Mars/moon impact rate ratio: 2000/2012 comparison Impact craters as a link to other terrestrial planets, satellites and asteroids Interplanetary comparisons.
Telling Tails About Galaxies (Stellar Halos, Satellites and Hierarchical Structure Formation) Kathryn V Johnston (Wesleyan) & James S Bullock (Harvard)
Astrometry (positions, proper motions, Trigonometric parallaxes)
