Waspie_Dwarf Posted March 30, 2006 #1 Share Posted March 30, 2006 Cassini Finds 'Missing Link' Moonlet Evidence in Saturn's Rings March 29, 2006(Source: NASA/JPL/Space Science Institute) Scientists with NASA's Cassini mission have found evidence that a new class of small moonlets resides within Saturn's rings. There may be as many as 10 million of these objects within one of Saturn's rings alone. The moonlets' existence could help answer the question of whether Saturn's rings were formed through the break-up of a larger body or are the remnants of the disk of material from which Saturn and its moons formed. "These moonlets are likely to be chunks of the ancient body whose break-up produced Saturn's glorious rings," said Joseph Burns of Cornell University, Ithaca, N.Y., a co-author of the report. Careful analysis of high-resolution images taken by Cassini's cameras revealed four faint, propeller-shaped double streaks. These features were found in an otherwise bland part of the mid-A Ring, a bright section in Saturn's main rings. Cassini imaging scientists reporting in this week's edition of the journal Nature believe the "propellers" provide the first direct observation of how moonlets of this size affect nearby particles. Cassini took the images as it slipped into Saturn orbit on July 1, 2004. Previous measurements, including those made by NASA's Voyager spacecraft in the early 1980s, have shown that Saturn's rings contain mostly small water-ice particles ranging from less than 1 centimeter (one-half inch) across to the size of a small house. Scientists knew about two larger embedded ring moons such as 30-kilometer-wide (19-mile) Pan and 7-kilometer-wide (4-mile) Daphnis. The latest findings mark the first evidence of objects of about 100 meters (300 feet) in diameter. From the number of moonlets spotted in the very small fraction of the A ring seen in the images, scientists estimated the total number of moonlets to be about 10 million. "The discovery of these intermediate-sized bodies tells us that Pan and Daphnis are probably just the largest members of the ring population, rather than interlopers from somewhere else," said Matthew Tiscareno, an imaging team research associate at Cornell and lead author on the Nature paper. Moons as large as Pan and Daphnis clear large gaps in the ring particles as they orbit Saturn. In contrast, smaller moonlets are not strong enough to clear out the ring, resulting in a partial gap centered on the moonlet and shaped like an airplane propeller. Such features created by moonlets were predicted by computer models, which give scientists confidence in their latest findings. "We acquired this spectacular, one-of-a-kind set of images immediately after getting into orbit for the express purpose of seeing fine details in the rings that we had not seen previously," said Carolyn Porco, Cassini imaging team leader and co-author. "This will open up a new dimension in our exploration of Saturn's rings and moons, their origin and evolution." The detection of moonlets embedded in a ring of smaller particles may provide an opportunity to observe the processes by which planets form in disks of material around young stars, including our own early solar system. "The structures we observe with Cassini are strikingly similar to those seen in many numerical models of the early stages of planetary formation, even though the scales are dramatically different," said co-author Carl Murray, an imaging team member at Queen Mary, University of London. "Cassini is giving us a unique insight into the origin of planets." For images showing the propeller-shaped features, visit: http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org . 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 NASAยฟs Science Mission Directorate, Washington. 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.Contacts: Carolina Martinez (818) 354-9382 Jet Propulsion Laboratory, Pasadena, Calif. Erica Hupp/Grey Hautaluoma (202) 358-1237/0668 NASA Headquarters, Washington Preston Dyches (720) 974-5859 Cassini Imaging Central Laboratory for Operations Space Science Institute, Boulder, Colo. NEWS RELEASE: 2006-046Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted March 30, 2006 Author #2 Share Posted March 30, 2006 (edited) Locating the Propellers March 29, 2006 This collection of Cassini images provides context for understanding the location and scale of propeller-shaped features observed within Saturn's A ring. Careful analysis of the highest resolution images taken by Cassini's cameras as the spacecraft slipped into Saturn orbit revealed the four faint, propeller-shaped double-streaks in an otherwise bland part of the mid-A ring. Imaging scientists believe the "propellers" provide the first direct observation of the dynamical effects of moonlets approximately 100 meters (300 feet) in diameter. The propeller moonlets represent a hitherto unseen size-class of particles orbiting within the rings. The left-hand panel provides broad context within the rings, and shows the B ring, Cassini Division, A ring and F ring. Image scale in the radial, or outward from Saturn, direction is about 45 kilometers (28 miles) per pixel; because the rings are viewed at an angle, the image scale in the longitudinal, or circumferential, direction is several times greater. The center image is a closer view of the A ring, showing the radial locations where propeller features were spotted. The view is approximately 1,800 kilometers (1,100 miles) across from top to bottom and includes a large density wave at bottom (caused by the moons Janus and Epimetheus), as well as two smaller density waves. The footprints of the propeller discovery images are between density waves, in bland, quiescent regions of the ring. The propellers appear as double dashes in the two close-up discovery images at the right and are circled. The unseen moonlets, each roughly the size of a football field, lie in the center of each structure. These two images were taken during Saturn orbit insertion on July 1, 2004, and are presented here at one-half scale. Resolution in the original images was 52 meters (171 feet) per pixel. The horizontal lines in the image represent electronic noise and do not correspond to ring features. The propellers are about 5 kilometers (3 miles) long from tip to tip, and the radial offset (the "leading" dash is slightly closer to Saturn) is about 300 meters (1,000 feet). The propeller structures are unchanged as they orbit the planet. In that way, they are much like the wave pattern that trails after a speedboat as it skims across a smooth lake. Such a pattern is hard to discern in a choppy sea. In much the same way, scientists think other effects may be preventing Cassini from seeing the propellers except in very bland parts of the rings. See Four Propellers and Propeller Motion for additional images showing these 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 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 Source: NASA/JPL - Cassini Edited March 30, 2006 by Waspie_Dwarf Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted March 30, 2006 Author #3 Share Posted March 30, 2006 (edited) Four Propellers March 29, 2006 These figures show four propeller-shaped structures discovered by the Cassini spacecraft in close-up images of Saturn's A ring. The propellers are about 5 kilometers (3 miles) long from tip to tip, and the radial offset (the "leading" dash is slightly closer to Saturn) is about 300 meters (1,000 feet). See Propeller Motion and Locating the Propellers for additional images and information about these features. The figures were cropped from two original Cassini spacecraft narrow-angle camera images and magnified for visibility. The images were then re-projected so that orbital motion is to the left and Saturn is up. The unseen moonlets lie in the center of each structure. The figures were cropped from two original Cassini spacecraft narrow-angle camera images, taken during Saturn orbit insertion on July 1, 2004, and magnified for 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 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 Source: NASA/JPL - Cassini Edited March 30, 2006 by Waspie_Dwarf Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted March 30, 2006 Author #4 Share Posted March 30, 2006 Propeller Motion March 29, 2006 This magnified view illustrates the general orientation of the "propeller" features in Saturn's rings as they orbit the planet. The propellers are features detected in Cassini images that reveal the gravitational influence of moonlets approximately 100 meters (300 feet) in diameter. The view is from one of the two Saturn orbit insertion images, taken on July 1, 2004, in which the propellers were discovered. The two dashes of the propeller are oriented in the direction of orbital motion. The "leading" dash is also slightly closer to Saturn; this "radial offset" is about 300 meters (1000 feet). The unseen moonlet lies in the center of the structure. The grainy appearance of the image is due to magnification and the fact that the propellers are very faint--just visible above the level of background noise. Consequently, the image enhancement procedures used have also enhanced the noise. This propeller image is identified as "feature 1" in Four Propellers. The original Cassini spacecraft narrow-angle camera image has been magnified from its original scale for presentation. 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Rykster Posted April 2, 2006 #5 Share Posted April 2, 2006 (edited) Saturn's Rings Created by Collision By Ker Than Staff Writer posted: 29 March 2006 12:37 pm ET Oddly shaped gaps found in Saturn's rings hint at the existence of long sought "moonlets" and support the theory that the rings are the broken remains of an icy moon shattered long ago in a violent collision, scientists say. Scientists think a comet or asteroid collided with one of Saturn's moons about 100 million years ago. Such an impact would have created debris in a range of sizes, but until now, scientists only had evidence for chunks of rock that were miles in diameter and smaller particles that were about 65 feet (20 km) across or less. The medium-sized moonletsโso named because their size would be between that of a moon and smaller particlesโpredicted by theory were missing. But in July 2004, NASA's Cassini spacecraft was hovering directly above Saturn's ring system when it detected strange gaps resembling S-shaped propellers in the planet's bright A-ring. Scientists think the gaps were formed by chunks of rock 300 feet (100 m) wide as they plowed through smaller particles in the ring. The finding is detailed in the March 30 issue of the journal Nature. Propellers in space... View: Full Article | Source: Space.com Edited April 2, 2006 by Rykster Link to comment Share on other sites More sharing options...
frogfish Posted April 2, 2006 #6 Share Posted April 2, 2006 nice find... Link to comment Share on other sites More sharing options...
Rykster Posted April 2, 2006 #7 Share Posted April 2, 2006 ^^^ Thanx Froggy. It seems that the more we look around our solar system, the more we find. The coming years are gonna be fascinating. Link to comment Share on other sites More sharing options...
frogfish Posted April 2, 2006 #8 Share Posted April 2, 2006 Imagine what we'll find when the probe reaches Pluto! Link to comment Share on other sites More sharing options...
x o i s k Posted April 2, 2006 #9 Share Posted April 2, 2006 Who knows, I hope something vast or understandable... Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted July 5, 2006 Author #10 Share Posted July 5, 2006 Saturn's Faint Rings Share Their Secrets Double-Banded E RingJuly 5, 2006 Dramatic edge-on Cassini views of Saturn's E ring, like these side-by-side images, reveal for the first time a double-banded structure. The structure is similar to that of Jupiter's gossamer ring and to the bands of dust found within the solar system's asteroid belt. Scientists believe that the E ring particles have their origins in the geysers erupting from the south polar of Enceladus. The double-banded appearance exists because there are fewer particles close to the ring plane than 500 to 1,000 kilometers (300 to 600 miles) above and below. This circumstance can arise if the particles making up the ring encircle Saturn on inclined orbits with a very restricted range of inclinations. This special condition might exist for two reasons. One possibility is that the particles being jetted out of Enceladus and injected into Saturn orbit may