What's Happening on Saturn's Moons?
This 25-minute film explores what we've learned about Saturn's various moons via space probes. The data comes primarily from NASA's Cassini, though some is from the Voyager and Galileo missions. Nitrogen geysers, bizarre surface ridges, and real atmospheres are all par for the course -- though no big creepy monoliths have been found. Here's a snippet from the film's description:
Flying by Europa, Voyager documented a complex network of criss-crossing grooves and ridges. In the 1990s, the Galileo spacecraft went back to get a closer look. It found that Europa's surface is a crazy quilt of fractured plates, cliff faces and gullies... amid long grooves like a network of superhighways. How did it get like this?
Then, heat rising up through a subsurface ocean of liquid water cracks, and shifts, and spreads the icy surface in a thousand different ways. Europa's neighbors, Callisto and Ganymede, show similar features, suggesting they too may have liquid oceans below their surfaces.
Crossing outward to Saturn, Voyager found a similar surface on the moon Enceladus. So when the Cassini spacecraft arrived in 2004, it came looking for answers to a range of burning questions: if this moon and others have subsurface oceans? Do they also have the ability to cook up and support life? And what could they tell us about the origin of life throughout the galaxy?
The big question is whether there is or was life on Saturn's moons. The answer is, in short, "We don't know." But this is a pretty good roundup of the stuff we do know.
(Via The Kid Should See This.)