By Randy Gener
NASA Images of the Day | THE RINGS OF SATURN
These views from NASA’s Cassini spacecraft showcase some of the amazingly detailed structure of Saturn’s rings.
The rings are made up of many smaller ringlets that blur together when seen from a distance. But when imaged up close, the rings’ structures display quite a bit of variation. Ring scientists are debating the nature of these features — whether they have always appeared this way or if their appearance has evolved over time.
The Cassini mission is a cooperative project of NASA, ESA (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. 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, Colorado.
PIA11142 | A Full Sweep of Saturn’s Rings (Image Taken from Illuminated Side)
Annotated Views of Saturn’s Ring System
PIA08389 | A Scan Across Saturn’s Incredible Halo of Ice Rings Yields a Study in Precision and Order. (Image Taken from Un-Illuminated Side)
PIA18365 | NASA’s Cassini Mission Forms The Great Divide, As Wide As Mercury
It’s difficult to get a sense of scale when viewing Saturn’s rings, but the Cassini Division (seen here between the bright B ring and dimmer A ring) is almost as wide as the planet Mercury. (See PIA11142 above for a labeled panorama of features in the rings.) [/caption]
The 2,980-mile-wide (4,800-kilometer-wide) division in Saturn’s rings is thought to be caused by the moon Mimas. Particles within the division orbit Saturn almost exactly twice for every time that Mimas orbits, leading to a build-up of gravitational nudges from the moon. These repeated gravitational interactions sculpt the outer edge of the B ring and keep its particles from drifting into the Cassini Division.
This view looks toward the sunlit side of the rings from about 4 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 28, 2016.
The view was acquired at a distance of approximately 740,000 miles (1.2 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 76 degrees. Image scale is 4 miles (7 kilometers) per pixel.
PIA20509 | Tiny Mimas, Huge Rings — Saturn’s Icy Moon Side by Side Its Rings
Saturn’s icy moon Mimas is dwarfed by the planet’s enormous rings.
Because Mimas (near lower left) appears tiny by comparison, it might seem that the rings would be far more massive, but this is not the case. Scientists think the rings are no more than a few times as massive as Mimas, or perhaps just a fraction of Mimas’ mass. Cassini is expected to determine the mass of Saturn’s rings to within just a few hundredths of Mimas’ mass as the mission winds down by tracking radio signals from the spacecraft as it flies close to the rings.
The rings, which are made of small, icy particles spread over a vast area, are extremely thin – generally no thicker than the height of a house. Thus, despite their giant proportions, the rings contain a surprisingly small amount of material.
Mimas is 246 miles (396 kilometers) wide.