Breathtaking NASA Video Shows Jupiter's Moons Race Across Its Great Red Storm. These are the inner two of Jupiter's four…

Breathtaking NASA Video Shows Jupiter's Moons Race Across Its Great Red Storm. These are the inner two of Jupiter's four largest moons (about the same size as our own). And they are both remarkable, but for very different reasons.

With over 400 active volcanoes, Io is the most geologically active object in the Solar System, and Europa has the smoothest surface of any known solid object in the Solar System.

In action, their splendour is only magnified. The second part of the video is equally impressive. It gives a close-up of Saturn's largest moon and the second largest in the entire Solar System: Titan.