In Focus shows us Enceladus, Saturn’s Amazing Snowball Moon “Saturn’s sixth-largest moon, Enceladus (504 kilometers or 313 miles across), is the subject of much scrutiny, in large part due to its spectacular active geysers and the likelihood of a subsurface ocean of liquid water. NASA’s Cassini orbiter has studied Enceladus, along with the rest of the Saturnian system, since entering orbit in 2004. Studying the composition of the ocean within is made easier by the constant eruptions of plumes from the surface, and on October 28, Cassini will be making its deepest-ever dive through the ocean spray from Enceladus—passing within a mere 30 miles of the icy surface. Collected here are some of the most powerful and revealing images of Enceladus made by Cassini over the past decade, with more to follow from this final close flyby as they arrive.”
I didn’t realize that Cassini flew through the plums. The NY Times reported, Cassini Seeks Insights to Life in Plumes of Enceladus, Saturn’s Icy Moon.
Discovering life was not on the agenda when Cassini was designed and launched two decades ago. Its instruments can’t capture microbes or detect life, but in a couple of dozen passes through the plumes of Enceladus, it has detected various molecules associated with life: water vapor, carbon dioxide, methane, molecular nitrogen, propane, acetylene, formaldehyde and traces of ammonia.
Wednesday’s dive was the deepest Cassini will make through the plumes, only 30 miles above the icy surface. Scientists are especially interested in measuring the amount of hydrogen gas in the plume, which would tell them how much energy and heat are being generated by chemical reactions in hydrothermal vents at the bottom of the moon’s ocean.