The Shape Of The Universe

  • Thread starter Delzac
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Main Question or Discussion Point

From what i heard(from my brother by the way), Einstein once predicted that the universe is spherifical( i don't know if it is true or not), is the universe really spherical??

if so, then what lies outside our universe??
 

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  • #2
selfAdjoint
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Delzac said:
From what i heard(from my brother by the way), Einstein once predicted that the universe is spherifical( i don't know if it is true or not), is the universe really spherical??

if so, then what lies outside our universe??
Your brother oversimplified what Einstein thought. He thought the universe was "finite but unbounded", and an analogy for this is the surface of a sphere (such as the Earth) which has a finite area but has no boundary. Einstein's theory does not itself predict the shape of the universe, but modern discoveries and measurements suggest that in the large scale it has a "flat" geometry which would argue that it is infinite in extent, but nobody really knows.

It is not necessary to have anything "outside the universe" in either Einstein's original thought or the modern understanding. We are used to seeing spheres - balls - in three space but that is no reason to suppose the universe behaves that way, and the mathematics does just fine without it.
 
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selfAdjoint said:
Your brother oversimplified what Einstein thought. He thought the universe was "finite but unbounded", and an analogy for this is the surface of a sphere (such as the Earth) which has a finite area but has no boundary. Einstein's theory does not itself predict the shape of the universe, but modern discoveries and measurements suggest that in the large scale it has a "flat" geometry which would argue that it is infinite in extent, but nobody really knows.

It is not necessary to have anything "outside the universe" in either Einstein's original thought or the modern understanding. We are used to seeing spheres - balls - in three space but that is no reason to suppose the universe behaves that way, and the mathematics does just fine without it.
So is it generally accepted that the universe is most likelly infinite if it is flat? It makes sense if this is true since it makes more sense for both space and time to be infinite rather than just time being infinite.

The universe being a threesphere is least likelly, correct?
 
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SpaceTiger
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Silverbackman said:
So is it generally accepted that the universe is most likelly infinite if it is flat?
No, mainstream theory says very little about the overall topology scale of the universe, other than to set limits on it (>~24 Gigaparsecs).
 
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Chronos
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