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Journalists look for big speed-of-light news in two physics papers

26 March 2013

Do the studies in European Physical Journal D deliver?

By Steven T. Corneliussen

In late 2011, news articles tracked the story of some physicists' mistaken belief that an experiment had shown neutrinos exceeding c, the speed of light. Now media outlets are reporting on two European Physical Journal D papers engaging the physics mysteries of vacuum in relation to c. Some in the media appear to be hoping for a rerun of 2011, when a fundamental physics law seemed in question.

'New research shows that the speed of light may not be fixed after all, but rather fluctuates,' says a brief announcement from the AlphaGalileo Foundation. That organization was created in 1998 by the UK's Particle Physics and Astronomy Research Council. It calls itself a 'bridge between the research community and the media.' Much of the media coverage appears to rely closely on the announcement.

The foundation reports that the two papers 'challenge established wisdom about the nature of vacuum,' then continues:

In one paper, Marcel Urban from the University of Paris-Sud, located in Orsay, France and his colleagues identified a quantum level mechanism for interpreting vacuum as being filled with pairs of virtual particles with fluctuating energy values. As a result, the inherent characteristics of vacuum, like the speed of light, may not be a constant after all, but fluctuate. Meanwhile, in another study, Gerd Leuchs and Luis L. Sánchez-Soto, from the Max Planck Institute for the Physics of Light in Erlangen, Germany, suggest that physical constants, such as the speed of light and the so-called impedance of free space, are indications of the total number of elementary particles in nature.

As of early on 26 March, no major media had picked up the story. But in the preceding 12 hours, coverage online expanded from a few reports to eleven.

One article offers this comparatively measured thumbnail summary: 'Two studies of vacuums suggest that the speed of light in a vacuum might fluctuate, pointing the way to a quantum mechanical explanation for why the speed of light and other so-called constants are what they are.'

But other headlines reach for the sensational:

* 'Speed of light might not be the constant we thought it was'

* 'Rethinking the cosmic speed limit'

* 'Light travels at many speeds, new studies suggest: A new study questions the speed of light'

The title of the paper by Urban and colleagues says merely, 'The quantum vacuum as the origin of the speed of light.' The Leuchs and Sánchez-Soto heading leaves c unmentioned. Its abstract begins, 'There may be a link between the quantum properties of the vacuum and the parameters describing the properties of light propagation.'


Steven T. Corneliussen, a media analyst for the American Institute of Physics, monitors three national newspapers, the weeklies Nature and Science, and occasionally other publications. He has published op-eds in the Washington Post and other newspapers, has written for NASA's history program, and is a science writer at a particle-accelerator laboratory.

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