Dione's North Polar View

The Cassini spacecraft looks down, almost directly at the north pole of Dione. The feature just left of the terminator at bottom is Janiculum Dorsa, a long, roughly north-south trending ridge.

Lit terrain seen here is on the anti-Saturn and trailing sides of Dione (1,126 kilometers, or 700 miles across). The image was taken with the Cassini spacecraft narrow-angle camera on March 22, 2008 using a spectral filter sensitive to wavelengths of ultraviolet light centered at 338 nanometers. The view was acquired at a distance of approximately 650,000 kilometers (404,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 99 degrees. Image scale is 4 kilometers (2 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Note: For more information, see Cassini Finds Hints of Activity at Saturn Moon Dione.

Ladoga Lacus

From the USGS Astrogeology Science Center:

The IAU Working Group for Planetary System Nomenclature has approved the name Ladoga Lacus for a lacus on Titan. For more information, see the image of the north pole region of Titan in the Gazetteer of Planetary Nomenclature.

Saturn's Rings and Shadow

NASA's Cassini spacecraft shows Saturn's shadow cutting sharply across its rings as the orbits of ring particles carry them suddenly from day to night. With no atmosphere to scatter light, shadows in space are much darker than we're used to here on Earth.

This view looks toward the unilluminated side of the rings from about 47 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on March 5, 2013.

The view was obtained at a distance of approximately 891,000 miles (1.434 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 85 degrees. Image scale is 51 miles (82 kilometers) per pixel.

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

Particle Population in Saturn's Magnetosphere

This is an artist's concept of the Saturnian plasma sheet based on data from Cassini magnetospheric imaging instrument. It shows Saturn's embedded "ring current," an invisible ring of energetic ions trapped in the planet's magnetic field.

Saturn is at the center, with the red "donut" representing the distribution of dense neutral gas outside Saturn's icy rings. Beyond this region, energetic ions populate the plasma sheet to the dayside magnetopause filling the faintly sketched magnetic flux tubes to higher latitudes and contributing to the ring current. The plasma sheet thins gradually toward the nightside. The view is from above Saturn's equatorial plane, which is represented by grid lines. The moon Titan's location is shown for scale. The location of the bow shock is marked, as is the flow of the deflected solar wind in the magnetosheath.

Illustration credit: NASA/JPL/JHUAPL

Note: For more information, see 'Tis the Season -- for Plasma Changes at Saturn.

Video of Saturn's North Polar Hurricane

This movie, made from images obtained by NASA's Cassini spacecraft, shows the clouds of a hurricane-like storm, which circulate around the north pole of Saturn out to 88.5 degrees north latitude. The latitude of the bright ring of clouds is 89.0 degrees, which is about 587 miles (945 kilometers) from the pole. The eye of the storm is about 20 times larger than the average hurricane eye on Earth.

Winds are measured by following small clouds over a five-hour period. The winds at the inner ring are moving the fastest, at speeds of about 330 mph (50 meters per second) relative to the nominal rate for the planet established by NASA's Voyager spacecraft in 1980. These winds are four times the speed of the Earth's jet streams and more than four times the definition of a hurricane force wind on Earth. (Hurricane force winds blow at 74 mph, or 119 kilometers per hour.)

The clouds at the very center are spinning rapidly -- almost twice as fast as the planet itself, with a period just over six hours. The direction of rotation is counterclockwise, like a northern hemisphere hurricane on Earth, except there is no ocean underneath. A similar feature exists at Saturn's southern pole, and it spins in the same direction as that of a southern hemisphere hurricane on Earth. However, the hurricanes on Earth begin in the tropics and drift around. The polar hurricanes on Saturn are locked to their poles.

The bright clouds form a tightly wrapped spiral that traces a path toward the center as one follows it in a counterclockwise direction. This spiral could be a wave or actual particle motion toward the center from a disturbance further out. Or it could be the remnants of a compact cloud that got sheared apart by the higher angular velocity closer to the center. Choosing among these possibilities is the subject of ongoing research. Other ongoing research involves inferring cloud heights, both from the changing shadows as the sun moves relative to the features, and from the appearance of the clouds in other wavelengths, not shown in this set of black and white images.

