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Finite universe

arcticpenguin

Philosopher
Joined
Sep 18, 2002
Messages
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http://story.news.yahoo.com/news?tm...53&e=8&u=/nm/20031008/sc_nm/space_universe_dc

LONDON (Reuters) - Scientists said Wednesday the universe could be spherical and patched together like a soccer ball -- and it may not be infinite.

effrey Weeks, a MacArthur Fellow based in Canton, New York, and researchers from the University of Paris and Observatory of Paris analyzed astronomical data which suggests the universe is finite and made of curved pentagons joined together into a ball.
Comments? Does he know what he's talking about or has Weeks scored an own goal?
 
arcticpenguin said:
http://story.news.yahoo.com/news?tm...53&e=8&u=/nm/20031008/sc_nm/space_universe_dc


Comments? Does he know what he's talking about or has Weeks scored an own goal?

The finite unbounded ("spherical") universe is the one where the Big Bang doesn't have enough momentum to prevent it all from falling back together in a Big Crunch. It was my understanding that this has been put to rest lately, but is not woo-woo stuff by any means.

I have no idea what "patched together like a soccer ball" might mean.
 
Since a soccer ball is actually patched together out of hexagons and pentagons (a truncated icosahedron), I'd say someone has got the story muddled a bit.

The idea of the universe as a dodecahedron (12 pentagons) goes back to Plato's Timaeus.

Not that I've clarified anything here, but I like to say "truncated icosahedron". "Great rhombicosidodecahedron" is even funner, though.
 
I hope they have rules out the possibility that it is an artifact of their mapping strategy.
 
the issue that I have is that it is very likely the observable universe does not show the whole universe, it is larger than light can travel across.

I thought the universe was foamy?
 
I had always thought the universe was finite, but I'd never thought of a soccerball shaped universe, I'd always assume the universe would look a bit like a not-quite-spherical blob.

I obviously have no idea what a patched dodecohedron universe might be or look like. As for what might exist outside the universe... uh... antimatter? It might be other universes? Hey, it's worth a guess.
 
Re: Re: Finite universe

Abdul Alhazred said:


The finite unbounded ("spherical") universe is the one where the Big Bang doesn't have enough momentum to prevent it all from falling back together in a Big Crunch. It was my understanding that this has been put to rest lately, but is not woo-woo stuff by any means.


I thought the most recent evidence suggested the universe was fairly "flat", and will continue to expand.
 
Yahweh said:
I had always thought the universe was finite, but I'd never thought of a soccerball shaped universe, I'd always assume the universe would look a bit like a not-quite-spherical blob.

I obviously have no idea what a patched dodecohedron universe might be or look like. As for what might exist outside the universe... uh... antimatter? It might be other universes? Hey, it's worth a guess.

You can construct an Euclidean space-filling lattice of squares arranged around their angles as cubes.

Easy to picture.

One way of constructing a dodecahedron is by arranging regular pentagons around their angles, but not an Euclidean space-filling lattice that way.

But with some degree of space curvature pentagons of a certain size will have right angles.

Hard to picture, but by analogy think of equilateral triangles having right angles on a sphere, if the size of the triangle is the same as one with a vertex on the north pole, one on the equator at 0 longitude, and one on the equator at 90 (either direction) longitude.

So you could have a space-filling lattice of dodecahedrons, given the right parameters.

Maybe it's my American bias, but it seems to me that the stitching on a regulation baseball divides a finite unbounded two dimensional space (otherwise known as the surface of a sphere) into a higher dimensional version of the Euclidean yin-yang.

