Enceladus passing Dione: Just another day in Saturn’s neighbourhood. #beautiful

by David Ng

More about Enceladus at Wired.com. Also wikipedia.

“Enceladus is one of only three outer Solar System bodies (along with Jupiter’s moon Io and Neptune’s moon Triton) where active eruptions have been observed. Analysis of the outgassing suggests that it originates from a body of sub-surface liquid water, which along with the unique chemistry found in the plume, has fueled speculations that Enceladus may be important in the study of astrobiology.”