begin their journey around Saturn with a certain velocity, and consequently a restricted range of inclinations, with respect to the ring plane. Another is that the particles may begin with a large range of inclinations, but those orbiting very close to the ring plane get gravitationally scattered and removed from that region by the passage of Enceladus. Scientists will continue to observe the E ring from various angles to confirm and understand the structure. Most of the bright specks in the images are background stars, although a few are cosmic ray hits on the camera's detector. The two images were taken five hours apart on Dec. 1, 2005, when Cassini was approximately 1.9 million kilometers (1.2 million miles) from Saturn. The image scale on the sky at the distance of Saturn is about 220 kilometers (137 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 InstituteSource: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted July 5, 2006 Author #11 Share Posted July 5, 2006 Persistent Arc July 5, 2006 This movie shows a bright arc of material flashing around the edge of Saturn's G ring, a tenuous ring outside the main ring system. The arc is the same feature identified in images of the G ring taken in May 2005 (see Rings image titled "Arc in the Tenuous G Ring"). Scientists have seen the arc a handful of times over the past year, and it always appears to be a few times brighter than the rest of the ring and very tightly confined to a narrow strip along the inside edge of the G ring. Imaging team members believe that this feature is long-lived and may be held together by resonant interactions with the moon Mimas of the type that corral similar ring arcs around Neptune. The movie consists of 15 frames acquired every half hour over a period of seven-and-a-half hours. The version in the lower panel is vertically stretched by a factor of five to make the arc easier to see. The clear-filter images in this movie sequence were acquired by the Cassini spacecraft narrow-angle camera on April 25, 2006, at a distance of 2 million kilometers (1.2 million miles) from Saturn. The image scale on the sky at the distance of Saturn is about 24 kilometers (15 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted September 15, 2006 Author #12 Share Posted September 15, 2006 Saturn's Rings To Shine As Never Before September 15, 2006 (Source: Jet Propulsion Laboratory) Ring scientists have been waiting for this. Finally, after more than two years orbiting Saturn, the Cassini spacecraft reaches one of the ultimate vantage points. The rings should shine with majesty worthy of the "Jewel of the Solar System."The imaging team will take this opportunity to stitch together a mosaic of the entire ring system. The event is a solar occultation -- when the sun passes directly behind the planet as Cassini looks on. And this is not just any solar occultation; it's a very long one. The Cassini spacecraft will be right where scientists studying the rings want it: far enough from Saturn to be able to image it all and, more importantly, with the Sun blocked by the planet for 12 hours, long enough to properly map the elusive microscopic particles moving within the extended ring system. Data collected during this observation might also uncover clues about Enceladus' past behavior and aid mission planners in refining ring hazard models for future ring crossings. Thanks to the slow occultation, images taken during this carefully designed orbit may also uncover new ring structures and, at the very least, capture truly spectacular views of the D, F, G and E rings. "We are all sort of on pins and needles waiting for the results," says Brad Wallis, Cassini Rings Discipline Scientist. "When you get these kinds of high phase angles, very small particles almost focus the light right at the observer. So these faint rings that are so hard to see are going to be considerably brighter and show us details that are just not possible to see in other viewing conditions. All the space between Enceladus and the G ring is probably going to be pretty well lit up. It's really a unique event." While solar occultations in the mission typically last only an hour, this time it will last almost 12 hours, truly a dream come true considering it takes about 30 minutes to turn the spacecraft to the proper position. During "regular" occultations, scientists can only take a few images before the Sun reappears and the spacecraft has to be turned away to avoid damaging its sensitive instruments. This computer simulated view of Saturn from the Cassini spacecraft shows the relative path of the Sun as it passes behind the planet. Click here for the video. "So far we have only had some tiny snapshots of the E ring at high phase angles," Wallis says. "In this case we can basically image the entire ring. During that period of time, we can image all of the rings from the outer E ring inward at very high phase angles, which means that we are almost looking straight into the sun, but the sun is behind Saturn." Besides mapping the E ring, the observation will allow scientists to learn if there are structures within the ring. Structure within the E ring would be a good indication that Enceladus is not spewing material out at a regular pace. "We know that the E ring is a large, diffuse cloud going out from a little beyond the G ring to far beyond Enceladus," Wallis says. "Enceladus seems to be the source of it, given the ice jets Cassini has recently discovered, so if the whole ring looks uniform, that means Enceladus has being spewing stuff at the same rate for quite a long time. But if there are clumps and/or ringlets in it that we can not explain, it means the spew rate out of Enceladus changes. This is the one chance we have to see a snapshot of the history of Enceladus." The E ring is a very large cloud of dust made up of extremely fine particles -- 1 or 2 microns -- more or less the size of smoke particles. It stretches from 150,000 to 240,000 kilometers (93,000 to 149,000 miles) from the center of Saturn and is about 5,000 to 10,000 kilometers (3,100 to 6,200 miles) thick. Crossing the E ring, however, poses no hazard to the spacecraft. "We pass through the E ring all the time, and we get samples of particles every time we cross it, but we have only a rough idea of what