You Rock
What would happen if you threw a rock midway between two planets?
If you threw a rock midway between two massive objects (e.g. planets), how would the rock move?
Would the pull from one planet cancel out the pull from the other, allowing your rock to continue unmolested? The question of how two heavy objects could come to be near each other in the first place is an odd one. Maybe they are not quite at rest, and are orbiting each other or something else.
Your last sentence has the crux of the problem in it. Planets or other celestial bodies don’t just sit stationary waiting for physics experimeters to come along. They are either orbiting a star or each other, and either way, they don’t maintain any fixed distance apart. To predict the movement of your rock you would have to know a lot of info about the relative movement of the bodies and the star, if any, they circle.
Michael Jackson – You Rock My World (Extended Version)
