It seems that you assume that energy is conserved. Energy is NOT conserved in the General Relativity (only in some particular cases). Our expanding universe is not one of these cases.
The more accurate statement would be that "energy of the whole universe" can't be correctly defined, rather...
I know. Even more: Hawking radiation "blocks" the Big Rip: very close to the rip, Hubble volumes become so tiny that the Hawking radiation (it's intensity grows much faster that the deterioration of space!) fills the space again with the particles, effectively "resetting" the expansion. I don't...
Yes, and the article discusses the difficulty of defining entropy - not only across different Hubble volumes, but also across different MWI universes. I was happy to see the claim I was talking about a long time ago - that total entropy of the whole multiverse is 0.
I see, there is no problem anyway - the inflation of any baby Universe had a beginning (branching from the bulk), I have no problems with it. The important thing is the boiling bulk, constantly generating baby universes - that thing exists forever (I am not sure that the word "forever" is valid...
But this is true only without dark energy, with it the matter (together with the associated degrees of freedom) constantly goes away thru the Hubble horizon, so we can end with an absolutely empty Hubble volume, without a single particle.
Thanks. Just to confirm, when you say "universe has a finite not eternal beginning" are you talking about one of the baby universes (particular bubble) (and I totally agree) or about the whole Multiverse? (if so I am confused)
I was thinking that "eternal inflation" model deals nicely with the problem of the beginning of the universe. If I understand this model correctly, Multiverse is a boiling bulk of some sort of very dense vacuum, creating inflationary "bubbles" (baby Universes), finite from the outside but...
Hi
Could you comment on Big Snap scenario briefly mentioned by Max Tegmark on page 12 (and I can't google more):
How unitary cosmology generalizes thermodynamics and solves the inflationary entropy problem
http://arxiv.org/abs/1108.3080
I understand that during the inflation the number of...
No, I meant the Second law.
If "something is conserved" (=const) is not well defined, then "something never decreases" is also not well defined. "Never decreases" means "never decreases in time", assuming that time is smooth enough, so moments "now" and "then" are well defined. Do you agree...
Additional question, after looking at your articles.
What's about Second Law of Thermodynamics in GR, specifically in curved spacetime?
I know that there are issues with Conservation of Energy in GR, mostly not because it is not conserved, but because sometimes it is impossible to define what...