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Fine-Structure Constant Maybe Not So Constant

Posted by samzenpus on from the variety-is-the-spice-of-life dept.

Kilrah_il writes "The fine-structure constant, a coupling constant characterizing the strength of the electromagnetic interaction, has been measured lately by scientists from the University of New South Wales in Sydney, Australia and has been found to change slightly in light sent from quasars in galaxies as far back as 12 billion years ago. Although the results look promising, caution is advised: 'This would be sensational if it were real, but I'm still not completely convinced that it's not simply systematic errors' in the data, comments cosmologist Max Tegmark of MIT. Craig Hogan of the University of Chicago and the Fermi National Accelerator Laboratory in Batavia, Ill., acknowledges that 'it's a competent team and a thorough analysis.' But because the work has such profound implications for physics and requires such a high level of precision measurements, 'it needs more proof before we'll believe it.'"

10 of 105 comments (clear)

  1. first constant post by Anonymous Coward · · Score: 3, Funny

    we need more research to tell if this is first or not.

    1. Re:first constant post by AnonymousClown · · Score: 5, Funny

      we need more research to tell if this is first or not.

      I am unable to reproduce your results.

      --
      RIP America

      July 4, 1776 - September 11, 2001

  2. Don't Hold Your Breath by CheshireCatCO · · Score: 4, Insightful

    This isn't the first time that some team has claimed this. Around 2000, someone made the same claim. I recall it not standing up when other teams checked it.

    Measurements like this have been done before and usually show a constant, er, constant to within experimental uncertainty.

    Note, for example, this paragraph buried at the end of the article:

    Nonetheless, the study “is as speculative as the previous claims,” asserts Patrick Petitjean of the Institute of Astrophysics in Paris, whose team has looked for variations in the fine-structure constant with the Very Large Telescope as far back as about 11.5 billion years ago and found none (SN: 4/8/04, p. 301).

    In other words, I wouldn't get excited at all yet.

    1. Re:Don't Hold Your Breath by Zocalo · · Score: 5, Informative
      The fine structure constant is given as being equal to "e^2/hc", so if the FSC is not a constant then one (or more) of the other values must also be a variable. Take your pick between:

      If any of those constants turned out to in fact be variable, or even a "constant" which has varied over the lifetime of the universe, then the implications would be profound to say the least.

      --
      UNIX? They're not even circumcised! Savages!
    2. Re: Don't Hold Your Breath by Black+Parrot · · Score: 4, Funny

      The fine structure constant is given as being equal to "e^2/hc", so if the FSC is not a constant then one (or more) of the other values must also be a variable.

      Or maybe the "2" is changing?

      Not mathematically, but 1.999--> 2.001 or such.

      --
      Sheesh, evil *and* a jerk. -- Jade
    3. Re:Don't Hold Your Breath by Idarubicin · · Score: 3, Informative

      Actually, it is possible to work in fundamental units in which hbar = c = 1, so the latter two can be considered constant by definition.

      Oh, so close -- you just needed to look up one more Wikipedia article to get a hint about why your reasoning is faulty. There are indeed systems of so-called natural units which assign a constant value of 1 to certain physical units. Yes, there are systems which define c and h-bar as 1, but there are also systems which define e to be exactly 1.

      Inconveniently, merely asserting a definition doesn't actually compel obedience on the part of the Universe. If I work in Stoney units, then I define e and c to be constant, so h-bar must be changing if the fine structure constant changes. In Schrodinger units, e and h-bar are constants, and c must be changing. The natural-unit systems only work properly if the assumption of constancy of their chosen fundamental constants is correct.

      --
      ~Idarubicin
  3. A link to the paper itself by nyri · · Score: 3, Informative

    Evidence for spatial variation of the fine structure constant

    An evaluation from a practicing physicist would be appreciated.

    1. Re:A link to the paper itself by CheshireCatCO · · Score: 3, Interesting

      Wow. Check out Figure 5. It's hard to believe there's any systematic signal in their data, they have blue and red points mixed up all over the sky. They claim there's an excess of one color in one hemisphere and the other color in the other hemisphere, but it's not very strong signal at all. This isn't my field (I work on Saturn's rings), but my first reaction is amazement that this is serious enough to be talking to the press about.

      (I'm also more than a little put off by the fact that this hasn't been accepted, evidently, merely submitted to a journal. And not even an astrophysical journal like AJ or ApJ which seem like a far better fit for this subject matter and the audience.)

    2. Re:A link to the paper itself by Inthewire · · Score: 3, Funny

      They seem to be in good shape. Thank you for your efforts.

      --


      Writers imply. Readers infer.
  4. "The Economist" article by PolygamousRanchKid+ · · Score: 5, Informative

    This week's "The Economist" has a good article on this: http://www.the-economist.com/node/16930866

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