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Has observing the universe sealed its fate?

  1. Nov 21, 2007 #1
    Mankind 'shortening the universe's life'
    http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/11/21/scicosmos121.xml
    http://www.newscientist.com/channel...s-observing-the-universe-sealed-its-fate.html
    http://www.news.com.au/adelaidenow/story/0,22606,22801758-5005962,00.html
    http://www.24.com/news/?p=tsa&i=761244

    New Scientist states that the article will be in their next issue. Has this theory been been under any type of peer review before? I did a fairly lengthy Google search but didn't amount to much... at least nothing published from anyone with a bit of credibility. I've never heard of this Krauss fellow so even his credibility is a big question to me. He's written a few books and received quite a few awards, but I've never heard of the guy.

    Lawrence M. Krauss... http://www.phys.cwru.edu/~krauss/


    I'm more-so interested in the logic behind it. Is this another multi-verse/type issue?
     
  2. jcsd
  3. Nov 21, 2007 #2

    Wallace

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    Sounds like bollocks to me. Seems like this guy has done some real research but I don't think you could get this idea in a peer-reviewed journal!
     
    Last edited: Nov 21, 2007
  4. Nov 22, 2007 #3
    well, if this isn't just a "spaced out theory of space", then it must certainly be the strongest possible, perhaps infinitely possible anthropic cosmological theory!

    Supposedly, for mere observation to have altered the fate of the universe would imply a central ultra strong extension to the principles behind the carter inequality formula which is a central tenet of SAP.
     
  5. Nov 22, 2007 #4
    link to paper

    I happened upon your blog. The paper in question is about late time decay and false vacua in inflationary cosmology. It can be found on the physics arxiv, at 0711.1821 for those who want to read it, although it is rather technical, and it has been submitted to Physical Review Letters. Most of the paper is about late time power law decay in false vacuum decays, but the bit that the papers seemed to pick up on involves the speculation at the end regarding quantum cosmology, the quantum zeno effect, and observations of the universe.

    ..and btw, regarding the Motl review of one of my books, Dr. Motl is now no longer associated with a physics dept, to my knowledge, which should reflect upon his supposed review of my book.
     
  6. Nov 22, 2007 #5

    Wallace

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    Good to get some input from the source! It is a shame when 99% percent of a good bit of research is ignored for the sake of over blowing 1%. I'm glad we got a chance to see the real story behind the headlines.

    Regarding the paper you linked, the issue I have with the last three sentences is that it mixes metaphors in a way that I don't think is plausible. An observation of a qauntum system in a lab requires that we interact directly with the wavefunction of that system, thus altering it and extracting information. On the other hand we 'measure' dark energy by absorbing photons into our CCD detectors that were produce billions of years ago. This process does not interact with a field that may dominate the universe that we dub dark energy. The dark energy causes the photons to have different properties however the absorption of them and the subsequent production of the idea of dark energy in the minds of theorists and the circuits of their computers hardly constitutes 'measurement' in the quantum mechanical sense.
     
  7. Nov 22, 2007 #6
    quantum wavefunction

    not so clear... which is why this was discussed.. if you use formalism where spreading of quantum wavefunction and backflow gives the late time behavior of false vacuum, then the question is, when we confirm that we are in false vacuum have we collapsed our wavefunction to the origin.... this is the standard conundrum of quantum cosmology.. and when one is living within the system what constitutes a measurement is not clear.
     
  8. Nov 22, 2007 #7

    Wallace

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    If we absorbed those photons, but that didn't lead to the idea within our minds of dark energy, would that constitute a measurement?
     
  9. Nov 24, 2007 #8

    Chronos

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    This is what I would call wandering down a 'dark alley' in science. It violates casuality, entropy, and logic. An observer dependent universe is unacceptable to me. How did it manage to persist before we came along to infuse it with anthropery?
     
