Cosmic Timeline (WWCoC)

4.6 Billion Years Ago/Ga (Gigaanum) : The Sun and Solar System come into being 

 4.54 Ga : Earth Forms 

 4.5 Ga: Moon Forms 

 4.4 Ga: Oceans Form 

 4.2 Ga : Earliest possible emergence of life on earth 

 3.5 Ga : Life develops Photosynthesis 

 717-660 Million Years Ago/Ma (Megaanum):  Sturtian Glacial Episode (Snowball Earth) 

 650-635 Ma: Marinoan Glacial Episode (Snowball Earth) 

 575 Ma: Avalon Explosion 

 525 Ma: Cambrian Explosion 

 444-445 Ma:   Late Ordovician Mass Extinction Event 

 327 Ma: Late Devonian Mass Extinction Event 

 252 Ma : Permian-Triassic Extinction Event 

 201.3 Ma : Triassic-Jurassic Extinction Event 

 66 Ma : Cretaceous-Paleogene Extinction Event 

 15-12 Ma: Solar System Crosses Through the Radcliffe Wave