Hi et

Drobyshevski believes the delay in Callisto's detonation is due to the weaker ambient magnetic field, thus lower electrolysis, and the lower impact energy of any objects acting as "triggers". At Callisto's orbit the escape velocity is just ~ 11.6 km/s and its orbital velocity is ~ 8.2 km/s, thus minimum energy impactors are going to strike at most at 19.95 km/s (Callisto's Ve = 2.45 km/s) - a head on smash at parabolic speed. Ganymede's orbital velocity is ~ 10.83 km/s, escape = 15.32 km/s, and surface escape = 2.74 km/s - thus parabolic impactor at 26.3 km/s. And of course higher still for Europa and Io. Callisto is also mostly out of the radiation belts and has experienced a lower induced solid-state current presumably.

Thus perhaps there hasn't been a hot enough match to set Callisto ablaze yet?

Nick's probably right that it's all pseudoscience, but exploding moons sure sound amazing.

Adam