Existing comment:
THE LATE HEAVY BOMBARDMENT
During this period, impacts on Earth created over 22,000 craters larger than 20 kilometers (km) in diameter, about 40 basins larger than 1,000 km, and several continent-sized basins larger than 5,000 km.
An ocean formed soon after the Moonforming impact, but life first appeared 800 million years later (3.7 billion years ago), after the Late Heavy Bombardment. Those impacts brought water and some of life's ingredients, and created hydrothermal systems on Earth that were excellent incubators for life. |