— Earth is formed by a collision between proto-Earth and the rogue planet Theia, a wayward fragment of which later becomes the Moon. The Hadean eon begins at this time. As the new Earth’s core forms, the very first Cycle likely begins at this time as well.
— The earliest fossil evidence of life on Earth – the ancestors of the bacterium Sarcophagus marabunta – dates to this time.
— Vaalbara, the Earth’s first major supercontinent, is formed.
— Ur, the Earth’s first minor supercontinent, is formed.
— Kenorland, the Earth’s second major supercontinent, is formed.
— The “Great Oxygen Catastrophe” occurs, supercharging Earth’s atmosphere with O₂ and inadvertently setting off one of t