Interesting : Can you please explain Einstein's theory of relativity and the reason why it is such a great theory?

Can you please explain Einstein's theory of relativity and the reason why it is such a great theory?

A little research on the Web revealed that Einstein introduced not one but two theories of relativity . The first one, A Special Theory of Relativity, was published in 1905 and it overthrew common sense perceptions and interpretations of space and time. The theory states that relative to the observer, both space and time are altered near the speed of light -- distances appear to stretch and clocks tick more slowly. Ten years later, Einstein's General Theory of Relativity challenged Newtonian assumptions about a "clockwork universe" and the nature of gravity. To Einstein, gravity is a local warp in the fabric of spacetime, rather than a distant force. This new theory of gravitation paved the way for scientists to first conceptualize, then study and simulate the behavior of black holes. But what's so special about relativity ? By creating two important ideas, Einstein developed his paradigm-shifting physics: The speed of light is a constant -- it's the same for all observers, regardless of how they are moving relative to the light source. All observers moving at constant speed should observe the same laws of physics. In the absence of gravity (a special-case scenario) intervals of time and/or length must depend on the speed of the system relative to the observer's frame of reference. This led Einstein to his famous realization that matter and energy are interrelated and to the famous formula that expresses this relationship mathematically: E = mc². (E is equal to energy, m is mass and c [constant] is the speed of light.) Experiments have shown that an atomic clock traveling at high speeds in a jet does indeed tick more slowly than the exact same clock on the ground. Through the exchange of articles, ideas, and equations with other scientists, Einstein worked out a "general" theory, publicized in 1915-1916, that accounted for the influence of gravity on the motion of bodies, the shape of space, and the flow of time. Einstein wrote, "General relativity is beautiful and simple (to a physicist), but mathematically it's very complicated and subtle." One of the great things about Einstein's theories is the exploration that they continue to generate. Scientists find new ways to test and communicate abstract concepts and models. In the words of physicist John Wheeler, "matter tells spacetime how to curve, and curved space tells matter how to move." Not sure what that means? Check out these movie simulations of the type of cosmic events that relativity aims to describe.