the structure looks like in detail because the difference between detecting three particles or four particles at any ring plane crossing is insignificant," Wallis explains. "This is the only chance we get to point the cameras right at the Sun and see these things in this very forward scattered mode." The same technique worked in the past, and it allowed mission planners to cross the rings safely. NASA's Voyager 2 looks at Uranus' rings. The view on the right, which was taken at much higher phase angle, shows details not visible from any other angle. Photojournal image: PIA00142 Photojournal image: PIA01977 "NASA's Voyager 2 discovered a vast and complex new system of ringlets around Uranus this way, using only one single image taken in several minutes. We'll have 10 straight hours," Wallis says. Cassini is slated to send home the images starting on Sept. 17. To better exploit the rare opportunity, Cassini will take images in multiple exposures and colors. The Imaging Science Subsystem and Visible and Infrared Mapping Spectrometer will be the prime instruments in this set of unique observations. "The imaging team will use the wide-angle camera to do a mosaic of the entire area in multiple colors and multiple exposures because the brightness of the particles changes very steeply when you move into these high-phase angle areas. The team will also use the narrow-angle camera to get some high resolution looks at selected areas." Wallis says. "Because this is somewhat uncharted territory (viewing these faint rings at these very high phase angles), and because we only have one opportunity like this in the entire 4-year mission, the teams planning this science want to be sure they get it and get it right," adds Wallis.Source: NASA/JPL - Cassini - Features Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted September 20, 2006 Author #13 Share Posted September 20, 2006 Scientists Discover New Ring and Other Features at Saturn September 19, 2006 (Source: Jet Propulsion Laboratory) Saturn sports a new ring in an image taken by NASA's Cassini spacecraft on Sunday, Sept. 17, during a one-of-a-kind observation.The new ring is a tenuous feature, and coincides with the orbits of Saturn's moons Janus and Epimetheus. Other spectacular sights captured by Cassini's cameras include wispy fingers of icy material stretching out tens of thousands of kilometers from the active moon, Enceladus, and a cameo color appearance by planet Earth. The images were obtained during the longest solar occultation of Cassini's four-year mission. During a solar occultation, the sun passes directly behind Saturn, and Cassini lies in the shadow of Saturn while the rings are brilliantly backlit. Usually, an occultation lasts only about an hour, but this time it was a 12-hour marathon. Sunday's occultation allowed Cassini to map the presence of microscopic particles that are not normally visible across the ring system. As a result, Cassini saw the entire inner Saturnian system in a new light.Wispy fingers of bright, icy material reach tens of thousands of kilometers outward from Saturn's moon Enceladus into the E ring. The new ring is a tenuous feature, visible outside the brighter main rings of Saturn and inside the G and E rings, and coincides with the orbits of Saturn's moons Janus and Epimetheus. Scientists expected that meteoroid impacts on Janus and Epimetheus might kick particles off the moons' surfaces and inject them into Saturn orbit, but they were surprised that a well-defined ring structure exists at this location. Saturn's extensive, diffuse E ring, the outermost ring, had previously been imaged one small section at a time. The 12-hour marathon enabled scientists to see the entire structure in one view. The moon Enceladus is seen sweeping through the E ring, extending wispy, fingerlike projections into the ring. These very likely consist of tiny ice particles being ejected from Enceladus' south polar geysers, and entering the E-ring. "Both the new ring and the unexpected structures in the E ring should provide us with important insights into how moons can both release small particles and sculpt their local environments," said Matt Hedman, a research associate working with team member Joseph Burns, an expert in diffuse rings, at Cornell University in Ithaca, N.Y.Earth from nearly 1.5 billion kilometers (930 million miles) away. In the latest observations, scientists once again see the bright ghost-like spokes -- transient, dusty, radial structures -- streaking across the middle of Saturn's main rings. Capping off the new batch of observations, Cassini cast its powerful eyes in our direction and captured Earth, a pale blue orb, and a faint suggestion of our moon. Not since NASA's Voyager 1 spacecraft saw Earth as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system. "Nothing has greater power to alter our perspective of ourselves and our place in the cosmos than these images of Earth we collect from faraway places like Saturn," said Carolyn Porco, Cassini imaging team leader at the Space Science Institute, Boulder, Colo. Porco was one of the Voyager imaging scientists involved in taking the Voyager 'Pale Blue Dot' image. "In the end, the ever-widening view of our own little planet against the immensity of space is perhaps the greatest legacy of all our interplanetary travels."Earth is captured here in a natural color portrait made possible by the passing of Saturn directly in front of the sun from Cassini's point of view. In the coming weeks, several science teams will analyze data collected by Cassini's other instruments during this rare occultation event. The data will help scientists better understand the relationship between the rings and moons, and will give mission planners a clearer picture of ring hazards to avoid during future ring crossings. Images of the new ring, the E-ring, Enceladus and Earth are available at: http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and http://ciclops.org. 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. 