What are the earth's early atmosphere in first billion years ago?

Question

List them.

Answer 1

Our early atmosphere consisted primarily of Nitrogen (N), Carbon dioxide (CO2), with lesser amounts of methane (CH4), and then some other gasses like argon and rarer noble gasses. The big difference is we didn't have any free oxygen (O2). Oxygen was a byproduct, basically waste, of the single celled critters that lived on the earth (cyano bacteria). They would suck up the CO2, keep the carbon and release the oxygen as O2. The earth is roughly 4.5 billion years old. Estimates for the first life to come/develop on earth is 3.8-4.0 billion years. From when life first developed till 2.0-2.2 billion years there was no free oxygen. All of it as getting sucked up into geologic sinks. Since there was no free O2, we didn't have an ozone layer, and there was significantly more solar radiation on the surface. Nothing could life on or near the surface without protection. Some things developed protection like the stromatolites (look up sharks bay Australia if you want to see them). It was hotter, but cool enough for free water to exist. I hope that helps.

Answer 2

It is believed that the early atmosphere of the earth included methane and ammonia. In addition to these, the early biosphere contained enormous amounts of radioactivity, as evidenced by the fact that there is still some background radiation left after all these thousands of millions of years.

Answer 3

there started off with no atmosphere, but than gasses came from inside the earth and were kept in our rellative vasinity due to the gravitational pull of the earth

Answer 4

Methane, Ammonia & Hydrogen Cyanide.

Answer 5

Very hot