> On 19 Jan 2020, at 11:26, Alan Grayson <[email protected]> wrote: > > > > On Sunday, January 19, 2020 at 2:54:49 AM UTC-7, Philip Thrift wrote: > > > On Saturday, January 18, 2020 at 6:04:53 PM UTC-6, Alan Grayson wrote: > > > On Saturday, January 18, 2020 at 2:55:16 PM UTC-7, Brent wrote: > > > On 1/18/2020 1:29 AM, Alan Grayson wrote: >> the infinite spatial extent must have occurred instantaneously, at the BB. > > It doesn't have to "occur". If the universe is infinite then it didn't > become infinite, it was always (in some timeless way) infinite. The > equations of cosmology are just for a scale factor. We estimate the > parameters from observation and project back to a beginning. So there's > really no sense in projecting back to zero scale factor...there the size of a > flat universe according the equations is infinity*zero. Hopefully a quantum > theory of gravity will replace that oo*0 with something more sensible. > > Brent > > What do "infinity*zero" and "oo*0" mean? I see your point. My problem is > that we seem to have a universe with a BEGINNING, called the BB, and I find > it virtually impossible to imagine it starting with an infinite spatial > extent. How could "nothing" become infinite in any parameter, suddenly, or > due to finite processes? What I can imagine is it emerging from something > flat and eternal, having an infinite past. AG > > > > > Any theory (of physics/cosmology) that asserts the existence of infinite > anythings as an "axiom" or starting point has no basis of any support by > empirical data. (That I am aware of.) > > So it seems useless to even talk about them. > > @philipthrift > > Hypothetically, one could measure the curvature of spacetime and conclude it > implies flatness. This wouldn't be an axiom, but an inference from data. As > I have previously stated, I don't think the measured curvature unambiguously > implies flatness. AG
All axioms/theories are inferred from data. The very idea that there is a physical reality is an inductive inference on a finite number of observations and data. In science we cannot prove that a theory is true. We can only refute it, and even this is only a local happening. In fact, we can only make argument of plausibility as far as we are interested in Reality. Bruno > > -- > 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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/676e6fa6-1df8-4cd3-9b1d-7e20b0683ace%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/676e6fa6-1df8-4cd3-9b1d-7e20b0683ace%40googlegroups.com?utm_medium=email&utm_source=footer>. -- 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/49F569A7-67AD-4DAB-957B-66616754EACA%40ulb.ac.be.
