Saturn's north polar hexagon basks in the Sun's light now that spring has come to the northern hemisphere. The image was taken with the Cassini spacecraft's wide-angle camera on Nov. 27, 2012. The view was acquired at a distance of approximately 403,000 miles (649,000 kilometers) from Saturn.
The above image from NASA's Cassini spacecraft reveals the wind patterns within a large vortex that was spawned by a giant northern storm on Saturn. The arrows indicate the local direction of the winds. The vortex, a clockwise-spinning swirl, was spun off from the head of this storm in early December 2010, shortly after the storm erupted. The bright head of the storm moved swiftly in a westward direction around the planet, while this vortex drifted more slowly.
These data were obtained on Jan. 11, 2011.
The above images show a storm on Saturn and how it has changed over time. A vortex that was part of a giant storm on Saturn slowly dissipates over time in this set of images from NASA's Cassini spacecraft. This clockwise vortex spun off the bright head of the storm shortly after the thunder-and-lightning storm erupted in early December 2010.
The top left image shows the vortex's most turbulent activity captured by Cassini's imaging cameras on Jan. 11, 2011. It was centered around 54 degrees west longitude and 35 degrees north latitude. At the time, it was the largest vortex ever observed in Saturn's troposphere, which is the layer of the atmosphere where weather occurs. It measured up to 7,500 miles (12,000 kilometers) across. This is comparable in size to the giant storm on Jupiter known as Oval BA, though Oval BA and Jupiter's more famous storm -- the Great Red Spot -- are not thunder-and-lightning storms. Jupiter's vortices are known for their stability and longevity. Precursors to Oval BA formed in the 1930s, and evolved into what finally became Oval BA in the late 1990s. The Great Red Spot has been in existence at least since 1879, and possibly since 1664. Jupiter and Saturn are similar in many respects. However, why Jupiter's vortices are long-lived and why Saturnian ones are so short remain a mystery.
The image in the top middle was taken on March 17, 2011, when the center of the vortex had drifted west to around 6 degrees west longitude. The image on the top right was taken on April 25, 2011, when the vortex had moved to about 315 degrees west longitude.
The bright head of the storm was moving more quickly westward than the vortex and collided with the vortex by mid-June. The image at bottom left was obtained on July 12, 2011, after the head and vortex collided. The vortex here is less turbulent and is centered around 247 degrees west longitude. The bottom middle image was taken on Aug. 24, 2011, about four days before the storm's thunder and lightning ceased completely. The vortex is swirling at about 218 degrees west longitude. The bottom right image was taken on Oct. 6, 2011, when the vortex had nearly faded away. What is left of the vortex is centered around 248 degrees west longitude.
The above image shows how ring-region Saturnian moons Prometheus and Pan are both caught "herding" their respective rings in this image. Through their gravitational disturbances of nearby ring particles, one moon maintains a gap in the outer A ring and the other helps keep a ring narrowly confined.
Prometheus (53 miles, or 86 kilometers across), together with Pandora (not seen in this image), maintains the narrow F ring seen at the bottom left in this image. Pan (17 miles, or 28 kilometers across) holds open the Encke gap in which it finds itself embedded in the center. The bright dot near the inner edge of the Encke gap is a background star.
This view looks toward the unilluminated side of the rings from about 29 degrees below the ring plane. The image was taken in visible violet light with the Cassini spacecraft narrow-angle camera on Sept. 18, 2012.
The view was acquired 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 98 degrees. Image scale is 9 miles (14 kilometers) per pixel.
The above artist's concept envisions what hydrocarbon ice forming on a liquid hydrocarbon sea of Saturn's moon Titan might look like. A new model from scientists on NASA's Cassini mission suggests that clumps of methane-and-ethane-rich ice - shown here as the lighter-colored clusters - could float under some conditions.
Janus is spotted over Saturn's north pole in this image while Mimas' shadow glides across Saturn.
Janus is the faint dot that appears just above Saturn's north pole. Mimas' shadow can be seen in the southern hemisphere of Saturn, south of the rings' shadow. (Both objects are easier to find in higher resolution versions.) This view looks toward the unilluminated side of the rings from about 25 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Aug. 24, 2012. The view was obtained at a distance of approximately 1.6 million miles (2.6 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 80 degrees. Image scale is 94 miles (152 kilometers) per pixel. Janus has been brightened by a factor of 1.3 relative to Saturn to enhance its visibility.
NASA's Cassini spacecraft has delivered a glorious view of Saturn, taken while the spacecraft was in Saturn's shadow. The cameras were turned toward Saturn and the sun so that the planet and rings are backlit. (The sun is behind the planet, which is shielding the cameras from direct sunlight.) In addition to the visual splendor, this special, very-high-phase viewing geometry lets scientists study ring and atmosphere phenomena not easily seen at a lower phase.
Since images like this can only be taken while the sun is behind the planet, this beautiful view is all the more precious for its rarity. The last time Cassini captured a view like this was in Sept. 2006. The images were obtained with the Cassini spacecraft wide-angle camera on Oct. 17, 2012 at a distance of approximately 500,000 miles (800,000 kilometers) from Saturn
Tethys may not be tiny by normal standards, but when it is captured alongside Saturn, it can't help but seem pretty small.
Even Saturn's rings appear to dwarf Tethys (660 miles, or 1,062 kilometers across), which is in the upper left of the image, although scientists believe the moon to be many times more massive than the entire ring system combined.
This view looks toward the unilluminated side of the rings from about 18 degrees below the ring plane. The image was taken in green light with the Cassini spacecraft wide-angle camera on Aug. 19, 2012. The view was acquired at a distance of approximately 1.5 million miles (2.4 million kilometers).
A giant of a moon appears before a giant of a planet undergoing seasonal changes in this natural color view of Titan and Saturn from NASA's Cassini spacecraft. Titan, Saturn's largest moon, measures 3,200 miles, or 5,150 kilometers, across and is larger than the planet Mercury. Cassini scientists have been watching the moon's south pole since a vortex appeared in its atmosphere in 2012.
As the seasons have changed in the Saturnian system, and spring has come to the north and autumn to the south, the azure blue in the northern Saturnian hemisphere that greeted Cassini upon its arrival in 2004 is now fading. The southern hemisphere, in its approach to winter, is taking on a bluish hue. This change is likely due to the reduced intensity of ultraviolet light and the haze it produces in the hemisphere approaching winter, and the increasing intensity of ultraviolet light and haze production in the hemisphere approaching summer. (The presence of the ring shadow in the winter hemisphere enhances this effect.) The reduction of haze and the consequent clearing of the atmosphere makes for a bluish hue: the increased opportunity for direct scattering of sunlight by the molecules in the air makes the sky blue, as on Earth. The presence of methane, which generally absorbs in the red part of the spectrum, in a now clearer atmosphere also enhances the blue.
This view looks toward the northern, sunlit side of the rings from just above the ring plane.
This mosaic combines six images -- two each of red, green and blue spectral filters -- to create this natural color view. The images were obtained with the Cassini spacecraft wide-angle camera on May 6, 2012, at a distance of approximately 483,000 miles (778,000 kilometers) from Titan.
NASA/JPL-Caltech/Space Science Institute