Talk:Oscillatory universe

Expanding universe uses the lower-case u; this article uses the capital, and even capitalizes the word oscillatory. Why? Michael Hardy 23:24, 1 Jun 2005 (UTC)

Beats me. If I had my way, Oscillatory Universe, Big Bang, Big Crunch and Big Rip should all have lowercase second words. –Joke137 23:43, 1 Jun 2005 (UTC)

== When was this proposed? ==to the highest livel

Why does this article have no date? --James S. 01:23, 21 February 2006 (UTC)[reply]

Beats me. I'm sure it was well before the discovery of the CMB, maybe in the thirties. I don't have online access, but I think it is this article

R. C. Tolman, Effects of inhomogeneity on cosmological models, Proc. Nat. Acad. Sci. 20, 169–76 (1934).

–Joke 01:33, 21 February 2006 (UTC)[reply]

Actually, it could also have been in Tolman's famous book,

R. C. Tolman, Relativity, theormodynamics and cosmology (Oxford U., 1934)

–Joke 01:39, 21 February 2006 (UTC)[reply]

Another reason why this is no good

Wasn't the recent discovery that the rate of expansion of the universe is increasing another reason for why the oscillating universe theory isn't valid? —The preceding unsigned comment was added by Gellender (talk • contribs) 06:54, 18 December 2006 (UTC).[reply]

New Developments

http://www.sciencedaily.com/releases/2007/01/070130091159.htm —The preceding unsigned comment was added by 84.108.255.105 84.108.255.105 16:54, 10 February 2007 (UTC)[reply]

Uh, why does it say that "Philosophers have demonstrated the impossibility of traversing an infinity"... it should say, that some philosophers, for example Whitrow, have presented arguments that traversing an actual infinity is impossible... but they have by no means demonstrated it: Quentin Smith argues against the point in an article you can find on google called "infinity and the past (1987)", saying that it is based on the fallacy of equivocation.

Other arguments presented regarding said impossibility are also being debated still today, so we should not be giving people the impression that the matter is over and done with.

New Developments

Agreed. Since nothing has been done to correct this horribly incorrect paragraph, I'm removing it entirely. Here it is, in case anyone chooses to try to resurrect it: "Another major issue posed to an oscillatory model is that of traversing infinites. As an external conceptual problem to this model of the universe, Philosophers have demonstrated that it is impossible to traverse an infinite amount of time while ending up in the present. This presents a serious challenge to Oscillatory concepts, since part of this theory includes the notion that the Universe has always existed."

User:Tarotcards 07:31, 20 March 2007 (UTC)[reply]

Since that para has gone and referencing is improved, I removed the Original Research template. PaddyLeahy 03:34, 24 April 2007 (UTC)[reply]

Entropy ?!

The article used to say:

Theoretically, the oscillating universe could not be reconciled with the second law of thermodynamics: entropy would build up from oscillation to oscillation and cause heat death.

I've been trying to get my head round this. Tolman thought that there was no upper limit to the entropy in this case (unlike a conventional closed system), which would mean no need for a heat death. This seems to imply that the (maximum) total energy of the universe increases on each cycle, which violates every conceivable notion of global energy conservation (quite a disputed concept in GR, I admit). Maybe the suggestion was that if each cycle is longer than the last there must be a beginning in time after all... but it is not obvious that the sequence has to converge. To the extent that heat death is reached, it seems to me that it would just make subsequent oscillations effectively reversible and so they would continue for ever, which doesn't seem to be consistent with the quoted sentence. On the other hand, Tolman didn't know about black hole entropy, e.g. discussion by Penrose about big bang vs big crunch asymmetries. Then again, the singularity theorem renders this moot, except that it assume a strong energy condition which is false now and was false during inflation, so why not during the bounce? Then again (again), if GR is wrong (which everyone agrees it is) all bets are off. My head hurts. PaddyLeahy 15:31, 24 April 2007 (UTC)[reply]

oscillating model

The amount of the change in the observed frequency of a wave due to Doppler effect, usually expressed in hertz. Also known as Doppler frequency.

Merge with Cyclic Model?

The Cyclic Model article is much more complete and describes the same thing. Perhaps these articles should be merged? 129.170.148.212 (talk) 19:01, 6 May 2010 (UTC)[reply]

supercluster of distant galaxies (right), as compared to absorption lines in the optical spectrum of the Sun (left). Arrows indicate redshift. Wavelength increases up towards the red and beyond (frequency decreases). —Preceding unsigned comment added by 98.226.140.126 (talk) 21:25, 9 September 2009 (UTC)[reply]