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

Details of Saturn’s icy rings are visible in this sweeping view from Cassini of the planet’s glorious ring system.
 
This natural color mosaic, taken from 10 degrees below the illuminated side of the rings, shows, from left to right, radially outward from Saturn, the C ring (with its Colombo and Maxwell gaps); the B ring and the Cassini division beyond, with the intervening Huygens gap; the A ring (with its Encke and Keeler gaps); and, on the far right, the narrow F ring.
The total span covers approximately 65,700 kilometers (40,800 miles).
Image credit: Cassini, NASA’s Image of the Day, Jet Propulsion Laboratory

It is interesting to compare this view with PIA08389, which shows the un-illuminated side of the rings (SEE BELOW). The difference in brightness of the B ring relative to the other rings is striking. When illuminated directly by the sun, the B ring appears brighter than the adjacent A and C rings; however, when viewing the unlit side of the B ring, the A and C rings appear brighter. This phenomenon occurs because the density of the B ring is greater than that of the A or C rings.

 

PIA08389 | A Scan Across Saturn’s Incredible Halo of Ice Rings Yields a Study in Precision and Order. (Image Taken from Un-Illuminated Side)

This natural color mosaic was acquired by the Cassini spacecraft as it soared 39 degrees above the un-illuminated side of the rings. Major named gaps are labeled at the top. The main rings themselves, along with the F ring, are labeled at the bottom, along with their inner and outer boundaries. This view combines 45 images — 15 separate sets of red, green and blue images — taken over the course of about 2.5 hours, as Cassini scanned across the rings.

The images in this view were obtained on May 9, 2007, at a distance of approximately 1.1 million kilometers (700,000 miles) from Saturn. Image scale in the radial (horizontal) direction is about 6 kilometers (4 miles) per pixel. Image credit: Cassini, NASA’s Image of the Day, Jet Propulsion Laboratory

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.

The Cassini Division (seen here between the bright B ring and dimmer A ring) is almost as wide as the planet Mercury.
The Cassini Division (seen here between the bright B ring and dimmer A ring) is almost as wide as the planet Mercury.

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.

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.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. The Cassini imaging team homepage is at http://ciclops.org.

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