According to this well-known equation, the quantities of energy (E) and mass (m) are identical. It is possible to convert one into the other by employing the square of the speed of light (c2) as the conversion factor. This implies that if you know the amount of energy that you have, you can figure out how much mass corresponds to that energy by using the constant c2. On the other hand, if you know the mass that you are working with, you can use c2 to determine the amount of energy that is associated with that mass.
