Simulation of an asteroid orbiting a moon using the 2D Rigid Body Physics Engine.
See if you can find the asteroid initial velocity that results in a nearly circular orbit without collisions.
Mars moon Phobos
Why does Phobos have parallel lines etched into its surface?
This simulation was suggested by Kenneth Ramsley at Brown University in 2011 regarding his ideas about the Mars moon Phobos. You can see these lines in the photo above. Ken's idea is that Phobos would occasionally capture a small asteroid which would orbit Phobos but keep bumping into it, similar to what is seen in the above simulation. See the Space.com article (May 2014) How the Mars Moon Phobos Got Its Grooves
Although it looks like the large moon in the simulation is stationary, it is actually moving. This is because the asteroid exerts a small gravitational pull on the large moon. You can confirm that the large moon is moving in a couple of ways:
Also available are: open source code, documentation and a simple-compiled version which is more customizable.
This web page was first published January 2011.