This set of images is among the first sunlit views of Saturn's north pole captured by Cassini's imaging cameras. When the spacecraft arrived in the Saturnian system in 2004, it was northern winter and the north pole was in darkness.

The movie was constructed from seven images taken over five hours by Cassini's imaging science subsystem when the spacecraft was about 45 degrees above the horizon. Imaging team scientists re-projected the images to show a view from directly over the pole, keeping up with the rotation of the planet to make the clouds at 89.3 degrees latitude appear stationary. The winds at other latitudes produce the motion seen on the screen. They determined the rotation rate at each latitude, and interpolated in time to make a 200-step movie that flows smoothly as the clouds swirl around the center. To show the features at the center, the movie displays the motion relative to the clouds at 89.3 degrees latitude.

Video credit: NASA/JPL-Caltech/SSI


Note: For more information, see Mysterious Hurricane at Saturn's North Pole, NASA Probe Gets Close-Up Views of Large Hurricane on Saturn, Saturn's North-Pole Hurricane Close Up, and Gigantic Hurricane Spotted on Saturn.

Saturn's North Polar Hurricane in (Psychadelic) False Colors

This spectacular, vertigo inducing, false-color image from NASA's Cassini mission highlights the storms at Saturn's north pole. The angry eye of a hurricane-like storm appears dark red while the fast-moving hexagonal jet stream framing it is a yellowish green. Low-lying clouds circling inside the hexagonal feature appear as muted orange color. A second, smaller vortex pops out in teal at the lower right of the image. The rings of Saturn appear in vivid blue at the top right.

The images were taken with Cassini's wide-angle camera using a combination of spectral filters sensitive to wavelengths of near-infrared light. The images filtered at 890 nanometers are projected as blue. The images filtered at 728 nanometers are projected as green, and images filtered at 752 nanometers are projected as red. At Saturn, this scheme means colors correlate to different altitudes in the planet's polar atmosphere: red indicates deep, while green shows clouds that are higher in altitude. High clouds are typically associated with locations of intense upwelling in a storm. These images help scientists learn the distribution and frequencies of such storms. The rings are bright blue in this color scheme because there is no methane gas between the ring particles and the camera.

The view was acquired at a distance of approximately 261,000 miles (419,000 kilometers) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 94 degrees. Image scale is 13 miles (22 kilometers) per pixel.

Image credit: NASA/JPL-Caltech/SSI


Note: For more information, see Mysterious Hurricane at Saturn's North Pole, NASA Probe Gets Close-Up Views of Large Hurricane on Saturn, Saturn's North-Pole Hurricane Close Up, and Gigantic Hurricane Spotted on Saturn.

Saturn's North Polar Hurricane in Natural Color

The north pole of Saturn, in the fresh light of spring, is revealed in this color image from NASA's Cassini spacecraft. The north pole was previously hidden from the gaze of Cassini's imaging cameras because it was winter in the northern hemisphere when the spacecraft arrived at the Saturn system in 2004.

A hurricane-like storm circling Saturn's north pole at about 89 degrees north latitude is inside the famous "hexagon" feature, which scientists think is a wandering jet stream that whips around the north pole at about 220 miles per hour (98 meters per second). It folds into a six-sided shape because the hexagon is a stationary wave that guides the path of the gas in the jet. The hexagon borders occur at about 77 degrees north latitude and the feature is wider than two Earths. Saturn's rings can be seen at the upper right of the image.

Images with red, green and blue spectral filters were combined to create this natural-color view, which is what the human eye would see if we were there at Saturn. The image here was acquired with the Cassini spacecraft wide-angle camera on Nov. 27, 2012 at a distance of approximately 260,000 miles (418,000 kilometers) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 96 degrees. Image scale is 18 miles (28.6 kilometers) per pixel.

A false-color version of this image can be seen at PIA14946.

