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Agitators of the Atmosphere
| Description |
Agitators of the Atmosphere |
| Full Description |
Two bright vortices roll across the cloud-lined face of Saturn, where winds howl at high speeds never experienced on Earth. This view was acquired at about the same time as Cloud Lanes but the planet appears darker here. This is because the spectral filter used to acquire this image looks at a part of the spectrum where methane absorption in Saturn's atmosphere is stronger. Thus, photons do not penetrate as deep into the Saturn atmosphere as they do at the wavelengths observed in Cloud Lanes. Since more photons are absorbed here, the planet looks darker. The icy particles composing the rings do not contain methane, and therefore appear bright relative to Saturn. The image was taken using a spectral filter sensitive to wavelengths of infrared light centered at 862 nanometers. The view was obtained using the Cassini spacecraft wide-angle camera on Dec. 13, 2006 at a distance of approximately 775,000 kilometers (481,000 miles) from Saturn. Image scale is 43 kilometers (27 miles) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
January 31, 2007 |
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Icy Outpost?
| Description |
The Cassini spacecraft looks down under at the tortured south polar region of Enceladus, crossed by its |
| Full Description |
The Cassini spacecraft looks down under at the tortured south polar region of Enceladus, crossed by its "tiger stripes," or sulci, as the long, nearly parallel fractures are officially known. The use of enhanced color in this and other composite images makes the fractures and faults easier for the eye to detect. The moon's excess warmth, water ice jets, and huge vapor plume laced with simple organic materials make it an excellent candidate for the search for pre-biotic chemistry, and possibly even life, beyond Earth. Enceladus is 505 kilometers (314 miles across). This false-color view is a composite of images obtained using filters sensitive to ultraviolet, green and infrared light. The images were taken by the Cassini spacecraft narrow-angle camera on Jan. 16, 2007 at a distance of approximately 657,000 kilometers (408,000 miles) from Enceladus. Image scale is 4 kilometers (2 miles) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
February 21, 2007 |
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Titan (T18) Viewed by Cassin
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| Description |
This radar image, obtained by Cassini's radar instrument during a near-polar flyby on Sept. 23, 2006, is the second scene that shows clear shorelines reminiscent of terrestrial lakes. |
| Full Description |
This radar image, obtained by Cassini's radar instrument during a near-polar flyby on Sept. 23, 2006, is the second scene that shows clear shorelines reminiscent of terrestrial lakes. With Titan's colder temperatures and hydrocarbon-rich atmosphere, these lakes most likely contain a combination of methane and ethane (both hydrocarbons), not water. This high-latitude opportunity confirmed scientists' predictions that lakes would be present here, consistent with calculations that suggested that hydrocarbons would be stable as liquids at the colder, high latitudes. It also showed unusual complex terrain, the origin of which remains a mystery. The image is illuminated by the radar from the top, and shows features as small as about 300 meters (980 feet). Starting at the left (63 degrees north latitude by 255 degrees west longitude), where the terrain appears bland and dark, the swath heads northeast into a more rugged, mottled terrain, probably containing dried lakes and canyons formed by the presence of liquid hydrocarbons. The first lake, an irregular, almost-triangular shape about 16 kilometers (10 miles) across at the widest point, can be seen near the bottom of the image, it appears to be fed by two channels from the south. Several more lakes can be seen about one-third of the way into the swath, near the closest approach to the pole, (north of 75 degrees north latitude), including Titan's "kissing lakes," each 20 to 25 kilometers (12 to 16 miles) across. Two other lakes feature narrow or angular bays, including a broad peninsula that on Earth would be evidence that the surrounding terrain is higher and confines the liquid. Continuing on, about three-quarters of the way through the swath, the terrain becomes brighter and more rugged, again indicating possible dried lakes and canyon-like structures. A long 100-kilometer (60-mile) series of grooves appears, likely carved by liquids. Next is an area of bright terrain with an unusual directional texture, indicating possible dunes, but brighter and perhaps different in nature than those seen elsewhere. Finally, towards the end of the swath, where the image quality is poorest, the terrain becomes mottled and difficult to interpret. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. Credit:NASA/JPL |
| Date |
February 20, 2007 |
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Titan (T25) Viewed by Cassin
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| Description |
Titan (T25) Viewed by Cassini's Radar Feb. 22, 2007 |
| Full Description |
This image of Saturn's largest moon, Titan, obtained by Cassini's radar instrument during a near-polar flyby on Feb. 22, 2007, features dunes and lakes, one of which is larger than any lake on Earth and could be legitimately called a sea. First discovered by Cassini's radar in July 2006 (see Lakes on Titan), Titan's lakes are thought to consist of liquid methane and ethane. The image runs from southern latitudes, starting at 32 degrees south, 55 degrees west, where we see featureless terrain with bright streaks, heading north and slightly east, through dune fields interspersed with exposed bright mounds. In places, the dunes wrap around the bright mounds, which suggests the mounds are raised (see Titan Features and Interactions). In one case, the dunes wrap around an unusual rose-shaped structure, approximately 70 kilometers (40 miles) across. Near the spacecraft's closest approach (33 degrees north, 28 degrees west), where the swath is at its narrowest, the terrain is dark and mottled, with occasional bright outcrops and fine dunes. As we continue to head north, we see the first signs of the action of liquids -- fine channels and canyon-like structures. Later, depressions can be seen. These are similar to those seen in the lake region and are interpreted as volcanic calderas or drained lakes. As the swath continues, these become more plentiful, and some are partly filled with dark material thought to be liquid hydrocarbons, hence lakes. In places, the lakes reside in what appear to be nested, near-circular depressions, reminiscent of nested calderas. The final section of the swath, which is closest to the pole, contains by far the largest lakes observed by Cassini's radar to date. Part of the first of these was seen during a previous flyby (see Titan's Great Lakes?), and is fed by a long river -- over 200 kilometers (120 miles) in length, and hundreds of meters to over 1 kilometer (0.6 miles) in width - running through what appears to be a flood plain. The lake's bright, jutting shoreline indicates that old, eroded landforms may have been flooded. The end of the next lake was also observed before (see Lakes and More lakes), appearing to be, in both form and scale, similar to Lake Powell, a flooded drainage system in Utah and Arizona. We can now see that this lake on Titan connects via a relatively narrow channel to a much larger (at least 45,000 square kilometers or 17,000 square miles) lake, containing a large (approximately 12,000 square kilometers or 4,600 square miles) island or peninsula (see Titan: Larger and Larger Lakes). The last part of the image passes close to the pole (86 degrees north, 290 degrees east), before heading east and slightly south. At the end of the swath, we see the largest lake observed yet -- at least 100,000 square kilometers (39,000 square miles), which is greater in extent than one of the largest lakes on Earth, Lake Superior (82,000 square kilometers or 32,000 square miles), and covers a greater fraction of, Titan than the largest terrestrial inland sea, the Black Sea. The Black Sea covers 0.085 percent of the surface of the Earth, this newly observed body on Titan covers at least 0.12 percent of the surface of Titan. Because of its size, scientists are calling this a sea. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. *Credit:* NASA/JPL |
| Date |
March 13, 2007 |
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Giant Lake on Titan
| Description |
Giant Lake on Titan |
| Full Description |
This view of Titan taken on Feb. 25, 2007, reveals a giant lake-like feature in Titan's North Polar Region. It is approximately 1,100 kilometers (680 miles) long and has a surface area slightly smaller than that of Earth's largest lake, the Caspian Sea. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . *Credit: *NASA/JPL/Space Science Institute |
| Date |
March 13, 2007 |
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Exploring the Wetlands of Ti
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| Description |
Exploring the Wetlands of Titan |
| Full Description |
