Planetary Accretion

Planetary Accretion

5 BCE

Formation of the Earth and the other terrestrial planets of our Solar System (Mercury, Venus and Mars) commenced 4.567 billion years ago and occurred on a time scale of about 100 million years. These planets grew by the process of accretion, which involved numerous collisions with smaller (Moon- to Mars-size) bodies.

Planetary Cooling

4 BCE

By 4 billion years ago the earth had cooled enough for the outer layers to have solidified and for oceans to form. Flying past the earth at this time we would see a vast ocean from pole to pole, with volcanoes scattered here and there but no continents - pretty much the scene to the right captured about about 3.8-4.0 billion years ago.