On Friday, February 28, 2025 at 1:22:43 PM UTC-7 Brent Meeker wrote:
On 2/27/2025 10:59 PM, Alan Grayson wrote: On Thursday, February 27, 2025 at 4:17:13 PM UTC-7 Brent Meeker wrote: On 2/26/2025 11:39 PM, Alan Grayson wrote: If we assume an infinite universe and run the clock backward, is it reasonable to conclude that the singularity we imagine forming in the observable region, The singularity is not IN the observable region, it is the limiting origin of the observable region. is identically the same singularity for the entire universe? Secondly, why do we imagine the hypothetical singularlty indicates the GR fails in this situation? After all, if the expanding universe is determined by measurements, and the average distances between galaxies decreases as the clock runs backward is also determined by measurements, what has this to do with GR, since it's all measurement determined? TY, AG You can't be so dense as to not know the difference between a measurement and an extrapolation. Brent I'm just saying that measurements suggest a singularity without applying GR. The reason the unobservable region is unobservable is because expansion in that region is faster than light speed. So if we run the clock backward, won't that region collapse faster than light speed, with the result that the entire universe converges to a single singularity? AG It depends I suppose on what "run the clock backwards" means. It's unphysical to have spheres of outgoing radiation contract backward to a point as in playing a video backwards. But if that's what you mean then yes the entire universe becomes infinitely dense, a singularity...but not a point, it's still infinite. Brent So, as we go backward in time, the observable universe seems to converge to a point, while the rate of expansion of the unobservable universe increases since the rate of expansion in earlier times was greater than it is at present? In this scenario, how could the unobservable univese reach an ultra high temperature as we approach the BB? 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 everything-list+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/everything-list/629ffae7-7336-4bc5-bb65-54e18e288147n%40googlegroups.com.
