On Monday, December 24, 2018 at 5:52:21 PM UTC, John Clark wrote: > > On Sun, Dec 23, 2018 at 7:47 PM <[email protected] <javascript:>> wrote: > > *> **If by "flat", you mean mathematically flat, like a plane extending >> infinitely in all directions, as opposed to asymptotically flat like a huge >> and expanding sphere, you have to reconcile an infinitesimally tiny >> universe at the time of the BB, and simultaneously an infinitely large >> universe extending infinitely in all directions. AG* >> > > You can never prove that any physical quantity is exactly zero, but we do > know from observations of the cosmic microwave background radiation that if > the universe is curved at all it is by less than one part in 100,000. > > John K Clark >
*Agreed. However, IMO the observed universe cannot be flat with exactly zero curvature, since that would imply infinite volume which contradicts its finite age. That is, if the observable universe started as infinitesimally small, and evolves for a finite time until the present, it cannot be mathematically flat. I believe it is shaped like a huge hyper-dimensional sphere, close to, but not "flat. The unobserved part could possibly be mathematically flat and therefore infinite in extent. I have discussed this with Brent in the past and he seems to disagree with my conclusion. But maybe we mis-communicated. 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 post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
