This week, we continue on our journey through the Solar System, flying by the gas giants, Jupiter and Saturn. This episode we focus on natural satellites - discussing Jupiter and Saturn’s moons and rings at length. Jupiter is famous for its large mass (2 times the mass of all the other planets combined!), Great Red Spot, and plentiful moons (53 current, but awaiting approval of 26 more). Galileo discovered Jupiter’s most famous moons - Io, Europa, Ganymede and Callisto. The Voyager missions (NASA, 1979) discovered Jupiter’s faint rings, several new moons, and Io’s volcanic activity. The most recent mission to Jupiter (Juno, NASA, 2011) discovered wave trains and weird lightning on Jupiter. Europa is the target of the next major mission and is thought to potentially be able to sustain life. Saturn has just as many moons (53 confirmed, 9 pending approval), but is more famous for its rings. Unfortunately, Saturn will likely lose its rings over the next few million years.