Rationalizing a Firefly - Serenity type setting

[mindstalk]

Originally Posted by Flyndaran

Except that in reality, gas giant moons would be within the radiation belts and inhospitable to earth like life. Not to mention have extremely long day/night cycles, again not very earth like.

In reality, Jupiter is the only one of our gas giants to have a huge and deadly radiation belt, and Callisto isn't within it. Long rotation periods seem more likely, given locking to synchronicity and multi-day revolutions around the giant.