On Wednesday, August 21, 2019 at 7:12:14 PM UTC-6, Alan Grayson wrote: > > > > On Wednesday, August 21, 2019 at 3:13:11 PM UTC-6, Lawrence Crowell wrote: >> >> On Tuesday, August 20, 2019 at 4:56:23 PM UTC-5, Alan Grayson wrote: >>> >>> https://en.wikipedia.org/wiki/Conformal_cyclic_cosmology >>> >>> Is this a viable theory for avoiding a BB interpreted as a singularity? >>> AG >>> >> >> Penrose proposed a conformal identification of spatial infinity in the >> past and future i^±∞ of FLRW spacetimes. A cosmology expands and in the >> limit time → ∞ it transitions into a new cosmology. The de Sitter vacuum is >> not eternally stable, so the idea may have some germ of relevancy. I am not >> sure about how this would work with vacuum to vacuum transitions. The >> exponential expansion of the universe is a sort of time dependent conformal >> transformation with a small vacuum expectation for the scale field. To >> transition to a new cosmology, say with inflationary expansion, this means >> the vacuum expectation is increased. >> >> The overall physics community response to this has been tepid at best. >> There are some possible conflicts with observed data. >> >> LC >> > > FWIW, ISTM that what GR might be indicating about the BB, is that, insofar > as it's a singularity, it couldn't have occurred, and didn't occur. This > is to say the universe didn't become infinitely small in spatial extent, > like a mathematical point, but rather that there was a maximal finite value > of its energy density, hugely high but not infinite. For this reason I find > the cyclic models promising, although, as you rightly indicate, they're far > from complete or bug-free. AG >
Which brings up a possibly relevant question: If the total energy of the universe occupied zero spatial volume (the presumed condition of the universe at t=o according to the BB theory), wouldn't that contradict the Uncertainty Principle? 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/08cf612c-8a7f-4762-aa7a-e55152f01560%40googlegroups.com.
