Ever since Einstein proposed his special theory of relativity in 1905, physicists have accepted as fundamental principle that the speed of light -- 300 million metres per second -- is a constant and that nothing has, or can, travel faster. John Moffat of the physics department disagrees -- light once travelled much faster than it does today, he believes.

Recent theory and observations about the origins of the universe would appear to back up his belief. For instance, theories of the origin of the universe -- the "Big Bang"-- suggest that very early in the universe's development, 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.

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 these cosmology problems.

"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."

His theory could also help explain astronomers' discovery last year that the universe's expansion is accelerating. Moffat's paper, co- authored with former U of T researcher Michael Clayton, appeared in a recent edition of the journal Physics Letters.