Thursday, October 28, 2010

Dawn of a New Physics?

While we are enjoying central Florida, the latest issue of New Scientist has on its cover "Dawn of a New Physics?" The article refers to the possibility of the Fine-Structure value changing. the fine-structure value $ \alpha$ is important in atomic energy levels. It is composed of the electron charge e, the Planck value h, and the speed of light c. New Scientist describes the trials of Australia's John Webb, Michael Murphy, and Victor Flambaum, whom this blog has noted many times. Their work seems to indicate that $ \alpha$ has varied over time. This is a big indicator that the speed of light itself has changed. Even if the variation in $ \alpha$ proves to be an artifact, "changing constants" have become part of the vocabulary.

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Blogger nige said...

The variations in alpha reported in star light for twenty years or more are trivial and where they exceed experimental error bars, the estimates of experimental error are probably low.

Builder's paper from Australian Journal of Physics, vol. 11, pp. 279-297 is now online, and indicates larger evidence for variations in c. It's the definitive analysis of the twins paradox in SR, and was confirmed and cited by the atomic clocks experiment paper of 1971 (J.C. Hafele, Science, vol. 177, 1972, pp 166-8).

Builder points out on page 296 that it's impossible to measure the absolute speed of light, only the average speed over a two-way journey. The average automatically eliminates absolute velocity effects. E.g. if you send a laser pulse of light from earth to a mirror left behind on the Moon, then if the light goes faster towards the Moon than on the return trip (due to absolute motion effects), you'll never know: the time you measure will be reflect the average velocity of light, which will obey SR.

This is how the idea of the constancy of the velocity of light is maintained by nature. Builder finishes his paper: “the relative retardation of clocks, predicted by the restricted theory, is an absolute effect which demands our recognition of the causal significance of absolute velocities.”

11:55 PM  

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