The atmosphere of Venus is mostly carbon dioxide, and the atmosphere of the Earth has water vapor. Why are these two gases absent in the atmosphere of the satellite around Saturn called Titan?
A) Titan's atmosphere was captured from the ring system of Saturn, and thus consists of small ice crystals
B) The energetic particles in the magnetosphere of Saturn have collided with and knocked away all the lighter gases in the atmosphere of Titan
C) There are life-forms on the surface of Titan which absorb carbon dioxide and water vapor as part of their life processes
D) Titan is so cold that carbon dioxide and water vapor freeze out
E) There is a runaway greenhouse effect on Titan
Extra: Some Review Questions Covering the Entire Solar System

Question

Quizplus · Accepted Answer

Titan's atmosphere is mostly composed of nitrogen and methane, which are both gases that can exist in their gaseous form at Titan's cold temperatures. However, carbon dioxide and water vapor are not present because they freeze out and form ice particles in Titan's atmosphere due to the low temperatures.

The Atmosphere of Venus Is Mostly Carbon Dioxide, and the Atmosphere