Callistoball is a moonball of Jupiterball. It isn't in a 1:2:4 reasonance like the other Galiliean Moons so he has no tidal heating effects. So he is geologically dead, And why he has so many white spots is because asteroids hit his clay nearly everytime is probably because
he is overweight and overall fatter than Kim Jong Un of his high gravity and large Hill sphere.
Orbit - Rotation
He is the outermost of the four Galilean Moons, and has a semi-major axis of about 1,880,000 km, which is significantly larger than Ganymedeball's SMA. Because he is so distant, he is not locked in the laplace resonance that the other three Galilean Moons are in. His orbit also is slightly eccentric and relatively inclined to Jupiterball's equatorial plane. Like many other Jovian moons, he is tidally locked to Jupiterball, rotating every 16.7 days. Such isolation means that Callistoball does not enjor significant tidal heating the other three Galilean Moons experience, and also means the charged-particle flux from Jupiterball's large magnetosphere is also significantly lower.