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Seeing in the Dark
| Description |
Seeing in the Dark |
| Full Description |
New details on Iapetus are illuminated by reflected light from Saturn in this revealing Cassini image. Never-before-seen features on the Saturn-facing part of Iapetus¿ bright trailing hemisphere are visible for the first time, including many dark spots, and a sharper view of a dark, circular structure that was first seen at very low resolution by NASA's Voyager 1 in 1980. Iapetus diameter is 1,436 kilometers (892 miles). The image shows mainly the night side of Iapetus, part of the far brighter sunlit side appears at the right and is overexposed due to the long integration time of 180 seconds. Despite this long exposure time, almost no blurring due to the spacecraft¿s motion is apparent. This technique for imaging the night side of Iapetus will be used again during a flyby on Jan. 1, 2005, when Cassini will pass 13 times closer to the icy moon. The image was taken in visible light with the Cassini spacecraft narrow angle camera on Oct. 22, 2004, at a distance of 1.6 million kilometers (994,000 miles) from Iapetus, and from a Sun-Iapetus-spacecraft, or phase, angle of 161 degrees. The view is centered on 0.4 degrees north latitude, 317 degrees west longitude on Iapetus. The image scale is 9.4 kilometers (5.8 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 Cassini-Huygens 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 team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org . *Image Credit:* NASA/JPL/Space Science Institute |
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Iapetus' Dark Side
| Description |
Iapetus' Dark Side |
| Full Description |
This image shows the dark, leading hemisphere of the mysterious moon Iapetus. The dark area is the Cassini region, named for Giovanni Cassini, who discovered the moon in 1672. The diameter of Iapetus is 1,436 kilometers (892 miles). Cassini noted that he was able to see the moon on one side of its orbit around Saturn, but not on the other side. From this, he correctly deduced that one hemisphere must be dark while the other is much brighter. The image was taken in visible light with the Cassini spacecraft narrow angle camera on Sept. 24, 2004, at a distance of 7.4 million kilometers (4.6 million miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 51 degrees. The image scale is 45 kilometers (28 miles) per pixel. The image has been magnified by a factor of four to aid visibility. 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 Cassini-Huygens 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 team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org . *Image Credit:* NASA/JPL/Space Science Institute |
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World of Contrast
| Description |
World of Contrast |
| Full Description |
This Cassini spacecraft view shows how the bright and dark regions on Iapetus fit together like the seams of a baseball. Some of the material that covers the moon's dark, leading side spills over into regions on the brighter trailing side, creating the feature near upper right referred to by some scientists as "the Moat." (See Iapetus by Saturn Shine for a higher resolution view of this region.) The large impact basin above center in the dark terrain has a diameter of about 550 kilometers (340 miles). This view looks toward the Saturn-facing hemisphere of Iapetus (1,468 kilometers, or 912 miles across). North is up. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 25, 2006 at a distance of approximately 1.6 million kilometers (1 million miles) from Iapetus. Image scale is 9 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 |
August 2, 2006 |
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Duotone Moon
| Description |
Duotone Moon |
| Full Description |
The many impact scars borne by Iapetus are made far more conspicuous in the region of transition from its dark hemisphere to its bright one. In this terrain, the dark material that coats Cassini Regio accentuates slopes and crater floors, creating a land of stark contrasts. North on Iapetus (1,468 kilometers, or 912 miles across) is up. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 6, 2006 at a distance of approximately 2.2 million kilometers (1.4 million miles) from Iapetus and at a Sun- Iapetus-spacecraft, or phase, angle of 26 degrees. Image scale is 13 kilometers (8 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 |
September 25, 2006 |
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Iapetus Thermal Radiation Im
…
| Description |
Iapetus Thermal Radiation Image |
| Full Description |
This image of the infrared heat radiation from Saturn's moon Iapetus was obtained by the Cassini composite infrared spectrometer instrument 16 hours before Cassini's closest approach to this mysterious moon, on December 31, 2004. The thermal radiation is shown as both a grayscale image, equivalent to what we would see if our eyes were sensitive to infrared wavelengths near 15 microns, and as a color-coded temperature map. A previously-released mosaic obtained by Cassini's imaging camera shortly before the composite infrared spectrometer observation, with similar scale and orientation, is also shown for comparison. Temperatures reach nearly 130 Kelvin (-226 Fahrenheit) at noon on the equator on the dark material that covers most of this side of Iapetus, making high noon on Iapetus's dark side probably the warmest places in the Saturn system. This is much warmer than temperatures on another Saturnian moon, Phoebe, measured by composite infrared spectrometer in June 2004. Those Phoebe temperature measurements peaked near 112 Kelvin (-258 Fahrenheit), because though Phoebe is almost as dark as Iapetus's dark material and absorbs nearly as much sunlight, Phoebe rotates much more quickly (once every 9 hours, compared to 79 days for Iapetus). That means the surface has less time to heat up during the day. Temperatures on Iapetus's bright material are much colder, peaking near 100 Kelvin (-280 Fahrenheit), both because the bright material absorbs less sunlight and because it is further from the equator on this side of Iapetus. Temperatures in the large crater near the center of the disc are slightly different from those in surrounding areas, because sloping surfaces within the crater are warmer where they are tilted towards the Sun and cooler when tilted away from the Sun. 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 composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the instrument team's home page, http://cirs.gsfc.nasa.gov/. *Credit*: NASA/JPL/GSFC |
| Date |
January 10, 2005 |
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Iapetus Surface Composition
| Description |
Iapetus Surface Composition |
| Full Description |
The Cassini visual and infrared mapping spectrometer analyzed the surface composition of Saturn's moon Iapetus as Cassini flew over the polar region on Dec. 31, 2004. The image at left shows the reflectance at 4-microns, which is dominated by the minerals on Iapetus' surface. Two large craters are seen in this image. The polar water ice is relatively dark at this wavelength, so the ice cap is not seen. The next frame shows carbon dioxide on the surface. The carbon dioxide peaks at mid latitudes and shows less strength at the pole and along the equator (the dark band curving near the left edge of the image). The third frame shows the strength of water absorption on Iapetus. The brightest regions are due to water ice near the pole. The grayer areas indicate water bound to minerals on the surface. The color composite shows water as blue, carbon dioxide as green, and non-ice minerals as red. 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 visible and infrared mapping spectrometer team is based at the University of Arizona, Tucson. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov. For more information about the visual and infrared mapping spectrometer visit http://wwwvims.lpl.arizona.edu/. *Credit*: NASA/JPL/GSFC |
