why does the moon of saturn titan have such a thick atmosphere?

Answer 1

1. Titan is big (twice the mass of our own Moon) therefore it has good gravity (as far as moons go).
2. Titan is c-c-c-cold, so that molecules in the atmosphere are very slow. Therefore, a lot less molecules achieve escape velocity; Titan loses a lot less atmosphere (in tonnes per second) than the Earth does. Our Moon, with less gravity and with a lot more heat from the sun, has no atmosphere left.

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Answer 2

Titan has three things that keep its atmosphere so thick.

First, it is very cold, so most of the gas molecules are moving very slowly, keeping them well below escape velocity.

Second, the gas that does escape is trapped in a torus (like a ring) in the same orbit around Saturn, so it can fall back to the moon again and again.

Third, there is a great deal of water ice inside Titan, and methane is trapped in that ice in a form called clathrate. As the ice melts from tidal force heating, some of the methane is released, replacing gas that is lost from the atmosphere.

Answer 3

Titan has 2 atmospheres, composed mostly of nitrogen. Because of the temperature on Titan, there is little water vapor settling in the atmosphere, therefore leaving a very thick smog like atmosphere.