Cassini peers through the murky orange haze of Titan to spy what are believed to be bodies of liquid hydrocarbons, two of them as large as seas on Earth, near the moon's north pole. This movie blends a near natural-color view and an infrared glimpse of Titan's surface obtained by the visual cameras, followed by a transition to imagery collected by the radar instrument aboard Cassini, for a dramatic reveal of the north pole of Saturn's largest moon. As the movie zooms in on the north pole, the most readily visible bodies are outlined in blue. The largest of these, on the left, is as big as the Caspian Sea on Earth, the next largest, on the right, is about the size of Lake Superior. When compared to the surface area of Titan however (which is six times smaller than Earth's), these bodies are equivalent in size to the Bay of Bengal and Timor Sea, respectively. Geographically speaking, they are more like seas. The movie continues with a gradual transition to a polar map of the radar imagery taken so far by Cassini of the north polar region. It is clear that one of the radar swaths has intersected a small upper bay of the largest sea, and has almost entirely imaged the second one. The extreme darkness of these regions in the radar data argues strongly for the presence of liquid hydrocarbons, such as methane and ethane, which remain liquid at Titan's frigid temperature of minus 180 degrees Celsius (minus 288 degrees Fahrenheit). See Titan (T25) Viewed by Cassini's Radar - Feb. 22, 2007. The movie continues with a pan across the pole and the radar imagery that has uncovered a multitude of much smaller lakes. Features of strikingly similar morphology to these dark northern seas and smaller lakes were first discovered in Cassini Imaging Science Subsystem images in June 2005, at Titan's south pole (see Land of Lakes?). The lake-like shoreline of the largest of these, called Ontario Lacus, its size (about the size of Lake Victoria), and its proximity to the south pole where the largest field of clouds yet seen on Titan had been observed, earned it the reputation as the best candidate for a body of liquid hydrocarbons on Titan up until that point, though the case for liquids was weak. When adjusted for the size of Titan, Ontario Lacus is equivalent in size to the Black Sea. Now, by inference, scientists are more confident that it, and the smaller features that dot the south pole, are also likely open bodies of liquid, and in aggregate make up a southern wetlands on Titan, similar to the one observed in the north polar movie. The images used to make this movie were taken with the Cassini spacecraft narrow-angle camera on Feb. 25, 2007, at a distance of approximately 1.3 million kilometers (800,000 miles) from Titan. The infrared images were taken with a special filter centered at 938 nanometers that provides the cameras' best view of Titan's surface features. This view was then composited with images taken at 619, 568 and 440 nanometers to, create a near natural color appearance. The radar data were acquired in synthetic aperture radar mode. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
March 15, 2007 |
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Hello Again, Jupiter!
| Description |
Hello Again, Jupiter! |
| Full Description |
The brick red, white and brown cloud bands of Jupiter are seen here from Saturn orbit. The Cassini spacecraft's powerful imaging cameras were specially designed to photograph nearby bodies (cosmically speaking) in the Saturn system, but as this image demonstrates, the cameras are actually telescopes. Jupiter is imaged here from more than 11 times the distance between Earth and the Sun, or slightly farther than the average Earth-Saturn distance. As demonstrated by Pale Blue Orb, Earth is only about a pixel across when viewed from Saturn by Cassini. Cassini's parting glance at Jupiter, following the spacecraft's 2000 flyby and gravity assist, is Cassini's Farewell to Jupiter. Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were taken with the Cassini spacecraft narrow-angle camera on Feb. 8, 2007 at a distance of approximately 1.8 billion kilometers (1.1 billion miles) from Jupiter and at a Sun-Jupiter-spacecraft, or phase, angle of 50 degrees. Scale in the original image was about 10,000 kilometers (6,000 miles) per pixel. The image was contrast enhanced and magnified by a factor of two and a half to enhance the visibility of cloud features on the planet. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
March 19, 2007 |
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Titan Sea and Lake Superior
| Description |
Titan Sea and Lake Superior |
| Full Description |
This side-by-side image shows a Cassini radar image (on the left) of what is the largest body of liquid ever found on Titan's north pole, compared to Lake Superior (on the right). This close-up is part of a larger image (see Titan (T25) Viewed by Cassini's Radar - Feb. 22, 2007) and offers strong evidence for seas on Titan. These seas are most likely liquid methane and ethane. This feature on Titan is at least 100,000 square kilometers (39,000 square miles), which is greater in extent than Lake Superior (82,000 square kilometers or 32,000 square miles), which is one of Earth's largest lakes. The feature covers a greater fraction of Titan than the largest terrestrial inland sea, the Black Sea. The Black Sea covers 0.085 percent of the surface of the Earth, this newly observed body on Titan covers at least 0.12 percent of the surface of Titan. Because of its size, scientists are calling it a sea. The image on the right is from the SeaWiFS project, NASA's Goddard Space Flight Center, Greenbelt, Md. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. *Credit:* NASA/JPL/GSFC |
| Date |
March 13, 2007 |
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Saturn's Strange Hexagon
| Description |
This is one of the first clear images taken of the north polar region ever acquired from a unique polar perspective. |
| Full Description |
This nighttime view of Saturn's north pole by the visual and infrared mapping spectrometer onboard NASA's Cassini orbiter clearly shows a bizarre six-sided hexagon feature encircling the entire north pole. This is one of the first clear images taken of the north polar region ever acquired from a unique polar perspective. In this image, the red color indicates the amount of 5-micron wavelength radiation, or heat, generated in the warm interior of Saturn that escapes the planet. Clouds near 3-bar (about 100 kilometers or 62 miles deeper than seen in visible wavelengths) block the light, revealing them in silhouette against the background thermal glow of Saturn. The bluish color shows sunlight striking the far limb (edge) of the planet, showing that the entire north pole is under the nighttime conditions characteristic of polar winter, as on Earth. This image is the first to capture the entire feature and north polar region in one shot, and is also the first polar view using Saturn's thermal glow at 5 microns (seven times the wavelength visible to the human eye) as the light source. This allows the pole to be revealed during the persistent nighttime conditions under way during winter. The hexagon feature was originally discovered by NASA's Voyager spacecraft in 1980, but those historic images and subsequent ground-based telescope images suffered from poor viewing perspectives, which placed the feature and the north pole at the extreme northern limb (edge) in those images. In the new infrared images, the strong brightness of the hexagon feature indicates that it is primarily a clearing in the clouds, which extends deep into the atmosphere, at least some 75 kilometers (47 miles) underneath the typical upper hazes and clouds seen in the daytime imagery by Voyager. Thick clouds border both sides of the narrow feature, as indicated by the adjacent dark lanes paralleling the bright hexagon. This and other images acquired over a 12-day period between Oct. 30 and Nov. 11, 2006, show that the feature is nearly stationary, and likely is an unusually strong pole-encircling planetary wave that extends deep into the atmosphere. This image was acquired with the Cassini visual and infrared mapping spectrometer on Oct. 30, 2006, from an average distance of 1.3 million kilometers (807,782 miles). The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Visual and Infrared Mapping Spectrometer team is based at the University of Arizona, where this image was produced. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. The visual and infrared mapping spectrometer team homepage is at, http://wwwvims.lpl.arizona.edu. Credit: NASA/JPL/University of Arizona |
| Date |
March 27, 2007 |
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Saturn's North Pole Hexagon
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| Description |
Clearly revealed is the bizarre six-sided hexagon feature present at the north pole of Saturn. |
| Full Description |
Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. The visual and infrared mapping spectrometer team homepage is at http://wwwvims.lpl.arizona.edu. Credit: NASA/JPL/University of Arizona, This nighttime view of Saturn's north pole by the visual and infrared mapping spectrometer on NASA's Cassini orbiter reveals a dynamic, active planet at least 75 kilometers (47 miles) below the normal cloud tops seen in visible light. Clearly revealed is the bizarre six-sided hexagon feature present at the north pole. This image is one of the first clear images of the north polar region ever acquired from a unique polar perspective. In this image, the blue color shows high-altitude emissions from atmospheric molecules excited by charged particles smashing into the atmosphere along Saturn's powerful magnetic field lines, producing the aurora at very high altitudes in Saturn's atmosphere. The red color indicates the amount of 5-micron wavelength radiation, or heat, generated in the depths of the warm interior of Saturn that escapes the planet. Clouds blocking this light are revealed as silhouettes against the background thermal glow of the planet. This image is among the first to capture the entire hexagonal feature and north polar region in one shot. It is also one of the first polar views using Saturn's thermal glow at 5 microns (seven times the wavelength visible to the human eye) as the light source. This allows polar cloud features to be revealed during the persistent nighttime conditions under way during north polar winter. The hexagonal feature was originally discovered by NASA's Voyager spacecraft in 1980, but those images and subsequent ground-based telescope images suffered from poor viewing perspectives, which placed the feature and the north pole at the extreme northern limb (edge) in those images. The strong brightness of the hexagon feature indicates that it is primarily a clearing in the clouds, which extends deep into the atmosphere, at least down to the 3-bar (3-Earth atmospheres pressure) level, about 75 kilometers (47 miles) below the clouds and hazes seen in visible wavelengths. Thick clouds border both sides of the narrow feature, as indicated by the adjacent dark lanes paralleling the bright hexagon. This image and other images acquired over a 12-day period between Oct. 30 and Nov. 11, 2006, show that the feature is nearly stationary, and likely is an unusually strong pole-encircling planetary wave that extends deep into the atmosphere. This image was acquired by the Cassini visual and infrared mapping spectrometer on Oct. 29, 2006, from an average distance of 905,000 kilometers (562,340 miles) above the clouds. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Visual and Infrared Mapping Spectrometer team is based at the University of Arizona, where this image was produced. For more information about the |
| Date |
March 27, 2007 |
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Moons in the Night
| Description |
Moons in the Night |
| Full Description |
Sunlight makes visible the faint band called the E ring as two moons meet in the sky. Enceladus (505 kilometers, or 314 miles across) and Tethys (1,071 kilometers, or 665 miles across) appear close together in the sky in this image, but in reality, Tethys was more than 260,000 kilometers (162,000 miles) farther from the Cassini spacecraft -- greater than half the distance from Earth to the Moon. Enceladus is easy to identify by the brilliant plume of ice erupting from its south pole. Although this perspective views the night sides of both moons, the Sun is not the only source of illumination in the Saturn system. Tethys is at a fuller phase with respect to Saturn, and thus its "night side" is more fully lit than that of Enceladus. The view was acquired from a Sun-Enceladus-spacecraft, or phase, angle of 163 degrees, a viewing geometry in which the microscopic ice particles in its plume brighten substantially. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 6, 2006 at a distance of approximately 3.9 million kilometers (2.4 million miles) from Enceladus and 4.2 million kilometers (2.6 million miles) from Tethys. Image scale is 23 kilometers (14 miles) per pixel on Enceladus and 25 kilometers (16 miles) on Tethys. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
April 16, 2007 |
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Seeing Farther North
| Description |
Seeing Farther North |
| Full Description |
High northern terrain on Titan is made visible by some image processing sleight of hand. The view is the product of a ratio between Titan images taken using two different spectral filters. This process improves the visibility of surface features on Titan by removing the effect of shading from differing lighting angles. Features nearest the terminator (the line between night and day) receive the greatest improvement in terms of visibility. In this particular frame, the process also makes visible features beyond the terminator. These features are illuminated by scattered light in the atmosphere, as during twilight on Earth. By this processing technique, surface features near the north pole can be viewed a full year-and-a-half before they are illuminated directly by the Sun. In most processed views of Titan, this ratio procedure produces images that show only the surface, and indeed, most of the features visible here are on the ground. However, the high altitude haze layers in Titan's north polar region are darker in the shorter wavelength image used to create this special product. This difference in brightness results in the bright latitudinal band seen here. The banding in the north polar haze layers can be seen in Circumpolar Bands. In the high north lie the large, dark features thought to be seas of liquid methane or ethane. Along the bottom of the image are Titan's equatorial dark regions, also thought to be seas -- but instead of liquid, they are seas of longitudinal dunes. The view is toward terrain centered at 34 degrees north latitude on Titan (5,150 kilometers, or 3,200 miles across). The image was taken with the Cassini spacecraft narrow-angle camera on March 29, 2007 at a distance of approximately 1.5 million kilometers (900,000 miles) from Titan. Image scale is 9 kilometers (6 miles) per pixel. Due to scattering of light by Titan's hazy atmosphere, the sizes of surface features that can be resolved are a few times larger than the actual pixel scale. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
May 1, 2007 |
|
Powering Saturn's Jets (with
…
| Description |
Powering Saturn's Jets (without labels) |
| Full Description |
+ View labeled version of the image Using images like the one presented here, Cassini imaging scientists have made a major finding about the mechanism powering the general circulation of Saturn. The image shows small-scale, sheared-out cloud features associated with turbulent eddies in the vicinity of one of Saturn's eastward flowing jet streams, or "jets." The jet itself, located at 27.5 degrees south latitude, is indicated by the large horizontal arrow. Winds in this jet have blown continuously at speeds close to 320 kilometers per hour (200 miles per hour) for as long as scientists have observed Saturn. By tracking the movements of these cloud features in successive images separated by about 10 hours (about one Saturn rotation), Cassini scientists have confirmed that the eddies on either side of the jet give up their energy and momentum to help keep the winds in the jet blowing. The tilted arrows indicate the direction in which the eddies move the energy and momentum that power the jet. The winds that accomplish this are so strong that they combine to stretch out the eddies into bright, tilted streaks that are visible here, parallel to the arrows. The analysis of Cassini images covering most of Saturn's southern hemisphere suggests that similar processes occurring all over Saturn explain the remarkable decades-long stability of its alternating pattern of eastward and westward jets. The same process also occurs on Jupiter, and on Earth in the storm track along the east coast of the United States. Prior to this discovery, it was thought that the jets on Saturn and Jupiter were powered by an entirely different process, analogous to the tropical circulation on Earth. But now it appears that a comparison to the atmospheric motions in the Earth's mid-latitudes is more appropriate. The eddies seen in this image also create circulation patterns of upward and downward motion (in altitude) at different latitudes that help explain the general banded structure of global cloud patterns on the Jovian planets. A labeled version of the image is presented here as well. The image was taken using a spectral filter sensitive to wavelengths of infrared light centered at 750 nanometers. The view was acquired with the Cassini spacecraft narrow-angle camera on Feb. 5, 2005, at a distance of approximately 3.4 million kilometers (2.1 million miles) from Saturn. Image scale is 20 kilometers (12 miles) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
May 8, 2007 |
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Cat's eye rings and peek-a-b
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| Description |
On Aug. 16, 2006, as the Cassini orbiter flew directly between the sun and Saturn, its Visual and Infrared Mapping Spectrometer captured a sequence of images that vividly show this opposition brightening. |
| Full Description |