  10. Nov 24, 2007 #9
    chronos, multiverse cosmologist max tegmark considers that observation is a fundamental property of subatomic particles, ie. dark energy has always been observed. tegmark's level 4 multiverse, if and that's a big if, it exists, requires no such or the weakest degree of inanimate thropy, ie. perhaps to bootstrap itself into existance and thereafter never needed again.

    scientist grandi 1744 reckowned that a mathematical universe got started with something like 1-1+1-1+1-1+...=0 or 1
     
  11. Nov 24, 2007 #10
    ...cont'd., i got cut off,

    the analytic philosophy of antrophic theory is so damm complex, arguments hinge often upon very slender threads of infinitary logic constructability omega-feedback etc. etc.

    i think that what is needed is a benchtop experiment on a very simplified system just to find out if a most basic principle can exist. presumably the quantum theorists could consider this...
     
  12. Nov 24, 2007 #11
    the paper is now clearer

    I have decided that indeed the final two sentences of the paper left the incorrect impression that causality was somehow involved. The purpose of these comments was to refer to work I have been discussing with Alan Guth related to this paper.. namely to what extent cosmological observations made today constrain the nature of the wavefunction and our quantum state in a way that may imply we are not in the late-decaying phase.. This is what I should have said, rather than leaving the incorrect impression that somehow actually making the measurement has a causal effect.. it does not.. it merely constrains our quantum state.. The new version of the paper with the last two sentences changed removes this ambiguity I hope, for all future journalists who look at it.

    L. Krauss
     
  13. Nov 25, 2007 #12

    Chronos

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    Thanks for sharing your thoughts and consideration of causal issues, Dr. Krauss. This bit of polishing has greatly enhanced your paper, IMO.
     
  14. Dec 3, 2007 #13

    Chris Hillman

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    Comments by John Baez

    Just dropped by to point out that John Baez has just posted some valuable comments at the N-Category Cafe on this latest example of "science reporting" [sic] from New Scientist :yuck: in which he clarifies the genuine issue underlying the eprint by Krauss and Dent:

    IMO, no responsible publication would have published a story like the NS story without first obtaining a "reality check" from Baez or someone of comparable stature.

    I cannot help but wonder: does this episode show that scientists--- particularly those who have stepped forward to defend science against organized anti-intellectual forces in our society--- need to learn to "write defensively"? Are "in-jokes" out?
     
    Last edited: Dec 3, 2007
  15. Dec 3, 2007 #14

    Is it possible to actually know for certain whether our present vacuum is or is not a "true" vacuum? Isn't it true that all we can measure is differences in energy and not the absolute energy level?

    Also, it may not be the actual observation of the universe that changes anything about it. But could it be that intellectual achievement may represent a reduction in entropy? And could accelerated expansion be a result of this intellectual reduction in entropy? I mean as I recall, there is an entropy associated wtih horizons - even the cosmological horizon that exists because of universal expansion. So if the the entropy inside the cosmological horizon is constrained by the cosmological event horizon, then could an intellectual reduction of entropy cause the cosmological horizon to shrink which means the universe would accelerate in its expansion? I'm not real sure about these things. I'm looking for comments of those who are more informed. Thanks.
     
    Last edited: Dec 3, 2007
  16. Dec 3, 2007 #15
    you can't seal the Universe's fate becasue it will have ALL POSSIBLE fates- which fate you see is another matter entirely
     
  17. Dec 3, 2007 #16

    Garth

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    Hi friend!

    In GR energy acts, together with mass and stress as a source of gravitational fields, i.e. space-time curvature. Therefore it might be argued that absolute energy levels can be measured, by the curvature that is generated.

    One of the problems at the interface of GR and Quantum theory is the QM expectation of the vacuum state having a very high zero point energy density whilst the value of the cosmological constant or false vacuum density from cosmological observations as interpreted by GR is very low. Generally the misfit is said to be OOM 10120 of thereabouts!

    Garth
     
  18. Dec 7, 2007 #17
    Go to the 'double slit experiment' ..to see real cause and affect of 'the observer' on the universe. hg
     
  19. Dec 8, 2007 #18

    Chronos

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    Hi huertg! Welcome to PF. Your idea is unsupported. Ask Zz [a real scientist] that question. You are alluding to an apparent 'inconsistency' in nature that has no observational support.
     
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