Saturn's Rings

 

Rings

Colorful Division

Beautiful, glamorous and mysterious, Saturn's rings are among the most recognizable features in the solar system. They spread over more than 480,000 kilometers (300,000 miles), yet they are extremely thin. Made up of billions of dancing ice particles and rocks, the rings circle the planet at high speed, creating waves, wakes and various other structures. While scientists still aren't sure exactly how old the rings are, or even why they exist, data from the Cassini mission have already solved a few puzzles.

Cassini mission's discoveries include new ringlets, new moons near the rings, a tiny moon stealing particles from the F ring, features resembling straw and rope, and dark contaminant material in the rings similar to dark material on the moons Phoebe and Iapetus. one exciting new finding was that the tiny moon Enceladus is a major source of material for Saturn's largest ring, the E ring.

The Cassini spacecraft started to send valuable data about the rings right from its arrival at Saturn in July 2004. During the Saturn orbital insertion maneuver, the spacecraft obtained high resolution images and radial profiles of ring structure in ultraviolet, near-infrared and thermal infrared wavelengths.

Four Propellers

"The images found evidence for new processes whereby particle sticking and self gravity interact to form structures never seen before," explains Dr. Jeff Cuzzi, a research scientist at NASA's Ames Research Center and Cassini's interdisciplinary scientist for rings and dust. "A number of high-quality stellar occultations by both the ultraviolet imaging spectrograph and visible and infrared mapping spectrometer and the cameras reveal not only hundreds of never-before seen spiral density and bending waves, but also the fine-scale structure of gravitational instabilities in the rings and how they vary with location. The properties of these 'gravity wakes' are also seen in thermal emission from the rings."

The Cassini mission continues to reveal even more about the nature of Saturn's rings, so stay tuned as the spacecraft continues its journey in the coming years.

 

 

 

In Saturn's Shadow (Color-exaggerated view) October 11, 2006

Full-Res: PIA08329

+ Original version + Image with labels With giant Saturn hanging in the blackness and sheltering Cassini from the sun's blinding glare, the spacecraft viewed the rings as never before, revealing previously unknown faint rings and even glimpsing its home world.   This marvelous panoramic view was created by combining a total of 165 images taken by the Cassini wide-angle camera over nearly three hours on Sept. 15, 2006. The full mosaic consists of three rows of nine wide-angle camera footprints; only a portion of the full mosaic is shown here. Color in the view was created by digitally compositing ultraviolet, infrared and clear filter images and was then adjusted to resemble natural color.   The mosaic images were acquired as the spacecraft drifted in the darkness of Saturn's shadow for about 12 hours, allowing a multitude of unique observations of the microscopic particles that compose Saturn's faint rings.   Ring structures containing these tiny particles brighten substantially at high phase angles: i.e., viewing angles where the sun is almost directly behind the objects being imaged.   During this period of observation Cassini detected two new faint rings: one coincident with the shared orbit of the moons Janus and Epimetheus, and another coincident with Pallene's orbit. (See The Janus/Epimetheus Ring and Moon-Made Rings for more on the two new rings.) The narrowly confined G ring is easily seen here, outside the bright main rings. Encircling the entire system is the much more extended E ring. The icy plumes of Enceladus, whose eruptions supply the E ring particles, betray the moon's position in the E ring's left-side edge.   Interior to the G ring and above the brighter main rings is the pale dot of Earth. Cassini views its point of origin from over a billion kilometers (and close to a billion miles) away in the icy depths of the outer solar system. See Pale Blue Orb for a similar view of Earth taken during this observation.   Small grains are pushed about by sunlight and electromagnetic forces. Hence their distribution tells much about the local space environment.   A second version of the mosaic view is presented here in which the color contrast is greatly exaggerated. In such views, imaging scientists have noticed color variations across the diffuse rings that imply active processes sort the particles in the ring according to their sizes.   Looking at the E ring in this color-exaggerated view, the distribution of color across and along the ring appears to be different between the right side and the left. Scientists are not sure yet how to explain these differences, though the difference in phase angle between right and left may be part of the explanation. The phase angle is about 179 degrees on Saturn.   The main rings are overexposed in a few places.   This view looks toward the unlit side of the rings from about 15 degrees above the ringplane. Cassini was approximately 2.2 million kilometers (1.3 million miles) from Saturn when the images in this mosaic were taken. Image scale on Saturn is about 260 kilometers (162 miles) per pixel.   The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.   For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .   Credit: NASA/JPL/Space Science Institute

 

 

 

 

This NASA Hubble Space Telescope image of the ringed planet Saturn shows a rare storm that appears as a white arrowhead-shaped feature near the planet's equator. The storm is generated by an upwelling of warmer air, similar to a terrestrial thunderhead. The east-west extent of this storm is equal to the diameter of the Earth (about 12,700 kilometers or 7,900 miles). Saturn's prevailing winds are shown as a dark 'wedge' that eats into the western (left) side of the bright central cloud. The planet's strongest eastward winds are at the latitude of the wedge. To the north of this arrowhead-shaped feature, the winds decrease so that the storm center is moving eastward relative to the local flow. The storm's white clouds are ammonia ice crystals that form when an upward flow of warmer gases shoves its way through Saturn's frigid cloud tops to even colder levels.

 

 

 

 

Moon-Made Rings October 11, 2006	Full-Res: PIA08328
This view, acquired with the sun almost directly behind Saturn, reveals a previously unknown faint ring of material coincident with the orbit of the small moon Pallene.

 

 

 

 

 

 

 

http://saturn.jpl.nasa.gov/science/index.cfm?PageID=55