Hi CD, good post.

I have been reading DR Brian Cox on the wonders of the solar system, and when i read the chapter about Saturn he came up with a very interesting statement.  that the planets Jupiter and Saturn have migrated from a close orbit around the sun to that of where they are now, and in the process moved the planet Neptune's orbit as well. This he say's was how the Late Heavy Bombardment started, as the two giant planets moved through the inner asteroid belt they unleashed havoc within the inner solar system. As yet there is no explination as to why Uranus has an axial tilt of about 90% (degrees), or why one of its main moons is a rehash....ie it has been blown to bits then reformed.