Astronomers have long known that Saturn's rings reflect sunlight most strongly when Earth is located directly between Saturn and the sun. Flat, shiny surfaces (like a mirror or a pond) can appear particularly bright when light reflects off them in a certain direction. Scientists call this "specular reflection," from the Latin word for mirror. However, even rough surfaces, like those of Earth's moon or Saturn's rings, can appear bright when the source of light is directly behind the observer's head, no matter what the orientation of the surface is. This latter phenomenon is known as the "opposition effect." Spectacular examples include the eyes of a cat, which seem to glow brightly when they are illuminated by a flashlight, or highway signs and reflectors that "light up" when they are caught in a car's headlights. On Aug. 16, 2006, as the Cassini orbiter flew directly between the sun and Saturn, its Visual and Infrared Mapping Spectrometer captured a sequence of images that vividly show this opposition brightening. Combined here into a mosaic, the images show -- from left to right -- a small, bright spot moving from the outermost B ring across the Cassini Division and all the way across the A ring. In each image, this spot is centered on the point in the rings directly opposite the sun. Theoretical models for the opposition effect suggest that it can be explained by light being scattered several times within the surfaces of individual, transparent, icy ring particles on scales of about 40 micrometers, or 1/500th of an inch. Similar effects are seen in laboratory studies of bright, finely-textured material such as snow or sugar crystals. In this mosaic, blue colors highlight the icy rings (2.35 microns), green represents sunlight reflected by the clouds of Saturn (2.86 microns) and red depicts thermal emission from the planet's interior (5.02 microns). The rings were observed while they were in front of the planet, producing a complex interplay of sunlight reflected from the rings and the shadows cast by the rings on the cloud tops of Saturn. The yellow-green sunlit clouds of Saturn are seen in the upper right corner of the mosaic beyond the outer edge of the A ring, and also through the 4,000-kilometer-wide (2,400 mile) Cassini Division in the left third of the mosaic. (Yellow indicates a mixture of reflected sunlight and thermal emission.) The shadowed regions of the planet, on the other hand, appear deep red because only thermal emission produced deep inside Saturn itself is visible. At exact opposition, the shadows of the rings are hidden behind the rings themselves, but away from this point shadows can be seen peeking out from behind the edges of the A and B rings into the Cassini Division, as well as beyond the outer edge of the A ring. If one looks closely, one can even trace the A ring's shadow behind the partly transparent A ring, as a faint purple band. Within this band, a thin blue-green line crossing obliquely behind the A ring is, caused by sunlight passing through the narrow Encke Gap in the outer A ring. The Cassini spacecraft was at a distance of 254,000 kilometers (157,800 miles) from the center of Saturn when these images were taken, while the opening angle of the rings to the sun was 16.3 degrees. The image scale at the rings is approximately 70 kilometers (40 miles) per pixel. All nine images were taken over a period of 27 minutes, and the vertical dimension of the mosaic is 1.8 degrees. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Visual and Infrared Mapping Spectrometer team is based at the University of Arizona, where this image was produced. For more information about the Cassini-Huygens mission, visit: http://saturn.jpl.nasa.gov/home/index.cfm. The visual and infrared mapping spectrometer team home page is at: http://wwwvims.lpl.arizona.edu . Credit: NASA/JPL/University of Arizona |
| Date |
June 26, 2007 |
|
Cat's eye rings and peek-a-b
…
| Description |
On Aug. 16, 2006, as the Cassini orbiter flew directly between the sun and Saturn, its Visual and Infrared Mapping Spectrometer captured a sequence of images that vividly show this opposition brightening. |
| Full Description |
See also the non-annotated version. Astronomers have long known that Saturn's rings reflect sunlight most strongly when Earth is located directly between Saturn and the sun. Flat, shiny surfaces (like a mirror or a pond) can appear particularly bright when light reflects off them in a certain direction. Scientists call this "specular reflection," from the Latin word for mirror. However, even rough surfaces, like those of Earth's moon or Saturn's rings, can appear bright when the source of light is directly behind the observer's head, no matter what the orientation of the surface is. This latter phenomenon is known as the "opposition effect." Spectacular examples include the eyes of a cat, which seem to glow brightly when they are illuminated by a flashlight, or highway signs and reflectors that "light up" when they are caught in a car's headlights. On Aug. 16, 2006, as the Cassini orbiter flew directly between the sun and Saturn, its Visual and Infrared Mapping Spectrometer captured a sequence of images that vividly show this opposition brightening. Combined here into a mosaic, the images show -- from left to right -- a small, bright spot moving from the outermost B ring across the Cassini Division and all the way across the A ring. In each image, this spot is centered on the point in the rings directly opposite the sun. Theoretical models for the opposition effect suggest that it can be explained by light being scattered several times within the surfaces of individual, transparent, icy ring particles on scales of about 40 micrometers, or 1/500th of an inch. Similar effects are seen in laboratory studies of bright, finely-textured material such as snow or sugar crystals. In this mosaic, blue colors highlight the icy rings (2.35 microns), green represents sunlight reflected by the clouds of Saturn (2.86 microns) and red depicts thermal emission from the planet's interior (5.02 microns). The rings were observed while they were in front of the planet, producing a complex interplay of sunlight reflected from the rings and the shadows cast by the rings on the cloud tops of Saturn. The yellow-green sunlit clouds of Saturn are seen in the upper right corner of the mosaic beyond the outer edge of the A ring, and also through the 4,000-kilometer-wide (2,400 mile) Cassini Division in the left third of the mosaic. (Yellow indicates a mixture of reflected sunlight and thermal emission.) The shadowed regions of the planet, on the other hand, appear deep red because only thermal emission produced deep inside Saturn itself is visible. At exact opposition, the shadows of the rings are hidden behind the rings themselves, but away from this point shadows can be seen peeking out from behind the edges of the A and B rings into the Cassini Division, as well as beyond the outer edge of the A ring. If one looks closely, one can even trace the A ring's shadow behind the partly transparent A ring, as a faint purple band. Within this band, a thin blue-green line, crossing obliquely behind the A ring is caused by sunlight passing through the narrow Encke Gap in the outer A ring. The Cassini spacecraft was at a distance of 254,000 kilometers (157,800 miles) from the center of Saturn when these images were taken, while the opening angle of the rings to the sun was 16.3 degrees. The image scale at the rings is approximately 70 kilometers (40 miles) per pixel. All nine images were taken over a period of 27 minutes, and the vertical dimension of the mosaic is 1.8 degrees. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Visual and Infrared Mapping Spectrometer team is based at the University of Arizona, where this image was produced. For more information about the Cassini-Huygens mission, visit: http://saturn.jpl.nasa.gov/home/index.cfm. The visual and infrared mapping spectrometer team home page is at: http://wwwvims.lpl.arizona.edu . Credit: NASA/JPL/University of Arizona |
| Date |
June 26, 2007 |
|
Rhea in Saturnshine
| Description |
Rhea in Saturnshine |
| Full Description |
The night side of Rhea shines softly in reflected light from Saturn. A similar effect, called Earthshine, can often be seen dimly illuminating the dark side Earth's moon. Background stars make short, dim trails across the black sky. The sunlit terrain on Rhea is so much brighter than the part lit by Saturn that the former is completely overexposed in this view, which took more than 30 seconds to acquire. This view looks toward the leading hemisphere on Rhea (1,528 kilometers, or 949 miles across). North is up and rotated 28 degrees to the left. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 11, 2007. The view was obtained at a distance of approximately 364,000 kilometers (226,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 154 degrees. Image scale is 4 kilometers (3 miles) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
July 18, 2007 |
|
Titan (T28) Viewed by Cassin
…
| Description |
Titan (T28) Viewed by Cassini's Radar April 10, 2007 |
| Full Description |
