Mass-Energy Equivalence

Einstein's equation E = mc² explains why nuclear energy is so powerful: energy equals mass times the speed of light squared. Because light travels about 300 million meters per second, squaring that produces an enormous multiplier — so converting even a tiny amount of mass releases a staggering amount of energy. In a fission reaction, the fragments weigh slightly less than the original atom plus neutron. That missing 0.1 percent of the mass has become pure energy. A single kilogram of uranium-235 holds as much energy as about 2,700 tons of coal.