The Hadean is the geological eon before the Archaean. It began at the Earth's formation about 4.6 billion years ago, and ended 4 billion years ago. The name "Hadean" comes from Hades, Greek for "Underworld", due to the conditions on the Earth at the time. The geologist Preston Cloud first used the term in 1972. Meteorite bombardment, volcanism and high temperatures were very widespread on the early Earth.