* Astronomy

The varying speed of light cosmology has been proposed independently by Jean-Pierre Petit from 1988 and then John Moffat in 1992 and the two-man team of Andreas Albrecht and João Magueijo in 1998 to explain the horizon problem of cosmology and propose an alternative to cosmic inflation.
In Petit's VSL model, the variation of c accompanies the joint variations of all physical constants combined to space and time scale factors changes, so that all equations and measurements of these constants remain unchanged through the evolution of the universe. The Einstein field equations remain invariant through convenient joint variations of c and G in Einstein's constant. Late-model restricts the variation of constants to the higher energy density of the early universe, at the very beginning of the Radiation-Dominated Era where spacetime is identified to space-entropy with a metric conformally flat. However it should be noted that while this was the first VSL model to be published, and the sole to date where an evolution law is given relating the joint variations of constants through time while leaving the physics unchanged, these papers received few citations in the later VSL literature.

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A brilliant young physicist João Magueijo  asks the heretical question: What if the speed of light - now accepted as one of the unchanging foundations of modern physics - were not constant?
Magueijo, a 40-year old native of Portugal, puts forth the heretical idea that in the very early days of the universe light travelled faster - an idea that if proven could dethrone Einstein and forever change our understanding of the universe. He is a pioneer of the varying speed of light (VSL) theory of cosmology -an alternative to the more mainstream theory of cosmic inflation- which proposes that the speed of light in the early universe was of 60 orders of magnitude faster than its present value.

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