The atmosphere of Mars and Venus are composed primarily of carbon dioxide.Why is Earth's atmosphere different?

Answer 1

Earth evolved cyanobacteria very early on, and these bacteria use photosynthesis to remove the carbon from carbon dioxide and use it to build proteins and other organic materials. The oxygen is released as waste. For the first few hundred million years this oxygen "rusted" all the surface metals; once this was done, it began to accumulate in the atmosphere.

Answer 2

I don't believe the atmosphere Venus is primarily composed of carbon dioxide (I can't remember what the thin atmosphere of Mars contains). If I remember correctly, the atmosphere of Venus is composed mostly of thick clouds of sulfur dioxide. The difference of composition of atmospheres of the three planets is probably due to the different chemical constituents of the rocks that released gases when heated by radioactive elements. Evidently Venus rocks contains more sulfur than do the Earth rocks.

Answer 3

This is my conclusion...
The density or weight of material and the force of gravity from both the sun and the formed planets has caused the lesser material to gather in accordance with there weight and the distance from the gravitational pull of both planets and the Sun. Hence the very light gaseous planets being furthest from the sun. And the rocky planets closer. I speculate that most other Solar Systems would form much in the same way...

Answer 4

Earth has an ozone layer that protects us from the sun's rays. And we have an atmosphere.

Answer 5

because of life. In the early days our atmosphere, too, was mostly CO2.

Answer 6

because plants convert co2 into o2