differently-shifted' depending on which direction (along the great-circle line) 'me' was looking at 'you' (ie, 'me' looking front/behind along that line). Do you see?
I DO see what you tried to say about NOT seeing 'you' coming TOWARDS 'me' from the other direction. But if we COMBINE an A-SYMMETRIC RECESSION BALLOON MODEL, and then compare the two images in that case, they WOULD, as you say, STILL both be 'receding' and shifted', but DIFFERENTLY SO AGAIN from Kaerolls comparison of the single/twice-round 'image' in the SYMMETRIC RECESSION case. So I agree with what you said.
(3) In the case where a star was JUST MOVING away from Kaeroll in the ABSENCE OF SPACE EXPANSION, then the star's light hitting her from the other direction, after curving around ONCE in a 'finite but unbounded' universe, WOULD INDEED make the star appear to be APPROACHING from that direction while receding from the other direction. But again, that supposes a 'finite but unbounded' universe WITHOUT GLOBAL SPACE EXPANSION.
This is the sort of 'complication' that creeps in to such 'finite but unbounded' scenarios, ESPECIALLY WHEN COMBINED WITH RECESSION purporting to be GLOBAL rather than LOCAL (and possibly hence ACTUALLY ASYMMETRIC). But you see the aspect which Kaeroll was pondering was 'simplistic' yet 'profound' within the context, even though Kaeroll only mentioned the 'twice-around' bit.
Good luck to us all, I say! I think Kaeroll has just opened a little 'finite but unbounded' PANDORA'S BOX, hehehe. Thanks again, Kaeroll! And good 'reality check' there for me too, Steveo; thanks!
Your friend in science: RealityCheck.
.
RC,
Likewise, to both of you! I've developed something of an interest in this, but most of it I don't really 'get' ... I imagine some physicists/cosmologists must just go nuts, between this and quantum theory ...
I actually wanted to study physics A level this year, but ended up having to take maths instead ... which is fun ... 
So I'm keeping my brain ticking over with some wider reading (currently "The Elegant Universe" by Brian Greene, as recommended to me by a member of this forum).
Steveo,
Thanks for the balloon analogy (and R.C. for your additions to it) - helps me understand things like this a lot easier, and I see what you mean. In addition to this, I seem to recall Hawking mentioning something about trying to travel at near-light speed and 'loop' round the universe to get to your starting point once more, not being possible - it was something along the lines of time ending before you could get back round. I returned the book to the library last week, so I can't look it up I'm afraid.
Still, if I recall that correctly - it might mean that in an expanding finite-but-unbounded universe, light cannot 'loop round', as such, and actually reach us. I can't remember it fully, but might this be the case?
Thanks all,
Kaeroll
(PS - I hate to be a pedant, but I am in fact a 'he' )
QUOTE
You've made my day, Kaeroll! Thanks.
Likewise, to both of you! I've developed something of an interest in this, but most of it I don't really 'get' ... I imagine some physicists/cosmologists must just go nuts, between this and quantum theory ...
I actually wanted to study physics A level this year, but ended up having to take maths instead ... which is fun ... So I'm keeping my brain ticking over with some wider reading (currently "The Elegant Universe" by Brian Greene, as recommended to me by a member of this forum).Steveo,
Thanks for the balloon analogy (and R.C. for your additions to it) - helps me understand things like this a lot easier, and I see what you mean. In addition to this, I seem to recall Hawking mentioning something about trying to travel at near-light speed and 'loop' round the universe to get to your starting point once more, not being possible - it was something along the lines of time ending before you could get back round. I returned the book to the library last week, so I can't look it up I'm afraid.
Still, if I recall that correctly - it might mean that in an expanding finite-but-unbounded universe, light cannot 'loop round', as such, and actually reach us. I can't remember it fully, but might this be the case?
Thanks all,
Kaeroll
(PS - I hate to be a pedant, but I am in fact a 'he'
)
QUOTE
(currently "The Elegant Universe" by Brian Greene, as recommended to me by a member of this forum).