Cassini's radar instrument obtained another in its series of north polar swaths of Titan on April 10, 2007. This image exposes more of the transition between the mid-latitudes and the polar area, and extends coverage of the lakes region previously described in Titan (T25) Viewed by Cassini's Radar - Feb. 22, 2007. This swath begins at 20 degrees south, 37 degrees west, continuing approximately north-northeast. Although it appears to be straight in this image, its path on Titan curves gently toward the east until it reaches 80 degrees north at 300 degrees west, then it turns south and ends at 51 degrees north, 213 degrees west. The swath width varies from about 200 kilometers (120 miles) at its center to about 500 kilometers (310 miles) at the ends, and is more than 6,700 kilometers (4,100 miles) long. Beginning at the left end of the image as shown, we see the dark sinuous features previously interpreted to be dunes, interspersed with bright features that appear to be higher. In some cases the dunes seem to bend around the bright features, and in others they may be climbing up onto them, both behaviors are commonly seen in dune fields on Earth. About one-third of the way through the swath, the dunes become rare and then disappear, to be replaced by more linear features. Some of these have rounded and brighter ends, similar to lava flows on Earth (in synthetic aperture radar images, rougher features appear as bright). Just past the midway point, we find relatively flat and featureless terrain with some structures that also resemble flow fronts, followed by a complex area of semi-circular to irregular depressions that may have formed by collapse. These give way to the lakes at the northernmost portion. Here T28 overlaps with the T25 synthetic aperture radar swath (see Titan (T25) Viewed by Cassini's Radar - Feb. 22, 2007), offering stereo coverage that will be used to determine feature heights. The lakes, which are thought to be filled with a combination of methane and ethane, have complex shorelines that often include channels. Some of these channels have well-developed tributary systems and drain many thousands of square kilometers of the surrounding terrain. As shown in the mosaic (see Exploring the Wetlands of Titan), these lakes are likely connected, and may form part of a larger sea. Brighter areas within the lakes may represent the lake bottom ¿ at the radar's 2-centimeter wavelength, it is possible that the liquid is transparent for many tens of meters (tens of yards) to the radar, allowing a reflection to be returned from the lake bottom. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and, the Italian Space Agency, working with team members from the United States and several European countries. For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov/home/index.cfm. *Credit:* NASA/JPL |
| Date |
July 27, 2007 |
|
Speckled Surface
| Description |
Dark material has coated the low-elevation terrain and the interiors of craters in the southern portions of the quadrant on Iapetus that faces away from Saturn. |
| Full Description |
Dark material has coated the low-elevation terrain and the interiors of craters in the southern portions of the quadrant on Iapetus that faces away from Saturn. This is part of the boundary region separating the dark leading and bright trailing hemispheres. The dark coating is thought to be no more than a few tens of centimeters thick (10 centimeters equals 4 inches) and, as seen here, predominately appears on the northern-facing walls of craters in the south. Farther south, the dark splotches are less numerous and appear almost absent at the highest latitudes (near the bottom of the frame). This is a strong indicator that thermal effects play a role in the darkening process of parts of Iapetus' surface: the colder the surface, the less common is the dark terrain. As on Earth, the higher latitudes on Iapetus receive less heating by sunlight. At left, below center, the eastern rim of a great and ancient impact basin can be seen. With a diameter of almost 500 kilometers (310 miles), it is one of the largest impact structures on Iapetus, 1,468 kilometers (912 miles) across, and in the entire Saturn system. This monochrome view shows terrain also seen in The Other Side of Iapetus but at higher resolution. The mosaic consists of three narrow-angle camera footprints across the surface of Iapetus. This view is centered on terrain near 35.1 degrees south latitude, 218.5 degrees west longitude. Image scale is approximately 231 meters (758 feet) per pixel. The clear spectral filter images in this mosaic were obtained with the Cassini spacecraft on Sept. 10, 2007, at a distance of approximately 40,000 kilometers (25,000 miles) from Iapetus and at a sun-Iapetus-spacecraft, or phase, angle of 31 degrees. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
October 8, 2007 |
|
Iapetus' Equatorial Region -
…
| Description |
Iapetus' Equatorial Region -- Labeled |
| Full Description |
Cassini made a close flyby of Saturn's moon Iapetus on Sept. 10, 2007, and the visual and infrared mapping spectrometer obtained these images during that event. These two images show a higher resolution version of the equatorial region shown in Tiny Grains on Iapetus. The equatorial region includes the equatorial bulge which shows no differences in these compositions compared to surrounding regions. The color image on the right shows the results of mapping for three components of Iapetus' surface: carbon dioxide that is trapped or adsorbed in the surface (red), water in the form of ice (green), and a newly-discovered effect due to trace amount of dark particles in the ice creating what scientists call Rayleigh scattering (blue). The Rayleigh scattering effect is the main reason why the Earth's sky appears blue. There is a complex transition zone from the dark region, on the right, which is high in carbon dioxide, to the more ice-rich region on the left. Some crater floors are filled with carbon dioxide-rich dark material. As the ice becomes cleaner to the left, the small dark particles become more scattered and increase the Rayleigh scattering effect, again indicative of less than 2 percent dark sub-0.5-micron particles. The visual and infrared mapping spectrometer is like a digital camera, but instead of using three colors, it makes images in 352 colors, or wavelengths, from the ultraviolet to the near-infrared. The many wavelengths produce a continuous spectrum in each pixel, and these spectra measure how light is absorbed by different materials. By analyzing the absorptions expressed in each pixel, a map of the composition at each location on the moon can be constructed. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Visual and Infrared Mapping Spectrometer team is based at the University of Arizona. For more information about the Cassini-Huygens mission, visit: http://saturn.jpl.nasa.gov/home/index.cfm. The visual and infrared mapping spectrometer team home page is at: http://wwwvims.lpl.arizona.edu. Credit: NASA/JPL/University of Arizona /USGS |
| Date |
October 8, 2007 |
|
Tiny Grains on Iapetus
| Description |
Tiny Grains on Iapetus |
| Full Description |
Cassini made a close flyby of Saturn's moon Iapetus on Sept. 10, 2007, and the visual and infrared mapping spectrometer obtained these images showing surface composition and particle size. The visual and infrared mapping spectrometer is like a digital camera, but instead of using three colors, it makes images in 352 colors, or wavelengths, from the ultraviolet to the near-infrared. The many wavelengths produce a continuous spectrum in each pixel, and these spectra measure how light is absorbed by different materials. By analyzing the absorptions expressed in each pixel, a map of the composition at each location on the moon can be constructed. The left image in the figure shows the amount of reflected light at a wavelength of 1.75 microns in the infrared (green light seen by our eyes is 0.53 microns). The color image on the right shows the results of mapping for three components of Iapetus' surface: carbon dioxide that is trapped or adsorbed in the surface (red), water in the form of ice (green), and a newly-discovered effect due to trace amount of dark particles in the ice creating what scientists call Rayleigh scattering (blue). The Rayleigh scattering effect is the main reason why the Earth's sky appears blue. The Rayleigh scattering effect on Iapetus provides evidence that tiny grains, less than the wavelength of visible light (less than 0.5 microns) have been embedded in the surface of Iapetus. The tiny grains must be well-separated for the Rayleigh effect to become prominent, so the abundance of particles must be less than about 2 percent. The Rayleigh scattering effect shows in all areas, although weakly in dark regions (the red carbon dioxide dominates the color image), and it appears stronger away from the equator. Investigating the trend from dark to bright areas, the Rayleigh effect changes with the amount of dark material in the ice, and becomes weaker as more dark material is added. This points to cleaner ice as one moves north or south from the equator and away from the dark leading side of the moon (toward the right in the image). This provides additional evidence for an external source for the dark material coating Iapetus, and for ice transport away from the warm dark regions and equator to the cooler poles. The ice transport away from the equator increases the concentration of dark material there and reduces the Rayleigh effect. With the volatile transport from the dark warm regions, the strong carbon dioxide signature is a surprise because frozen carbon dioxide is more volatile than water ice. Therefore, the carbon dioxide must be trapped, making its presence stable in the warm equatorial region. The trapping mechanism is currently under study. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate,, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Visual and Infrared Mapping Spectrometer team is based at the University of Arizona. For more information about the Cassini-Huygens mission, visit: http://saturn.jpl.nasa.gov/home/index.cfm. The visual and infrared mapping spectrometer team home page is at: http://wwwvims.lpl.arizona.edu. Credit: NASA/JPL/University of Arizona/USGS |
| Date |
October 8, 2007 |
|
Mimas and the Great Division
| Description |
Mimas and the Great Division |
| Full Description |
