Rings, dark side of Saturn glow in new Cassini image

Oct 17, 2013
This colorized mosaic from NASA's Cassini mission shows an infrared view of the Saturn system, backlit by the sun, from July 19, 2013. The image, made from data obtained by Cassini's visual and infrared mapping spectrometer, covers a swath of Saturn and its rings about 340,000 miles (540,000 kilometers) across that includes the planet and its rings out to the diffuse E ring, Saturn's second most distant ring. The mosaic covers an area about 9,800 miles (16,000 kilometers) from top to bottom. Credit: NASA

(Phys.org) —The gauzy rings of Saturn and the dark side of the planet glow in newly released infrared images obtained by NASA's Cassini spacecraft.

"Looking at the Saturn system when it is backlit by the sun gives scientists a kind of inside-out of Saturn that we don't normally see," said Matt Hedman, a participating scientist based at the University of Idaho, Moscow, Idaho. "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."

It can be difficult for scientists to get a good look at the faint outer F, E and G rings, or the tenuous inner known as the D ring when light is shining directly on them. That's because they are almost transparent and composed of small particles that do not reflect light well. What's different about this viewing geometry?

• When these small particles are lit from behind, they show up like fog in the headlights of an oncoming vehicle.

• The C ring also appears relatively bright here; not because it is made of dust, but because the material in it—mostly dirty water ice—is translucent. In fact, in the 18th and 19th centuries, it was known as the "crepe ring" because of its supposed similarity to crepe paper.

• The wide, middle ring known as the B ring—one of the easiest to see from Earth through telescopes because it is densely packed with chunks of bright water ice—looks dark in these images because it is so thick that it blocks almost all of the sunlight shining behind it.

Infrared images also show thermal, or heat, radiation. While a visible-light image from this vantage point would simply show the face of the planet as dimly lit by sunlight reflected off the rings, Saturn glows brightly in this view because of heat from Saturn's interior.

In a second version of the image, "stretched" or exaggerated the contrast of the data, which brings out subtleties not initially visible.

• Structures in the wispy E ring—made from the icy breath of the moon Enceladus—reveal themselves in this exaggerated view.

This high-contrast, colorized mosaic from NASA's Cassini mission shows an infrared view of the Saturn system, backlit by the sun, from July 19, 2013. Exaggerating the contrast of the data brings out subtleties not initially visible. For example, structures in Saturn's wispy E ring -- made from the icy breath of the moon Enceladus -- reveal themselves in this exaggerated view. The image, made from data obtained by Cassini's visual and infrared mapping spectrometer, covers a swath of Saturn and its rings about 340,000 miles (540,000 kilometers) across that includes the planet and its rings out to the E ring, Saturn's second most distant ring. The mosaic covers an area about 5,000 miles (8,000 kilometers) from top to bottom. Credit: NASA

"We're busy working on analyzing the infrared data from this special view of the Saturn system," said Phil Nicholson, a visual and team member from Cornell University, Ithaca, N.Y. "The 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."

Launched in 1997, Cassini has been exploring the Saturn system for more than nine years with a suite of instruments that also includes visible-light cameras, ultraviolet and infrared spectrometers, as well as magnetic field and charged particle sensors. Scientists working with the visible light cameras are still busy putting together and analyzing their mosaic—or multi-image picture—of the Saturn system.

"Cassini's long-term residency at the ringed planet means we've been able to observe change over nearly half a Saturn-year (one Saturn-year is equal to almost 30 Earth-years) with a host of different tools," said Linda Spilker, Cassini project scientist, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Earth looks different from season to season and Saturn does, too. 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.'"

Explore further: Cassini releases image of Earth waving at Saturn

Related Stories

Cassini releases image of Earth waving at Saturn

Aug 21, 2013

(Phys.org) —People around the world shared more than 1,400 images of themselves as part of the Wave at Saturn event organized by NASA's Cassini mission on July 19—the day the Cassini spacecraft turned ...

Saturn's B-ring: Taking a closer look

Sep 11, 2012

(Phys.org)—Clumpy particles in Saturn's B-ring provide stark contrast to the delicately ordered ringlets seen in the rest of this view presented by the Cassini spacecraft.

From Cassini for the holidays: A splendor seldom seen

Dec 19, 2012

(Phys.org)—Just in time for the holidays, NASA's Cassini spacecraft, in orbit around Saturn for more than eight years now, has delivered another glorious, backlit view of the planet Saturn and its rings.

Saturn shows off its shadow

Sep 21, 2012

Take a look up at the enormous shadow cast by Saturn onto its own rings in this raw image, acquired by NASA's Cassini spacecraft on September 18, 2012.

A ghostly 'ladder' in Saturn's F ring

Jun 03, 2013

Saturn's F ring is certainly a curious structure. Orbiting the giant planet 82,000 kilometers above its equatorial cloud tops, the F ring is a ropy, twisted belt of bright ice particles anywhere from 30-500 ...

Recommended for you

NASA's space station Robonaut finally getting legs

16 hours ago

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Sun emits a mid-level solar flare

Apr 18, 2014

The sun emitted a mid-level solar flare, peaking at 9:03 a.m. EDT on April 18, 2014, and NASA's Solar Dynamics Observatory captured images of the event. Solar flares are powerful bursts of radiation. Harmful ...

Impact glass stores biodata for millions of years

Apr 18, 2014

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...

The importance of plumes

Apr 18, 2014

The Hubble Space Telescope is famous for finding black holes. It can pick out thousands of galaxies in a patch of sky the size of a thumbprint. The most powerful space telescope ever built, the Hubble provided ...

User comments : 0

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Cosmologists weigh cosmic filaments and voids

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...