Saturn and Shadows

Saturn's rings cast shadows on the planet, except their shadows appear to be inside out! The edge of the outermost A ring can be seen at the top left corner of the image. Moving towards the bottom of the page, one can see the faint Cassini Division, the opaque B ring and the innermost C ring, which contains several ringlets that appear dark against Saturn in this geometry. The bottom half of the image features the shadows of these rings in reverse order superposed against the disk of the planet: the C ring, the B ring, the Cassini Division and the inner half of the A ring.

This view looks toward the unilluminated side of the rings from about 28 degrees below the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on December 2, 2013 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers.

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 57 degrees. Image scale is 45 miles (72 kilometers) per pixel.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Pan in the Encke Gap

Saturn's moon Pan, named for the Greek god of shepherds, rules over quite a different domain: the Encke gap in Saturn's rings.

Pan (17 miles, or 28 kilometers across) keeps the Encke gap open through its gravitational influence on the ring particles nearby.

This view looks toward the sunlit side of the rings from about 48 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on December 25, 2013.

The view was obtained at a distance of approximately 1.4 million miles (2.3 million kilometers) from Pan and at a Sun-Pan-spacecraft, or phase, angle of 87 degrees. Image scale is 9 miles (14 kilometers) per pixel.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Saturn

Saturn's winds race furiously around the planet, blowing at speeds in excess of 600 miles (1,000 kilometers) per hour at the equator. As they do so, they form distinct belts and zones which encircle the planet's pole, as well as its famous hexagon. These zonal winds spin off swirls and eddies, which are significant storms in their own right.

This view looks toward the sunlit side of the rings from about 51 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on December 27, 2013 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers.

The view was acquired at a distance of approximately 1.3 million miles (2 million kilometers) from Saturn. Image scale is 75 miles (120 kilometers) per pixel.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Possible New Moon Forming Around Saturn

The disturbance visible at the outer edge of Saturn's A ring in this image from NASA's Cassini spacecraft could be caused by an object replaying the birth process of icy moons.

The image is adapted from one in a paper in the journal Icarus, reporting the likely presence of an icy body causing gravitational effects on nearby ring particles, producing the bright feature visible at the ring's edge. The object, informally called "Peggy," is estimated to be no more than about half a mile, or one kilometer, in diameter. It may be in the process of migrating out of the ring, a process that one recent theory proposes as a step in the births of Saturn's several icy moons.

This image is a portion of an observation recorded by the narrow-angle camera of Cassini's imaging science subsystem on April 15, 2013. The bright feature at the edge of the A ring is about 750 miles (about 1,200 kilometers) long.

This view looks toward the illuminated side of the rings from about 53 degrees above the plane of the rings. It was obtained from a distance of approximately 775,000 miles (1.2 kilometers) from Saturn, with a sun-Saturn-spacecraft, or phase, angle of 31 degrees. The scale is about 4 miles (about 7 kilometers) per pixel.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Note: For more information, see NASA Cassini Images May Reveal Birth of a Saturn Moon and Possible New Moon Forming Around Saturn.

Northern Lakes on Titan

The Cassini spacecraft peers down though layers of haze to glimpse the lakes of Titan's northern regions.

Titan (3,200 miles, or 5,150 kilometers across) has a hydrological cycle similar to Earth's, but instead of water, Titan's lakes and seas are filled with liquid methane and ethane.

Lit terrain seen here is on the leading hemisphere of Titan. North on Titan is up. The image was taken with the Cassini spacecraft wide-angle camera on January 1, 2014 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 939 nanometers.

The view was obtained at a distance of approximately 114,000 miles (183,000 kilometers) from Titan. Image scale is 7 miles (11 kilometers) per pixel.

Image credit: NASA/JPL-Caltech/Space Science Institute

Titan Dunes

The moons of our Solar System are brimming with unusual landscapes. However, sometimes they look a little more familiar, as in this new radar image from the Cassini orbiter. The image shows dark streaks carved into dunes reminiscent of those we might find on a beach on Earth, or raked with flowing lines in a Japanese Zen garden — but this scene is actually taking place on Saturn’s moon Titan.

While our sand is composed of silicates, the ‘sand’ of these alien dunes is formed from grains of organic materials about the same size as particles of our beach sand. The small size and smoothness of these grains means that the flowing lines carved into the dunes show up as dark to the human eye.

These grains are shunted around by winds shifting over the moon’s surface. These winds aren’t particularly fast — only moving at around 1 m/s — but they blow in opposing directions throughout the year, causing Titan’s ‘sand’ to pile up in certain places over time.

Titan seems to be full of features and phenomena that are quite familiar to those found on Earth. Since Cassini arrived in the Saturn system in 2004, and dropped off ESA’s Huygens probe in 2005, scientists have been studying the similarities between Titan and Earth by exploring sand dunes, channels and lakes of liquid ethane and methane scattered across its surface.

While previous images have spotted these eerily familiar patterns on Titan’s dunes, this new image shows them in greater detail. The image was obtained by Cassini’s Titan radar mapper on 10 July 2013, by a team led by Steve Wall at NASA’s Jet Propulsion Laboratory in California, USA. The horizontal seam near the center is an artifact of radar image data processing.

Image credit: NASA/JPL-Caltech

Enceladus' Plumes

Dramatic plumes, both large and small, spray water ice out from many locations along the ‘tiger stripes’ near the south pole of Saturn’s moon Enceladus. The tiger stripes are fissures that spray icy particles, water vapor and organic compounds. More than 30 individual jets of different sizes can be seen in this image, which is a mosaic created from two high-resolution images captured when Cassini flew past Enceladus and through the jets on 21 November 2009. This view was obtained at a distance of about 14,000 km from Enceladus.

Image credit: NASA/JPL/Space Science Institute

Enceladus' Ocean

This diagram illustrates the possible interior of Saturn's moon Enceladus based on a gravity investigation by NASA's Cassini spacecraft and NASA's Deep Space Network, reported in April 2014. The gravity measurements suggest an ice outer shell and a low density, rocky core with a regional water ocean sandwiched in between at high southern latitudes.

Views from Cassini's imaging science subsystem were used to depict the surface geology of Enceladus and the plume of water jets gushing from fractures near the moon's south pole.

Enceladus is 313 miles (504 kilometers) in diameter.

Illustration credit: NASA/JPL-Caltech

Note: This is the big story of the day. For more information, see Inside Enceladus, Icy Moon Enceladus Has Underground Sea, NASA Space Assets Detect Ocean inside Saturn Moon, and Deep Ocean Detected Inside Saturn's Moon.

Prometheus and the F-Ring

Saturn's moon Prometheus orbits near some of its handiwork in the F ring.

Prometheus (53 miles, or 86 kilometers across) and its partner Pandora gravitationally sculpt and maintain the narrow F ring.

This view looks toward the unilluminated side of the rings from about 53 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on August 24, 2013.

The view was acquired at a distance of approximately 1.1 million miles (1.8 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 104 degrees. Image scale is 7 miles (11 kilometers) per pixel.

Photo credit: NASA/JPL-Caltech/Space Science Institute