I've been resisting all urges to speculate on what kinds of geological features are present on Ceres, until now. Finally, Dawn has gotten close enough that the pictures it has returned show geology: bright spots, flat-floored craters, and enigmatic grooves.
About four years ago I wrote a blog entry about an ESA press release about paper published in Nature that suggested that Saturn's moons Tethys and Dione might have volcanic activity, like Enceladus. A new paper published in Icarus casts doubt on that conclusion.
I'm preparing a talk for the Pacific Astronomy and Telescope Show here in Pasadena on Sunday afternoon at 1:45. I have spent the morning putting together a slide that I have long wanted to have for presentations.
Last week I got very excited about a set of pictures that had appeared on Cassini's raw images website, but was sad that I couldn't make color versions myself. I was so excited that I failed to identify the little icy moon in the picture correctly.
It figures. I just start a three-week trip, with my only computer a diminutive Netbook, and guess what's just been radioed across the 1.3 billion kilometers separating us and Saturn? A set of photos that should become -- when properly processed -- an iconic image from Cassini's fourteen-year mission to the Saturn system.
Daniel Macháček has reached into the dark side of Prometheus and pulled out an incredible amount of detail where the potato-shaped moon is illuminated by Saturnshine. He produced an animation that morphs among the three sets of four-filter color images that Cassini snapped during the flyby.
Over the last couple of days Cassini flew past Enceladus, Tethys and Dione, so there are lots of treats to see on the raw images website! You should go check it out for yourself, but here are a couple of real favorites.
It's been a little while since I posted any Cassini pictures just because they were pretty, so here's a few recent ones, produced by amateurs from the images available on the Cassini raw images website.