Le mer. 12 févr. 2025, 22:30, Alan Grayson <agrayson2...@gmail.com> 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. 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. Calling it trivial isn’t bias—it’s just stating that this is a well-known, uncontroversial fact. The debate was never about whether a finite universe was possible; 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. Quentin > Quentin > > Le mer. 12 févr. 2025, 21:48, Alan Grayson <agrays...@gmail.com> a écrit : > > > > On Wednesday, February 12, 2025 at 1:12:13 PM UTC-7 Quentin Anciaux wrote: > > AG, if you’re postulating a closed universe, that’s entirely different > from claiming an infinite universe contradicts high temperature at the Big > Bang. It just means you're favoring a specific topology. > > The problem is that your argument keeps shifting. Initially, you argued > that an infinite universe contradicts high temperature at the Big Bang to > saying a finite, positively curved universe is a possible model—which is > trivially true but irrelevant to your claim. > > > Can't I make more than one claim without being accused of "shifting"? I > concluded that a flat geometry is infinite, so it can't be the case IF our > universe is finite; that is, If it's finite, it can't be flat. In such > case, it's very likely slightly positively curved and spherical, thus > closed and finite. I am virtually certain that some cosmologists claim the > entire universe actually decreased in volume as we run the clock backward. > I'll try to name names if I can. BTW, I'm not making a category error when > applying the Cosmological Principle. It says what you said it says, but > there's more to it than that. Being the same everywhere in terms of > distribution of matter is just one example of sameness. Finite or infinite > *everywhere* is another example of sameness. AG > > > If your point is just "a finite universe is possible," sure, but if you're > still trying to argue that an infinite universe is incompatible with high > density at early times, you haven't demonstrated that at all. > > > I'm arguing that super high temperature is ALSO compatible with very low > volume. So, I would think some "expert" would have made the effort to prove > this contradicts GR, instead of relying solely on showing that a small > volume is actually not compatible with GR. 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 everything-li...@googlegroups.com. > > To view this discussion visit > https://groups.google.com/d/msgid/everything-list/6c9177dc-c913-472a-b0b2-fc4a23b9bd0an%40googlegroups.com > <https://groups.google.com/d/msgid/everything-list/6c9177dc-c913-472a-b0b2-fc4a23b9bd0an%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 everything-list+unsubscr...@googlegroups.com. > To view this discussion visit > https://groups.google.com/d/msgid/everything-list/4674fd64-971c-4938-bd88-58b25872a156n%40googlegroups.com > <https://groups.google.com/d/msgid/everything-list/4674fd64-971c-4938-bd88-58b25872a156n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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