A SPECIAL CENTURY

___________________________________

A very special centenary

_______________________________________________________

Einstein's theory of special relativity has been a cornerstone of modern physics for decades, but, as Robert Bluhm describes, physicists are still putting it to the test.

Every physics teacher recognizes the look of astonishment that appears on a student's face when they are taught special relativity. The first tenet on which the theory is built goes along with common sense: the laws of physics are the same in all inertial or nonaccelerating frames. Billiards, for example, can be played on a steady cruise ship just as well as it can be played on solid land.

It is the second tenet – that the speed of light in a vacuum is the same in all inertial frames – that causes jaws to drop. It is a bit like saying that two police officers, one standing still and the other in a fast-moving car, will both clock the same speed for a passing motorist. Clearly, this defies all common sense. It took the genius of Einstein to suspend his disbelief and explore the consequences of these two requirements.