On Saturday, March 1, 2025 at 4:02:15 PM UTC-7 Quentin Anciaux wrote:
On the 26th and in other replies I did say: As I've explained already, it's not that the volume goes to zero, but density that goes to infinity, everywhere, there is no valid notion of volume in an infinite universe. What is difficult to understand? Quentin I deleted that post. You must have replied to your email list. But you misconstrued the question posed. As the density goes to infinity, the rate of expansion keeps increasing (but not to infinity), so how do the competing rates result in an ultra high temperature? I suppose it's because the first is unbounded and latter bounded. AG Le sam. 1 mars 2025, 06:42, Alan Grayson <[email protected]> a écrit : 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 [email protected]. To view this discussion visit https://groups.google.com/d/msgid/everything-list/629ffae7-7336-4bc5-bb65-54e18e288147n%40googlegroups.com <https://groups.google.com/d/msgid/everything-list/629ffae7-7336-4bc5-bb65-54e18e288147n%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 visit https://groups.google.com/d/msgid/everything-list/89941b02-58f3-49a2-8f97-49fa0e1f1e99n%40googlegroups.com.