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.Contacts: Carolina Martinez 818-354-9382 Jet Propulsion Laboratory, Pasadena, Calif. Preston Dyches 720-974-5859 Cassini Imaging Central Laboratory for Operations Space Science Institute, Boulder, Colo. NEWS RELEASE: 2006-110Source: NASA/JPL - Cassini - Press Release Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted September 20, 2006 Author #14 Share Posted September 20, 2006 Ghostly Fingers of Enceladus September 19, 2006 Wispy fingers of bright, icy material reach tens of thousands of kilometers outward from Saturn's moon Enceladus into the E ring, while the moon's active south polar jets continue to fire away. This astonishing, never-before-seen structure is made visible with the sun almost directly behind the Saturn system from Cassini's vantage point. The sun-Enceladus-spacecraft angle here is 175 degrees, a viewing geometry in which structures made of tiny particles brighten substantially. These features are very likely the result of particles injected into Saturn orbit by the Enceladus geysers: Those injected in the direction of the moon's orbital motion end up on larger, slower orbits and trail Enceladus in its orbit, and those injected into the opposite direction end up smaller, faster orbits and lead Enceladus. (Orbital motion is counter-clockwise.) In addition, the configuration of wisps may hint at an interaction between Saturn's magnetosphere and the torrent of particles issuing from Enceladus. In addition to the wisps, another unexpected detail is the dark gore in the center of the ring, following the moon in its orbit, likely brought about by the sweeping action of Enceladus as it orbits in the center of the E ring. The view looks down onto Enceladus (505 kilometers, or 314 miles across) from about 15 degrees above the ringplane. Tethys (1,071 kilometers, or 665 miles across) is visible to the left of Enceladus. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Sept. 15, 2006, at a distance of approximately 2.1 million kilometers (1.3 million miles) from Enceladus. Image scale is 128 kilometers (80 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted September 20, 2006 Author #15 Share Posted September 20, 2006 The Janus/Epimetheus Ring September 19, 2006 A new diffuse ring, coincident with the orbits of Saturn's moon's Janus and Epimetheus, has been revealed in ultra-high phase angle views from Cassini. Ultra-high phase angle indicates the sun is behind the target. The new ring is visible in this image (marked by a cross in the inset) outside the overexposed main rings and interior to the G and E rings. The G ring has a sharp inner boundary; the E ring is extremely broad and arcs across the upper and lower portions of the scene. While it is not unexpected that impact events on Janus and Epimetheus might kick particles off the moons' surfaces and inject them into Saturn orbit, it is, surprising that a well-defined structure exists at this location. The view looks down from about 15 degrees above the un-illuminated side of the rings. Some faint spokes can also be spotted in the main rings, made visible by sunlight diffusing through the B ring. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Sept. 15, 2006, at a distance of approximately 2.2 million kilometers (1.3 million miles) from Saturn and at a sun-Saturn-spacecraft angle of almost 179 degrees. Image scale is 130 kilometers (81 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted September 20, 2006 Author #16 Share Posted September 20, 2006 Pale Blue Orb (1) September 19, 2006 Not since NASA's Voyager 1 spacecraft saw our home as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system. Now, Cassini casts powerful eyes on our home planet, and captures Earth, a pale blue orb -- and a faint suggestion of our moon -- among the glories of the Saturn system. Earth is captured here in a natural color portrait made possible by the passing of Saturn directly in front of the sun from Cassini's point of view. At the distance of Saturn's orbit, Earth is too narrowly separated from the sun for the spacecraft to safely point its cameras and other instruments toward its birthplace without protection from the sun's glare. The Earth-and-moon system is visible as a bright blue point on the right side of the image above center. Here, Cassini is looking down on the Atlantic Ocean and the western coast of north Africa. The phase angle of Earth, seen from Cassini is about 30 degrees. A magnified view of the image taken through the clear filter (monochrome) shows the moon as a dim protrusion to the upper left of Earth. Seen from the outer solar system through Cassini's cameras, the entire expanse of direct human experience, so far, is nothing more than a few pixels across. Earth no longer holds the distinction of being our solar system's only "water world," as several other bodies suggest the possibility that they too harbor liquid water beneath their surfaces. The Saturnian moon, Enceladus, is among them, and is also captured on the left in this image (see inset), with its plume of water ice particles and swathed in the blue E ring which it creates. Delicate fingers of material extend from the active moon into the E ring. See Ghostly Fingers of Enceladus, for a more detailed view of these newly-revealed features. The narrow tenuous G ring and the main rings are seen at the right. The view looks down from about 15 degrees above the un-illuminated side of the rings. Images taken using red, green and blue spectral filters were combined to create this view. The image was taken by the Cassini spacecraft wide-angle camera on Sept. 15, 2006, at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn and at a sun-Saturn-spacecraft angle of almost 179 degrees. Image scale is 129 kilometers (80 miles) per pixel. At this time, Cassini was nearly 1.5 billion kilometers (930 million miles) from Earth. 