On Nov. 11, 2015, NASA’s Cassini spacecraft passed relatively closely by Saturn’s moon Tethys, one of the ringed planet’s larger icy satellites. The animation above was made from 29 raw images acquired with Cassini’s narrow-angle camera as it passed by; you can see part of the incredibly cratered and ancient surface of this 662 mile (1,065 km) wide moon. Talk about flyover country!
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.
It’s been a while since I last made one of these: it’s an animation comprising 27 images acquired by Cassini in various color channels on October 11, 2015. It shows Saturn’s second-largest moon Rhea passing in front of the smaller and more distant* Dione, both partially illuminated by sunlight. I cleaned up some image artifacts from each frame and adjusted the levels to make the blacks black and not banded, like is often found in images like these. I also added a bit of a glow to the moons, to enhance the sense of light (and bring out some of the detail in the darker areas.)
There’s nothing particularly scientific here, just an enjoyment of the endless and ongoing dance of the spheres!
Check out an older moon animation of Rhea here.
*Dione is more distant from the Cassini spacecraft in these views; it’s actually closer to Saturn in its orbit than Rhea.
People of past civilizations had their own ideas of what the stars in the night sky are… distant campfires, lights shining through holes in a vast blanket covering the Earth, deceased ancestors, countless and constantly-traveling gods… whether or not they really believed these stories or if they were just tales to inspire poets and provide entertainment on dark nights is hard to tell. But one thing is for certain: we now know what those points of light really are, thanks to the past several centuries of hard work by astronomers, scientists, and engineers, and although that may make ancient tales about the stars obsolete it certainly doesn’t reduce the inherent wonder and beauty of the night sky – if anything, it has increased it many times over.
Recently French cartoonist Boulet illustrated his own lifelong fascination with space in a webcomic published on his Bouletcorp.com site. In a Dante-esque fashion he takes the figure of French singer Georges Brassens on a trip across the solar system, showing him why science and rational thought have not chased away fascination and beauty along with “the old gods”, as Brassens sang in a 1964 song (which I was not familiar with.) “Eureka” was not a death sentence for wonder!
It’s a really beautiful comic, with brilliant timing and subtle animations to highlight keep points along the way. Don’t scroll too fast.
HT to Laurie C. for the link.
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: