Celestia Forums

Came across this paper on arXiv, where it describes a model of the universe as a "flat torus" or "cubic torus".

Now, as far as I understand it (which isn't all that much), a rectangular region in the xy-plane where if you go off the edge you end up on the opposite edge (rather like old computer games like Asteroids) is topologically a torus, but presumably would also be flat.

So is the shape being described basically the same thing but for a cube (i.e. if you go out through one face of the cube you end up on the opposite face)?

chaos syndrome wrote:Came across this paper on arXiv, where it describes a model of the universe as a "flat torus" or "cubic torus".

Now, as far as I understand it (which isn't all that much), a rectangular region in the xy-plane where if you go off the edge you end up on the opposite edge (rather like old computer games like Asteroids) is topologically a torus, but presumably would also be flat.

So is the shape being described basically the same thing but for a cube (i.e. if you go out through one face of the cube you end up on the opposite face)?

One of the authors I know very well since decades. Before becoming a full Professor at Ulm University, he was a colleague of mine at Hamburg University.

I have discussed such finite cubic Universes in my "Purgatory lecture" some time ago:

http://www.celestiaproject.net/forum/viewtopic ... c&start=16

Bye Fridger

Ah, thanks, I think I missed that one first time round (I don't read Purgatory all that often). So looks like the cubic torus is what I thought it was.

chaos syndrome wrote:Ah, thanks, I think I missed that one first time round (I don't read Purgatory all that often). So looks like the cubic torus is what I thought it was.

You apparently havn't found out yet that Purgatory is the best board in town ?

Cheers,
Fridger