29 August 2008

Weird physics

Here’s an interesting snippet from the physics arXiv blog. It is usually assumed that nuclear decay rates are constant, but re-examination of some data from the 1980s seems to suggest that the decay rates of silicon-32 and radium-226 vary on an annual cycle. What is more, the variations are synchronized with each other and with the Earth’s distance from the Sun. The folk who have re-analysed the data have suggested two possible explanations:

First, they say a theory developed by John Barrow at the University of Cambridge in the UK and Douglas Shaw at the University of London, suggests that the sun produces a field that changes the value of the fine structure constant on Earth as its distance from the sun varies during each orbit. Such an effect would certainly cause the kind of an annual variation in decay rates that Jenkins and co highlight.

Another idea is that the effect is caused by some kind of interaction with the neutrino flux from the sun’s interior, which could be tested by carrying out the measurements close to a nuclear reactor (which would generate its own powerful neutrino flux).

For more on this, see Do nuclear decay rates depend on our distance from the sun?

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