Maybe the universe is a baseball, not a soccer ball, after all. I like that. It proves God is on our side. But I hate to think of the possibility of the universe being shaped like an (American-style) football. :roll:
 
I personally think the universe is shaped like a donut (I forget the geometric name - torus?) ... as the great physicist Homer suggests ;)
 
BTox said:
I personally think the universe is shaped like a donut (I forget the geometric name - torus?) ... as the great physicist Homer suggests ;)

Are you a Taurus? Sorry, I mean a torus. I am. We all are. Some folks around here will understand what I just said as being literal truth. :p
 
Abdul Alhazred said:

Are you a Taurus? Sorry, I mean a torus. I am. We all are. Some folks around here will understand what I just said as being literal truth. :p

We're pretzels, not toruses. You forgot the nose. :p
 
Re: Re: Re: Finite universe

BTox said:


I thought the most recent evidence suggested the universe was fairly "flat", and will continue to expand.

I don't think they mean flat in the geometric sense, but in the equilibrium sense.
 
arcticpenguin said:
http://story.news.yahoo.com/news?tm...53&e=8&u=/nm/20031008/sc_nm/space_universe_dc


Comments? Does he know what he's talking about or has Weeks scored an own goal?

I just have this nagging feeling that it will always look like a sphere to us, from our perspective, but we can't know the real shape until we view the universe from outside of the universe.

Did you ever make a curve by drawing a series of straight lines? (Not meant to invoke any images of Yalel and his "where is the arc" thing, BTW)
 
I have to admit, physics has never been my area.

However I must admit, I would have always thought a shape must have boundaries to be discernable. And a boundary can only be defined in terms of the two 'things' it distinguishes (no?). So if there is a boundary to the universe, what exists on the outside? It can't be nothing, as to be a boundary it must be something. It can't be something, as to my knowledge the universe is the 'everything'.

Ouch...oops...brain cell just popped. My head now hurts.

Athon
 
I agree!

athon said:
I have to admit, physics has never been my area.

However I must admit, I would have always thought a shape must have boundaries to be discernable. And a boundary can only be defined in terms of the two 'things' it distinguishes (no?). So if there is a boundary to the universe, what exists on the outside? It can't be nothing, as to be a boundary it must be something. It can't be something, as to my knowledge the universe is the 'everything'.

Ouch...oops...brain cell just popped. My head now hurts.

Athon

Since we consider empty space as inside the universe, then how can you just have a curving line that simply divides universe from nonuniverse? And how can you HAVE nonuniverse? Shouldn`t we consider the nothingness as part of the universe?

If you mean the space that has matter, then yes it could have a boundary, and would probably be vaguely spherical.

Now here`s something to think about: If vacuum fluxuation theory is correct, and the nothingness(vacuum) stretches on forever (How could it stop?) , and unlimited time, then could literally have trillions of universes, but separated by such great distances that we can never know.

But, since we can never know, the theory is pointless.
 
Okay, two points.

Firstly everyones responses suggest that they are thinking of the Universe as some bound (finite) three dimensional space which exists within some larger unbound (infinite) three dimensional space. The Universe is not three dimensional it's multi-dimensional, we only experience three of those dimensions. Furthermore, as I have said on previous threads, when you hear that there is nothing beyond the edges of the Universe this doesn't mean that there is a "beyond the Universe" which contains nothing, it means that there is no such thing as beyond the Universe. At least not in any sense that we would understand it. Space as we understand it (ie 3-D) is a function of the Universe we live in, no more, no less.

Secondly to the dodecahedral space thing. Before I go further I have to admit that cosmology isn't my area of expertise, but I have been talking about this to two people who are cosmologists. The upshot of that conversation is that these results are based on one point of the WMAP anisotropy power spectrum. If this point is correct then the results are fine. However, the point the work is based on is for angular scales > 60 degrees, and although the random errors at these angular scales are virtually zero, they are subject to massive systematic uncertainties. This means that the results are a tad on the dodgy side. Fortunately there is a test that would confirm or deny the result, but it will require data from the Planck satellite, so don't expect any real news on this before about 2010!
 
To clarify, what is beyond one face of the dodecahedron is the opposite face of the dodecahedron. Think Pacman.
 

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