Titan's Senkyo Region and South Polar Vortex

The Cassini spacecraft simultaneously peers through the haze in Titan's equatorial region down to its surface and captures the vortex of clouds hovering over its south pole just to the right of the terminator on the moon's dark side.

The dark region near Titan's equator is Senkyo. See PIA11636 for a closer view of Senkyo and to learn more. For a color image of the south polar vortex on Titan, see PIA14919. For a movie of the vortex, see PIA14920.

Lit terrain seen here is on the Saturn-facing hemisphere of Titan (3,200 miles, or 5,150 kilometers across). North on Titan is up and rotated 11 degrees to the left. The image was taken with the Cassini spacecraft narrow-angle camera on September 20, 2012 using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers.

The view was obtained at a distance of approximately 1.8 million miles (2.9 million kilometers) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 84 degrees. Image scale is 11 miles (17 kilometers) per pixel.

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

Prometheus and Pan

The 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 ringplane. The image was taken in visible violet light with the Cassini spacecraft narrow-angle camera on September 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.

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

Sinlap and Soi Craters

This set of images from the radar instrument on NASA's Cassini spacecraft shows a relatively "fresh" crater called Sinlap (left) and an extremely degraded crater called Soi (right). Sinlap has a depth-to-diameter ratio close to what we see on Jupiter's moon Ganymede. Soi has a shallow depth compared to similar craters on Ganymede. These craters are both about 50 miles (80 kilometers) in diameter.

The Sinlap image was taken by Cassini's radar instrument on February 15, 2005. The Soi image is a mosaic of two images from May 21, 2009 and July 22, 2006.

Image credit: NASA/JPL-Caltech/ASI/GSFC

Note: For more information, see Titan Gets a Dune 'Makeover'.

Saturn Secrets Revealed

Thirty years ago the Voyager spacecraft offered the first closeup views of Saturn. Launched in 1997 Cassini-Huygens, a joint NASA/ESA/ASI mission, arrived around Saturn in July 2004 and the Huygens Probe landed on Titan, Saturn's largest moon, in January 2005. The ESA probe was the first to land on a world in the outer Solar System. Since 2005 Cassini-Huygens mission has obtained infinitely more detailed and beautiful images of the ringed planet and its many moons. Data from Cassini and Huygens are offering clues about how life began on Earth.

Text credit: ESA; video credit: ESA.

Brother Moons

Saturn's small moons Atlas, Prometheus, and Epimetheus keep each other company in this Cassini spacecraft image of the planet's night side. It seems fitting that they should do so since in Greek mythology, their namesakes were brothers.

Prometheus (53 miles, or 86 kilometers across) is just inside the F ring in this image, while Epimetheus (70 miles, or 113 kilometers across) is farther from the rings, due right of Prometheus in this image. Atlas (19 miles, or 30 kilometers across) is between the A and F rings almost right below Epimetheus and is very faint.

This view looks toward the unilluminated side of the rings from about 30 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on September 19, 2012.

The view was obtained at a distance of approximately 1.4 million miles (2.2 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 96 degrees. Image scale is 80 miles (128 kilometers) per pixel. Epimetheus has been brightened by a factor of 1.5 and Atlas' brightness has been enhanced by a factor of 3 relative to the rings and Prometheus to improve visibility.

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

The Huygens Experience

Eight years ago today [14 January 2013], ESA’s Huygens bounced, slid and wobbled its way to rest on the surface of Saturn’s moon Titan, the first time a probe had touched down on an alien world in the outer Solar System.

The animation was created using real data recorded by Huygen’s instruments, allowing us to witness this historical moment as if we had been there.

The animation takes into account Titan’s atmospheric conditions, including the Sun and wind direction, the behavior of the parachute (with some artistic interpretation only on the movement of the ropes after touchdown), and the dynamics of the landing itself.

Even the stones immediately facing Huygens were rendered to match the photograph of the landing site returned from the probe, which is revealed at the end of the animation.

