Dione’s Wispy Cliffs

First spotted by the Voyager spacecraft thirty years ago, it wasn’t until Cassini that the linear features criscrossing Saturn’s moon Dione known as “wispy lines” were confirmed to be the icy faces of high cliff walls rising hundreds of feet from the moon’s frozen surface. Possibly caused by tectonic activity Dione’s cliff walls shine brightly…

The Feeling’s Mutual

Dione slips behind Rhea in this animation made from 19 raw images taken by the Cassini spacecraft on January 20, 2011. Called a mutual event, the two moons seem to just miss each other โ€“ even though in reality they are separated by over 93,400 miles! Rhea and Dione are similar in composition and size,….

Backlit Dione

Here’s a beautiful new image just in from Cassini: the silhouette of 700-mile-wide Dione seen against the sunlit limb of Saturn, its rings seen edge-on just above the moon. Some of Dione’s heavily-cratered terrain can be discerned along its southeastern edge. I particularly like the light halo effects along the edges of the moon and…

Dione and Tethys in Passing

Two of Saturn’s moons pass each other from Cassini’s perspective on December 6, 2010, in this animation compiled from 70 raw image files. This was more an experiment in using iMovie HD to create an animation from a lot of individual images than anything else…I didn’t take the time to clean up the specks and…

Peak Time

A crater’s central peak casts a long shadow in this image from Cassini, taken on October 17 as the spacecraft passed by Dione at a distance of 25,000 miles. 700-mile-wide Dione is literally covered in craters, faults and gouges, a testament to the ancient age of its frozen terrain. Many larger craters โ€“ like the…

Details of Dione

Here’s some awesome just-released raw images from Cassini’s flyby of Dione earlier this morning! The low angle of sunlight brings out the detail of the moon’s rugged terrain, peppered with ancient craters of all sizes and gouged by long scars of steep, icy cliffs. Fantastic! Thanks to team leader Carolyn Porco for alerting us to…

Frozen Cliffs

One of the newest raw images from Cassini’s latest flyby shows the icy terrain of Saturn’s moon Dione, with steep hills, ridges and the bright face of one of the many deep canyons that meander across its surface. Known as “wispy lines”, these canyon walls expose bright water ice (that makes up about a quarter…

Just Passing By

It’s been a while since I posted one of these…it’s an animation made up of 16 raw images from the Cassini spacecraft, taken on March 12, showing Saturn’s moons Dione and Titan passing each other. The small, cratered and frozen Dione couldn’t be more different than her much larger, haze-enshrouded sister Titan, but we’re reminded…

Holy Dione

The heavily creased and cratered face of 700-mile-wide Dione is partially lit by the Sun in this image from Cassini, taken on March 4. Some of the moon’s characteristic “wispy lines” can be seen along its sunlit limb…these are the bright, exposed walls of icy canyons caused by ancient tectonic activity. The darker surface material…

Saturn’s Darker Side

Released November 9, 2009, this image from Cassini shows the northern night side of Saturn sending a deep shadow across its rings while the 700-mile-wide Dione looks on. The shepherd moon Pandora can be seen here as well, orbiting just outside the thin F ring, at center. The Cassini spacecraft was over 800,000 miles from…

A Passing of Spheres

Rhea overlaps sister moon Dione in this image, taken by Cassini on October 22. One of a series of raw images showing the moons approach and then pass each other. Even at their closest passing the two moons are separated by more than 90,000 miles. Image: NASA/JPL/SSI

Craternator

ย  A large-scale crater rides the terminator between day and night on Dione, a 700-mile-wide moon of Saturn. The moon’s signature “wispy lines” can be seen on the sunlit side. These are long fractures in the moon’s surface, exposed ice-covered cliffs hundreds of feet high. Scientists believe they indicate past tectonic activity, or possibly the…