… But it Probably Is
Speed of Light May Not Be Constant
Two papers, published in the European Physics Journal D in March, attempt to derive the speed of light from the quantum properties of space itself. Both propose somewhat different mechanisms, but the idea is that the speed of light might change as one alters assumptions about how elementary particles interact with radiation. Both treat space as something that isn’t empty, but a great big soup of virtual particles that wink in and out of existence in tiny fractions of a second.
The problem I find with articles like this is that they don’t place enough emphasis on the speculative nature of the work — something is being assumed about nature that hasn’t yet been observed, and the authors are investigating the consequences. From the perspective of science this is fine — that’s one way of going about it: think of some novel way nature might be structured, come up with a model, and test it. That’s valid science. But at this point that last part is missing, and as long as it is, one has to worry about over-selling the idea.
http://www.npl.washington.edu/AV/altvw43.html
Altered c is across the gap, amongst other problems.
Graphite, MgB2, (W,Ta,Mo)S2, zirconium phosphonates, and smectite clays.
http://arXiv.org/abs/gr-qc/0107091
http://arXiv.org/abs/quant-ph/0010055
Phys. Lett. B236 354 (1990)
Phys. Lett. B250 133 (1990)
http://arxiv.org/abs/1110.1919
Huge Casimir effect at finite temperature in electromagnetic Rindler space
The Scharnhorst effect apparently allows local speed of light exceeding bulk vacuum lightspeed only when the Casimir energy is negative. Finite temperature-Casimir energy appears to be positive in published cases.
Thermonuclear warheads, pulsars, supernovae, RHIC and LHC heavy ion (gold, lead) collisions, 3×10^20 eV (50 joules) cosmic rays… suggest superluminal physics requires finesse, if not unobtainium (e.g, the Alcubierre drive).