Mass energy equivalence...

Mass-energy equivalence is the famous concept in physics represented mathematically by E=mc^2 , which states that mass and energy  are one and the same .This equation gives the amount of energy equivalent to a certain mass and is a result derived from Einstein's theory of relativity.A consequence of the mass–energy equivalence is that if a body is stationary, it still has some internal or intrinsic energy, called its rest energy, corresponding to its rest mass.