Split into four sequences, the animation first shows a wide-angle view of the descent and landing followed by two close-ups of the touchdown from different angles, and finally a simulated view from Huygens itself – the true Huygens experience.

New results published last year revealed that on first contact with Titan’s surface, Huygens dug a hole 12 cm deep, before bouncing out and sliding 30–40 cm across a flat surface.

The probe then wobbled back and forth five times until coming to a standstill about 10 seconds after touchdown – this is best seen in the final two sequences.

A ‘fluffy’ dust-like material – most likely organic aerosols that are known to drizzle out of the Titan atmosphere – was thrown up and suspended for around four seconds around the probe following the impact. The dust was easily lifted, suggesting it was most likely dry and that there had not been any ‘rain’ of liquid ethane or methane for some time prior to the landing.

Huygens was released from the international Cassini spacecraft on Christmas Day 2004, arriving at Titan three weeks later. Cassini has been in orbit around Saturn since July 2004, and will continue operations until 2017.

Video credit: ESA. Text credit: ESA.

Note: For more information, see When Huygens Met Titan.

Sunset on Enceladus' Jets

As the long winter night deepens at Enceladus' south pole, its jets are also progressively falling into darkness. The shadow of the moon itself is slowly creeping up the jets making the portions closest to the surface difficult to observe by the Cassini spacecraft.

Cassini looks toward the night side of Enceladus (313 miles, or 504 kilometers across) in this image. Enceladus is lit by light reflected off Saturn rather than by direct sunlight.

This view looks toward the Saturn-facing hemisphere of Enceladus. North on Enceladus is up. The image was taken with the Cassini spacecraft narrow-angle camera on September 24, 2012 using a spectral filter sensitive to wavelengths of near-infrared light centered at 930 nanometers.

The view was acquired at a distance of approximately 452,000 miles (728,000 kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 170 degrees. Scale in the original image was 3 miles (4 kilometers) per pixel. The image was magnified by a factor of three to enhance the visibility of jets.

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

Possible Hydrocarbon Ice in Titan's Lakes

Lakes on Saturn's moon Titan reflect radio waves in varying ways in this image from NASA's Cassini spacecraft. Scientists think the variations in reflectivity, or brightness, have to do with the smoothness or texture of the surface. If a lake is fully liquid, it looks dark, but if it is only partially liquid, it looks brighter.

In this image taken from Titan's high northern latitudes on May 22, 2012, the lakes on the left are full of liquid hydrocarbons and the lakes on the top right are only partially filled, or represent saturated ground (i.e., a mudflat). The lakes in this image are each about 35 to 45 kilometers (22 to 30 miles) across, or about the size of Lake Tahoe on the California-Nevada border. Some of the differences in reflectivity could also be explained by the presence of floating hydrocarbon ice.

This image was obtained by Cassini's radar mapper at a scale of about 350 meters (1,100 feet) per pixel. It is presented in polar stereographic projection with a logarithmic stretch.

For perspective, a wider view of these lakes can be seen in PIA16167.

Image credit: NASA/JPL-Caltech/ASI/Cornell

Note: For more information, see PIA16634: Floating Ice on Titan Lakes? and Cassini Suggests Icing on a Lake.

Daphnis and the Keeler Gap

Saturn's small moon Daphnis is caught in the act of raising waves on the edges of the Keeler gap, which is the thin dark band in the left half of the image. Waves like these allow scientists to locate small moons in gaps and measure their masses.

For more on Daphnis (5 miles, or 8 kilometers across) and the Keeler gap, see PIA11655 and PIA06238.

This view looks toward the sunlit side of the rings from about 13 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on August 14, 2012.

The view was obtained at a distance of approximately 483,000 miles (778,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 4 degrees. Image scale is 3 miles (4 kilometers) per pixel. The F ring has been brightened by a factor of 1.5 relative to the main rings to enhance visibility.

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