Mass Equals Energy

Einstein revealed that mass itself is a form of energy. E = mc² means a tiny amount of mass holds an enormous amount of energy, because c (the speed of light) is a huge number — and you square it. One kilogram of matter, fully converted, releases about 21 megatons of TNT — roughly 1,400 Hiroshima bombs from a bag of sugar.

This is how the Sun works. In its core, hydrogen nuclei fuse into helium that is slightly lighter than the original hydrogen. That missing mass — about 0.7% — becomes the sunlight warming your face. Nuclear plants exploit the same trick with uranium: a small mass difference, a staggering energy release.