Tuesday, April 30, 2013

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

Friday, April 26, 2013

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.

Thursday, April 25, 2013

Enceladus


This face-on color view of Enceladus was taken by the international Cassini spacecraft on 31 January 2011, from a distance of 81,000 km, and processed by amateur astronomer Gordan Ugarković.

Image credit: NASA/JPL-Caltech/SSI/G. Ugarković

Tuesday, April 23, 2013

Daphnis in the Keeler Gap


The tiny wavemaker moon Daphnis is dwarfed by the very waves it creates on the edge of the Keeler gap. Daphnis (5 miles, or 8 kilometers across), a tiny dot in the Keeler gap, raises waves on the edges of that gap as it passes the ring material. Daphnis' gravitational encounters also maintain the gap, shepherding material back into the ring.

The two bright dots between the A and F ring are stars. For more about Daphnis, see PIA06238.

This view looks toward the unilluminated side of the rings from about 50 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on January 15, 2013.

The view was acquired at a distance of approximately 870,000 miles (1.4 million kilometers) from Daphnis and at a Sun-Daphnis-spacecraft, or phase, angle of 99 degrees. Image scale is 5 miles (8 kilometers) per pixel.

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

Friday, April 19, 2013

Titan's Ligeia Mare and Other Lakes



These images from NASA's Cassini spacecraft show one of the large seas and a bounty of smaller lakes on Saturn's moon Titan. Scientists saw these small lakes in data obtained by both Cassini's visual and infrared mapping spectrometer (left) and radar instrument (right).

Ligeia Mare, about 50,000 square miles (125,000 square kilometers) in area, is the large lake near the bottom of both images. Three new lakes of about 100 to 300 square miles (a few hundreds of square kilometers) identified first in the visual and infrared mapping spectrometer images are labeled in the annotated version as Freeman (VimsNN1), Cardiel (VimsNN2) and VimsNN4. The new lakes can be seen at the top left and middle right. The small lake Towada first seen in radar images was also seen in this VIMS investigation (VimsNN3) and can be seen in the middle right.

The images that went into the VIMS mosaic were taken in June 2010. The images that make up the radar mosaic were taken in April 2007. The small lakes remained relatively consistent between 2007 and 2010.

Image credit: NASA/JPL-Caltech/University of Arizona

Note: For more information, see Titan's Methane: Going, Going, Soon to Be Gone?

Thursday, April 18, 2013

Small Lakes on Titan


Three new small lakes, 100 to 300 square miles (a few hundreds of square kilometers) in surface area, have been identified on Saturn's moon Titan in data from NASA's Cassini spacecraft. In the image from Cassini's visual and infrared mapping spectrometer at the bottom part of the image, Freeman, Cardiel and a lake currently designated as VIMSNN4 join the cast of small lakes already discovered by Cassini's radar. Towada (VIMSNN3) is a lake originally seen in radar data that was also seen in the VIMS data. Radar views of some of the lakes are shown as the insets.

Studies of the surface areas of these small lakes can yield big results in determining the evolution of liquid bodies on Titan, and shed light on the past and future of methane in shaping Titan's environment.

The VIMS images were taken in 2010. The radar images were taken in 2007.

Image credit: NASA/JPL-Caltech/University of Arizona

Note: For more information, see Titan's Methane: Going, Going, Soon to Be Gone?

Wednesday, April 17, 2013

Wetlands on Titan



A dense network of small rivers or swampy areas appears to connect some of the seas on Saturn's moon Titan, as seen in this comparison of data of the same area from two instruments on NASA's Cassini spacecraft. Images from the radar instrument are on the left and images from the visual and infrared mapping spectrometer (VIMS) are on the right.

At approximately 50,000 square miles (about 125,000 square kilometers), Ligeia Mare (middle of the images) is larger than any North American lake. The labels K1, K2, and K3 in the radar mosaic (a) refer to different parts of Kraken Mare that appear interconnected in the VIMS mosaic (b).

Photo credit: NASA/JPL-Caltech/University of Arizona

Note: For more information, see Titan's Methane: Going, Going, Soon to Be Gone?

