How did the earths atmosphere used to be?

Answer 1

Very early it would have been mainly hydrogen & helium,

then the sun lit up (fusion started) and they would have been lost leaving mostly Argon & nitrogen with traces of stuff from volcanic out-gassing: H2O, CO2, SO2, H2S, & HCl.

After life formed there would have been methane,

but not until after chlorophyll was invented was there any oxygen.

Answer 2

Earth's early atmosphere is theorized to have been similar to that of the planet Venus. It was raw and harsh and did not support life; it was comprised mostly of CO2. Gradually, the sun cooled to near current activity and the atmosphere of earth cooled as well. Hydrogen combined with the Oxygen released from the crust and water formed in greater amounts till the oceans began to form. The water helped to stabilized the atmosphere till it became sufficient to support life.

Answer 3

Earth's early atmosphere contained a lot of water vapors and other gases, such as carbon dioxide, hydrogen sulfide, and nitrogen, and was extremely hot. During earth's youth, the sun's light barely penetrated the planet's atmosphere.

Answer 4

The Earth's atmosphere has changed due to global warming. which means the earth is getting hotter so the way that the earth's atmosphere is it getting hotter.

Answer 5

It Was Like A Massive Ball That Was Round And Full Of Water And Stuff... That Is All

Answer 6

Polution.