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted September 20, 2006 Author #17 Share Posted September 20, 2006 Pale Blue Orb (2) September 19, 2006 Not since NASA's Voyager 1 spacecraft saw our home as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system. Now, Cassini casts powerful eyes on our home planet, and captures Earth, a pale blue orb -- and a faint suggestion of our moon -- among the glories of the Saturn system. Earth is captured here in a natural color portrait made possible by the passing of Saturn directly in front of the sun from Cassini's point of view. At the distance of Saturn's orbit, Earth is too narrowly separated from the sun for the spacecraft to safely point its cameras and other instruments toward its birthplace without protection from the sun's glare. The Earth-and-moon system is visible as a bright blue point on the right side of the image above center. Here, Cassini is looking down on the Atlantic Ocean and the western coast of north Africa. The phase angle of Earth, seen from Cassini is about 30 degrees. A magnified view of the image taken through the clear filter (monochrome) shows the moon as a dim protrusion to the upper left of Earth. Seen from the outer solar system through Cassini's cameras, the entire expanse of direct human experience, so far, is nothing more than a few pixels across. Earth no longer holds the distinction of being our solar system's only "water world," as several other bodies suggest the possibility that they too harbor liquid water beneath their surfaces. The Saturnian moon, Enceladus, is among them, and is also captured on the left in this image, with its plume of water ice particles and swathed in the blue E ring which it creates. Delicate fingers of material extend from the active moon into the E ring. See Ghostly Fingers of Enceladus, for a more detailed view of these newly-revealed features. The narrow tenuous G ring and the main rings are seen at the right. The view looks down from about 15 degrees above the un-illuminated side of the rings. Images taken using red, green and blue spectral filters were combined to create this view. The image was taken by the Cassini spacecraft wide-angle camera on Sept. 15, 2006, at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn and at a sun-Saturn-spacecraft angle of almost 179 degrees. Image scale is 129 kilometers (80 miles) per pixel. At this time, Cassini was nearly 1.5 billion kilometers (930 million miles) from Earth. 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted October 11, 2006 Author #18 Share Posted October 11, 2006 NASA Finds Saturn's Moons May Be Creating New Rings October 11, 2006 (Source: Jet Propulsion Laboratory) Cassini scientists are on the trail of the missing moons of Saturn. A recent observation by the spacecraft leads them to believe that they will find the moons near newly discovered rings around the planet. During an unprecedented opportunity, with the sun poised behind Saturn, Cassini scientists discovered two new rings and confirmed the presence of two others. The new rings are associated with one or more small moons and share their orbits with the moons, while scientists suspect a moon is lurking near a third ring.Imaging scientists have noticed color variations across the diffuse rings that imply active processes sort the particles in the ring according to their sizes. "Just like the old maxim that says where there's smoke, there's fire, at Saturn, where there's a new ring, there's bound to be a moon," said Dr. Jeff Cuzzi, Cassini interdisciplinary scientist at NASA's Ames Research Center, Moffett Field, Calif. Under the cover of Saturn's shadow in mid-September, the entire ring system became visible, and never-before-seen microscopic particles began to appear. A single, faint new ring at the orbits of two moonlets, Janus and Epimetheus, was discovered. A second ring was found a week later. It is narrow and overlies the orbit of the tiny moon Pallene, which Cassini discovered back in 2004. A third and fourth ring are visible in the Cassini Division, the big gap in Saturn's main ring system. Curiously, these rings were not seen in images from NASA's Voyager spacecraft. Cassini spent nearly 12 hours in Saturn's shadow on Sept. 15, 2006, making observations like this one. "We are hot on the trail of these possible elusive moonlets," said Dr. Joe Burns, Cassini imaging scientist at Cornell University, Ithaca, N.Y. "Finding the moons and learning about their interactions with the rings will help us understand how the moons formed and perhaps how the Saturn system formed." When viewed by Cassini's infrared instrument, one of the rings in the Cassini Division has unusual coloring and brightening, a trait it shares with fresh, faint rings like the F ring, or those in the Encke Gap in Saturn's outer A ring. Saturn's smallest moons have weak gravity and cannot retain any loose material on their surfaces. When these moons are struck by rapidly moving interplanetary meteoroids, this loose material is blasted off their surfaces and into Saturn orbit, creating diffuse rings along the moons' orbital paths. Collisions among several moonlets, or clumps of boulder-sized rubble, might also lead to debris trails. For instance, Saturn's G ring seems not to have any single moon large enough to see; it might have formed from a recent breakup of a moon. The unusual viewing geometry provided other insights into the changing nature of Saturn's rings. In addition to the dazzling images, data from Cassini's visual and infrared mapping spectrometer also show distinct color differences, indicating variations in composition and in microscopic particles in the Cassini Division, the diffuse E- and G-rings, lying outside the main rings, and the D ring, which is the ring closest to Saturn. "These tiny grains are like spices -- even a little bit of material can alter the ring's character," said Dr. Matt Hedman, another Cassini scientist at Cornell. Color variation in the rings might imply particles are being sorted by size. "We expected to see things we haven't seen before, but we are really, really puzzled by these new images of Saturn's main ring system," said Dr. Phil Nicholson, of Cornell, Cassini visual and infrared spectrometer team member. "The rings appear very different, with none of their usual calling card of water-ice features. There are hints that other material besides ice might finally be detected within the rings." "The main rings show a neutral color, while the C ring is reddish, and the D and E rings are quite blue," added Nicholson. "We don't quite understand if these variations are due to differences in particle size or composition, but it's nice to be surprised every once in a while." The latest Cassini findings are being presented today at the Division for Planetary Sciences Meeting of the American Astronomical Society held in Pasadena, Calif. Images to support this release, including an infrared mosaic and visible light mosaic of Saturn, can be found at http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org . 