Originally Posted By: Orac


Originally Posted By: Bill

Now I will give my take on perpetual motion in space.

Imagine a universe with just 2 perfect masses in it. That is they are point source masses. Assume they are in a circular orbit around their common center of mass. I believe this is one stable solution to the 2 body problem. Under these conditions I believe you would have a system in perpetual motion. They would circle each other for eternity.


Nope not even if you make the two bodies perfect you would have to extend your universe to be a perfect vacuum as well as your two planets would bump into the few molecules floating around imparting them with energy and slowing down be it ever so infintesimal.



That was part of my set up. I said that there were just 2 perfect masses. That excludes all other matter. So, no dust, no nothing, they should orbit forever.

Of course this is in a Newtonian universe. I'm not sure what QM would do to them.

Bill Gill

C is not the speed of light in a vacuum.
C is the universal speed limit.