newtboy says... You've ignored the fact that they did it inside, so there's also the pull of the bowling ball on the walls and ceiling, and vice versa! ;-) I'm pretty sure we agree on all counts except how detailed one must be when teaching simple lessons. ShakaUVM said: It's not falsifying details. It's nonsensical to pose the problem so that surface irregularities are taken into consideration. Or the fact like in this video the feather started below the bowling ball. It's a trivial 3-body problem. You can represent them by three balls, one of mass Heavy, one of mass Medium, one of mass Light. As long as Medium and Light start at the same distance from Heavy, Medium and Heavy will always hit first. You can run this test in an orbital simulator if you don't believe me.