| Date |
January 10, 2005 |
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Iapetus by Saturn Shine
| Description |
Iapetus by Saturn Shine |
| Full Description |
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 team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For images visit the Cassini imaging team home page http://ciclops.org . Credit: NASA/JPL/Space Science Institute, This almost surreal view of Iapetus was acquired by Cassini about 10 minutes after the spacecraft's closest approach to the icy moon during a close flyby on New Year's Eve 2004. The image shows Iapetus' surface illuminated by reflected light from Saturn (not by the Sun) and is the highest resolution view acquired to date of this part of Iapetus' surface. Compared to the approximately one second exposure times used for imaging Iapetus' sunlit side, this view required a very long exposure time of 82 seconds. Cassini was designed to pivot while moving in order to keep its cameras and other remote sensing instruments pointed `on target' with great precision. Consequently, despite the large relative speed between Iapetus and the spacecraft during this long exposure -- about 2 kilometers per second or almost 4,500 miles per hour at closest approach -- the image of the moon's surface is un-smeared (although the background stars are smeared). This image reveals a heavily cratered surface and shows the boundary between Iapetus' bright trailing hemisphere and Cassini Regio -- a large, dark region that covers the leading hemisphere of the moon¿s surface. Some of the dark material appears to have collected inside the rim of a large impact structure about 250 kilometers across (155 miles) that lies just beyond the edge of the dark region (seen here near the right of the image). NASA's Voyager images (see PIA02268) this feature appeared as a dark 'moat' and had been hypothesized to be an impact structure. The recent images from Cassini confirm an impact origin for this feature. In contrast, the origin of the dark material is currently unknown and the recent images have sparked exciting debates among Cassini imaging scientists. Some characteristics of the dark region revealed in this and other images taken during the encounter suggest that dark material from elsewhere in the Saturnian system -- perhaps the result of an impact on another nearby moon -- has coated this side of Iapetus with a relatively thin layer. However, an internal origin for the material has not been ruled out and, if correct, may be related to the long equatorial ridge discovered in Cassini images to span Cassini Regio. Regardless of its origins, the dark material appears to lie on top of other geologic features seen on Iapetus thus far, implying that the event which formed the dark coating occurred later in Iapetus' history. A closer encounter with this moon later in the Cassini mission (September 2007) may reveal more detail and help answer the question of the origin and age of the dark material on Iapetus. The image was obtained in visible light with the Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance of about 123,370 kilometers (76,659 miles) from Iapetus. The image scale is 730 meters (2,395 feet) per pixel. The image has been contrast enhanced to aid visibility of surface features. The Cassini-Huygens mission is a cooperative project of NASA, the |
| Date |
January 7, 2005 |
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Iapetus' New Year's Flyby
| Description |
Iapetus' New Year's Flyby |
| Full Description |
This map of the surface of Saturn's moon Iapetus (1,436 kilometers, or 892 miles across), generated from images taken by NASA's Voyager spacecraft, illustrates the imaging coverage planned during Cassini's flyby on Dec. 31, 2004. Cassini will glide past Iapetus at a distance of approximately 123,400 kilometers (76,700 miles) on New Year's Eve, at a speed of about 2 kilometers per second (4,474 miles per hour). Imaging coverage will be focused primarily on the dark terrain of Iapetus' leading hemisphere, in the area known as Cassini Regio. The spacecraft's namesake, Jean-Dominique Cassini, discovered Iapetus in 1672 and was only able to see the moon's bright trailing hemisphere. Colored lines on the map enclose regions that will be covered at different imaging scales as Cassini approaches Iapetus. Images from Cassini's flyby will be superior in resolution to those obtained by Voyager 2 in August 1981. Voyager 2 passed Iapetus at a distance of approximately 909,000 kilometers (564,800 miles) at closest approach, yielding a best resolution image of about 8 kilometers per pixel. The resolution of Cassini images from this flyby will be 1.5 kilometers per pixel and better. 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 team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org . *Credit*: NASA/JPL/Space Science Institute |
| Date |
December 30, 2004 |
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Iapetus: A View from the Top
| Description |
Iapetus: A View from the Top |
| Full Description |
This oblique view of Saturn's moon Iapetus from high latitude shows how the dark, heavily cratered terrain of Cassini Regio transitions to a bright, icy terrain at high latitudes. In this mosaic of two high resolution images taken during Cassini's New Year's Eve 2004 flyby of Iapetus, the direction toward the north pole is approximately 15 degrees below the horizontal on the right. At the equator terrains are uniformly covered with a dark mantle of material that has a reflectivity of about 4 percent. At latitudes toward the pole of about 40 degrees, the dark deposits become patchy and diffuse as the surface transitions to a much brighter, icy terrain near the pole. The brightest icy materials exhibit visual reflectivity over 60 percent. Superimposed on the bright terrain is a subtle, ghostly pattern of crudely parallel, north-south trending wispy streaks. The streaks, which were discovered during this flyby of Iapetus, are typically a few kilometers wide and sometimes tens of kilometers long. Their appearance and orientation may be connected with the emplacement of dark materials that cover Cassini Regio. The dark materials might represent the gradual accumulation of dark debris falling from space, or alternatively, may represent fallout from plume-style eruptions that may have accompanied the formation of Iapetus's enigmatic equatorial ridge (see PIA 06166). Also seen in this mosaic are conspicuous, north-facing bright crater walls. An example can be seen in the upper left where the bright, 4-kilometer-high (2.5 miles) walls of a 70 kilometer (44 mile) central-peak crater lies. The bright crater walls are often higher in brightness than the corresponding south-facing walls of the same crater. They are vaguely reminiscent of bright north-facing crater walls that were discovered by NASA's Voyager and Galileo spacecraft in craters near the poles of the Jovian satellites Callisto and Ganymede. In the case of the Jovian satellites, cold-trapping of frosts on north-facing slopes and sublimation of ices from south-facing slopes are thought to produce the north-south asymmetries in crater wall brightness. However, the occurrence of some young-appearing craters on Iapetus that have bright north-facing and dark south-facing slopes, and the pattern of streaks near the north pole of Iapetus suggests that another mechanism may be responsible for the crater wall brightness asymmetries on Iapetus. One possibility is that the south-facing slopes may be stained by the same process that emplaced the low brightness coating throughout the region. In this case, the north-pointing scarps might be bright because they face away and are shielded from the putative falling spray of dark materials. Bright south-facing slopes would exist primarily on young craters that have not been exposed to the darkening agent long enough to be stained. The image was obtained in visible light with the Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance of, about 123,370 kilometers (76,658 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 93 degrees. Resolution achieved in the original image was 732 meters (2,401 feet) 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 team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For images visit the Cassini imaging team home page http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