Yuk, not my favorite book! haha. I found that it jumped around way to much, and for me I didn't get as much out of it as I could have. I also, now have little faith in string theory. But thats my personal opinion.
QUOTE (->
| QUOTE |
| (currently "The Elegant Universe" by Brian Greene, as recommended to me by a member of this forum). |
Yuk, not my favorite book! haha. I found that it jumped around way to much, and for me I didn't get as much out of it as I could have. I also, now have little faith in string theory. But thats my personal opinion.
I actually wanted to study physics A level this year, but ended up having to take maths instead ... which is fun ...
If you can take physics after math, that is a good idea. Its so nice to be able to follow physically whats going on and not have to worry about the math. If you struggle with the math, sometimes in your battle to do problems you miss the physics. Although, sometimes its easy to learn the math when you can actually see a point, or application to what your learning.
QUOTE
Steveo,
Thanks for the balloon analogy (and R.C. for your additions to it) - helps me understand things like this a lot easier, and I see what you mean. In addition to this, I seem to recall Hawking mentioning something about trying to travel at near-light speed and 'loop' round the universe to get to your starting point once more, not being possible - it was something along the lines of time ending before you could get back round. I returned the book to the library last week, so I can't look it up I'm afraid. sad.gif
Still, if I recall that correctly - it might mean that in an expanding finite-but-unbounded universe, light cannot 'loop round', as such, and actually reach us. I can't remember it fully, but might this be the case?
Thanks for the balloon analogy (and R.C. for your additions to it) - helps me understand things like this a lot easier, and I see what you mean. In addition to this, I seem to recall Hawking mentioning something about trying to travel at near-light speed and 'loop' round the universe to get to your starting point once more, not being possible - it was something along the lines of time ending before you could get back round. I returned the book to the library last week, so I can't look it up I'm afraid. sad.gif
Still, if I recall that correctly - it might mean that in an expanding finite-but-unbounded universe, light cannot 'loop round', as such, and actually reach us. I can't remember it fully, but might this be the case?
As to the rest of this, I have no idea if it is or is not possible. Just sort of interesting.
Steveo,
I'm finding The Elegant Universe interesting - I'm not actually up to the chapters on string theory yet, the author is giving me a crash course in quantum mechanics currently I find his writing style more confusing than Hawking's by far, but some of the analogies are a good laugh. Once you get past people walking through walls in the h-bar, it does make sense.
I won't have a chance to study physics next year, unfortunately - I'm hoping to move on to study chemistry at university. If I don't get the grades, however, I'll probably end up doing a third year at 6th form college, and may pick up physics then. That said most of the chemistry courses I've applied for have optional, unrelated modules you can take in your first year - stuff like philosophy, history of science, and probably physics, so I could pick one up then I guess.
Cheers
Kaeroll
I'm finding The Elegant Universe interesting - I'm not actually up to the chapters on string theory yet, the author is giving me a crash course in quantum mechanics currently
I find his writing style more confusing than Hawking's by far, but some of the analogies are a good laugh. Once you get past people walking through walls in the h-bar, it does make sense.I won't have a chance to study physics next year, unfortunately - I'm hoping to move on to study chemistry at university. If I don't get the grades, however, I'll probably end up doing a third year at 6th form college, and may pick up physics then. That said most of the chemistry courses I've applied for have optional, unrelated modules you can take in your first year - stuff like philosophy, history of science, and probably physics, so I could pick one up then I guess.
Cheers
Kaeroll
QUOTE
I'm finding The Elegant Universe interesting - I'm not actually up to the chapters on string theory yet, the author is giving me a crash course in quantum mechanics currently laugh.gif I find his writing style more confusing than Hawking's by far, but some of the analogies are a good laugh. Once you get past people walking through walls in the h-bar, it does make sense.
