Saturn’s Most Habitable Moon Offers Ice, Water, Killer Views
1. Enceladus’ southern tiger stripes are actively spewing jets of ice into space. The region is also anomalously warm relative to the rest of the planet, and releasing three times more heat than a similar sized area on Earth. Until recently, scientists didn’t know why.
A study in Nature Geoscience in January explains that the heat is caused by blobs of warmer ice moving toward the surface and pushing colder ice down. Scientists think these eras of churning ice last around 10 million years, while the intervening quiet times last 100 million to 2 billion years, so Cassini is lucky to have visited during one of the active times that make up between 1 and 10 percent of the moon’s history.
“Cassini appears to have caught Enceladus in the middle of a burp,” UC Santa Cruz planetary scientist Francis Nimmo, co-author of the new study, said in a press release. “These tumultuous periods are rare, and Cassini happens to have been watching the moon during one of these special epochs.”
2. Enceladus is the sixth largest of Saturn’s 62 moons. The plumes emanating from its southern pole are just visible in this image.
3. This spectacular image of Enceladus nestled next to Saturn below the planet’s rings was taken by Cassini on Christmas Day, 2009. It was captured by the spacecraft’s wide-angle camera from 384,000 miles away.
4. Here, Enceladus is speeding by Dione, a moon more than twice its size. Enceladus orbits faster and closer to Saturn than Dione. The ring is Saturn’s outermost F-ring.
(Source: Wired)
Dark Side Ring of Light
The Cassini spacecraft looks toward the dark side of Saturn’s largest moon as a circle of light is produced by sunlight scattering through the periphery of Titan’s atmosphere.
A detached, high-altitude global haze layer encircles the moon. Small particles that populate high hazes in Titan’s atmosphere scatter short wavelengths more efficiently than longer visible or infrared wavelengths, so the best possible observations of the detached layer are made in ultraviolet light. The image was taken in visible blue light with the Cassini spacecraft narrow-angle camera on Oct. 9, 2009.
Serene Scene
Even in a peaceful looking scene such as this one of Saturn and its moon Tethys, the Cassini spacecraft reveals clues about how Saturn is ever-changing. Saturn’s northern hemisphere still shows the scars of the huge storm that raged through much of 2011 (see PIA14905). And, day by day, the shadows cast by the rings on the planet’s southern hemisphere are growing wider as the seasons progress toward northern summer. See PIA11667 and PIA09793 to learn about the changing seasons and the shadows cast by the rings.
Tethys (660 miles, or 1,062 kilometers across) appears above the rings to the left of the center of the image.
The image was taken with the Cassini spacecraft wide-angle camera on Jan. 10, 2012 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers. The view was obtained at a distance of approximately 1.4 million miles (2.3 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 39 degrees. Image scale on Saturn is 84 miles (136 kilometers) per pixel.
Approaching Enceladus near midnight
Cassini approached for its October 19, 2011 flyby of Enceladus from almost directly behind it — only the faintest sliver of crescent is illuminated. In the background, Saturn’s crescent sweeps past as Enceladus grows in Cassini’s view. Credit: NASA / JPL / SSI / animation by Emily Lakdawalla
Inner beauty
1. X-ray of a sea urchin
2. X-ray of a sea star
