Fine-Structure Constant Maybe Not So Constant

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.'"

Comments

A link to the paper itself

[nyri]

Evidence for spatial variation of the fine structure constant

An evaluation from a practicing physicist would be appreciated.

Re:Don't Hold Your Breath

[CheshireCatCO]

If it varied at all, the result would be significant just on principle. It would mean that the laws of physics have varied in time, which is not something that most current models allow for. (At least, not that I've heard. I work on something a little closer to home, so I might have missed something.)

Re:Don't Hold Your Breath

[Zocalo]

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:

• e, The elementary charge
• h, The reduced Planck constant
• c, The speed of light in a vacuum

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.

"The Economist" article

[PolygamousRanchKid]

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

Repeating ourselves are we

[Gruturo]

Ok, I guess 9 years is acceptable for a dupe, and tbh I didn't even read the article, in /.'s finest tradition, so it might be an actual new development :-)

Kinda sure there was some piece of news on the subject from around 2005-2006 too, but can't find it atm. Meh, google-fu weak at 3am, should sleep, work in under 5 hours.

Re:Don't Hold Your Breath

[Idarubicin]

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.

Re:QED

[Artifakt]

Quantum Electro-Dynamics, not Quod Est Demonstratum.