The Eoarchean era lasted from 4.0bya to 3.6bya and was the period of time when the Earth's crust solidified. The first life in the form of phospholipid bubbles appeared at the beginning of the era and the first prokaryotes appeared 3.8bya. Water vapor had cooled and fell to Earth as precipitation, which created lakes, rivers, and oceans. Then also the formation of the Moon that stabilises the planet to make it sustainable for life.