Impact geometry seen in the rest frame of Earth a) and Moon b). a) The Moon is assumed to be where a_M = 60 R_⊕, with v_M = 1.0 km s^-1. The impactors, distributed extensively enough to cover the lunar orbit (black circle), are in the common direction of v_enc (black dashed arrow). Where f_M = 0°,45°,...,315°, the lunar velocity v_M (black solid arrow) and the impact velocity v for v_enc = 5 or 10 km s^-1 (red or blue solid arrows) are all plotted to the same scale. b) Under the same conditions, v is plotted pointing at the normal impact points on the lunar surface.