On Mon, Dec 24, 2018 at 3:33 PM <[email protected]> wrote: > On Monday, December 24, 2018 at 4:22:24 AM UTC, [email protected] wrote: >> >> On Monday, December 24, 2018 at 3:50:33 AM UTC, Brent wrote: >>> >>> On 12/23/2018 4:47 PM, [email protected] 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* >>> >>> >>> All that's "infinitesimally tiny" is the visible universe. You must >>> know that the Friedmann equation just defines the dynamics of a scale >>> factor, not a size. >>> >> >> *Are you claiming the visible universe at the BB was infinitesimally >> tiny, but the non visible part was infinitely large (mathematically flat), >> or huge (asymptotically flat)? AG * >> > > *Bruce says the universe is always flat if k=1. How can it be everywhere > flat if there's a region which is infinitely tiny; hence not flat in the > visible region? How are we to imagine this? TIA, AG * >
That's a bit confused. k=0 corresponds to a universe that is everywhere flat (in space, but not necessarily in the time dimension - i.e., it might be expanding. Our current visible universe originated in a small (tiny) region of the total structure, which might be infinite in extent, but flat everywhere, even in our tiny region. Bruce -- 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.
