First discovered in the 18th century, uranium is an element found everywhere on Earth, but mainly in trace quantities.
In 1938, German physicists Otto Hahn and Fritz Strassmann showed that uranium could be split into parts to yield energy.
Alchemists observed the element’s rapid, liquid flow, and likened it to the fastest moving planet, Mercury.
(The planet had been named after the fast moving Roman messenger of the gods, Mercury.
But as the ratio of protons to neutrons is increases, protons cannot be held firmly together and hence form an unstable nucleus.