Although the Cassini spacecraft in orbit around Saturn has completed its four-year nominal mission, it's gone into overtime, with NASA continuing to send it on close flybys of Saturn's moons. On October 9, Cassini passed a mere 25 miles above the icy surface of Enceladus, and will make another close pass (this one at 197 miles) of this enigmatic moon on Halloween.

Although Enceladus is small (310 miles in diameter), it's geologically active, emitting heat and spewing jets of microscopic ice particles, water vapor, and organic molecules through its "ice volcanoes." Its terrain is surprisingly varied, including cratered areas, smooth plains, and networks of cracks and vents, including four linear features dubbed the "Tiger Stripes," which appear to be the source of the vapor plumes. The Boston Globe has put together a dazzling collection of Cassini images of Enceladus including the one shown above, complete with explanatory notes.

Post by Tony Hoffman