Image credit: NASA/JPL-Caltech/SSI


Note: For more information, see Mysterious Hurricane at Saturn's North Pole, NASA Probe Gets Close-Up Views of Large Hurricane on Saturn, Saturn's North-Pole Hurricane Close Up, and Gigantic Hurricane Spotted on Saturn.

False Color Image of Saturn's North Pole Hurricane

The spinning vortex of Saturn's north polar storm resembles a deep red rose of giant proportions surrounded by green foliage in this false-color image from NASA's Cassini spacecraft. Measurements have sized the eye at a staggering 1,250 miles (2,000 kilometers) across with cloud speeds as fast as 330 miles per hour (150 meters per second).

This image is among the first sunlit views of Saturn's north pole captured by Cassini's imaging cameras. When the spacecraft arrived in the Saturnian system in 2004, it was northern winter and the north pole was in darkness. Saturn's north pole was last imaged under sunlight by NASA's Voyager 2 in 1981; however, the observation geometry did not allow for detailed views of the poles. Consequently, it is not known how long this newly discovered north-polar hurricane has been active.

The images were taken with the Cassini spacecraft narrow-angle camera on November 27, 2012, using a combination of spectral filters sensitive to wavelengths of near-infrared light. The images filtered at 890 nanometers are projected as blue. The images filtered at 728 nanometers are projected as green, and images filtered at 752 nanometers are projected as red. In this scheme, red indicates low clouds and green indicates high ones.

The view was acquired at a distance of approximately 261,000 miles (419,000 kilometers) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 94 degrees. Image scale is 1 mile (2 kilometers) per pixel.

Image credit: NASA/JPL-Caltech/SSI

Note: For more information, see Mysterious Hurricane at Saturn's North Pole, NASA Probe Gets Close-Up Views of Large Hurricane on Saturn, Saturn's North-Pole Hurricane Close Up, and Gigantic Hurricane Spotted on Saturn.

Enceladus

Like a proud peacock displaying its tail, Enceladus shows off its beautiful plume to the Cassini spacecraft's cameras.

Enceladus (313 miles, or 504 kilometers across) is seen here illuminated by light reflected off Saturn.

This view looks toward the Saturn-facing side of Enceladus. North on Enceladus is up and rotated 45 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 18, 2013.

The view was acquired at a distance of approximately 483,000 miles (777,000 kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 173 degrees. Image scale is 3 miles (5 kilometers) per pixel.

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

Clouds from Meteor Impacts with Saturn's Rings

Five images of Saturn's rings, taken by NASA's Cassini spacecraft between 2009 and 2012, show clouds of material ejected from impacts of small objects into the rings. Clockwise from top left are two views of one cloud in the A ring, taken 24.5 hours apart, a cloud in the C ring, one in the B ring, and another in the C ring. Arrows in the annotated version point to the cloud structures, which spread out at visibly different angles than the surrounding ring features.

The clouds of ejected material were visible because of the angle sunlight was hitting the Saturn system and the position of the spacecraft. The first four images were taken near the time of Saturn equinox, when sunlight strikes the rings at very shallow angles, nearly directly edge-on. During Saturn equinox, which occurs only every 14.5 Earth years, the ejecta clouds were caught in sunlight because they were elevated out of the ring plane. The last image was taken in 2012 at a very high-phase angle, which is the sun-Saturn-spacecraft angle. This geometry enabled Cassini to see the clouds of dust-sized particles in the same way that dust on a surface is easier to see when the viewer is looking toward a light source.

The angle that the clouds are canted gives the time elapsed since the cloud was formed (see PIA14941). The A ring cloud formed 24 hours before its first apparition in the top left box; it formed 48.5 hours before the top middle image. The other three clouds were approximately 13 hours, four hours, and one hour old (respectively) at the times they were seen. See PIA11674 for more information on ring impacts.

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

Note: For more information, see PIA14941: A Race Around Saturn, PIA14942: A Race Around Saturn (Animation), NASA Probe Observes Meteors Colliding with Saturn's Rings, and Cassini Catches Meteors Hitting Saturn's Rings.