- 646 billion years ago Earth's gases came together through a densification process.
- 5 billion years ago Earth first became solid and the first primeval life began.
- The process of development of the pure-Earth human can be classified into 3 principal phases when it concerns a physically recognisable human.
- 8.5-6 million years ago.
- 4.8-4.5 million years ago.
- 4.5 million years ago the human developed reason and understanding
- 3.9-1.5 million years ago.