Posts Tagged satellites (moons)

Credit: NASA/JPL/Space Science Institute

Saw this lovely new Cassini image at Universe Today:

Rhea, saturn’s second largest moon sits in front of the rings, joined by two smaller moons in the background. Rhea (1528 kilometers, 949 miles across) is in the center foreground. Janus (179 kilometers, 111 miles across) can be seen beyond the rings on the right of the image. Prometheus (86 kilometers, 53 miles across) is visible orbiting between the main rings and the thin F ring on the left of the image. Lit terrain seen on Rhea is on the area between that moon’s trailing hemisphere and anti-Saturn side. This view looks toward the northern, sunlit side of the rings from just above the ringplane.

Gorgeous stuff, I’m loving everything Cassini sends back to us!

An incredible image of Saturn’s moon Enceladus venting jets of ice:

What’s happening on the surface of Saturn’s moon Enceladus? Enormous ice jets are erupting. Giant plumes of ice have been photographed in dramatic fashion by the robotic Cassini spacecraft during this past weekend’s flyby of Saturn’s moon Enceladus. Pictured above, numerous plumes are seen rising from long tiger-stripe canyons across Enceladus’ craggy surface. Several ice jets are even visible in the shadowed region of crescent Enceladus as they reach high enough to scatter sunlight. Other plumes, near the top of the above image, appear visible just over the moon’s sunlit edge. That Enceladus vents fountains of ice was first discovered on Cassini images in 2005, and has been under close study ever since. Continued study of the ice plumes may yield further clues as to whether underground oceans, candidates for containing life, exist on this distant ice world.

Saturn has some weird moons. Check this bad boy out.

What has happened to Saturn’s moon Iapetus? Vast sections of this strange world are dark as coal, while others are as bright as ice. The composition of the dark material is unknown, but infrared spectra indicate that it possibly contains some dark form of carbon. Iapetus also has an unusual equatorial ridge that makes it appear like a walnut. To help better understand this seemingly painted moon, NASA directed the robotic Cassini spacecraft orbiting Saturn to swoop within 2,000 kilometers in 2007. Pictured above, from about 75,000 kilometers out, Cassini’s trajectory allowed unprecedented imaging of the hemisphere of Iapetus that is always trailing. A huge impact crater seen in the south spans a tremendous 450 kilometers and appears superposed on an older crater of similar size. The dark material is seen increasingly coating the easternmost part of Iapetus, darkening craters and highlands alike. Close inspection indicates that the dark coating typically faces the moon’s equator and is less than a meter thick. A leading hypothesis is that the dark material is mostly dirt leftover when relatively warm but dirty ice sublimates. An initial coating of dark material may have been effectively painted on by the accretion of meteor-liberated debris from other moons. This and other images from Cassini’s Iapetus flyby are being studied for even greater clues.