Question

Why is `E=mc^2` important, and what does it tell us?

Answer 1

`E=mc^2` tells us that mass and energy are equivalent.

Explanation:

`E=mc^2` tells us that mass can be converted into energy and vice versa.

The `m` term includes the amount of mass an object gains as its speed increases. Actually `m=m_0/sqrt(1-v^2/c^2` where `m_0` is the rest mass and `v` is the speed of the body.

It is an important equation as it relates energy to mass. It changes the conservation of energy to the conservation of mass-energy.

It explains the energy emitted by radioactive decay and nuclear fission and nuclear fusion. It also explains the mass/energy change when a high energy photon, which has energy but no mass, splits into a particle and its anti-particle which both have mass.