Beginning of Essay
A whiff of heresy is in the air. There are very few beliefs in science that have the force of doctrine, but among them is the conviction that the speed of light is fixed. It forms the rock upon which Einstein built one of the 20th century's most enduring monuments ....

Middle of Essay
.... on his desk at Imperial College. "The best book ever written about physics," as he calls it, set him on a course that took him to the University of Lisbon, then Cambridge as a research fellow at St John's, and now London. But if he is right, Einstein's conviction that light travels at a fixed and unalterable speed is about to be dethroned. Dr Magueijo and colleagues with whom he has worked - Dr Andy Albrecht, of the University of California at Davis, and Professor John Barrow, of Cambridge - were not quite the first to have this idea. Dr John Moffat of the University of Toronto had floated it, but they were unaware of his work until he complained it ....