What will happen to the universe?

[Urban Ranger]

Originally posted by KrazyHorse
You are talking about cosmology from 25 years ago. Inflationary cosmology makes nonsense of the notion of specifying a point in time for the "big bang"....

Well if that's 25 years old what's the current theory like?

No I didn't have the chance to listen to Hawking's seminar last Thursday.

[Urban Ranger]

Originally posted by KrazyHorse
Vacuum energy = the energetic cost of having space. And it exists everywhere, not just in volumes under vacuum.

Is that the same as "zero point" energy?

[KrazyHorse]

Yes

[Urban Ranger]

If there are multiple universes, is it likely that their laws of physics are identical (or similar)?

[chequita guevara]

Originally posted by Lancer
Btw, granite flows, did you know that Geronimo?

Granite does flow . . . under enormous pressure, very, very slowly. All rocks do.

[chequita guevara]

Originally posted by Urban Ranger
If there are multiple universes, is it likely that their laws of physics are identical (or similar)?

Since we can't observe those other universes, how could we even guess?

[KrazyHorse]

Originally posted by Urban Ranger
If there are multiple universes, is it likely that their laws of physics are identical (or similar)?

You're asking me to speculate on the laws of physics in another Universe with absolutely no experimental or observational basis?

[Drake Tungsten]

Come on dude, don't sell yourself short.

[Seeker]

haven't we already had this thread?? And recently to boot?

http://apolyton.net/forums/showthread.php?s=&threadid=152579&perpage=30&pagenumber=3

And no one has even linked to any recent articles, not even popular tripe like Discover magazine or Scientific American to piss off KH??

My position in a nutshell from the last thread: I don't think the 'Big Rip' scenario holds water over an infinite period of time.

Pertinent Info from the last thread:
“In place of a classical Big Bang there is in fact a quantum bounce,” said Ashtekar. “We were so surprised by the finding,” he added, that the team repeated the calculations for months to include different different possible values of some numbers representing the current universe. But the results kept pointing to a bounce.

The findings appear in the current issue of the research journal Physical Review Letters.

While the general idea of another, pre-Big Bang universe isn’t new, Ashtekar said, this is the first mathematical study that systematically establishes its existence and deduces properties of its spacetime geometry.

(Abbay Ashtekak is the physicist)

[KrazyHorse]

I don't think the 'Big Rip' scenario holds water over an infinite period of time.

?

a) Why not?

b) What makes you think that I assume that the equation of state for dark energy is with w < -1? The best we can do (assuming a constant equation of state for dark energy) is to put the constraint w < -0.7 or so.

[Seeker]

http://prl.aps.org/

arrghh! It's going to be very diffcult to get back to you with specifics...I don't seem able to search PRL easily

The excerpts which I have found quoted on popular websites are all vague and don't show

April Article Abstract:

http://scitation.aip.org/vsearch/servlet/VerityServlet?KEY=PRLTAO&CURRENT=NO&ONLINE=YES&smode=strresults&sort=rel&maxdisp=25&threshold=0&allprl=1&pyears=aps2000s&possible1zone=multi&bool1=and&possible2=Abhay+Ashtekar&possible2zone=author&OUTLOG=NO&viewabs=PRLTAO&key=DISPLAY&docID=1&page=1&chapter=0

The website got the actual article's date wrong, it was published in April not May.
Here is the claim, that there is a "mathematical study" documented in that article that INDIRECTLY poses problems for the 'Big Rip' theory, since it is obviously incompatible with what the author calls a 'quantum bounce' (lol the Big Bounce Theory?):

"In place of a classical Big Bang there is in fact a quantum bounce,” said Ashtekar. “We were so surprised by the finding,” he added, that the team repeated the calculations for months to include different different possible values of some numbers representing the current universe. But the results kept pointing to a bounce.

The findings appear in the current issue of the research journal Physical Review Letters.

While the general idea of another, pre-Big Bang universe isn’t new, Ashtekar said, this is the first mathematical study that systematically establishes its existence and deduces properties of its spacetime geometry."

Now obviously I'm not going to dig out his numbers, as a layperson I must trust that he knows what he is talking about in order to get past peer review, and that therefore the final fate of the universe may not be as cut and dried and uncontroversial as you were making it out to be. But you can look it up, and tell me if he is full of it or what.

[KrazyHorse]

a) Thanks for providing a link to the front page of the most famous physics journal in the world. I never would have found it otherwise

b) Seeker, all that article is is a highly speculative study of the cosmological consequences of one specific brand of particle theory. It is by no means any sort of "proof" of anything, other than within the confines of a narrowly defined set of axioms

c) Even if you assume that the Universe must necessarily have already undergone one compression, it does not at all imply that it needs to undergo another one. Given the current state of the Universe there is no reason whatsoever to assume that it will ever undergo another compression. It has become dark energy dominated, and thus the expansion is accelerating. As time goes on, DE will dominate more and more strongly, assuming no odd evolution of w (no reason to assume that w evolves at all at this point), so point where deceleration can happen is already passed.

[Urban Ranger]

Originally posted by KrazyHorse
You're asking me to speculate on the laws of physics in another Universe with absolutely no experimental or observational basis?

Why not?

Don't tell me cosmologists are dead serious all the time.

[Lancer]

What if it keeps expanding until it arrives at the point(s) from which it bounced?

[KrazyHorse]

Originally posted by Lancer
What if it keeps expanding until it arrives at the point(s) from which it bounced?

What the **** are you talking about?