## Sunday, September 21, 2008 ... /////

### Annual variations of nuclear decay rates?

A paper in August 2008,

Evidence for correlations between nuclear decay rates and Earth-Sun distance
summarized some experimental evidence suggesting that the decay rates of nuclei could periodically vary every year - by up to 0.5% or so. They link the variations to the Earth-Sun distance which doesn't seem inevitable: the phase doesn't seem to work too well (there's a lag). There exist other quantities that may change during the year - such as the relative orientation of the Earth's and Sun's magnetic field etc.

At any rate, if these oscillations are real, they're really bizarre. Some people suggested variations of the fine-structure constant as a function of the distance from the Sun or an effect of the neutrino flux. The first explanation is far-fetched while the latter is down-to-Earth. There could exist even more down-to-Earth explanations.

Via arXivblog.