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Speed Of Light May Not Be Constant

A Canadian physicist believes that one of the most sacrosanct rules of 20th-century science - that the speed of light has always been the same - is wrong.

In a recent edition of the journal Physics Letters, John Moffat, University of Toronto, and co-author Michael Clayton, say that light once travelled much faster than it does today. Moffat's theory - that the speed of light at the beginning of time was much faster than it is now - provides an answer to some of the puzzles in cosmology.

Theories of the origin of the universe - the Big Bang - suggest that, at the beginning, its edges were farther apart than light, moving at a constant speed, could possibly have travelled in that time. To explain this, scientists have focused on strange, unknown and as-yet-undiscovered forms of matter that produce gravity that repulses objects.

"It is easier for me to question Einstein's theory than it is to assume there is some kind of strange, exotic matter around me in my kitchen," said Moffatt.

His theory could also help explain astronomers' discovery last year that the rate of expansion of the universe is accelerating.

Ever since Einstein proposed his special theory of relativity in 1905, physicists have accepted, as a fundamental principle, that the speed of light - 300 million metres per second - is a constant and that nothing has, or can, travel faster.

Tags: astronomy-space, physics