Saturn's faintest rings shine in new Cassini photo
New infrared images will help scientists learn more about these rings' chemical compositions and sizes.
Mon, Oct 28, 2013 at 10:49 AM
The mesmerizing rings of Saturn glimmer in a series of new photos that illuminate parts of the planet that normally appear darkened.
NASA's Cassini spacecraft captured the new infrared images, which offer unique views of Saturn's dark side, and the planet's signature rings, bathed from behind in the sun's light.
"Looking at the Saturn system when it is backlit by the sun gives scientists a kind of inside-out view of Saturn that we don't normally see," Matt Hedman, a Cassini mission scientist at the University of Idaho in Moscow, Idaho, said in a statement. "The parts of Saturn's rings that are bright when you look at them from backyard telescopes on Earth are dark, and other parts that are typically dark glow brightly in this view." [Photos: Saturn's Glorious Rings Up Close]
Saturn's rings are labeled alphabetically in the order of their discovery. The main rings are A, B, and C, with C being the one closest to the planet. The innermost D ring was discovered by the Voyager 1 probe in 1980. The F ring lies just outside the A ring, while the G and E rings can be found even further beyond.
Typically, scientists have a hard time observing the faint outer F, E and G rings, and the tenuous inner D ring, when light is shining directly on them. This is because they are almost transparent, and the billions of particles that make up the rings are not highly reflective.
But, when these particles are lit from behind, they become illuminated, similar to how fog appears to glow in the headlights of an oncoming vehicle, NASA scientists explained.
This colorized mosaic from NASA's Cassini mission shows an infrared view of the Saturn system, backlit by the sun, from July 19. The image covers a swath of Saturn and its rings about 340,000 miles across that includes the planet and its rings out to the diffuse E ring, Saturn's second most distant ring. (Photo: NASA/JPL-Caltech/University of Arizona/Cornell)
In these new Cassini images, Saturn's C ring appears relatively bright, and the wide B ring — one of the easiest to spot from telescopes on Earth — looks darker because it is so thick that it blocks out majority of the sun's light, according to NASA scientists.
Visible-light images from this vantage point would show Saturn dimly lit, with sunlight reflecting off the planet's rings. But, through infrared eyes, which sense thermal radiation, the heat from Saturn's interior lights up the entire planet.
Researchers created a second version of the image by exaggerating the contrast of the data to accentuate details not initially visible. In this "stretched" version, structures in the wispy E ring — created by debris shed from Saturn's icy moon Enceladus — are revealed.
"We're busy working on analyzing the infrared data from this special view of the Saturn system," Phil Nicholson, a visual and infrared mapping spectrometer team member from Cornell University in Ithaca, N.Y., said in a statement. "The infrared data should tell us more about the sizes of the particles which make up the D, E, F and G rings, and how these sizes vary with location in the rings, as well as providing clues as to their chemical composition."
Cassini was launched in 1997 and has been exploring Saturn and its moons for more than nine years. The spacecraft is equipped with visible-light cameras, ultraviolet and infrared instruments, and a suite of sensors.
"Earth looks different from season to season and Saturn does, too," Linda Spilker, a Cassini project scientist based at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement. "We can't wait to see how those seasonal changes affect the dance of icy particles as we continue to observe in Saturn's rings with all of Cassini's different eyes."
Follow Denise Chow on Twitter @denisechow. Follow us @Spacedotcom, Facebook or Google+. Originally published on SPACE.com.
Related on SPACE.com and MNN: