A simple explanation of Einstein's equation, E = mc squared, is that small amounts of mass are equivalent to huge amounts of energy. Einstein's equation was revolutionary because it showed that matter and energy were different sides of the same thing.

In Einstein's most famous equation, "E" stands for energy, "m" stands for mass and "c" stands for the speed of light.

Mass is one of the basic properties of all physical objects. It quantifies how much matter is present in an object. It is also a measure of an object's inertia: how difficult it is to move an object from rest or change its course while moving.

His equation technically deals with mass in the sense of inertia. It states that the total amount of energy in a stationary system or object is equivalent to its mass, multiplied by the square of the speed of light. "C," the speed of light, is 186,000 miles per second.

Because the square of the speed of light is such a large figure, Einstein's equation states that small amounts of mass are equivalent to huge amounts of energy. This equation was a powerful aid in the development of nuclear weapons.