1 Jan (midnight) Big Bang – Universe forms
15 Mar First stars and galaxies form
1 May Milky Way galaxy forms
8 Sep Sun forms
9 Sep Solar system forms
12 Sep Earth forms
13 Sep Moon forms
20 Sep Earth’s atmosphere forms
1 Oct Earliest known life on Earth
7 Oct Earliest known fossils
18 Dec First many-celled life forms
19 Dec First fish
21 Dec First land planets; First insects
23 Dec First reptiles
24 Dec First dinosaurs
26 Dec First mammals
27 Dec First birds
28 Dec First flowering plants
28 Dec Dinosaurs extinct
31 Dec (11:55 pm) Homo sapiens (modern humans)