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 Posted: Sun Feb 25, 2007 4:41 pm
I have a question regarding higher dimensions. If the universe has a particular size we are aware of (If I am mistaken in anything I say correct me please) and having taken a 'picture' of background radiation we have seen that it is circular, and if time and space do not exist outside of our universe, then isn't it fair to say that the three spacial dimensions (and one time dimension) of which we know of are curved? Doesn't this agree with the fact that if you start in one direction and keep going straight you will end up in the same spot? (considering you had enough time or you went fast enough before dying)
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Posted: Wed Feb 28, 2007 6:25 pm
So I asked a panel of expert judges today, no really there were four astrophysicist at a talk today, and they said that SPACE IS FLAT. It was once thought that if one travelled in one direction they would end up back in the place they started, not so anymore, if you go in one direction you will keep on going indefinitely.
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Posted: Fri Mar 09, 2007 8:26 am
poweroutage So I asked a panel of expert judges today, no really there were four astrophysicist at a talk today, and they said that SPACE IS FLAT. It was once thought that if one travelled in one direction they would end up back in the place they started, not so anymore, if you go in one direction you will keep on going indefinitely. Hi poweroutage, It's still possible to have a wrap-around universe when space is flat. It requires the 3-dimensional equivalent of a torus and the proper choice of metric, but it works as well as an infinite plane.
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Posted: Wed Mar 14, 2007 11:38 pm
grey wanderer poweroutage So I asked a panel of expert judges today, no really there were four astrophysicist at a talk today, and they said that SPACE IS FLAT. It was once thought that if one travelled in one direction they would end up back in the place they started, not so anymore, if you go in one direction you will keep on going indefinitely. Hi poweroutage, It's still possible to have a wrap-around universe when space is flat. It requires the 3-dimensional equivalent of a torus and the proper choice of metric, but it works as well as an infinite plane. it is. I was kind of hoping we'd live in one, the idea got me excited. but... no, we have to live in a boring flat universe. not that that would change things very much, only, well, I'd be entertained in contemplating the possibilities. wouldn't a curved universe necessarily imply at least one higher dimension which we are not aware of?
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Posted: Thu Mar 15, 2007 7:40 pm
poweroutage it is. I was kind of hoping we'd live in one, the idea got me excited. but... no, we have to live in a boring flat universe. not that that would change things very much, only, well, I'd be entertained in contemplating the possibilities. wouldn't a curved universe necessarily imply at least one higher dimension which we are not aware of? i hope also we are not in a flat universe. i would hate to see someone prove Isaac Brock wrong... the last model of the universe i learned about was from A Brief History of Time by Stephen Hawking... i have a pretty good feeling it's outdated, but I remember because a red shift can be seen while observing stars in all directions it was thought the universe was constantly expanding. actually, as far as i know that would prove the universe is expanding. could we ever experience the phenomena and "go straight long enough and end up where we were"?
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Posted: Thu Mar 15, 2007 8:48 pm
super.funk poweroutage it is. I was kind of hoping we'd live in one, the idea got me excited. but... no, we have to live in a boring flat universe. not that that would change things very much, only, well, I'd be entertained in contemplating the possibilities. wouldn't a curved universe necessarily imply at least one higher dimension which we are not aware of? i hope also we are not in a flat universe. i would hate to see someone prove Isaac Brock wrong... the last model of the universe i learned about was from A Brief History of Time by Stephen Hawking... i have a pretty good feeling it's outdated, but I remember because a red shift can be seen while observing stars in all directions it was thought the universe was constantly expanding. actually, as far as i know that would prove the universe is expanding. could we ever experience the phenomena and "go straight long enough and end up where we were"? no space is flat, it's been shown.
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Posted: Fri Mar 16, 2007 11:12 am
hah ok. well what about grey wanderers comment? universe could still wrap around, meaning you could still go in circles by heading straight?
so isaac brock still has a chance...
what is this flat universe model called? i'd like to look up more information on it...
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Posted: Sat Mar 17, 2007 12:54 pm
grey wanderer poweroutage So I asked a panel of expert judges today, no really there were four astrophysicist at a talk today, and they said that SPACE IS FLAT. It was once thought that if one travelled in one direction they would end up back in the place they started, not so anymore, if you go in one direction you will keep on going indefinitely. Hi poweroutage, It's still possible to have a wrap-around universe when space is flat. It requires the 3-dimensional equivalent of a torus and the proper choice of metric, but it works as well as an infinite plane. why do you need a torus, why can't you do with a sphere or some other curved shape?
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Posted: Wed May 30, 2007 3:57 pm
poweroutage I have a question regarding higher dimensions. If the universe has a particular size we are aware of (If I am mistaken in anything I say correct me please) and having taken a 'picture' of background radiation we have seen that it is circular, and if time and space do not exist outside of our universe, then isn't it fair to say that the three spacial dimensions (and one time dimension) of which we know of are curved? Doesn't this agree with the fact that if you start in one direction and keep going straight you will end up in the same spot? (considering you had enough time or you went fast enough before dying) your serius???? if you start at one place in space u end up in the same place>???? wierd. but i already knew taht spacetime is curved. its curved because of one explanation. the theory of general relativity which states that Mass- energy tells spacetime how to curve and the curvature of spacetime tells mass- energy how to move.
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Posted: Wed May 30, 2007 4:57 pm
SS4 Gogeta Forever poweroutage I have a question regarding higher dimensions. If the universe has a particular size we are aware of (If I am mistaken in anything I say correct me please) and having taken a 'picture' of background radiation we have seen that it is circular, and if time and space do not exist outside of our universe, then isn't it fair to say that the three spacial dimensions (and one time dimension) of which we know of are curved? Doesn't this agree with the fact that if you start in one direction and keep going straight you will end up in the same spot? (considering you had enough time or you went fast enough before dying) your serius???? if you start at one place in space u end up in the same place>???? wierd. but i already knew taht spacetime is curved. its curved because of one explanation. the theory of general relativity which states that Mass- energy tells spacetime how to curve and the curvature of spacetime tells mass- energy how to move. no it's not, read some other posts in this thread, it explains it.
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Posted: Mon Jun 04, 2007 3:23 pm
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Posted: Thu Jun 14, 2007 7:22 am
I think the question is asking about global spacetime curvature, not "local." As in, the entire universe can have a curved structure which is then enhanced at more "local" points by gravity. (I don't want to say local in the absolute sense, but I can't think of a better word).
I guess it's best explained by the rubber sheet analogy. Take your flat, rubber sheet, drop a ball in it, and it curves. Now take that rubber sheet, curve it into something wierd at one end, and drop a ball in it somewhere entirely different. If these two "curves" interfere, it's only slightly. This is what I mean by global vs. "local" curvature; there is an overarching structure of the rubber sheet which is only somewhat dependent on the "local" structure given by gravity.
Am I allowed to ask Grey Wanderer about that 4d torus and whether or not it's compatible with the Robertson-Walker metric?
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