January 7, 2005 |
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VIMS Iapetus Two Shooter
| Description |
VIMS Iapetus Two Shooter |
| Full Description |
These two color composite images of Saturn's moon Iapetus from Cassini's visual and infrared mapping spectrometer were obtained on Dec. 31, 2004, an hour and a half before the New Year, at a distance of 121,000 kilometers (75,186 miles), with a spatial resolution of about 60 kilometers (37 miles). The three colors used in the left mosaic correspond to 1.01, 1.51, and 2 microns, while the right mosaic is comprised of images at 3.0, 3.21, and 4.60 microns. The two images show the vast difference in the composition of the bright and dark regions of Iapetus. As one moves from the near infrared 1 to 2 micron spectral region (left image) to the 3 to 5 micron spectral region (right image) the bright, ice-rich region on Iapetus turns dark and the dark region rich in organics turns bright. 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 visible and infrared mapping spectrometer team is based at the University of Arizona, Tucson. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov. For more information about the visual and infrared mapping spectrometer visit http://wwwvims.lpl.arizona.edu/. *Credit*: NASA/JPL/University of Arizona |
| Date |
January 10, 2005 |
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Iapetus Temperature Variatio
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| Description |
Iapetus Temperature Variation Map |
| Full Description |
This plot shows how daytime temperatures at low latitudes on the dark material on Saturn's moon Iapetus vary with time of day, from about 130 Kelvin (-226 Fahrenheit) at noon to about 70 Kelvin (-334 Fahrenheit) at sunset. The observations are compared to a "forecast" model (green line) which predicts temperatures based on an assumed value of a parameter called the "thermal inertia. This measures how well the surface can retain heat as conditions change. Rock or solid ice has a high thermal inertia, roughly 2,000,000 as measured in the obscure units used for thermal inertia, meaning that it is good at storing heat and cools down or heats up relatively slowly. On Iapetus, in contrast, temperatures drop precipitously in the afternoon as the Sun sinks towards the horizon, and a very small value of the thermal inertia (30,000 units) is needed in the model to match the data. This means that Iapetus's surface is extremely bad at storing heat, and is thus extremely fluffy, probably due to the pulverizing effect of billions of years of meteorite impacts, though the mysterious process that has darkened this side of Iapetus may also have played a role. 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 composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the instrument team's home page, http://cirs.gsfc.nasa.gov/. *Credit*: NASA/JPL/GSFC |
| Date |
January 10, 2005 |
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Giant Landslide on Iapetus
| Description |
Giant Landslide on Iapetus |
| Full Description |
A spectacular landslide within the low-brightness region of Iapetus's surface known as Cassini Regio is visible in this image from Cassini. Iapetus is one of the moons of Saturn. The landslide material appears to have collapsed from a scarp 15 kilometers high (9 miles) that forms the rim of an ancient 600 kilometer (375 mile) impact basin. Unconsolidated rubble from the landslide extends halfway across a conspicuous, 120-kilometer diameter (75-mile) flat-floored impact crater that lies just inside the basin scarp. Landslides are common geological phenomena on many planetary bodies, including Earth and Mars. The appearance of this landslide on an icy satellite with low-brightness cratered terrain is reminiscent of landslide features that were observed during NASA's Galileo mission on the Jovian satellite Callisto. The fact that the Iapetus landslide traveled many kilometers from the basin scarp could indicate that the surface material is very fine-grained, and perhaps was fluffed by mechanical forces that allowed the landslide debris to flow extended distances. In this view, north is to the left of the picture and solar illumination is from the bottom of the frame. The image was obtained in visible light with the Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance of about 123,400 kilometers (76,677 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 78 degrees. Resolution achieved in the original image was 740 meters (2,428 feet) per pixel. The image has been contrast-enhanced and magnified by a factor of two to aid visibility. 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 team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For images visit the Cassini imaging team home page http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
January 7, 2005 |
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Dark-stained Iapetus
| Description |
Dark-stained Iapetus |
| Full Description |
This near-true color view from Cassini reveals the colorful and intriguing surface of Saturn's moon Iapetus in unrivaled clarity. The images taken with different spectral filters and used for this composite were taken at the same time as the clear frames used in PIA06166. The use of color on Iapetus is particularly helpful for discriminating between shadows (which appear black) and the intrinsically dark terrain (which appears brownish). This image shows the northern part of the dark Cassini Regio and the transition zone to a brighter surface at high northern latitudes. Within the transition zone, the surface is stained by roughly north-south trending wispy streaks of dark material. The absence of an atmosphere on Iapetus means that the material was deposited by some means other than precipitation, such as ballistic placement from impacts occurring elsewhere on Iapetus, or was captured from elsewhere in the Saturn system. Iapetus's north pole is not visible here, nor is any part of the bright trailing hemisphere. Images taken with infrared (centered at 930 nanometers), green (568 nanometers), and ultraviolet light (338 nanometers) filters were combined to create this image. The view was obtained with the Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance of about 172,900 kilometers (107,435 miles) from Iapetus. Resolution achieved in the original image was 1 kilometer (0.6 miles) per pixel. The image has been magnified by a factor of two to aid visibility of surface features. 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 team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For images visit the Cassini imaging team home page http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
January 7, 2005 |
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Brightside in View
| Description |
Brightside in View |
| Full Description |
The Cassini spacecraft continues to image terrain on Iapetus that is progressively eastward of the terrain it has previously seen illuminated by sunlight. The region seen here was imaged in reflected light from Saturn at excellent resolution in the close flyby on New Year's Eve 2004 (see Iapetus by Saturn Shine). This view looks toward the equator of Iapetus (1,468 kilometers, or 912 miles across) on the moon's Saturn-facing side. North is up and rotated 11 degrees to the right. The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on Nov. 27, 2006 at a distance of approximately 2 million kilometers (1.2 million miles) from Iapetus. Image scale is 12 kilometers (7 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 5, 2007 |
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Cloaking Iapetus
| Description |
Cloaking Iapetus |
| Full Description |