Tuesday, April 16, 2013

Saturn's Clouds and Storms


Saturn's richly dynamic atmosphere rewards viewers with unique and fascinating structures with every new observation. Here, the Cassini spacecraft uses the near-infrared filters on its wide-angle camera to get a better look at some of Saturn's cloud patterns, shaped by wind and storms in Saturn's atmosphere.

This view is centered on 30 degrees north latitude, 42 degrees west longitude. North is up and rotated 44 degrees to the right. The image was taken with the Cassini spacecraft wide-angle camera on December 24, 2012 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers.

The view was acquired at a distance of approximately 440,000 miles (710,000 kilometers) from Saturn's surface and at a Sun-Saturn-spacecraft, or phase, angle of 14 degrees. Image scale is 26 miles (42 kilometers) per pixel.

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

Friday, April 12, 2013

Titan's South Polar Vortex


The recently formed south polar vortex stands out in the color-swaddled atmosphere of Saturn's largest moon, Titan, in this natural color view from NASA's Cassini spacecraft.

See PIA14919 and PIA14920 to learn more about this mass of swirling gas around the pole in the atmosphere.

Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were acquired with the Cassini spacecraft wide-angle camera on July 25, 2012, at a distance of approximately 64,000 miles (103,000 kilometers) from Titan. Image scale is 4 miles (6 kilometers) per pixel.

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

Note: For more information, see Ice Cloud Heralds Fall at Titan's South Pole.

Thursday, April 11, 2013

Rain from Saturn's Rings


This artist's concept illustrates how charged water particles flow into the Saturnian atmosphere from the planet's rings, causing a reduction in atmospheric brightness. The observations were made with the W.M. Keck Observatory on Mauna Kea, Hawaii, with NASA funding. The analysis was led by the University of Leicester, England.

Image credit: NASA/JPL-Caltech/Space Science Institute/University of Leicester

Note: For more information, see Blame it on the Rain (from Saturn's Rings).

Tuesday, April 9, 2013

Titan's Senkyo Region and South Polar Vortex


The Cassini spacecraft peers through Titan's thick clouds to spy on the region dubbed "Senkyo" by scientists. The dark features include vast fields of dunes, composed of solid hydrocarbon particles precipitated out of Titan's atmosphere. And Titan's southern pole is shrouded in the recently formed polar vortex.

Titan, Saturn's largest moon, is 3,200 miles (5,150 kilometers) across.

For more on Senkyo, see PIA08231. 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. North on Titan is up and rotated 18 degrees to the right. The image was taken with the Cassini spacecraft narrow-angle camera on January 5, 2013 using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers.

The view was obtained at a distance of approximately 750,000 miles (1.2 million kilometers) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 79 degrees. Image scale is 4 miles (7 kilometers) per pixel.

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

Thursday, April 4, 2013

Simulating Titan-Like Smog


In a laboratory experiment at NASA's Jet Propulsion Laboratory, Pasadena, Calif., scientists simulating the atmosphere of Saturn's moon Titan have brewed up complex organic molecules that they think could eventually lead to the building blocks of life. In this picture, molecules of dicyanoacetylene are seen on a special film on a sapphire window. They are the result of exposing simple organic molecules known to exist at Titan with sun-like radiation on August 4, 2010. The residue is among the smog-like airborne molecules with carbon-nitrogen-hydrogen bonds that the astronomer Carl Sagan called "tholins" that give orange-brown color to Titan.

The experiment was conducted at JPL's Titan Organic Aerosol and Surface Chemistry laboratory.

Photo credit: NASA/JPL-Caltech

Note: For more information, see NASA Team Investigates Complex Chemistry at Titan.

Tuesday, April 2, 2013

Prometheus and the F-Ring


Like a shepherd guarding his sheep, Prometheus keeps a lonely watch over the F ring.

Gravitational interactions between the ring and its shepherd moons, Prometheus (53 miles, or 86 kilometers across) and Pandora (not shown here), keep the F ring narrowly confined. The five small, bright dots in this image (one of them seen through the A ring, which is on the right) are stars.

This view looks toward the unilluminated side of the rings from about 52 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on January 15, 2013.

The view was obtained at a distance of approximately 810,000 miles (1.3 million kilometers) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 110 degrees. Image scale is 5 miles (8 kilometers) per pixel.

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