Having recently rounded the ansa, or outer edge of the rings, Mimas heads off toward right. This view from the Cassini spacecraft provides a crisp look at the fine material and detailed structure in the Cassini Division that is not readily visible from the Earth. The faint F ring, just visible between Mimas and the A ring, bounds the main rings of Saturn. Mimas is 397 kilometers (247 miles) across. This view looks toward the sunlit side of the rings from about 4 degrees below the ringplane. The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on Sept. 7, 2007. The view was acquired at a distance of approximately 2.9 million kilometers (1.8 million miles) from Saturn. Image scale is 18 kilometers (11 miles) per pixel on Mimas. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
October 16, 2007 |
|
Cold Kingdom
| Description |
Cold Kingdom |
| Full Description |
Icy sentinels stand guard on Saturn's doorstep, defying the distant Sun. Tethys (1,071 kilometers, or 665 miles across) is seen here at left, along with Enceladus (505 kilometers, 314 miles across), against the planet. At the distance of Saturn, the Sun's light is only about one-hundredth of its intensity at Earth, making this a dim and cold domain. This view looks toward the sunlit side of the rings from about 5 degrees below the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on Sept. 20, 2007 using a spectral filter sensitive to wavelengths of infrared light centered at 752 nanometers. The view was acquired at a distance of approximately 3.3 million kilometers (2 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 52 degrees. Image scale is 193 kilometers (120 miles) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
November 1, 2007 |
|
| Description |
This is a false color map of the intensity of the energetic neutral atoms emitted from the ring current through a processed called charged exchange. |
| Full Description |
Like Earth, Saturn has an invisible ring of energetic ions trapped in its magnetic field. This feature is known as a "ring current." This ring current has been imaged with a special camera on Cassini sensitive to energetic neutral atoms. This is a false color map of the intensity of the energetic neutral atoms emitted from the ring current through a processed called charged exchange. In this process a trapped energetic ion steals and electron from cold gas atoms and becomes neutral and escapes the magnetic field. The Cassini Magnetospheric Imaging Instrument's ion and neutral camera records the intensity of the escaping particles, which provides a map of the ring current. In this image, the colors represent the intensity of the neutral emission, which is a reflection of the trapped ions. This "ring" is much farther from Saturn (roughly five times farther) then Saturn's famous icy rings. Red in the image represents the higher intensity of the particles, while blue is less intense. Saturn's ring current had not been mapped before on a global scale, only "snippets" or areas were mapped previously but not in this detail. This instrument allows scientists to produce movies (See PIA10083) that show how this ring changes over time. These movies reveal a dynamic system, which is usually not as uniform as depicted in this image. The ring current is doughnut shaped but in some instances it appears as if someone took a bite out of it. This image was obtained on March 19, 2007, at a latitude of about 54.5 degrees and radial distance 1.5 million kilometres (920,000 miles). Saturn is at the center, and the dotted circles represent the orbits of the moon's Rhea and Titan. The Z axis points parallel to Saturn's spin axis, the X axis points roughly sunward in the sun¿spin axis plane, and the Y axis completes the system, pointing roughly toward dusk. The ion and neutral camera's field of view is marked by the white line and accounts for the cut-off of the image on the left. The image is an average of the activity over a (roughly) 3-hour period. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The magnetospheric imaging instrument was designed, built and is operated by an international team lead by the Applied Physics Laboratory of the Johns Hopkins University, Laurel, Md. For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the instrument team's home page, http://sd-www.jhuapl.edu/CASSINI/index.html. Credit: NASA/JPL/APL |
| Date |
December 12, 2007 |
|
Titan Features and Interacti
…
| Description |
This radar image, obtained by Cassini's radar instrument during a near-polar flyby on Feb. 22, 2007, shows dunes surrounding a bright feature on Saturn's moon Titan. |
| Full Description |
This radar image, obtained by Cassini's radar instrument during a near-polar flyby on Feb. 22, 2007, shows dunes surrounding a bright feature on Saturn's moon Titan. Dunes have been previously seen on Titan, so far concentrated near the equator. They are thought to be composed of small hydrocarbon or water ice particles -- probably about 250 microns in diameter, similar to sand grains on Earth. These are formed into dunes by the prevailing west-to-east surface winds. Because of the shape and length of the dunes, they are probably "longitudinal" (lying in the same direction as the average wind) rather than transverse dunes, which form across the wind and are more common on Earth. There are several kinds of interaction between the dunes and the brighter features in this image. At the left, the dunes seem to be covering the bright material, while at the center and right, they seem to be terminated against it. At the lower center and lower right, they flow around it (see also Swimming in Dunes and Dunes and More Dunes). These various interactions will help us to determine the nature of both of these features. This image was taken in synthetic aperture mode at 700-meter (2,300-foot) resolution. North is toward the left. The image is centered at about 3.5 degrees south latitude and 37.3 degrees west longitude. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. Credit: NASA/JPL |
| Date |
March 1, 2007 |
|
The Familiar Division
| Description |
The Familiar Division |
| Full Description |
The Cassini Division appears to emerge out of Saturn's shadow in this Cassini spacecraft image. This division between the A and B rings, visible through modest telescopes from Earth, actually contains five dim bands of ring material, here seen near the left side of the image between two small dark gaps. This detailed view also displays a great deal of structure in the B ring, left of the division. The Cassini Division is 4,800 kilometers (2,980 miles) wide. This view looks toward the unlit side of the rings from about 59 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 9, 2007 at a distance of approximately 1.7 million kilometers (1.1 million miles) from Saturn. Image scale is 10 kilometers (6 miles) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
March 21, 2007 |
|
Powering Saturn's Jets (with
…
| Description |
Powering Saturn's Jets (with labels) |
| Full Description |
+ View unlabeled, uncropped version of the image Using images like the one presented here, Cassini imaging scientists have made a major finding about the mechanism powering the general circulation of Saturn. The image shows small-scale, sheared-out cloud features associated with turbulent eddies in the vicinity of one of Saturn's eastward flowing jet streams, or "jets." The jet itself, located at 27.5 degrees south latitude, is indicated by the large horizontal arrow. Winds in this jet have blown continuously at speeds close to 320 kilometers per hour (200 miles per hour) for as long as scientists have observed Saturn. By tracking the movements of these cloud features in successive images separated by about 10 hours (about one Saturn rotation), Cassini scientists have confirmed that the eddies on either side of the jet give up their energy and momentum to help keep the winds in the jet blowing. The tilted arrows indicate the direction in which the eddies move the energy and momentum that power the jet. The winds that accomplish this are so strong that they combine to stretch out the eddies into bright, tilted streaks that are visible here, parallel to the arrows. The analysis of Cassini images covering most of Saturn's southern hemisphere suggests that similar processes occurring all over Saturn explain the remarkable decades-long stability of its alternating pattern of eastward and westward jets. The same process also occurs on Jupiter, and on Earth in the storm track along the east coast of the United States. Prior to this discovery, it was thought that the jets on Saturn and Jupiter were powered by an entirely different process, analogous to the tropical circulation on Earth. But now it appears that a comparison to the atmospheric motions in the Earth's mid-latitudes is more appropriate. The eddies seen in this image also create circulation patterns of upward and downward motion (in altitude) at different latitudes that help explain the general banded structure of global cloud patterns on the Jovian planets. An unlabeled, uncropped version of the image is presented here as well. The image was taken using a spectral filter sensitive to wavelengths of infrared light centered at 750 nanometers. The view was acquired with the Cassini spacecraft narrow-angle camera on Feb. 5, 2005, at a distance of approximately 3.4 million kilometers (2.1 million miles) from Saturn. Image scale is 20 kilometers (12 miles) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the, Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
May 8, 2007 |
|
Eyes on Iapetus!