Darkness sweeps over Iapetus as the Cassini spacecraft watches the shadow of Saturn's B ring engulf the dichotomous moon. The image at left shows the unshaded moon, while at right, Iapetus sits in the shadow of the densest of Saturn's rings. North on Iapetus (1,468 kilometers, or 912 miles across) is up and rotated eight degrees to the left. The images were taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 13, 2007 at a distance of approximately 2.3 million kilometers (1.4 million miles) from Iapetus. Image scale is 14 kilometers (8 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 22, 2007 |
|
On the Bright Side
| Description |
On the Bright Side |
| Full Description |
The Cassini spacecraft views terrain on the bright, trailing side of Iapetus in natural color. This side of Iapetus starkly contrasts with the much darker leading hemisphere, and some of the dark material seen here in association with craters near the terminator is an extension of the leading hemisphere terrain. This region was previously imaged by the spacecraft at a much finer resolution -- a spatial scale of less than 1 kilometer (0.6 miles) per pixel -- during a flyby at the close of 2004. This terrain was then on the moon's night side at the time, and Cassini imaged it using weak, reflected light from Saturn (see Iapetus by Saturn Shine ). The present view looks toward Iapetus (1,468 kilometers, or 912 miles across) from about 24 degrees above the moon's equator. 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 April 15, 2007 at a distance of approximately 2.3 million kilometers (1.4 million miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 66 degrees. Scale in the original images is 13 kilometers (8 miles) per pixel. The view has been magnified by a factor of three. 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 29, 2007 |
|
Cassini to Fly By Tethys and
…
| Description |
Cassini to Fly By Tethys and Titan |
| Full Description |
This week, Cassini's travels will bring it by Saturn's moon Tethys (June 27) and Titan (June 29). Cassini will get a close-up look at the large crater Odysseus, which is 450 kilometers (280 miles) in diameter, and Ithaca Chasma, a canyon that is four times as long as Earth's Grand Canyon. Scientists are studying how this canyon formed and whether Tethys was active in the past, like Enceladus is currently. Scientists will also obtain close-up images of mysterious dark patches on the moon, and they will be taking data to understand what the surface is made of. Scientists would like to learn if Tethys is only pure water ice, or if it's contaminated with dark material rich in organics, like the material that covers the dark side of Iapetus. Two days later Cassini returns to Titan. The spacecraft will send back radio waves to Earth as our home planet moves behind Titan (as seen from Cassini). The goal is to map Titan's shape in order to seek clues for a subsurface ocean, and to probe the atmosphere of the giant moon. |
| Date |
June 25, 2007 |
|
Unveiling Iapetus
| Description |
Unveiling Iapetus |
| Full Description |
As the Cassini spacecraft sets up for its September 2007 close encounter with the two-toned moon Iapetus, the spacecraft is seeing more of the moon's bright, trailing hemisphere. This is a region Cassini has seen relatively little of until recently. The September encounter will provide high resolution images of this region, including the large crater seen here at about the five o'clock position. North on Iapetus (1,468 kilometers, or 912 miles across) is up and rotated about 5 degrees to the right. The image was taken using a spectral filter sensitive to wavelengths of ultraviolet light centered at 338 nanometers. The view was acquired with the Cassini spacecraft narrow-angle camera on July 3, 2007. The view was acquired at a distance of approximately 2.2 million kilometers (1.4 million miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 53 degrees. Image scale is 13 kilometers (8 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 |
August 21, 2007 |
|
The 'Voyager' Mountains
| Description |
The 'Voyager' Mountains |
| Full Description |
Cassini zooms in, for the first time, on the patchy, bright and dark mountains originally identified in images from the NASA Voyager spacecraft taken more than 25 years earlier. The image was acquired during Cassini's only close flyby of Iapetus, a two-toned moon of Saturn. The terrain seen here is located on the equator of Iapetus at approximately 199 degrees west longitude, in the transition region between the moon's bright and dark hemispheres. North is up. The image was taken on Sept. 10, 2007, with the Cassini spacecraft narrow-angle camera at a distance of approximately 9,240 kilometers (5,740 miles) from Iapetus. Image scale is 55 meters (180 feet) 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 |
September 12, 2007 |
|
Iapetus Up Close
| Description |
Iapetus Up Close |
| Full Description |
This is a raw, or unprocessed, image taken by the Cassini spacecraft during its close flyby of Saturn's moon Iapetus on Sept. 10, 2007. |
| Date |
September 11, 2007 |
|
The Himalayas of Iapetus
| Description |
PIA08372 |
| Full Description |
This stunning close-up view shows mountainous terrain that reaches about 10 kilometers (6 miles) high along the unique equatorial ridge of Iapetus. The view was acquired during Cassini's only close flyby of the two-toned Saturn moon. Above the middle of the image can be seen a place where an impact has exposed the bright ice beneath the dark overlying material. The image was taken on Sept. 10, 2007, with the Cassini spacecraft narrow-angle camera at a distance of approximately 3,870 kilometers (2,400 miles) from Iapetus. Image scale is 23 meters (75 feet) 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 |
September 12, 2007 |
|
Coated Craters
| Description |
Coated Craters |
| Full Description |
Cassini surveys a bright landscape coated by dark material on Iapetus. This image shows terrain in the transition region between the moon's dark leading hemisphere and its bright trailing hemisphere. The view was acquired during Cassini's only close flyby of the two-toned Saturn moon. The image was taken on Sept. 10, 2007, with the Cassini spacecraft narrow-angle camera at a distance of approximately 5,260 kilometers (3,270 miles) from Iapetus. Image scale is 32 meters (105 feet) 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 |
September 12, 2007 |
|
Inky Stains on a Frozen Moon
| Description |
Inky Stains on a Frozen Moon |
| Full Description |
Dark material splatters the walls and floors of craters in the surreal, frozen wastelands of Iapetus. This image shows terrain in the transition region between the moon's dark leading hemisphere and its bright trailing hemisphere. The view was acquired during Cassini's only close flyby of the two-toned Saturn moon. The image was taken on Sept. 10, 2007, with the Cassini spacecraft narrow-angle camera at a distance of approximately 6,030 kilometers (3,750 miles) from Iapetus. Image scale is 36 meters (118 feet) 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 |
September 12, 2007 |
|
Exposing Iapetus' Dark Side
| Description |
Exposing Iapetus' Dark Side |
| Full Description |
Images taken with Cassini's ultraviolet imaging spectrograph shed some light on the dark side of Saturn's moon Iapetus. Scientists are trying to figure out what painted Iapetus' dark side. This is one of the biggest mysteries scientists are trying to answer during the upcoming Sept. 10, 2007, flyby. The ultraviolet image on the left indicates water ice abundance across the surface: the bright north polar terrain (shown in red) is the iciest region in this view. Away from the pole, as the color shifts to blue, less water ice is present in the surface. The darkest terrain, which includes very little water ice, is shown in light blue. The dark sky background viewed during the observation is shown as purple in this color scheme. The ultraviolet-light image was taken during a flyby in December 2004. A visible light image taken on the same date is shown on the right for reference (see Encountering Iapetus). 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 ultraviolet imaging spectrograph was designed and built at, and the team is based at the University of Colorado, Boulder. 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/home/index.cfm. The ultraviolet imaging spectrograph team home page is at http://lasp.colorado.edu/cassini. The Cassini imaging team homepage is at http://ciclops.org. Credit: NASA/JPL/University of Colorado/Space Science Institute |
