### Quick Answer

**In the equation E=mc², e stands for energy, m stands for mass and c² stands for the speed of light squared.** First proposed by Albert Einstein, this equation demonstrates that energy and matter are interchangeable.

### Full Answer

Einstein first published the formula in 1905, which is often called his "miracle year," according to the Encyclopaedia Britannica. It was part of a paper titled “Does the Inertia of a Body Depend Upon Its Energy Content?”

The equation established the first mechanism to explain the energy source of stars such as the sun, and it opened the way for new advances in nuclear power and nuclear medicine.