You can see Jupiter's four largest moons with a pair of binoculars. Their movement around Jupiter is like a miniature model of our solar system. In fact, it was just these movements that got Galileo thinking dangerously back in the days when people still believed the sun revolved around the Earth. If these objects could revolve around something other than Earth, then maybe Earth wasn't the center of the universe after all.

As you watch these four Galilean satellites orbit Jupiter, one or two may, at times, appear to be missing. They're still there, of course, either behind Jupiter or crossing the planetary disk and difficult to spot. The dance of Jupiter's moons presents an ever-changing show.