| Description |
This map of the surface of Iapetus, generated from images taken by NASA's Cassini and Voyager spacecraft, illustrates the imaging coverage planned for Cassini's very close flyby of the two-toned moon on Sept. 10, 2007. |
| Full Description |
This map of the surface of Iapetus, generated from images taken by NASA's Cassini and Voyager spacecraft, illustrates the imaging coverage planned for Cassini's very close flyby of the two-toned moon on Sept. 10, 2007. This flyby will be Cassini's only close approach to Iapetus (1,468 kilometers, or 912 miles across) during the entire planned mission. At closest approach, Cassini will be 1,640 kilometers (1,020 miles) above the surface of Iapetus. The spacecraft will pass the moon at a speed of about 2.4 kilometers (1.5 miles) per second--a relatively leisurely pace that will allow plenty of time for the scientific instruments on board to collect massive amounts of data. Cassini's previous encounter with Iapetus, on Dec. 31, 2004, focused on the mysterious territory in Cassini Regio, the region blanketed by dark material that covers most of the moon's leading hemisphere. The upcoming encounter will be primarily concerned with terrain farther west, in the important transition region between Cassini Regio and the bright trailing hemisphere. Scientists hope to learn a great deal more about the composition of the materials that compose the surface of Iapetus during this encounter. Another area of focus is the large equatorial ridge that overlies the moon's equator (see Encountering Iapetus). The ridge reaches 20 kilometers (12 miles) high in some places and extends over 1,300 kilometers (808 miles) in length. No other moon in the solar system has a geological feature like this striking ridge. The tallest mountains on the ridge rival Olympus Mons on Mars, which is approximately three times the height of Mt. Everest. Such giant mountains are a surprising feature for such a small body as Iapetus, which is nearly five times smaller than Mars and nearly nine times smaller than Earth. Colored lines on the map enclose regions that will be covered at different imaging scales as Cassini encounters Iapetus. The highest expected resolution of Cassini images from this flyby is about 20 meters (65 feet) per pixel--significantly higher than the 2004 encounter. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . *Credit:* NASA/JPL/Space Science Institute |
| Date |
September 5, 2007 |
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Whirlwinds of Saturn
| Description |
Whirlwinds of Saturn |
| Full Description |
Incredible gales blow in Saturn's twisted atmosphere. Winds in this region of Saturn have been measured at greater than 360 kilometers (225 miles) per hour, faster than the most powerful hurricanes on Earth. The image was taken with the Cassini spacecraft narrow-angle camera on Sept. 17, 2007, using a spectral filter sensitive to wavelengths of infrared light centered at 750 nanometers. The view was obtained at a distance of approximately 3.5 million kilometers (2.2 million miles) from Saturn. Image scale is 21 kilometers (13 miles) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
October 23, 2007 |
|
Hubble Maps the Cosmic Web o
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| Title |
Hubble Maps the Cosmic Web of "Clumpy" Dark Matter in 3-D |
| General Information |
What is an American Astronomical Society Meeting release? A major news announcement issued at an American Astronomical Society meeting, the premier astronomy conference. An international team of astronomers using NASA's Hubble Space Telescope has created a three-dimensional map that provides the first direct look at the large-scale distribution of dark matter in the universe. Read more: * NASA Press Release [ http://hubblesite.org/newscenter/archive/releases/2007/01/text/ ] * The Full Story [ http://hubblesite.org/newscenter/archive/releases/2007/01/full/ ] |
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Hubble Maps the Cosmic Web o
…
| Title |
Hubble Maps the Cosmic Web of "Clumpy" Dark Matter in 3-D |
| General Information |
What is an American Astronomical Society Meeting release? A major news announcement issued at an American Astronomical Society meeting, the premier astronomy conference. An international team of astronomers using NASA's Hubble Space Telescope has created a three-dimensional map that provides the first direct look at the large-scale distribution of dark matter in the universe. Read more: * NASA Press Release [ http://hubblesite.org/newscenter/archive/releases/2007/01/text/ ] * The Full Story [ http://hubblesite.org/newscenter/archive/releases/2007/01/full/ ] |
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Hubble Sees 'Comet Galaxy' B
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| Title |
Hubble Sees 'Comet Galaxy' Being Ripped Apart By Galaxy Cluster |
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The Carina Nebula: Star Birt
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| Title |
The Carina Nebula: Star Birth in the Extreme |
| General Information |
What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. In celebration of the 17th anniversary of the launch and deployment of NASA's Hubble Space Telescope, a team of astronomers is releasing one of the largest panoramic images ever taken with Hubble's cameras. READ: Junior version of this article Amazing Space Learn about this story in the Star Witness, a science newspaper available on our sister site, Amazing Space. [ http://amazing-space.stsci.edu/news/archive/2007/02/ ] It is a 50-light-year-wide view of the central region of the Carina Nebula where a maelstrom of star birth —, and death —, is taking place. This image is a mosaic of the Carina Nebula assembled from 48 frames taken with Hubble's Advanced Camera for Surveys. The Hubble images were taken in the light of neutral hydrogen during March and July 2005. Color information was added with data taken in December 2001 and March 2003 at the Cerro Tololo Inter-American Observatory in Chile. Red corresponds to sulfur, green to hydrogen, and blue to oxygen emission. |
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The Carina Nebula: Star Birt
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| Title |
The Carina Nebula: Star Birth in the Extreme |
| General Information |
What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. In celebration of the 17th anniversary of the launch and deployment of NASA's Hubble Space Telescope, a team of astronomers is releasing one of the largest panoramic images ever taken with Hubble's cameras. READ: Junior version of this article Amazing Space Learn about this story in the Star Witness, a science newspaper available on our sister site, Amazing Space. [ http://amazing-space.stsci.edu/news/archive/2007/02/ ] It is a 50-light-year-wide view of the central region of the Carina Nebula where a maelstrom of star birth —, and death —, is taking place. This image is a mosaic of the Carina Nebula assembled from 48 frames taken with Hubble's Advanced Camera for Surveys. The Hubble images were taken in the light of neutral hydrogen during March and July 2005. Color information was added with data taken in December 2001 and March 2003 at the Cerro Tololo Inter-American Observatory in Chile. Red corresponds to sulfur, green to hydrogen, and blue to oxygen emission. |
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The Carina Nebula: Star Birt
…
| Title |
The Carina Nebula: Star Birth in the Extreme |
| General Information |