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. 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.Contacts: Carolina Martinez 818-354-9382 Jet Propulsion Laboratory, Pasadena, Calif. Dwayne Brown/Erica Hupp 202-358-1726/1237 NASA Headquarters, Washington NEWS RELEASE: 2006-126Source: NASA/JPL - Cassini - Press Release Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted October 11, 2006 Author #19 Share Posted October 11, 2006 Saturn's Rings Show Evidence of a Modern-day Collision October 11, 2006 (Source: Jet Propulsion Laboratory) Scientists with NASA's Cassini mission have spied a new, continuously changing feature that provides circumstantial evidence that a comet or asteroid recently collided with Saturn's innermost ring, the faint D ring.Saturn's D ring -- the innermost of the planet's rings -- sports an intriguing structure that appears to be a wavy, or "vertically corrugated," spiral. Imaging scientists see a structure in the outer part of the D ring that looks like a series of bright ringlets with a regularly spaced interval of about 30 kilometers (19 miles). An observation made by NASA's Hubble Space Telescope in 1995 also saw a periodic structure in the outer D ring, but its interval was then 60 kilometers (37 miles). Unlike many features in the ring system that have not changed over the last few decades, the interval of this pattern has been decreasing over time. These findings are being presented today at the Division for Planetary Sciences Meeting of the American Astronomical Society held in Pasadena, Calif. Images are available at http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org . "This structure in the D ring reminds us that Saturn's rings are not eternal, but instead are active, dynamical systems, which can change and evolve," said Dr. Matt Hedman, Cassini imaging team associate at Cornell University, Ithaca, N.Y. A vertical corrugation in Saturn's almost transparent D ring can give rise to brightness variations. When Cassini researchers viewed the D ring along a line of sight nearly parallel to the ringplane, they observed a pattern of brightness reversals: a part of the ring that appears bright on the far side of the rings appeared dark on the near side of the rings, and vice versa. This phenomenon would occur if the region contains a sheet of fine material that is vertically corrugated, like a tin roof. In this case, variations in brightness would correspond to changing slopes in the rippled ring material. Both the changes over time and the "corrugated" structure of this region could be explained by a collision of a comet or meteoroid into the D ring, which then kicked out a cloud of fine particles. This cloud might have inherited some of the tilt of the colliding object's path as it slammed into the rings. An alternate explanation could be that the object struck an already inclined moonlet, shattering it to bits and leaving its debris in an inclined orbit. In either case, the researchers speculate the aftermath of such a collision would be a ring slightly tilted relative to Saturn's equatorial plane. Over a period of time, as the inclined orbits of the ring particles evolve, this flat sheet of material would become a corrugated spiral that appears to wind up like a spring over time, which is what was observed. Based on observations between 1995 and 2006, scientists reconstructed a timeline and estimated that the collision occurred in 1984. 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. 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.Contacts: Carolina Martinez (818) 354-9382 Jet Propulsion Laboratory, Pasadena, Calif. Preston Dyches (720) 974-5859 Cassini Imaging Central Laboratory for Operations Space Science Institute, Boulder, Colo. NEWS RELEASE: 2006-127Source: NASA/JPL - Cassini - Press Release Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted October 11, 2006 Author #20 Share Posted October 11, 2006 Saturn's Rings in Infrared October 11, 2006 This mosaic of Saturn's rings was acquired by Cassini's visual and infrared mapping spectrometer instrument on Sept. 15, 2006, while the spacecraft was in the shadow of the planet looking back towards the rings from a distance of 2.16 million kilometers (1.34 million miles). Data at wavelengths of 1.0 micron, 1.75 micron and 3.6 microns were combined in the blue, green and red channels to make the pseudo-color image shown here. The brightest feature in the mosaic is the F ring, located at the outer edge of the main rings. The F ring is overexposed and appears white in this image. Of the main A, B and C rings; the C ring is the most prominent and reddish in color, becoming saturated close to the sun. The more opaque A and B rings are muddy in color and very dark in this geometry. By contrast, the normally faint D ring, located just interior to the C ring, is quite bright and blue, indicating the presence of very small ring particles. Similarly, a narrow, green ringlet in the Cassini Division, as well as the greenish G ring and blue E ring -- located at increasing distances outside the F ring -- are predominantly composed of small particles. The faint reddish band immediately outside the F ring is likely to be an artifact caused by the extremely bright F ring. 