Sunday, August 20, 2006

Neil Turok's Colliding Universes

If you miss one theory of cosmic origins, you can be pretty sure there will be another one along in a minute. The latest comes from Neil Turok - see here. Turok, seemingly supported by Stephen Hawking, thinks a Big Bang happens every trillion years or so when two universes collide and start - I think this is right - all over again. I have always been puzzled by the exact status of these ideas. I know they are part of physics but are they a necessary part? How could we ever know whether they were right or wrong? The very fact that they change so often suggests that any evidence either way must be very inconclusive. They seem so remote from any experimental confirmation that it might be more accurate to treat them as theology, games or even insanely elaborate metaphors. Perhaps, in spite of Wallace Stevens' efforts, they are what poetry is now. But science? Somehow I doubt it.

8 comments:

  1. I'm not very au fait with science despite the occasional attempt to read something relevant. Are they searching for an adequate way of explaining the existence of ....well anything, without recourse to an external force, or in other words that physics desires that the universe be sufficient to bring about its own existence? But as a result they're left with having to make do with a perpetual state of existence for reality or the universe(s). As the something from nothing scenario is obviously irrational.
    And do they find this irritating?
    Anyway I think I'll have a go at cosmology, it seems easy enough.
    Every trillion or so years Jeffrey Archer and Paris Hilton get stuck in a lift and all sorts of wonderful things start to happen... I promise to share the royalties, Bryan.

    ReplyDelete
  2. Andrew, thanks for that. You have unearthed a consistency in my thoughts processes that had eluded me. It is all one and Jeffrey and Paris are there.

    ReplyDelete
  3. I was surprised to see this article in the Sunday Times because Turok's idea was proposed some years ago, and hasn't excited much general interest since. The idea was originally called the Ekpyrotic universe. See

    J Khoury, B A Ovrut, P J Steinhardt, N Turok, ?The Ekpyrotic Universe: Colliding Branes and the Origin of the Hot Big Bang?. Phys.Rev. D64: 123522 (2001)

    The Ekpyrotic universe proposal is based upon some ideas from M-theory, which itself is a development of string theory. Hence, if M-theory is of no physical relevance, as many outside the M-theory research community now believe, then the Ekpyrotic universe is also of no physical relevance. The Ekpyrotic universe proposal suggests that the big-bang was caused by a collision between 'branes' in a higher-dimensional space-time. M-theory generally postulates that space-time is 11-dimensional, and these 'branes' are lower-dimensional surfaces embedded in this 11-dimensional space-time. It is suggested that our universe might coincide with, or be a subset of, such a brane. This is a distinct proposal from that entertained by the pioneers of (super-)string theory, who proposed that our universe itself has 11-dimensions, but seven of them are too small to detect.

    For those interested in the claims made by modern cosmology to explain the creation of the universe, may I provide a 'vanity-reference' to one of my own papers:

    http://www.arxiv.org/abs/gr-qc/0503029

    Don't let the technicalities deter you!

    Note that the article by Jonathan Leake in the Sunday Times contains the false claim that dark energy "is now thought to be the cause of the universe?s expansion." Dark energy is held to be responsible for the accelerating expansion of the universe, not the expansion per se.

    ReplyDelete
  4. Good grief, Gordon, I had no idea you were in this game. I trust I did not offend you by suggesting your discipline was poetry. Anyway, thanks for a welcome note of authority.

    ReplyDelete
  5. Like yourself, Bryan, I went to university to study English Literature, so I certainly wasn't insulted by such a suggestion! Are the more speculative parts of modern physics a form of poetry? If we assume that theories such as M-theory really are of no physical relevance, then what we have are extremely beautiful pieces of mathematics, but slightly more than merely pure mathematics, for the proponents of these theories claim that it is as if the physical world has the structure specified by these theories. What we have, then, are pieces of beautiful, imaginative fiction, and this might indeed be taken as a sufficient condition for poetry.

    ReplyDelete
  6. GM, my major was in History and Philosophy of Science (with a minor-major in Aerody...no, maybe that should be a 'very flat minor-minor diminished seventh'....sorry, I digress). One thing I could never quite get an 'ear' for was mathematics as an aesthetic discipline, an art. It drives me nuts with envy when the Sum Monkies use words like 'elegant', 'beautiful' and (yes) 'poetic' to describe solutions, because (like chess) it's a language I've never quite grasped.

    Q. Can you point me towards any simple(-ish) and/or famous examples of what would be called 'beautiful' mathematics by the expert fraternity? Is there an album of 'Easy Listening Sum Classics', say? What characteristics are 'beautiful' to the mathematician?

    I am still moderately literate, if rusty, in basic Bachelor grad-level number-crunching...I think.

    ReplyDelete
  7. 'Easy Listening Sum Classics'? Well, if you take the following link,

    http://us.metamath.org/mpegif/mmmusic.html

    then you'll be able to listen to some famous mathematical proofs set to music!

    ReplyDelete
  8. Ted Tegmark (MIT) has shown that within 10 raised to the power 10 trillion light years (this is a really big number; for example, our known universe has 10 raised to the power 81 protons)there will be at least one earth identical to ours in which all of us are doing exactly the same things as we are here.

    Within that radius will be any number of earths where we are doing different things.

    So somewhere out there, Paris Hilton and Jeffery Archer have gotten/are/will get together in that elevator - all these states have to be valid somewhere in the universe (with a big U). So somewhere out there Andrew and Bryan have collected/are collecting/will collect royalties.

    So not to worry about the money: its yours - somewhere out there.

    ReplyDelete