On Monday, December 24, 2018 at 9:47:52 PM UTC, Jason wrote: > > > > On Mon, Dec 24, 2018 at 4:04 PM <[email protected] <javascript:>> wrote: > >> >> >> On Monday, December 24, 2018 at 8:25:11 PM UTC, [email protected] >> wrote: >>> >>> >>> >>> On Monday, December 24, 2018 at 6:40:03 AM UTC, Brent wrote: >>>> >>>> >>>> >>>> On 12/23/2018 8:22 PM, [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 * >>>> >>>> >>>> Right. Although we can't be sure whether it is actually flat or just >>>> very big. >>>> >>>> Brent >>>> >>> >>> *OK. Agreed. We seemed to disagree on this in the past, but maybe we >>> miscommunicated. AG* >>> >> >> Here's what Ned Wright wrote. >> >> Is the Universe really infinite or just really big? >> >> We have observations that say that the radius of curvature of the >> Universe is bigger than 70 billion light years. But the observations allow >> for either a positive or negative curvature, and this range includes the >> flat Universe with infinite radius of curvature. The negatively curved >> space is also infinite in volume even though it is curved. So we know >> empirically that the volume of the Universe is more than 20 times bigger >> than volume of the observable Universe. Since we can only look at small >> piece of an object that has a large radius of curvature, it looks flat. The >> simplest mathematical model for computing the observed properties of the >> Universe is then flat Euclidean space. This model is infinite, but what we >> know about the Universe is that it is really big >> <http://www.astro.ucla.edu/~wright/HGTTG.html>. >> >> >> <http://www.astro.ucla.edu/~wright/cosmology_faq.html#top> >> >> *It is misleading. He's referring to the VISIBLE universe and concludes >> it might be infinite in spatial extent. Impossible due to its finite age. I >> wrote him about this, but never received a reply. AG* >> >> >> > It's only impossible if you believe the believe the big bang occurred only > at a point, rather than everywhere. > > Consider that every point in space sees everything else around it flying > away from it, such that if you rewound time, everything would return to a > single point centered at that location. But this is true for every point in > space, so the implication is that the BigBang didn't happen at one > particular location long in the past, but at every point, including the > period at the end of this sentence. >
*You seem inclined to extreme hypotheses for which there is no data. AG * > > Jason > -- 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.
