The Evolution of the Atmosphere
Phase 1 (Volcanoes gave out gases):
1) The earth's surface was originally molten. It was so hot that any atmosphere just 'boiled away' into space.
2) Eventually, after the earth started to cool down, a thin crust formed, but volcanoes kept erupting.
3) The volcanoes gave out lots of gases such as carbon dioxide and nitrogen, along with water vapour too.
4) According to this theory, the early atmosphere was mostly carbon…