Einstein's famous equation, E=mc2, describes the relationship between energy (E) and mass (m). The equation states that the energy of an object is equal to its mass multiplied by the speed of light squared (c2), where c is the speed of light in a vacuum, which is approximately 299,792,458 meters per second.

In other words, the equation suggests that even a small mass has a tremendous amount of energy stored within it, and this energy can be released and transformed into different forms. This concept has important implications in the fields of physics, especially in nuclear energy and particle physics.

To put it simply, the equation means that a small amount of mass can produce a large amount of energy, which is why nuclear explosions and nuclear power generation are possible. The equation also suggests that mass and energy are not entirely separate entities but are instead interchangeable, an idea that challenges traditional concepts of matter and energy.