What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. In celebration of the 17th anniversary of the launch and deployment of NASA's Hubble Space Telescope, a team of astronomers is releasing one of the largest panoramic images ever taken with Hubble's cameras. READ: Junior version of this article Amazing Space Learn about this story in the Star Witness, a science newspaper available on our sister site, Amazing Space. [ http://amazing-space.stsci.edu/news/archive/2007/02/ ] It is a 50-light-year-wide view of the central region of the Carina Nebula where a maelstrom of star birth —, and death —, is taking place. This image is a mosaic of the Carina Nebula assembled from 48 frames taken with Hubble's Advanced Camera for Surveys. The Hubble images were taken in the light of neutral hydrogen during March and July 2005. Color information was added with data taken in December 2001 and March 2003 at the Cerro Tololo Inter-American Observatory in Chile. Red corresponds to sulfur, green to hydrogen, and blue to oxygen emission. |
|
The Carina Nebula: Star Birt
…
| Title |
The Carina Nebula: Star Birth in the Extreme |
| General Information |
What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. In celebration of the 17th anniversary of the launch and deployment of NASA's Hubble Space Telescope, a team of astronomers is releasing one of the largest panoramic images ever taken with Hubble's cameras. READ: Junior version of this article Amazing Space Learn about this story in the Star Witness, a science newspaper available on our sister site, Amazing Space. [ http://amazing-space.stsci.edu/news/archive/2007/02/ ] It is a 50-light-year-wide view of the central region of the Carina Nebula where a maelstrom of star birth —, and death —, is taking place. This image is a mosaic of the Carina Nebula assembled from 48 frames taken with Hubble's Advanced Camera for Surveys. The Hubble images were taken in the light of neutral hydrogen during March and July 2005. Color information was added with data taken in December 2001 and March 2003 at the Cerro Tololo Inter-American Observatory in Chile. Red corresponds to sulfur, green to hydrogen, and blue to oxygen emission. |
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Hubble Images of Asteroids H
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| Title |
Hubble Images of Asteroids Help Astronomers Prepare for Spacecraft Visit |
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Hubble Images of Asteroids H
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| Title |
Hubble Images of Asteroids Help Astronomers Prepare for Spacecraft Visit |
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Astronomers Find Highly Elli
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| Title |
Astronomers Find Highly Elliptical Disk Around Young Star |
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Going, Going, Gone: Hubble C
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| Title |
Going, Going, Gone: Hubble Captures Uranus's Rings on Edge |
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Hubble Zooms In on Heart of
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| Title |
Hubble Zooms In on Heart of Mystery Comet |
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Hubble Zooms In on Heart of
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| Title |
Hubble Zooms In on Heart of Mystery Comet |
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Holiday Wishes from the Hubb
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| Title |
Holiday Wishes from the Hubble Space Telescope |
| General Information |
What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. Resembling festive lights on a holiday wreath, this NASA/ESA Hubble Space Telescope image of the nearby spiral galaxy M74 is an iconic reminder of the impending season. Bright knots of glowing gas light up the spiral arms, indicating a rich environment of star formation. M74 is located roughly 32 million light-years away in the direction of the constellation Pisces, the Fish. The image is a composite of Advanced Camera for Surveys data taken in 2003 and 2005. |
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Hubble Zooms In on Heart of
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| Title |
Hubble Zooms In on Heart of Mystery Comet |
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Hubble Zooms In on Heart of
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| Title |
Hubble Zooms In on Heart of Mystery Comet |
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Internal Heat Drives Jupiter
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| Title |
Internal Heat Drives Jupiter's Giant Storm Eruption |
| General Information |
What is a News Nugget? News Nuggets are bulletins from the world of astronomy. Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding this outbreak could be the key to unlock the mysteries buried in the deep Jovian atmosphere. An international team coordinated by Agustin Sánchez-Lavega from the Universidad del País Vasco in Spain presents its findings about this event in the January 24 issue of the journal Nature. The team monitored the new eruption of cloud activity and its evolution with an unprecedented resolution using NASA's Hubble Space Telescope, the NASA Infrared Telescope Facility in Hawaii, and telescopes in the Canary Islands (Spain). A network of smaller telescopes around the world also supported these observations. |
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Hubble Images of Asteroids H
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| Title |
Hubble Images of Asteroids Help Astronomers Prepare for Spacecraft Visit |
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Gruber Cosmology Prize Award
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| Title |
Gruber Cosmology Prize Awarded to STScI Dark Energy Discoverers |
| General Information |
What is a News Nugget? News Nuggets are bulletins from the world of astronomy. Four astronomers at the Space Telescope Science Institute in Baltimore, Md. are on two teams sharing the $500,000 2007 Gruber Cosmology Prize for their discovery that the expanding universe is accelerating under a mysterious cosmic force called dark energy. The astronomers are Andrew Fruchter (top left), Ron Gilliland (top right), Nino Panagia (bottom left), and Adam Riess (bottom right). Gilliland and Riess are on the High-z Supernova Search Team led by Brian Schmidt of the Australian National University. Fruchter and Panagia are on the Supernova Cosmology Project led by Saul Perlmutter of the University of California at Berkeley. Read more: * The Full Story [ http://hubblesite.org/newscenter/archive/releases/2007/29/full/ ] |
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Hubble Images of Asteroids H
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| Title |
Hubble Images of Asteroids Help Astronomers Prepare for Spacecraft Visit |
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Hubble Zooms In on Heart of
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| Title |
Hubble Zooms In on Heart of Mystery Comet |
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Comparison of Minimum Sea Ic
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| Title |
Comparison of Minimum Sea Ice Between 2005 and 2007 - Split Screen |
| Abstract |
Sea ice is frozen seawater floating on the surface of the ocean. Some sea ice is semi-permanent, persisting from year to year, and some is seasonal, melting and refreezing from season to season. The sea ice cover reaches its minimum extent at the end of each summer and the remaining ice is called the perennial ice cover. The 2007 Arctic summer sea ice has reached the lowest extent of perennial ice cover on record - nearly 25% less than the previous low set in 2005. The area of the perennial ice has been steadily decreasing since the satellite record began in 1979, at a rate of about 10% per decade. But the 2007 minimum, reached on September 14, is far below the previous record made in 2005 and is about 38% lower than the climatological average. Such a dramatic loss has implications for ecology, climate and industry. This animation compares the difference between the perennial sea ice minimum extent on September 21, 2005 and September 14, 2007. With a split screen, the area of the melted region is compared with the size of the state of California. |
| Completed |
2007-09-28 |
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