On Monday, September 16, 2019 at 11:31:26 AM UTC-6, Jason wrote: > > > > On Mon, Sep 16, 2019 at 3:31 AM Alan Grayson <[email protected] > <javascript:>> wrote: > >> >> >> On Wednesday, September 11, 2019 at 10:45:41 PM UTC-6, Alan Grayson wrote: >>> >>> >>> https://www.wired.com/story/sean-carroll-thinks-we-all-exist-on-multiple-worlds/ >>> >> >> Jason; it turns out you were right about the consensus among >> cosmologists; that the universe is thought to be *flat*. But I am >> studying some videos which seem to suggest that a flat universe can be* >> finite* in spatial extent, maybe like a cyclinder without an edge. Try >> try this, and the two which follow: >> >> https://www.youtube.com/watch?v=_k3_B9Eq7eM&feature=youtu.be >> >> > That is interesting and it is a good reminder how how flexible math is to > representing various spaces and geometries. Most cosmologists work under > the assumption that space is "simply connected", rather than doughnut > shaped or otherwise, in which case if space is simply connected, and flat, > then it ought to be infinite. > > There are also interesting things that can be done as far as compacting > space, so that a finite cylinder can represent an infinite space evolving > through time. There are some good illustrations of this here: > > https://www.podevin.com/single-post/2019/01/24/Einsteins-Dream-of-a-Grand-Unified-Theory > > Also known as a "Poincare disk" > https://en.wikipedia.org/wiki/Poincar%C3%A9_disk_model > http://mathworld.wolfram.com/PoincareHyperbolicDisk.html > > Jason >
Concerning a flat and spatially finite geometry, say shaped like a square, when you get to what appears an edge, how do you wind up emerging on the opposite appearing edge? AG -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/bfd2b9e9-9331-4d20-a550-8e2c5b512bb2%40googlegroups.com.
