Fine Structure Constant May Not Be So Constant 273
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."
Comment removed (Score:5, Interesting)
Reproducibility? (Score:5, Interesting)
Very much want to see independent confirmation of this result, if instrumentation error hasn't been controlled for
But which constant isn't? (Score:3, Interesting)
not new; not really controversial, just wrong (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 [arxiv.org] . 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 [arxiv.org]
J.K. Webb et al., 2010, "Evidence for spatial variation of the fine structure constant," http://arxiv.org/abs/1008.3907 [arxiv.org]
H. Chand et al., 2004, Astron. Astrophys. 417: 853, http://arxiv.org/abs/astro-ph/0401094 [arxiv.org]
Srianand et al., 2004, Phys.Rev.Lett.92:121302, http://arxiv.org/abs/astro-ph/0402177 [arxiv.org]
Duff, 2002, "Comment on time-variation of fundamental constants," http://arxiv.org/abs/hep-th/0208093 [arxiv.org]
Baez, http://math.ucr.edu/home/baez/constants.html [ucr.edu]
Rosenband et al., 2008, 319 (5871): 1808-1812, http://www.sciencemag.org/content/319/5871/1808.abstract [sciencemag.org]