How is Saturn's moon, Titan, able to hold onto its atmosphere?

A. It is very cold at Titan. Cold gases are more easily held in place by gravity, so although Titan is the size of Mercury, it is able to cling to this gold gas.

B. Nitrogen is very, very heavy, so Titan is able to hold on even though there is not much gravity.

C. Titan does not spin on its axis, so the atmosphere is not thrown off.

D. Titan has no appreciable atmosphere, so the question is meaningless.

A. It is very cold at Titan. Cold gases are more easily held in place by gravity, so although Titan is the size of Mercury, it is able to cling to this gold gas.

Explanation:

Titan is among Saturn's numerous moons the largest one. It is remarkable for many reasons but the most intriguing one is his atmosphere.

At first, all planets, as well as big moons, have an atmosphere. But there are many factors that can lead to its loss, just as Mars, a planet larger than Titan, lost its atmosphere.

The problem with Mars is it is too close to the Sun. The temperature was high and the molecules managed to escape its gravity.

But Saturn and Titan are really far and the temperatures are low. The molecules are not able to move fast enough and this way Titan manages to hold on to its atmosphere.