Earth History
Hadean Eon
The Hadean Eon begins with the formation of Earth, around 4.54 billion years ago, roughly 9.26 billion years after the Big Bang. At this stage, the planet is defined by extremes. Frequent impacts, intense heat, and…
Archean Eon
The Archean Eon begins around 4.0 billion years ago, roughly 9.8 billion years after the Big Bang. By this time, Earth has cooled enough to sustain long-lived oceans and a more stable crust. It is during the Archean…
Proterozoic Eon
The Proterozoic Eon begins around 2.5 billion years ago, roughly 11.3 billion years after the Big Bang. Its defining feature is the gradual oxygenation of Earth. Photosynthetic organisms produce oxygen faster than…
Phanerozoic Eon
The Phanerozoic Eon marks the period when life on Earth becomes abundant, diverse, and visible in the fossil record. It begins around 541 million years ago, long after the planet itself formed, and occupies only a thin…