PIA18360: Dark Moons, Dark Rings


Dark Moons, Dark Rings

Caption:

When taking images in directions opposite from the sun, most objects appear dark. Surprisingly, however, some of Saturn's rings get brighter.

Parts of Saturn's main rings appear dark in backlit views, particularly the dense B ring (as can been seen in PIA14934 ). However, some rings are comparatively tenuous and made up of dust particles that tend to scatter light in roughly the original direction it was traveling. This is called "forward scattering." Because of forward scattering, rings like the F ring, which encircles the outer edge of the main rings, appear to glow brightly at this large viewing angle.

Two moons hover above the rings from this perspective -- Enceladus (313 miles or 504 kilometers across), at left, and Janus (111 miles or 179 kilometers across), at right.

This view looks toward the unilluminated side of the rings from about 0.5 degrees below the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 21, 2015.

The view was acquired at a distance of approximately 750,000 miles (1.2 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 136 degrees. Janus' brightness was enhanced by a factor of two to improve its visibility in this image.

Background Info:

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.

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 .

Cataloging Keywords:

Name Value Additional Values
Target Saturn Rings B Ring, Enceladus, F Ring, Janus, Saturn, Sun
System Saturn
Target Type Ring Planet, Satellite, Sun
Mission Cassini-Huygens
Instrument Host Cassini Orbiter
Host Type Orbiter
Instrument Imaging Science Subsystem (ISS)
Detector Narrow Angle Camera
Extra Keywords Dust, Grayscale
Acquisition Date
Release Date 2016-03-28
Date in Caption 2015-12-21
Image Credit NASA/JPL-Caltech/Space Science Institute
Source photojournal.jpl.nasa.gov/catalog/PIA18360
Identifier PIA18360