On Sunday, October 18, 2020 at 10:11:15 AM UTC-5 [email protected] wrote:
> > > On Sunday, October 18, 2020 at 6:09:39 AM UTC-6, John Clark wrote: >> >> On Sun, Oct 18, 2020 Alan Grayson <[email protected]> wrote: >> >> *> If the very early universe is a hot photon gas, wouldn't that be a >>> very high entropy initial condition?* >> >> >> That would be true if gravity was not an important factor as is the case >> for most experiments we can produce in the lab where gravity can be safely >> ignored, but in the very early universe gravity was enormously important >> and can not be ignored. >> > > > *In Boltzmann's formula for entropy, gravity isn't a parameter. I think > entropy only depends on the number of possible microstates, and therefore > on the volume. AG * > Totally wrong. Entropy is given by the area of a black hole, where the area is A = 4πr^2 and r = 2GM/c^2 or just 2m. Gravity is equivalent to temperature and T = 1/8πm. LC > > The early universe was very smooth but, due to random quantum variations, >> not perfectly smooth. So some parts of the universe had very slightly more >> mass/energy than other parts. As time progressed, because of gravity, the >> slightly denser regions pulled in slightly more particles into themselves >> than the slightly less dense regions did, and so those tiny variations >> started to grow larger. As a result of that growth of variations entropy >> increased and the Universe never again reached the very low entropy level >> it had when it was young. >> >> *> For a given volume, the entropy is what it is, related to the possible >>> microstates as given by Boltzmann's formula. If the volume increases, the >>> entropy increases, and it starts at a maximum level depending on the volume >>> of the very early universe. So I see no distinguishing the Actual Entropy >>> from the Maximum Possible Entropy. AG* >> >> >> The point is that if the universe is expanding (and accelerating) then >> there is no such thing as the universe having a Maximum Possible Entropy, >> whatever entropy value you give me no matter how large I can show you a >> time when the universe will have an even larger entropy. >> > > *The concept of Maximum Possible Entropy was introduced by Jason, via his > reference, and shown schematically in his diagram. Supposedly it can be > compared with actual entropy at any time. I have no idea what this means. > AG * > >> >> John K Clark >> > -- 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/216240cf-f75a-4169-b2a4-d64bcd71f0ebn%40googlegroups.com.
