|MadSci Network: Astronomy|
Wow! I did not know about this at all. Thanks for bringing it to my attention. It is kind of neat. A great web site to go to for information on the solar system is: www.seds.org The SEDS site says that the two moons have nearly equal orbital velocities and the lower, faster one slowly overtakes the other. "As they approach each other they exchange a bit of momentum the end result of which is to boost the lower one into a higher orbit and to drop the higher one to a lower orbit. They thus exchange places" The quoted stuff is straight from the page. The important thing to remember about orbital mechanics is that you need more energy to get into a higher orbit. This is why the momentum exchange is important. A good analogy is sometimes when my friend rollerblades behind me while I'm biking, he likes to get a boost from me by grabbing my bike seat and transferring momentum from me to him. He goes shooting off ahead of me while I practically come to a halt. Give it a try. That is momentum transfer. Thanks for the cool question.
Try the links in the MadSci Library for more information on Astronomy.