I've made some rigging tutorials for Blender 3D on YouTube.
I'm interested in games and worked on one called SmashTrix.
Stern-Levinson paper on criteria for planets. Use of Hubble time and 1 radian subjective? Need to ask a question about this. Seems to be based on a measure of likelihood that a large object deflects a small object by one radian, over a period of one Hubble time.