On Wednesday, February 12, 2025 at 2:43:01 PM UTC-7 Quentin Anciaux wrote:
Le mer. 12 févr. 2025, 22:30, Alan Grayson <[email protected]> a écrit : On Wednesday, February 12, 2025 at 2:17:30 PM UTC-7 Quentin Anciaux wrote: AG, you can make multiple claims, but when you start with "an infinite universe contradicts high temperature at the Big Bang" and then pivot to "a finite universe is possible," it is shifting the argument. If your real point was just that a finite universe is possible, we could have skipped all the contradictions that weren’t actually contradictions. You're correct that a finite universe can't be spatially flat—a positively curved, closed universe would be finite. That’s basic topology, and it’s a valid possibility. But whether the universe is finite or infinite is still an open question in cosmology, and current observations suggest it’s either infinite or so large that any curvature is undetectable. As for your claim that some cosmologists say the entire universe decreased in volume as we go backward, that only applies to finite universes. An infinite universe doesn’t have a meaningful "volume" in the same way—only the density increases. If you find specific names making this claim, make sure they’re talking about the global universe, not just the observable one. Your argument about high temperature being "ALSO compatible with very low volume" is trivial—it’s true for finite universes. But you started by arguing that an infinite universe was somehow incompatible with high density, which is false. GR allows both scenarios. You haven’t shown any physical reason why an infinite, high-density early universe would be impossible. You’re just asserting that a small volume would be possible, which no one is disputing. So we're on the same page. But what I am claiming is plausible and possible, and my initial comment was too extreme, so I corrected it. But it's certainly not trivial. Calling it trivial shows your bias, which you essentially presented as a certainty, AG AG, if your point is simply that a finite universe shrinking in volume as we go backward in time is possible, then sure, that’s a valid scenario within GR. But that was never in question—cosmologists already consider positively curved, closed universes as a possibility. What was in question was your earlier claim that an infinite universe contradicts high temperature at the Big Bang, which was incorrect. It's not incorrect; just not generally accepted at this time. AG That’s why your shift to simply defending the plausibility of a finite universe seems like a retreat rather than an actual defense of your original argument. You have an agenda to prove me wrong. I changed my position in response to your comments. Maybe you'd prefer that I stubbornly insist on a contradiction. I believe that a super high temperature is more plausible due to spatial contraction, than simply due to infinite space in the context of shortening distances between galaxies. AG Calling it trivial isn’t bias—it’s just stating that this is a well-known, uncontroversial fact. It is a bias IMO. You've fallen in love with your theory because that's the prevailing opinion based on measurements of a flat universe. You can't seem to imagine a universe finite but so large that the distinction between flat and slightly spherical is a reasonable position. AG The debate was never about whether a finite universe was possible; At first you seemed to suggest it was *not* possible, if not expressly than implicitly, then you were clearer, so that was useful information, causing me to change my mind. But apparently you insist on being right, so you refuse to allow that. AG it was about whether an infinite one was impossible under high density, which you originally suggested. If you’re now just saying a finite universe is a possibility, then there’s no actual argument left. I think it's not just possible but *likely* because if it started out infinite in spatial extent, IOW from Nothing to instantaneously infinite, that would be a type of singularity which seems impossible and to be avoided in any physical theory. Now that's my opinion, and last I heard I allowed to have it. AG Quentin -- 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/44628f56-69b4-47a0-9284-ca2a5c724817n%40googlegroups.com.
