Category Archives: Saturn’s Moons

Cassini Has Just Taken the Best Picture of Daphnis Yet!

Image of Daphnis captured by Cassini on Jan. 18, 2017. (NASA/JPL-Caltech/SSI)

Image of Daphnis captured by Cassini on Jan. 16, 2017. (NASA/JPL-Caltech/SSI)

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.

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Revisit Our First (and Only) Landing on Titan

View from Huygens’ camera as it descended to the surface of Titan on Jan. 14, 2005. ESA/NASA/JPL/University of Arizona

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

Light and Dark: the Two Faces of Dione

Global map of Dione’s surface. NASA/JPL-Caltech/SSI/LPI

Saturn’s moon Dione (pronounced DEE-oh-nee) is a heavily-cratered, 700-mile-wide world of ice and rock, its surface slashed by signature “wispy lines” that mark the bright faces of sheer ice cliffs. But Dione has some strange colorations too, evident here in a global map created in 2014 from Cassini images. Its leading half—the side that faces “forward” as it moves around Saturn in its tidally-locked orbit—is pale and bright, while its trailing hemisphere is stained a brownish color, the result of surface interaction with  charged particles in Saturn’s magnetic field.

Read more from ESA here: Space in Images – Global colour mosaic of Dione and see more pictures and news about Dione here.

Bright Clouds Make a Comeback on Titan’s North Pole

Titan’s methane lake-covered north pole imaged in infrared on Oct. 29, 2016 (NASA/JPL-Caltech/SSI)

Floating high above Titan’s hydrocarbon lakes, wispy clouds have finally started to return to the moon’s northern latitudes…but in much less numbers than expected.

Models of Titan’s climate have predicted more cloud activity during early northern summer than what Cassini has observed so far, suggesting that the current understanding of the giant moon’s changing seasons is incomplete.

Watch an animation of the clouds above in action here, and read the full story at: Send in the Clouds

Watch Saturn’s Moons Race Inside the Rings

Saturn's moons Prometheus and Atlas are captured by Cassini in these images from Aug. 23, 2016

Saturn’s moons Prometheus and Atlas are captured by Cassini in these images from Aug. 23, 2016

Round and round they go… the animation above, made from 14 raw images taken by NASA’s Cassini spacecraft on August 23, 2016, shows the moons Prometheus and Atlas orbiting Saturn within the Roche Division gap between its A (top right) and F (center) rings. The gravitational tug of Prometheus (92 miles / 148 km long) is strong enough to pull on the fine, smoke-like icy particles of the F ring, creating streamer and “clump” features that follow it along.

The much smaller Atlas (23 miles / 37 km wide) follows a path around Saturn just past the outer edge of the A ring. It was once thought to be a “shepherd moon” of the A ring, but it’s now known that the pull of the more distant Janus and Epimetheus are responsible for that.

Atlas does have its very own ring, though—a very faint (i.e., not visible above) band of material that runs along its orbit named R/2004 S 1, discovered by the Cassini mission in July 2004.

Image credit: NASA/JPL-Caltech/SSI. Animation by Jason Major.

Enceladus’ Jets: the Farther They Are, the Harder They Spray

Enceladus surrounds Saturn with its icy spray

Plumes of icy vapor erupt from cracks in Enceladus’ south pole. (NASA/JPL-Caltech/SSI)

A crowning achievement of the Cassini mission to Saturn is the discovery of water vapor jets spraying out from Enceladus‘ southern pole. First witnessed by the spacecraft in 2005, these icy geysers propelled the little 320-mile-wide moon into the scientific spotlight. After 22 flybys of Enceladus during its nearly twelve years in orbit around Saturn, Cassini has gathered enough data to determine that there is a global subsurface ocean of salty liquid water beneath Enceladus’ frozen crust—an ocean that gets literally sprayed into space.  Now, new findings from Cassini and researchers at the Planetary Science Institute—with a little help from a star called Epsilon Orionis—has shown that at least some of the vapor jets get a boost in activity when Enceladus is farther from Saturn.

Read the full story on Universe Today.

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