Theory of relativity 2012

The true nature of Albert Einstein’s theory that time is a relative concept and the higher you live above sea level, the faster you should age, has been demonstrated with the world’s most accurate clock for the first time. Experts found that time really does run more quickly the higher you are – just as Einstein predicted, The Independent reported Tuesday. They monitored two atomic clocks positioned just a foot apart in height above sea level.  Einstein had proposed 100 years ago in his theory of relativity that time and space are not as constant as everyday life would suggest. 
He suggested that the only true constant, the speed of light, meant that time can run faster or slower depending on how high you are, and how fast you are travelling.

James Chin-Wen Chou and his colleagues from the US National Institute of Standards and Technology in Boulder, Colorado, conducted the study. ”These precise clocks reveal the effects of gravitational pull, so if we position one clock closer to a planet, you also increase the gravitational pull and time actually runs slower than for another, similar clock positioned higher up,” Chou said.  ”No one has seen such effects before with clocks which is why we wanted to see if these effects are there. We would say our results agree with Einstein’s theory – we weren’t expecting any discrepancies and we didn’t find any,” the newspaper quoted him as saying.
 
Special relativity is a theory of the structure of spacetime. It was introduced in Einstein's 1905 paper "On the Electrodynamics of Moving Bodies" (for the contributions of many other physicists see History of special relativity). Special relativity is based on two postulates which are contradictory in classical mechanics:      The laws of physics are the same for all observers in uniform motion relative to one another (principle of relativity).     The speed of light in vacuum is the same for all observers, regardless of their relative motion or of the motion of the source of the light.
 
 The resultant theory copes with experiment better than classical mechanics, e.g. in the Michelson-Morley experiment that supports postulate 2, but also has many surprising consequences. Some of these are:      Relativity of simultaneity: Two events, simultaneous for one observer, may not be simultaneous for another observer if the observers are in relative motion.     Time dilation: Moving clocks are measured to tick more slowly than an observer's "stationary" clock.     Length contraction: Objects are measured to be shortened in the direction that they are moving with respect to the observer.     Mass–energy equivalence: E=mc^2, energy and mass are equivalent and transmutable.     Maximum speed is finite: No physical object, message or field line can travel faster than the speed of light in a vacuum.  The defining feature of special relativity is the replacement of the Galilean transformations of classical mechanics by the Lorentz transformations. (See Maxwell's equations of electromagnetism and introduction to special relativity).