ABOUT E=mc²
In physics, mass–energy equivalence is the relationship between mass and energy in a system's rest frame, where the two quantities differ only by a multiplicative constant and the units of measurement. The principle is described by the physicist Albert Einstein's formula: 𝐸=𝑚c².
In a reference frame where the system is moving, its relativistic energy and relativistic mass (instead of rest mass) obey the same formula.
The formula defines the energy E of a particle in its rest frame as the product of mass (m) with the speed of light squared (c²).
The formula implies that a small amount of "rest mass", measured when the system is at rest, corresponds to an enormous amount of energy when in motion (put to work), which is independent of the composition of the matter.