Perhaps if the main body is close enough/massive enough, the tidal forces conspire to eventually kill the tilt, e.g., Mercury/Sun (0 degrees) & Earth/Moon (1.5 degrees) ? http://en.wikipedia.org/wiki/Axial_tilt So perhaps it might take longer, perhaps much, much longer, for a tilt to dissipate? Maybe this sort of tidal effect falls off exponentially with distance, so bodies far enough away are "protected"? At 09:46 PM 4/10/2010, Joshua Zucker wrote:

Tidal forces don't get rid of the tilt, they cause precession.