[Spaceships] Million Merchant Marathon

[Agemegos]

Originally Posted by scc

Atmosphere or lack there of is more a matter of capturing said atmosphere, Titan is only a bit bigger then our moon and has a greater atmospheric pressure then Earth.

Titan is 48% larger than the Moon. On the other hand it is less dense. Taking one thing with another, Titan's escape velocity is 2.64 km/s, whereas the Moon's is only 2.38 km/s. That's a small difference, but Titan is also a lot colder than the Moon. That means that the gas molecules in its atmosphere move more slowly, and therefore that fewer reach escape velocity.

Using the formulas in GURPS Space, Titan's black-body temperature is 90 K and its minimum molecular weight retained works out to 26.9 a.m.u. Whereas the Moon's black-body temperature is 278 and its minimum molecular weight retained works out to 102.5 a.m.u. The molecular weight of nitrogen gas is 28 a.m.u. So that's why Titan has retained nitrogen whereas nitrogen would escape fairly quickly from the Moon.