Cosmology: Black holes constrain varying constants

  title={Cosmology: Black holes constrain varying constants},
  author={Paul C. W. Davies and Tamara M. Davis and C. Lineweaver},
There is evidence to suggest that the fine-structure constant, α — a measure of the strength of the electromagnetic interaction between photons and electrons — is slowly increasing over cosmological timescales. As α = e2/[planck]c (where e is the electronic charge, [planck] is Planck's constant and c is the speed of light), this would call into question which of these fundamental quantities are truly constant. Here we consider black-hole thermodynamics as a test of which constants might… 

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