On Wed. Oct. 28 Cassini performed its lowest-altitude dive yet through the icy plumes of Enceladus, coming just 30 miles from the moon’s surface — that’s only about 6 times higher than a commercial airliner at cruising altitude. But, traveling over 19,000 mph relative to Enceladus (which is 38 times faster than a jet plane!) the pass was over in just a few seconds. Still, Cassini managed to capture some images before, during, and after closest approach — and they’ve arrived on Earth today.
Here are some of the raw images from the E-21 flyby. These have not been validated or made into official releases by NASA or the Cassini imaging team yet, but they are a nice teaser of what we might expect once they are. (And, of course, the science performed during the flyby has yet to be revealed.) So pics only for now!
On Wednesday, Oct. 14 2015, Cassini performed its scheduled “E-20” close pass of Enceladus, a 320-mile-wide moon of Saturn that is now famous for the organics-laden ice geysers that fire from cracks in its southern crust. E-20 is the first of a series of three flybys to be performed before the end of 2015, specifically timed to give the spacecraft a good view of Enceladus’ north polar region now that Saturn is moving into its summer season.
The raw image data from E-20 has just arrived on Earth today (which, by the way, is the 18th anniversary of Cassini’s launch!) and I particularly liked the one above. Crescent-lit by the Sun, Enceladus’ night side is seen bathed in the dimmer glow of reflected light off Saturn and its rings. Dead-center is the 6.5-mile-wide crater Bahman, surrounded by a wrinkly field of cracks and troughs in the moon’s highly-reflective icy surface.
So on the same week that the highly-anticipated film “The Martian” opens in U.S. theaters (you are going to go see it, I assume) NASA revealed the latest discovery regarding the Red Planet: there is water on the surface there, salty rivulets that periodically run down steep slopes in Hale Crater and stain its sands with dark streaks.
It might not be something that Mark Watney would want to guzzle a glassful of, but it is a major finding for planetary scientists!
Ever since we got our first good look at Comet 67P/Churyumov-Gerasimenko from the approaching Rosetta spacecraft in 2014 it has been considered to be a textbook example of a contact binary, with its “rubber duckie” double-lobed shape consisting of an oval “head” and flat-bottomed “body” joined by a “neck.’ Now, using data gathered by Rosetta’s OSIRIS instrument while in permanent orbit, scientists are certain that this is indeed the case: 67P/C-G as we see it today was created by the slow-speed collision of two separate comets, each once an independent and fully-formed object in its own right (and not, as the alternate hypothesis suggested, via the gradual erosion of a once-larger single object.)
Read more about these findings and how they were determined on ESA’s Rosetta site here.
Last night a large part of the world’s population was treated to a relatively rare variety of a not-so-rare night sky spectacle: a total lunar eclipse that happened to coincide with the closest perigee Moon (aka “supermoon”) of the year. The last time these scenarios lined up this way was in 1982, and it won’t occur exactly like that again until 2033. While some parts of the U.S. were clouded out (Los Angeles and Las Vegas included, oddly enough) it was a clear night here in Rhode Island and I took the opportunity to capture some photos of the eclipse from the State House lawn, where I could include the iconic statue of the “Independent Man” atop the capitol’s neoclassical dome.
See some photos of the eclipse from around the world on NASA’s Flickr album here, and check out a couple more of my photos below:
NASA’s venerable Cassini spacecraft may still have another two years left in its exploration of the Saturn system but on Monday, August 17, it had its final intimate visit with Dione, one of Saturn’s largest natural satellites at nearly 700 miles (1,126 km) across. On that day Cassini passed within 300 miles (480 km) of Dione at 2:33 p.m. EDT (18:33 UTC), not its closest flyby ever but certainly near enough to get some truly spectacular views of the icy moon’s ancient and cratered surface.
Check out some of Cassini’s last close-up images of Dione below: