Alan Grayson <[email protected]> wrote: *>> If you're assuming that at T=0 the ENTIRE universe could be contained > in a sphere of finite size then you're assuming that space is finite, the > very thing you're trying to prove. * > > > *> No. Not assuming that. Since there's universal agreement that our > bubble is expanding, you can always go back in time, to any time, say T = > 10 BY, and put a finite sphere around it.* >
*But that wouldn't be the entire universe, that wouldn't even be the entire observable universe, so what would be the point? * *> The question is whether that's the whole universe or just the observable > part,* > *We know the observable universe is flat, or at least very nearly flat, and we know there is no evidence the observable universe is a 3-torus, so if the observable part of the universe is the only part there is then the Earth really is the center of the universe. Do you really wanna die on that hill? * *> Apparently, you love spooky action at a distance. * > *I love any idea that fits the observational facts, and I don't care if it's spooky or not. * > *> Dark Energy, like Inflation, hasn't been "discovered".* > *Inflation is a theory that may or may not be true, Dark Energy is an observational fact. Astronomers discovered in 1997 that the universe is accelerating, and energy is required for something to accelerate, we had to find a name for whatever is causing that acceleration; "unknown energy" would've probably been a better name but for some reason "dark energy" is the name that was picked and we're stuck with that. * * > I would conjecture that GR might be able to establish that gravity can > be repulsive and attractive, and their respective influence over time might > change.* > *Every physicist who read the astronomer's paper showing that the universe is accelerating started thinking about changing General Relativity to explain it, but nobody can make it work. * > *It would be a great doctoral thesis. AG* *It sure would! It would be the greatest breakthrough in physics since Einstein, but it's easier said than done. * * > Because the universe is huge, our measurements can't distinguish flat > from slightly curved.* > *Nobody will ever prove that the universe is absolutely flat because there is always some measurement error, but the Planck satellite discovered that the cosmological scale curvature of space is 0.0007 ± 0.0019, and that is consistent with zero, AKA perfect flatness. If the universe is curved but it's too small for the Planck satellite to observe then it would have to be at least 9.3 TRILLION light years in diameter. Please understand that is just the lower bound, the upper bound is an infinite number of light years. * *>>> I then realized that the unobservable part was very likely caused by > Inflation, and therefore the entire universe would remain finite provided > we ran the clock backward, prior to Inflation. * > > > *>> And as I said before, IF the universe was finite before inflation then > it was finite after it, and IF the universe was infinite before inflation > it was infinite after inflation.* > > > > *You've made this statement before, and I told you I agree. What's the > point in repeating it?* > *I repeated that point because you have apparently forgotten that the question we were discussing is whether the universe is finite or infinite, and in that context inflation is irrelevant. * *>> inflation is irrelevant in a finite versus infinite discussion, * > > > *> If the unobservable part came into existence via Inflation we agree > it's finite,* > *No we do not agree! If both the transition between non-existence and existence AND the finite process called "inflation" started at T=0 and stopped at some unknown time later then: * *1) The entire universe is finite if and only if it was finite at T=0 * *2) The entire universe is infinite if and only if it was infinite at T=0 * *And inflation has absolutely positively nothing to do with it. * *> Do you believe Euclid's 5th postulate?* > *Of course not! It is not true in general, only in the very special case of a perfectly flat space. If the fifth postulate was correct then General Relativity would be nonsense. * John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis> 76c -- 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 on the web visit https://groups.google.com/d/msgid/everything-list/CAJPayv176ZgUzz-rfmsi7wB%2B7DauLbYwWdpL4%3DdcnwsQyVj3DA%40mail.gmail.com.