I actually really liked his analogies and explanations of relativity and quantum theory. Although I read that book 2 1/2 years ago, and have forgotten what they were. Now that I have taken a real course in quantum mechanics, and a real course in special relativity (not General relativity, maybe next year) I should go back and reread it to see if they are actually good explanations. But I am lazy, and have to much on my plate all the time, so I probably won't get to. I hope you get to study physics....its very interesting.....although probably only 1 or 2 courses wouldn't be enough
haha
Steveo,
Most of the analogies are pretty surreal. Getting used to them, though ... I'm up to the beginning of his explanations of string theory, and to be honest, so far I find GR and quantum theory more interesting Some of the implications of this stuff is mind-blowing, though.
The thing I find most difficult to accept/understand is a point about electron energy/velocity. The uncertainty principle explains that we can't accurately measure both position and velocity of an electron (have I understood that correctly?), but logically they'd still have a defined position, energy, direction, etc. at any given moment - even if we can't measure this. Greene points that out as being logical, but says it's not true, without elaborating too much. Which leaves Kaeroll very confused (so much so that he begins to talk in the third person).
Kaeroll
Most of the analogies are pretty surreal. Getting used to them, though ... I'm up to the beginning of his explanations of string theory, and to be honest, so far I find GR and quantum theory more interesting
Some of the implications of this stuff is mind-blowing, though.The thing I find most difficult to accept/understand is a point about electron energy/velocity. The uncertainty principle explains that we can't accurately measure both position and velocity of an electron (have I understood that correctly?), but logically they'd still have a defined position, energy, direction, etc. at any given moment - even if we can't measure this. Greene points that out as being logical, but says it's not true, without elaborating too much. Which leaves Kaeroll very confused
(so much so that he begins to talk in the third person).Kaeroll
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Most of the analogies are pretty surreal. Getting used to them, though ... I'm up to the beginning of his explanations of string theory, and to be honest, so far I find GR and quantum theory more interesting laugh.gif Some of the implications of this stuff is mind-blowing, though.
I agre, GR and QM are more interesting to me than String Theory. You have to be amazingly good at math to do anything that resembles string theory.
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| Most of the analogies are pretty surreal. Getting used to them, though ... I'm up to the beginning of his explanations of string theory, and to be honest, so far I find GR and quantum theory more interesting laugh.gif Some of the implications of this stuff is mind-blowing, though. |
I agre, GR and QM are more interesting to me than String Theory. You have to be amazingly good at math to do anything that resembles string theory.
The thing I find most difficult to accept/understand is a point about electron energy/velocity. The uncertainty principle explains that we can't accurately measure both position and velocity of an electron (have I understood that correctly?), but logically they'd still have a defined position, energy, direction, etc. at any given moment - even if we can't measure this. Greene points that out as being logical, but says it's not true, without elaborating too much. Which leaves Kaeroll very confused sad.gif (so much so that he begins to talk in the third person).
The thing is, that they don't. You can set up the same experiment, with the exact same parameters. And each time you measure, say, the electron's position, you will get a different value, and if you do this enough times, it will agree with the probability from squaring the electron's wave function, as found from the Schrodinger equation.
If you have no knowledge of math, this next paragraph may not make sense, so pay no attention to it. And if you know math (this includes anyone else reading it, and I made an error, please correct me)
The interesting thing is there are much more uncertainty principles than just position/momentum(velocity). There are uncertainty equations for spin, time/energy, and others. In mathematical terms I think (if I remember correctly.....march seems like a LONG time ago) your observables do not commute, which I think means, if you described them as matrices, they can not both be diagnolized with the same set of operations.
Anyways, don't worry to much about this. Some of the greatest physicists in the world can not agree on the reasons why things are in QM, but they can all do it mathematically. So if your confused, your not alone. And I have heard over and over again, if someone claims to totally understand the 'physics' behind QM they are lying through their teeth.
Steveo,
Most of the maths went over my head, but I get your point, I think.
The one I heard was that the only people who understand QM are the people who've never studied it.
I'm beginning to see why.
Kaeroll
Most of the maths went over my head, but I get your point, I think.
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And I have heard over and over again, if someone claims to totally understand the 'physics' behind QM they are lying through their teeth
The one I heard was that the only people who understand QM are the people who've never studied it.
I'm beginning to see why.Kaeroll
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