Albert Einstein's relativity has changed forever the way we think about space, time and the universe. In two papers published in 1905, he proposed a new way of looking at motion, mass and energy, and in 1915 he postulated a new conception of gravity. His 1905 papers on special relativity were just a part of his remarkable "miracle year," whose 100th anniversary physicists worldwide are celebrating with the World Year of Physics. Some scholars have even suggested that …showed first 75 words of 2099 total…

…showed last 75 words of 2099 total…of the force of gravity between tiny objects separated by fractions of a millimetre to see if gravity at short distances behaves the same as gravity at solar-system distances. How well the general theory will fare in the face of this experimental onslaught is anybody's guess. But given that Einstein derived his theory using only principles of beauty, simplicity and symmetry, it is truly remarkable how right it has turned out to be so far.