Up to the present, many scientists have made great contributions to the understanding of the universe.
One of them is Albert Einstein, a German physicist, who revolutionized our concepts of space and time with his theories of relativity. In 1905 Einstein published his special theory of relativity. The foundation of the theory is the observation that light moves at a constant speed as measured by all observers, whatever its state of motion. One consequence is that measurements of distance and time are not absolute quantities but very relative to the motion of an observer. Another is that energy(E) can be converted into mass(m), and vice versa, according to the formula E=mc2 ,where c is the speed of light. Ten years later, Einstein’s general theory of relativity extended this work to include acceleration and gravity — stating that the two are equivalent. Einstein showed that gravity is actually the warping of space by matter. One consequence is that l
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