It's official: Enceladus has joined the rarefied community of Solar System objects that have been caught in the act of making new geology. The only other members of the club are Earth and Io. A whole slew of observations have come together from different Cassini instruments to make this conclusion:
- ISS saw an uncratered surface with strong local differences in color (suggestive of recent but not necessarily ongoing activity)
- MAG saw Saturn's magnetic field lines bending around Enceladus (indicates a likely atmosphere; because of Enceladus' small size this was very suggestive but also not conclusive of ongoing activity)
- CIRS spotted a "hot spot" at the south pole, MUCH hotter than expected (pretty much conclusive)
- UVIS spotted a water vapor atmosphere near the south pole but not mid-latitudes (again, pretty much conclusive)
- CDA scooped up lots of water vapor during the flyby -- but, like with UVIS, saw much more on the inbound flyby (near the south pole) than the outbound (nearer mid latitudes)
I've added all the relevant data to my Enceladus-11 Flyby page, so go check it out! The CIRS hot spot data is at left. I have also just spoken with Cassini Deputy Project Scientist Linda Spilker. She is thrilled about these Enceladus discoveries, and filled me in about how the discoveries came together. I'll be writing up a news story on all of this.
Congratulations to everyone on the Cassini science teams! And kudos, too, to the navigators, for coming up with a trajectory for Cassini that took it so close to Enceladus, only 173 kilometers above the surface! And thanks to Jason at Titan Today for being so quick to post the new data as soon as it was released!