| Date |
September 5, 2007 |
|
Cassini's Closest Visit of I
…
| Description |
Cassini s Closest Visit of Iapetus |
| Full Description |
On Sept. 10, the Cassini spacecraft performs its closest flyby during the entire mission of the odd moon Iapetus, passing by about 1,640 kilometers (1,000 miles). Iapetus is a world of sharp contrasts. The leading hemisphere is as dark as a freshly-tarred street, and the white, trailing hemisphere resembles freshly-fallen snow. Scientists want to know more about the composition of the dark material that coats Iapetus. They also want to learn more about Iapetus' distinctive walnut shape and the chain of mountains along its equator. |
| Date |
September 4, 2007 |
|
Spotty Iapetus
| Description |
At high resolution, terrain in the transition region between bright and dark hemispheres on Saturn's moon Iapetus reveals a spotty appearance reminiscent of a Dalmatian. |
| Full Description |
At high resolution, terrain in the transition region between bright and dark hemispheres on Saturn's moon Iapetus reveals a spotty appearance reminiscent of a Dalmatian. The bright material on the frozen surface of Iapetus, 1,468 kilometers (912 miles) across, is water ice, and the dark material is likely carbonaceous in composition. The dark material is preferentially found at the bottoms of craters. Bright water ice forms the "bed rock" on Iapetus, while the dark, presumably loose material apparently lies on top of the ice. The terrain seen here is also visible in Speckled Surface, but it is viewed here at higher resolution. The mosaic consists of two image footprints across the surface of Iapetus. The view is centered on terrain near 42 degrees south latitude and 209.3 degrees west longitude, on the anti-Saturn facing hemisphere. Image scale is approximately 32 meters (105 feet) per pixel. The clear spectral filter images in this mosaic were obtained with the Cassini spacecraft narrow- angle camera on Sept. 10, 2007, at distances ranging from 5,363 to 5,884 kilometers (3,332 to 3,656 miles) from Iapetus. 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 |
|
Approaching Iapetus
| Description |
The slim crescent of Iapetus looms before the Cassini spacecraft as it approaches the mysterious moon. |
| Full Description |
The slim crescent of Iapetus looms before the Cassini spacecraft as it approaches the mysterious moon. Iapetus, 1,468 kilometers (912 miles) across, seen here in false color, is unique in its dramatic variation in brightness between the northern polar region and the middle and low latitudes. Equally prominent is the moon's equatorial ridge of towering mountains. The profile of the ridge against the darkness of space reveals that it is topped by a cratered plateau approximately 15 kilometers (9 miles) wide. Further west, the profile of the ridge changes from a long plateau to discrete peaks. The mosaic consists of four image footprints across the surface of Iapetus and has a resolution of 489 meters (0.3 miles) per pixel. A full-resolution clear filter image was combined with half-resolution images taken with infrared, green and ultraviolet spectral filters (centered at 752, 568 and 338 nanometers, respectively) to create this full-resolution false color mosaic. The color seen in this view represents an expansion of the wavelength region of the electromagnetic spectrum visible to human eyes. The intense reddish-brown hue of the dark material is far less pronounced in true color images. The use of enhanced color makes the reddish character of the dark material more visible than it would be to the naked eye. In addition, the scene has been brightened to improve the visibility of surface features. This view was acquired with the Cassini spacecraft narrow-angle camera on Sept. 10, 2007, at a distance of about 83,000 kilometers (51,600 miles) from Iapetus. 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 |
|
The Transition Zone
| Description |
NASA's Cassini spacecraft captured a series of high-resolution images of the transition region from dark to bright terrain at southern middle latitudes on Iapetus. |
| Full Description |
Soaring above the alien, icy wastelands of Saturn's moon Iapetus, NASA's Cassini spacecraft captured a series of high-resolution images of the transition region from dark to bright terrain at southern middle latitudes that have been mosaicked together in this view. An important characteristic of the terrain in the boundary region is that the isolated bright patches are mainly found on slopes facing toward the bright trailing hemisphere or toward the south pole. The same polarity is found within the bright terrain, where the dark material can be seen at the bottom of craters and on equator-facing slopes. These indicate that thermal effects are at play in painting the surface of Iapetus, 1,468 kilometers (912 miles) across. The mosaic consists of eight image footprints across the surface of Iapetus. The view is centered on terrain near 38.6 degrees south latitude, 171.3 degrees west longitude. Image scale is approximately 52 meters (171 feet) per pixel. The clear spectral filter images in this mosaic were obtained with the Cassini spacecraft narrow- angle camera on Sept. 10, 2007, at a distance of approximately 5,000 kilometers (3,100 miles) from Iapetus. 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 |
|
Closest View of Iapetus
| Description |
This mosaic of Cassini images shows the smallest details ever observed on Saturn's moon Iapetus. |
| Full Description |
This mosaic of Cassini images shows the smallest details ever observed on Saturn's moon Iapetus. Visible here are small craters as well as the base of a large mountain ridge located just south of the mosaic. At several places, bright spots about 20 to 50 meters (66 to 164 feet) across are visible. At these locations, more recent impactors have punched through the overlying blanket of dark material to reveal brighter, cleaner ice beneath. Since the bright craters are relatively small and very shallow, it is likely that the dark blanket is rather thin in this area, it is assumed that its actual average thickness might be on the order of a foot. The small crater at the upper left edge of the mosaic has a diameter of about 50 meters (164 feet) and shows a distinct ray pattern from excavated ice. This feature is so bright in comparison to the dark surrounding terrain that it had to be darkened manually so as not to look overexposed in this mosaic. The mosaic consists of eight image footprints across the surface of Iapetus, presented here in simple cylindrical projection. The view is centered on terrain near 0 degrees north latitude, 164.9 degrees west longitude, within the dark leading hemisphere of Iapetus. Image scale is approximately 10 meters (33 feet) per pixel. The clear spectral filter images in this mosaic were obtained with the Cassini spacecraft narrow-angle camera on Sept. 10, 2007, at distances ranging from 1,627 to 2,040 kilometers (1,011 to 1,268 miles) from Iapetus. Iapetus is 1,468 kilometers (912 miles) across. 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 |
|
A Scene of Craters
| Description |
This high-resolution view shows a vast range of crater sizes in the dark terrain of the leading hemisphere of Saturn's moon Iapetus. |
| Full Description |
