The Hadean is the earliest geological eon in Earth's history, spanning from about 4.6 billion to 4 billion years ago. It is named after Hades, the ancient Greek god of the underworld, reflecting the extreme conditions on Earth during this time. The planet was still forming, characterized by intense volcanic activity, a molten surface, and frequent collisions with other celestial bodies. During the Hadean, the Earth's atmosphere was likely composed of toxic gases, and there were no stable landmasses. This eon ended with the formation of the first solid crust, paving the way for the subsequent Archean eon, where conditions began to stabilize and life could potentially emerge.