Researchers think they have evidence of a new planet deep in our solar system that is the size of Neptune and orbits the sun far beyond Pluto. The orbit simulator shows the orbits of our well-known planets, as well as Pluto and the comet...

This site from the National Aeronautics and Space Administration provides a fun project on rockets. "Nothing in space stands still. Everything either orbits around something else, or moves toward or away from something else. So how do...