This high-resolution view shows a vast range of crater sizes in the dark terrain of the leading hemisphere of Saturn's moon Iapetus. Across the scene, a few small bright spots indicate fresh, rayed craters where impactors have punched through the thin blanket of dark material to the cleaner ice beneath. The slight elevation on the bottom half of the image is part of the giant equatorial ridge that spans a wide fraction of Iapetus' circumference. The numerous craters on top of the ridge indicate that it is an old surface feature. The mosaic consists of three image footprints across the surface of Iapetus. The view is centered on terrain near 0.5 degrees north latitude, 141.6 degrees west longitude. Image scale is approximately 22 meters (72 feet) per pixel. Illumination is from the left. The clear spectral filter images in this mosaic were obtained with the Cassini spacecraft narrow-angle camera on Sept. 10, 2007, at a distance of approximately 63,000 kilometers (39,000 miles) from Iapetus and at a sun-Iapetus-spacecraft, or phase, angle of about 125 degrees. Iapetus is 1,468 kilometers (912 miles) across. 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 |
|
Towering Peaks of Iapetus
| Description |
This stereo image, or anaglyph, shows huge mountains on Saturn's moon Iapetus, imaged by NASA's Cassini spacecraft during its very close flyby in Sept. 2007. These mountains are located at the moon's equator in the westward-most part of the dark terrain. |
| Full Description |
This stereo image, or anaglyph, shows huge mountains on Saturn's moon Iapetus, imaged by NASA's Cassini spacecraft during its very close flyby in Sept. 2007. These mountains are located at the moon's equator in the westward-most part of the dark terrain. Here, the brightness pattern on the surface is very complex. The mountain in the center of this view is part of the range informally named "the Voyager mountains" that were first detected on the limb of the moon in NASA Voyager spacecraft images. Interestingly, its eastern (right) flank is dark, while the other flanks are bright. This suggests that external material arriving on Iapetus from its orbital motion might play a role in the darkening process. One plausible source, the outer moons of Saturn, might provide a very thin but steady stream of very dark particles from the eastern direction as seen from this mountain. The mosaic consists of six image footprints across the surface of Iapetus. The view is centered on terrain near 0.1 degree north latitude, 199 degrees west longitude. Image scale is approximately 46 meters (151 feet) per pixel. The clear spectral filter images in this mosaic were obtained with the Cassini spacecraft narrow- angle camera on Sept. 10, 2007. Distances for the blue portion of the image range from 7,744 to 9,135 kilometers (4,812 to 5,676 miles) from Iapetus, distances for the red portion of the image range from 20,267 to 21,595 kilometers (12,593 to 13,418 miles) from the moon. A separate, non-stereo version of the scene is included for comparison. Iapetus is 1,468 kilometers (912 miles) across. 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 |
|
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 |
|
A Complex Transition
| Description |
The transition region from Saturn's moon Iapetus' dark leading hemisphere to its bright trailing hemisphere |
| Full Description |
The transition region from Saturn's moon Iapetus' dark leading hemisphere to its bright trailing hemisphere is a complicated patchwork of craters and highlands, with low elevations filled in by dark material. An explanation of the pattern visible here might be key to a full understanding of the bright/dark dichotomy on Iapetus, 1,468 kilometers (912 miles) across. The view is centered on the equator and covers an area 711 kilometers wide by 417 kilometers tall (442 by 259 miles). The giant equatorial ridge visible on the dark leading hemisphere is not present anymore in this region. Instead, large, isolated mountains more than 10 kilometers (6 miles) tall are spread along the equator. These mountains show bright western flanks, while the surrounding lowlands are generally dark. The bright mountains at center right, surrounded by dark terrain, are also visible in the stereo view Towering Peaks of Iapetus. The region of Iapetus seen in this mosaic is also visible in the color full-disk mosaic The Other Side of Iapetus. The mosaic is an orthographic projection consisting of 21 image footprints across the surface of Iapetus. The view is centered on terrain near 0.1 degree north latitude, 199 degrees west longitude, in the quadrant of Iapetus that faces away from Saturn. Image scale is approximately 83 meters (272 feet) per pixel. An orthographic view is most like the view seen by a distant observer looking through a telescope. The clear spectral filter images in this mosaic were obtained with the Cassini spacecraft narrow- angle camera on Sept. 10, 2007, at distances ranging from 13,857 to 21,846 kilometers (8,610 to 13,574 miles) from Iapetus. 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 |
|
Shadowing Saturn
| Description |
Like a silvery pearl, an icy moon crosses the face of Saturn, while two of its siblings cast shadows onto the planet. |
| Full Description |
Like a silvery pearl, an icy moon crosses the face of Saturn, while two of its siblings cast shadows onto the planet. Rhea (1,528 kilometers, or 949 miles across) hangs in the foreground. Near upper left on Saturn is the small shadow of Mimas. Near lower right is the penumbral shadow of Iapetus -- the part of the moon's shadow where Iapetus does not completely block the sun. This view looks toward the unilluminated side of the rings from less than a degree above the ringplane. The rings' shadows drape across the northern hemisphere. Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini spacecraft wide-angle camera on June 15, 2007, at a distance of approximately 1.2 million kilometers (744,000 miles) from Rhea and 1.7 million kilometers (1.1 million miles) from Saturn. Image scale is 71 kilometers (44 miles) per pixel on Rhea and 103 kilometers (64 miles) on Saturn. 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 15, 2007 |
|
The View from Iapetus
| Description |
While on final approach for its Sept. 2007 close encounter with Saturn's moon Iapetus, Cassini spun around to take in a sweeping view of the Saturn System. |
| Full Description |
While on final approach for its Sept. 2007 close encounter with Saturn's moon Iapetus, Cassini spun around to take in a sweeping view of the Saturn System. Iapetus (1,468 kilometers, or 912 miles across) is the only major moon of Saturn with a significant inclination to its orbit. From the other major satellites, the rings would appear nearly edge-on, but from Iapetus, the rings usually appear at a tilt, as seen here. This natural color mosaic consists of 15 red, green and blue spectral filter images acquired in five wide-angle camera footprints that swept across the scene. Moons visible in this image: Dione (1,126 kilometers, or 700 miles across) at center left, Enceladus (505 kilometers, or 314 miles across) near the left side ansa (or ring edge), Mimas (397 kilometers, or 247 miles across) a speck against the ring shadows on Saturn's western limb, Rhea (1,528 kilometers, or 949 miles across) against the bluish backdrop of the northern hemisphere, Tethys (1,071 kilometers, or 665 miles across) near the right ansa, and Titan (5,150 kilometers, or 3,200 miles across) near lower right. The images were obtained on Sept. 10, 2007, at a distance of approximately 3.3 million kilometers (2.1 million miles) from Saturn at a sun-Saturn-spacecraft, or phase, angle of 33 degrees. Image scale is about 195 kilometers (121 miles) per pixel 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 |
October 15, 2007 |
|
Warm and Dry on Iapetus
| Description |
T |
| Full Description |
