Amazing New Close-up Images of Enceladus


Oh, wow! This is one of the best images yet from the Cassini spacecraft of the “tiger stripes” in the south polar region of Saturn’s moon Enceladus. Over the weekend, Cassini flew by Enceladus, and has sent back some incredible new images, such as the one above. The tiger stripes are actually giant fissures that spew jets of water vapor and organic particles hundreds of kilometers, or miles, out into space, and here, Cassini is staring right down into one of the fissures. See more great images of Enceladus below, plus images of the moons Dione and Tethys.

Close-up of the cracked, crevassed surface of Enceladus. Credit: NASA/Space Science Institute.

While the winter is darkening the moon’s southern hemisphere, Cassini has its own version of “night vision goggles” — the composite infrared spectrometer instrument – to track heat even when visible light is low. It will take time for scientists to assemble the data into temperature maps of the fissures.

Enceladus against Saturn's limb. Credit: NASA/Space Science Institute.
More plumes on Enceladus. Credit: NASA/Space Science Institute.
Close-up of Tethys. Credit: NASA/Space Science Institute

Dione from 115,370 kilometers away. Credit: NASA/Space Science Institute

See more amazing images from Cassini’s latest at the CICLOPS website.

Emily Lakdawalla at the Planetary Blog also has created some very cool movies from the flyby images.

Hat tip to Stu Atkinson

Titan + Dione = New Desktop


Another stunning image from the Cassini spacecraft, suitable for wallpaper on your desktop. Click image for larger version, or click here for a large 1.125 MB version.

This is Saturn’s moon Dione, in crisp detail, against a hazy, ghostly Titan. Simply stunning.

The “wispy” terrain on Dione is visible, and on Titan are hints of atmospheric banding around Titan’s north pole. This view looks toward the Saturn-facing hemisphere of Dione (1123 kilometers, 698 miles across) and Titan (5150 kilometers, 3200 miles across), and was taken on April 10, 2010.

No images available yet from Cassini’s extremely close flyby of Titan over the weekend where it buzzed the hazy moon at an altitude of just 880 kilometers (547 miles) above the surface.

That is 70 kilometers (43 miles) lower than it has ever been at Titan before. The reason for attempting such a close pass is to try and establish if Titan has a magnetic field of its own. But the Cassini team went through hours and hours of calculations for this close flyby, as Titan’s atmosphere applies torque to objects flying through it, much the same way the flow of air would wiggle your hand around if you stuck it outside a moving car window. According to the Cassini website, when engineers calculated the most stable and safe angle for the spacecraft to fly, they found it was almost the same as the angle that would enable Cassini to point its high-gain antenna to Earth. So they cocked the spacecraft a fraction of a degree, enabling them to track the spacecraft in real-time during its closest approach. They set up the trajectory with thrusters firing throughout the flyby to maintain pointing automatically.

The images and data gathered should be amazing, as if everything went as planned, the flyby ended with the ultra violet imaging spectrograph (UVIS) instrument capturing a stellar occultation outbound from Titan. We’ll keep you posted!

Source: CICLOPS, Carolyn Porco on Twitter

A Double-Dose of Cassini Goodness

The Cassini mission is just a non-stop faucet of fantastic images! Here are two that were released today, for your viewing pleasure. The first image, above, is an eclipse of Saturn’s moon Tethys, which lies in the background, by Dione. The three images were each taken one minute apart.

As you can see, from Cassini’s perspective Dione passes right in front of Tethys. Make no mistake in thinking that these two Saturnian companions are close together in this shot, however; Dione, the moon in the foreground, is 2.2 million kilometers (1.4 million miles) from the Cassini spacecraft, while Tethys is 2.6 million kilometers (1.6 million miles) away.

An interesting feature of the image is how Tethys appears brighter on the side of the moon opposite the Sun. This is because Saturn, which lies out of the image to the right, is reflecting light from the Sun back onto the moon. Dione is not being backlit by Saturn from the vantage point of Cassini, so its face that is opposite the Sun appears darker.

Visible on Tethys is the Odysseus Crater, which spans a whopping 400km (240 miles). Given that Tethys is only 1,062 kilometers, or 660 miles across, the crater appears very large in comparison to the moon. It also makes the moon very much resemble the Death Star from Star Wars, don’t you think? These images were taken using Cassini’s narrow-angle camera on Nov. 28, 2009.

This second image is a synthetic aperture radar image of the surface of Saturn’s moon Titan. In the lower right and upper center of the image, the two wrinkly features are actually small Titanian mountains. What exactly causes the grooves in these mountains has still to be determined.

On Earth, the shifting of tectonic plates can form such structures, as well as the processes of water flowing, freezing, and melting.

Since Titan has an atmosphere composed mostly of methane and ethane, and experiences rain much like here on Earth, it’s quite possible that these processes are the cause of such features.

Because the illumination of this image comes from the radar on Cassini, the peaks of these formations should be the brightest. As is visible, this isn’t the case. Notice how the left side of the upper mountain in the image, and right side of the lower-right mountain are brighter. The materials that make up the darker and lighter areas are the cause for this lighting effect.

The image represents a patch of Titan’s surface 250 km (155 miles) high and 285 km (180 miles) wide, and the resolution is about 350 meters (1,150 feet) per pixel, and it was taken on December 28th, 2009.

Source: Cassini Equinox Mission, here and here.