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Fine Structure Constant May Not Be So Constant

Posted by Soulskill on from the pi-is-exactly-three dept.

BuzzSkyline writes "According to a post at Physics Buzz, 'Just weeks after speeding neutrinos seem to have broken the speed of light, another universal law, the fine structure constant might be about to crumble.' Astronomical observations seem to indicate that the constant, which controls the strength of electromagnetic interactions, is different in distant parts of the universe. Among other things, the paper may explain why the laws of physics in our corner of the universe seem to be finely tuned to support life. The research (abstract) is so controversial that it took over a year to go from submission to publication in Physical Review Letters, rather than the weeks typical of most other papers appearing in the peer-reviewed journal."

4 of 273 comments (clear)

  1. Zones of thought! by CRCulver · · Score: 5, Interesting

    When this news was published on another news for nerds site (Slashdot is quite slow these days), several commenters brought up Vernor Vinge's novel A Fire upon the Deep . In that far-future musing on the growth of civilizations and technological singularities, Vinge had the Milky Way galaxy divided into various zones which limited how complex technology could be. At the centre, even the simplest machines would fall apart. Further out, electronics and other 20th-century devices worked, but nanotechnology was less effective. Any race moving to the outskirts of the galaxy reached technological progress undreamed of elsewhere.

    Vinge made it clear that the Zones were the artificial creation of an ancient advanced race, not the natural result of physics. This news is thought-provoking in that the constants for life and perhaps technology change naturally throughout the universe. It's not just science catching up with science-fiction, but rather science anticipating something generally unexpected., though didn't Poul Anderson write a story of changing laws of physics too?

  2. Reproducibility? by n5vb · · Score: 5, Interesting

    '“The thing that troubles me about it is [in] the preprint, [t]hey had originally had a supplemental figure at the end that showed the original results for the individual quasars they measured,” Orzel said. He explained that in that figure, the Keck telescope in the Northern Hemisphere seemed to predominantly measure the variation of alpha in one direction while Chile’s VLT in the Southern Hemisphere measured it in going the other way. “It looks a lot like what they’re seeing is coming from a difference between the two telescopes.”'

    Very much want to see independent confirmation of this result, if instrumentation error hasn't been controlled for ..

  3. But which constant isn't? by YTMDetc · · Score: 3, Interesting

    Alpha is actually made up of several constants, as shown in the wikipedia article. So, the question is, if this is indeed the case that alpha isn't constant, which of these 'constants' is actually not a constant? e is the elementary charge. The charge on a proton (-e for an electron). Somehow I think this is unlikely not to be a constant as for all intents and purposes all protons are the same as any other proton, same with electrons. h is the Planck constant, which relates energy to frequency of electromagnetic waves, for example. I'd say that it's a relational constant to create different ways of saying the same thing, so I wouldn't think this is a variable. c is the speed of light in vacuum, 0 is the permittivity of free space, 0 is the magnetic constant or permeability of free space. All three are related by Maxwell's laws. My guess is that it might be one (or all, or some) of these that would be the most likely to not be a variable. Of course, as with the faster-than-light neutrinos, we'll just have to wait for the results to be checked before we can jump to any radical conclusions...

  4. not new; not really controversial, just wrong by bcrowell · · Score: 5, Interesting

    First off, the slashdot summary is somewhat misleading, because the result is not new. Their result was announced in August 2010: http://arxiv.org/abs/1008.3907 . What is new is that they finally managed to get it published in a peer-reviewed journal. You can't judge whether it's right or wrong simply based on whether it's been published in a peer-reviewed journal. Peer review doesn't judge whether a result is right, or whether it can be reproduced. Peer review just tries to judge whether there are obvious mistakes, and things like whether it properly cites the previous literature. The fact that the journal is a prestigious one also doesn't mean it's right; it just means that *if* it were right, it would be of a high level of scientific importance.

    Second, it's not really correct to say that the result is controversial. It's not controversial. It's wrong, and the fact that it's wrong is uncontroversial. Just because there's an overwhelming consensus that a result is wrong, that doesn't mean it can't be published in a peer-reviewed journal. Below is a FAQ entry I wrote about this stuff.

    Has the fine structure constant changed over cosmological timescales?

    It has been claimed based on astronomical observations that the unitless fine-structure constant alpha=e^2/hbar*c actually varies over time, rather than being fixed.[Webb 2001] This claim is probably wrong, since later attempts to reproduce the observations failed.[Chand 2004] Rosenband et al.[Rosenband 2008] have done laboratory measurements that rule out a linear decrease of alpha with time large enough to be consistent with Webb's results.

    Webb et al. have recently made even more extraordinary claims that the fine structure constant varies over the celestial sphere.[Webb 2010] Extraordinary claims require extraordinary proof, and Webb et al. have not supplied that; their results are at the margins of statistical significance compared to their random and systematic errors.

    Even if their claims are correct, this is not evidence that c is changing, as is sometimes stated in the popular press. If an experiment is to test whether a fundamental constant is really constant, the constant must be unitless.[Duff 2002] If the fine-structure constant does vary, there is no empirical way to assign blame to c as opposed to hbar or e. John Baez has a nice web page discussing the unitless constants of nature.

    J.K. Webb et al., 2000, "Further Evidence for Cosmological Evolution of the Fine Structure Constant," http://arxiv.org/abs/astro-ph/0012539v3

    J.K. Webb et al., 2010, "Evidence for spatial variation of the fine structure constant," http://arxiv.org/abs/1008.3907

    H. Chand et al., 2004, Astron. Astrophys. 417: 853, http://arxiv.org/abs/astro-ph/0401094

    Srianand et al., 2004, Phys.Rev.Lett.92:121302, http://arxiv.org/abs/astro-ph/0402177

    Duff, 2002, "Comment on time-variation of fundamental constants," http://arxiv.org/abs/hep-th/0208093

    Baez, http://math.ucr.edu/home/baez/constants.html

    Rosenband et al., 2008, 319 (5871): 1808-1812, http://www.sciencemag.org/content/319/5871/1808.abstract

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