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 composite infrared spectrometer team homepage is http://cirs.gsfc.nasa.gov/. The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/GSFC/SwRI/SSI, This image compares midday temperatures on Saturn's moon Iapetus, recorded by the composite infrared spectrometer instrument during Cassini's close Sept. 10, 2007 flyby, with images of the same region recorded during the same flyby by the Cassini imaging science subsystem, shown on the right. See The Other Side of Iapetus for full imaging mosaic. Smallest features visible in the composite infrared spectrometer image (on the left) are about 8 kilometers (5 miles) across. The red rectangle on the visible light (right) image shows the region covered by infrared spectrometer, which extends a distance of 385 kilometers (240 miles) from 36 north, 212 west to 22 south, 220 west. The composite infrared spectrometer determined surface temperatures by measuring the spectrum of infrared radiation emitted by Iapetus in the 9 to 16 micron wavelength range. The dark regions are warmer because they absorb more of the sunlight shining on Iapetus, so dark spots in the visible (right) image show up as warm spots in the infrared image on the left. Temperatures near the equator vary between about 128 Kelvin (minus 229 degrees Fahrenheit) in the darkest regions and about 113 Kelvin (minus 256 degrees Fahrenheit) in the brightest regions. This relatively small temperature difference has a large effect on Iapetus, because at the temperature of the dark regions, a large amount of water ice, which is abundant on most moon surfaces in the Saturn system, can be lost by evaporation over the several-billion year age of Iapetus' surface. Composite infrared spectrometer scientists calculate that when daytime temperatures reach 128 Kelvin (minus 229 degrees Fahrenheit), about 20 meters (65 feet) of ice can be lost per billion years. In the bright regions, with peak temperatures of 113 Kelvin (minus 256 degrees Fahrenheit), only about 10 centimeters, or 2.5 inches, of ice is lost in the same period. It is thus likely that the ice has evaporated completely from the surface of the dark regions of Iapetus, darkening them further, and has collected in the neighboring bright regions, making them brighter, thereby exaggerating initially modest brightness variations. This process is known as thermal segregation. Models by the composite infrared spectrometer team also show that ice evaporated from the warm dark terrain at low latitudes can collect at higher latitudes, and can thus explain the bright polar caps on the dark leading side of Iapetus as well as the relatively dark equatorial regions on the bright trailing side. 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 composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. |
| Date |
October 8, 2007 |
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Iapetus' Equatorial Region -
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| 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 |
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Two Ultraviolet Views of Iap
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| Description |
Two Ultraviolet Views of Iapetus |
| Full Description |
The far left image shows the bright-dark boundary region on Saturn's moon Iapetus at far-ultraviolet wavelengths, viewed by Cassini's ultraviolet imaging spectrograph on Sept. 10, 2007. These wavelengths represent reflected solar light and indicate where the surface is brightest and highest in water ice abundance. (Red indicates the brightest regions, purple the darkest.) The bright "Voyager Mountains", part of the equatorial ridge, are seen as bright spots against a dark background. The dark material that covers one hemisphere of Iapetus is indicated in purple and is seen on the right side of this image. The middle image is a color composite: blue-green (longer ultraviolet wavelengths) indicates where the surface is bright and probably richest in water ice. Red (short ultraviolet wavelengths) indicates where the surface is low in water ice and relatively high in dirty material. The sky background is also bright at these wavelengths, making the limb, or edge, of Iapetus where the surface is dark indistinguishable from the sky background. The image on the right, taken by the imaging science subsystem, is for reference, with the regions observed by Cassini's ultraviolet imaging spectrometer outlined in red. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's 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 ultraviolet imaging spectrograph was designed and built at, and the team is based at the University of Colorado, Boulder. 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/home/index.cfm . The ultraviolet imaging spectrograph team home page is at http://lasp.colorado.edu/cassini . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/University of Colorado/Space Science Institute |
| Date |
October 8, 2007 |
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The Other Side of Iapetus
| Description |
Cassini captures the first high-resolution glimpse of the bright trailing hemisphere of Saturn's moon Iapetus. |
| Full Description |
Cassini captures the first high-resolution glimpse of the bright trailing hemisphere of Saturn's moon Iapetus. This false-color mosaic shows the entire hemisphere of Iapetus (1,468 kilometers, or 912 miles across) visible from Cassini on the outbound leg of its encounter with the two-toned moon in Sept. 2007. The central longitude of the trailing hemisphere is 24 degrees to the left of the mosaic's center. Also shown here is the complicated transition region between the dark leading and bright trailing hemispheres. This region, visible along the right side of the image, was observed in many of the images acquired by Cassini near closest approach during the encounter. Revealed here for the first time in detail are the geologic structures that mark the trailing hemisphere. The region appears heavily cratered, particularly in the north and south polar regions. Near the top of the mosaic, numerous impact features visible in NASA Voyager 2 spacecraft images (acquired in 1981) are visible, including the craters Ogier and Charlemagne. The most prominent topographic feature in this view, in the bottom half of the mosaic, is a 450-kilometer (280-mile) wide impact basin, one of at least nine such large basins on Iapetus. In fact, the basin overlaps an older, similar-sized impact basin to its southeast. In many places, the dark material -- thought to be composed of nitrogen-bearing organic compounds called cyanides, hydrated minerals and other carbonaceous minerals -- appears to coat equator-facing slopes and crater floors. The distribution of this material and variations in the color of the bright material across the trailing hemisphere will be crucial clues to understanding the origin of Iapetus' peculiar bright-dark dual personality. The view was acquired with the Cassini spacecraft narrow-angle camera on Sept. 10, 2007, at a distance of about 73,000 kilometers (45,000 miles) from Iapetus. The color seen in this view represents an expansion of the wavelengths of the electromagnetic spectrum visible to human eyes. The intense reddish-brown hue of the dark material is far less pronounced in true color images. The use of enhanced color makes the reddish character of the dark material more visible than it would be to the naked eye. This mosaic consists of 60 images covering 15 footprints across the surface of Iapetus. The view is an orthographic projection centered on 10.8 degrees south latitude, 246.5 degrees west longitude and has a resolution of 426 meters (0.26 miles) per pixel. An orthographic view is most like the view seen by a distant observer looking through a telescope. At each footprint, a full resolution clear filter image was combined with half-resolution images taken with infrared, green and ultraviolet spectral filters (centered at 752, 568 and 338 nanometers, respectively) to create this full-resolution false color mosaic. 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 |
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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 |
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Snapshot from Afar
| Description |
Snapshot from Afar |
| Full Description |
