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 (which I refer to as "mathematically flat) 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 exactly "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.
