Category Archives: Saturn’s Moons
A field of spike-like structures rise up over two miles from the outer edge of Saturn’s B ring in the amazing image above, captured by Cassini during Saturn’s spring equinox in August 2009. These pointy perturbations are caused by the gravitational nudges of tiny (~1/2 mile) embedded moonlets traveling around Saturn within the B ring, causing fine icy particles to “splash” upwards from the otherwise relatively flat ring when they pass by them. The moonlets themselves are held in their orbits by the gravity of Mimas.
The spikes were made visible mainly because of the angle of illumination at the time of equinox, which on Saturn occurs every 15 years and in this instance was on Aug. 11, 2009.
Even if you’re feeling inundated by Valentine-themed everything at the moment, if you love space and you’re at all creative you’re definitely going to adore this. With Cassini in the final months of its 13 years at Saturn, NASA wants you to share your love of the spacecraft, its discoveries, and the ringed planet and its fascinating family of moons.
“We’re so gratified that Cassini’s images have inspired people to work with the pictures themselves to produce such beautiful creations,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory. “It’s been truly wonderful for us to feel the love for Cassini from the public. The feeling from those of us on the mission is mutual.”
In honor of Cassini’s last year in orbit (as well as its last Valentine’s Day!) the mission team is inviting all the Saturn lovers out there to share their Cassini-inspired creations through the “Cassini Inspires” outreach program. Digital art, processed images, paintings, drawings, songs, poems…if it drew any inspiration at all from something Cassini made possible, share it with the world!
This is a color image of Saturn’s moon Tethys I made from raw images acquired by Cassini on Feb. 1, 2017 in visible-light color channels. It shows the moon’s sunlit leading side—the face that aims in the direction that it moves in its orbit around Saturn. (Click image for a larger version.)
While this icy moon is mostly monochromatic—appearing quite grey even in a color image—there are some subtle variations over large parts of its surface. Here you can just make out a slightly darker bluish band that runs across Tethys’ equatorial region. This is the result of surface weathering by high-energy electrons within Tethys’ orbit. The pale pinker regions to the north and south of the band are thought to be a coating of small ice particles that have been expelled from nearby Enceladus.
Also visible along the terminator is part of the 1,200-mile long, 60-mile-wide Ithaca Chasma, an enormous and ancient canyon system that runs almost all the way from Tethys’ north to south poles.
Tethys is 662 miles (1,065 km) in diameter and composed mostly of water ice and rock. It orbits Saturn at a distance of 183,000 miles (295,000 km) and takes 45.3 hours to complete one orbit. Read more about Tethys here.
Saturn’s 250-mile-wide icy moon Mimas shines in direct sunlight and reflected light from Saturn in this image, a composite of raw images acquired by NASA’s Cassini spacecraft on Jan. 30, 2017 and received on Earth today, Feb. 1. This is a bit of a “Frankenstein” job I made, assembled from five separate narrow-angle camera images taken in various wavelengths so the proportions are slightly off here and there, but the general placement of surface features are about right and the lighting is accurate to the scene. Mimas’ south pole is within the deeply shadowed area at the bottom; north is up.
Hello, Daphnis! On January 16, 2017, the Cassini spacecraft captured the best photo yet of Daphnis, a 5-mile-wide shepherd moon that orbits Saturn inside the Keeler Gap at the outermost edge of the A ring (and also just so happens to be my personal favorite moon of Saturn!) The raw image arrived on Earth today, and it’s just beautiful.
When you think of spacecraft landings on other worlds, you probably first think of Mars, the Moon, Venus, and comet 67P (if you’ve been following along over the past couple of years.) But—in addition to the asteroid Eros and hard impacts on a comet and Mercury—Saturn’s moon Titan was also visited by an alien (i.e., Earthly) spacecraft back in January of 2005. ESA’s Huygens probe, which traveled to Saturn onboard the Cassini orbiter, was deployed to the surface of Titan six months after Cassini arrived in orbit at Saturn. Huygens took 20 days to reach the cloud-covered moon, and during its two-and-a-half hour descent on Jan. 14, 2005 transmitted our first—and last—views from below Titan’s clouds and even from its methane-slush-covered surface. It was the first landing on a moon other than our own and the farthest landing from the Sun, but hopefully not the final time we’ll visit the fascinating surface of this icy moon.
Read more and watch the video of the Huygens probe landing on the Cassini mission site: Huygens: ‘Ground Truth’ from an Alien Moon