This important measurement was made using Cassini's INMS instrument, which detects gases with the goal of determining their composition. INMS was designed to sample the upper atmosphere of Saturn's large, smoggy moon Titan. However, after Cassini's surprising discovery of a tall plume if icy spray erupting from cracks on Enceladus in 2005, planetary scientists turned its detectors to that small moon.
I know what you're thinking..."Better put on the hip waders, and not just because we're going fishing!" Believe it or not, the moon has far more to do with catching fish than you might think. Bear with me for a minute, try to keep an open mind, and I will show you a secret that most people don't know about.
The rifts themselves are buried far, far down, deep beneath dark volcanic plains on the near-side of our Moon and have been spotted only in the gravity data provided by GRAIL. The lava-flooded rift valleys are not like anything seen anywhere else on the lunar surface--but some planetary scientists think that they may have, at one time, long ago, resembled rift zones on our own planet, Venus, and Mars. The new findings are published in the October 1, 2014 issue of the journal Nature.