Hardest and Trickiest Question I've Encountered. Please Help! 1. The problem statement, all variables and given/known data An alien spaceship is revolving around a spherical asteroid in a very low circular orbit. The period of revolution of the spaceship is 15 minutes. A research party of the alien students lands on the steroid and drills a tunnel through it along a diameter. They then launch a rock into the tunnel with an initial speed equal to that of the orbiting spaceship. How long would it be before the rock comes back to the launch point? 2. Relevant equations None that I know of 3. The attempt at a solution Here is what I think, since T= 2piR/v, I thought I could get v. However, I dont even know R and I dont even know distance if I am to use v as in d/t. There seems to be too many variables involved and too little equations to use. I believe that words, very low circular orbit, could mean something. I guess I only know that the period is 15 mintues and that the rock is launched at an initial speed equal to teh orbiting space ship. That means that the velocity of the rock is equal to 2piR/15 minutes. however, i still dont know r.