The History of the Earth

Planetary Accretion

4600 BCE

Earth’s Core Formation

4550 BCE

During this stage, the temperature was really hot because of the radiation from the recent supernova and the inexistence of oxygen. Also, meteorites and asteroids frequently slammed to earth which led the rocks and metals to melt, and molten materials separated into layers. Gravity pulled denser materials into the center and lighter materials rose to the surface. This formed the solid inner core, liquid outer core, mantle, and crust.

End of Heavy Bombardment

4500 BCE

During the end of heavy bombardment (4500-3800 million BC), Jupiter and Saturn, the two gas giants, migrated towards the inner planets and cleared out a lot of ore of the rocks and other things in space. Jupiter and Saturn migrated back out after this. Also, at this stage, comets carrying water hit the earth and this is how the earth had water.

Formation of the Moon

4490 BCE

The current theory of the moon’s formation is a mars-sized asteroid crashed into the earth and knocked some debris off. The energy from the impact melted most of the earth and also the asteroid. The very hot molten materials from the earth and the asteroid was thrown out into the orbit. They stayed in orbit around the earth. The materials cooled into a spherical object and became the Moon. The formation of the moon happened during the end of heavy bombardment stage.

Planetary Cooling

4400 BCE