The Cassini spacecraft snapped this Saturn portrait from the distance of Iapetus, just before beginning its close encounter with the two-toned moon. Rhea (1,528 kilometers, or 949 miles across) is visible against the clouds of the northern hemisphere. Mimas (397 kilometers, or 247 miles across) stands out as a bright speck against the dark ring shadows, near center. Enceladus is not pictured here, although it casts its shadow upon the northern hemisphere, to the left of Rhea. This view looks toward the sunlit side of the rings from about 4 degrees below the ringplane. The rings disappear into the planet's shadow at right. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Sept. 9, 2007. The view was obtained at a distance of approximately 3.3 million kilometers (2.1 million miles) from Saturn. Image scale is 195 kilometers (121 miles) per pixel 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 |
October 19, 2007 |
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Flyby Follow-up
| Description |
Flyby Follow-up |
| Full Description |
Following Cassini's highly successful flyby of Iapetus in September 2007, the spacecraft repeatedly glanced back at the two-toned moon for some time. As Cassini receded from Iapetus, more and more of the bright trailing hemisphere rotated into view. This image shows terrain farther west of that visible in The Other Side of Iapetus. Most notably in this view, it can be seen that the dark equatorial terrain reaches onto the moon's trailing side by the same amount on the western and eastern sides. This view looks toward Iapetus (1,468 kilometers, or 912 miles, across) from about 10 degrees south of the moon's equator and is centered on 284 degrees west longitude. North is up and rotated 16 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 19, 2007. The view was acquired at a distance of approximately 1.7 million kilometers (1 million miles) from Iapetus and at a sun-Iapetus-spacecraft, or phase, angle of 32 degrees. 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. 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 24, 2007 |
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Iapetan Geography
| Description |
Cassini soars above the many pits and basins in the rolling landscape of Saturn's moon Iapetus. |
| Full Description |
Cassini soars above the many pits and basins in the rolling landscape of Saturn's moon Iapetus. This mosaic view looks out onto an area close to the northern bright/dark boundary, but still within the dark region, Cassini Regio. Near upper left is a large crater with terraced walls, a mostly flat floor and a prominent group of peaks in its center. The sharp features make this likely one of the youngest craters in this area of Iapetus. Cassini imaged another similarly flat-floored and relatively fresh crater during its Dec. 2004 Iapetus flyby (see Giant Landslide on Iapetus). The mosaic consists of three image footprints across the surface of Iapetus (1,468 kilometers, or 912 miles across). The view is centered on terrain near 43.3 degrees north latitude, 138 degrees west longitude. Image scale is approximately 75 meters (246 feet) per pixel. The clear spectral filter images in this mosaic were obtained with the Cassini spacecraft narrow-angle camera on Sept. 10, 2007, at a distance of approximately 13,500 kilometers (8,400 miles) from Iapetus and at a sun-Iapetus-spacecraft, or phase, angle of 139 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 15, 2007 |
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| Description |
Saturn |
| Full Description |
This computer rendering shows the surface of Rhea, Saturn's second largest satellite behind Titan. Like Dione and Iapetus, there is a noticeable difference between the two hemispheres of the satellite. Rhea is a densely cratered satellite, and this image shows two of the most prominent craters, Izanagi (the larger) and Izanami (the smaller), which partially overlap. These craters are well into the southern hemisphere. Saturn is seen on the horizon, and a small meteor is seen striking the surface inside the Izanagi crater. This image was created at JPL using KPT Bryce, animation software developed by Jim Blinn, and Adobe Photoshop. For a high resolution image, click here. |
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| Description |
Saturn |
| Full Description |
This computer rendering shows the surface of Rhea, Saturn's second largest satellite behind Titan. Like Dione and Iapetus, there is a noticeable difference between the two hemispheres of the satellite. Rhea is a densely cratered satellite, and this image shows two of the most prominent craters, Izanagi (the larger) and Izanami (the smaller), which partially overlap. These craters are well into the southern hemisphere. Saturn is seen on the horizon, and a small meteor is seen striking the surface inside the Izanagi crater. This image was created at JPL using KPT Bryce, animation software developed by Jim Blinn, and Adobe Photoshop. For a high resolution image, click here. |
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| Description |
Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn. |
| Full Description |
This computer rendering shows the surface of Rhea, Saturn's second largest satellite behind Titan. Like Dione and Iapetus, there is a noticeable difference between the two hemispheres of the satellite. Rhea is a densely cratered satellite, and this image shows two of the most prominent craters, Izanagi (the larger) and Izanami (the smaller), which partially overlap. These craters are well into the southern hemisphere. Saturn is seen on the horizon, and a small meteor is seen striking the surface inside the Izanagi crater. This image was created at JPL using KPT Bryce, animation software developed by Jim Blinn, and Adobe Photoshop. For a high resolution image, click here. |
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| Description |
Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn. |
| Full Description |
This computer rendering shows the surface of Rhea, Saturn's second largest satellite behind Titan. Like Dione and Iapetus, there is a noticeable difference between the two hemispheres of the satellite. Rhea is a densely cratered satellite, and this image shows two of the most prominent craters, Izanagi (the larger) and Izanami (the smaller), which partially overlap. These craters are well into the southern hemisphere. Saturn is seen on the horizon, and a small meteor is seen striking the surface inside the Izanagi crater. This image was created at JPL using KPT Bryce, animation software developed by Jim Blinn, and Adobe Photoshop. For a high resolution image, click here. |
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| Description |
Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn. |
| Full Description |
In this extremely narrow angle field-of-view artist's rendering Iapetus, with its notable dark surface, occupies the foreground with a dimly lit crescent Saturn low in the sky. Iapetus' surface shows some strange wavy ice formations, some low scoured hills, and mountains in the background. The Sun as well as three other satellites are also visible. By David Seal (only available electronically). |
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Iapetus Flyby Animation
| Description |
Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn. |
| Full Description |
Cassini's flyby of Saturn's icy moon Iapetus is set for Dec. 31, 2004. Iapetus is Saturn's two-faced moon -- one side is very bright, and the other is very dark. One scenario for this striking difference is that the moon's surface is being resurfaced by some material spewing from within. |
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| Description |
Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn. |
| Full Description |
Jean Dominique Cassini (1625-1712) discovered Saturn's moons Iapetus, Rhea, Tethys, and Dione. In 1675, Cassini discovered that Saturn's rings are separated into two parts by a gap. The gap is now called the Cassini Division in his honor. |
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