[Space] GURPS Handbook of the Planets

[Whill]

Originally Posted by Nemoricus

Since it's possible that this could vary more, I'd say that as long as your gas giant has at least 1000 Earth masses, you could probably have an Earth sized moon without raising too many eyebrows.

How about 2 or 3 Earth-sized moons? Possibly harsh yet still habitable for hardy species? Pushing it too far?

Originally Posted by Nemoricus

It's a general rule that a gas giant will have a total mass of moons equivalent to about 1/10000 of its own. However, it's not a hard and fast rule, and in our own solar system it varies from about 1/1000 to 1/4000.

This strikes me as odd. 1/1000 to 1/4000 > 1/10000. Our system's gas giant moons are the only gas giant moons who existence is even confirmed so far. If our system varies from 1/1000 to 1/4000, what could they possibly be basing that general rule for gas giant moons in the universe at large on anyway?