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 visual and infrared mapping spectrometer team homepage is at http://wwwvims.lpl.arizona.edu. Credit: NASA/JPL/University of Arizona Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted October 11, 2006 Author #21 Share Posted October 11, 2006 A Twisted Tale October 11, 2006 Saturn's D ring--the innermost of the planet's rings--sports an intriguing structure that appears to be a wavy, or "vertically corrugated," spiral. This continuously changing ring structure provides circumstantial evidence for a possible recent collision event in the rings. Support for this idea comes from the appearance of a structure in the outer D-ring that looks, upon close examination, like a series of bright ringlets with a regularly spaced interval of about 30 kilometers (19 miles). When viewed along a line of sight nearly in the ringplane, a pattern of brightness reversals is observed: a part of the ring that appears bright on the far side of the rings appears dark on the near side of the rings, and vice versa (see D Ring Sight Lines). This phenomenon would occur if the region contains a sheet of fine material that is vertically corrugated, like a tin roof. In this case, variations in brightness would correspond to changing slopes in the rippled ring material (see image with inset graphic). An observation made with NASA's Hubble Space Telescope in 1995 also saw a periodic structure in the outer D ring, but its wavelength was then 60 kilometers (37 miles). There were insufficient observations to discern the spiral nature of the feature. Thus, it appears the wavelength of the wavy structure has been decreasing: that is, this feature has been winding up like a spring over time. The rate at which the pattern appears to be winding up is quite close to the rate scientists would expect for a vertically corrugated spiraling sheet of material at this location in the rings that is responding to gravitational forcing from Saturn. As Cassini imaging scientists extrapolated the spiraling trend backward in time, they found that it completely unwound in 1984, leaving only an inclined, or tilted, sheet of material. The researchers speculate such an inclined sheet may have been produced around that time by the impact of a comet or meteoroid into the D ring which kicked out a cloud of fine particles that ultimately inherited some of the tilt of the impactor's trajectory as it slammed into the rings. Another possibility is that the impactor struck an already inclined moonlet, shattered it to bits and the debris remained in an inclined orbit. 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted October 11, 2006 Author #22 Share Posted October 11, 2006 A Twisted Tale (with inset graphic) October 11, 2006 Saturn's D ring--the innermost of the planet's rings--sports an intriguing structure that appears to be a wavy, or "vertically corrugated," spiral. This continuously changing ring structure provides circumstantial evidence for a possible recent collision event in the rings. Support for this idea comes from the appearance of a structure in the outer D-ring that looks, upon close examination, like a series of bright ringlets with a regularly spaced interval of about 30 kilometers (19 miles). When viewed along a line of sight nearly in the ringplane, a pattern of brightness reversals is observed: a part of the ring that appears bright on the far side of the rings appears dark on the near side of the rings, and vice versa (see D Ring Sight Lines). This phenomenon would occur if the region contains a sheet of fine material that is vertically corrugated, like a tin roof. In this case, variations in brightness would correspond to changing slopes in the rippled ring material. An observation made with NASA's Hubble Space Telescope in 1995 also saw a periodic structure in the outer D ring, but its wavelength was then 60 kilometers (37 miles). There were insufficient observations to discern the spiral nature of the feature. Thus, it appears the wavelength of the wavy structure has been decreasing: that is, this feature has been winding up like a spring over time. The rate at which the pattern appears to be winding up is quite close to the rate scientists would expect for a vertically corrugated spiraling sheet of material at this location in the rings that is responding to gravitational forcing from Saturn. As Cassini imaging scientists extrapolated the spiraling trend backward in time, they found that it completely unwound in 1984, leaving only an inclined, or tilted, sheet of material. The researchers speculate such an inclined sheet may have been produced around that time by the impact of a comet or meteoroid into the D ring which kicked out a cloud of fine particles that ultimately inherited some of the tilt of the impactor's trajectory as it slammed into the rings. Another possibility is that the impactor struck an already inclined moonlet, shattered it to bits and the debris remained in an inclined orbit. 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted October 11, 2006 Author #23 Share Posted October 11, 2006 D Ring Sight Lines October 11, 2006 Saturn's D ring--the innermost of the planet's rings--sports an intriguing structure that A vertical corrugation in Saturn's almost transparent D ring can give rise to brightness variations. In this graphic representation, the diagonal lines (or arrows) correspond to lines of sight through the corrugated ring. The grayscale plot along the bottom shows the ring's total optical depth (a measure of opacity) and brightness as seen by the observer. See A Twisted Tale for more details about the vertically corrugated structure in Saturn's D ring. 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted October 11, 2006 Author #24 Share Posted October 11, 2006 Rounding the Corner October 11, 2006 + View Movie A movie sequence of Saturn's G ring over a full orbital revolution captures its single bright arc on the ring's inner edge. The movie is composed of 70 individual narrow-angle camera images taken during a period of just over 20 hours while Cassini stared at the ring. The orbital period for particles in the center of the G ring is about 19.6 hours. At the beginning of the sequence, the ring arc, a site of concentrated ring particles, is seen rounding the ring edge. The arc orbits at a distance of 167,496 kilometers (104,080 miles). It is about 180 kilometers (110 miles) wide in radius and subtends about 30 degrees of orbital longitude. The classical position of the G ring is about 172,600 kilometers (107,250 miles) from Saturn, and the arc blends smoothly into this region. Scientists suspect that bodies trapped in this remarkably bright feature may be the source of the G ring material, driven outward from the arc by electromagnetic forces in the Saturn system. The arc itself is likely held in place by gravitational resonances with Mimas of the type that anchor the famed arcs in Neptune's rings. There is an obvious narrow dark gap in the G ring beyond the arc. This feature is close to yet another resonance with Mimas, but no arcs are present at this locale. This view looks toward the unlit side of the rings from about 10 degrees above the ringplane. Imaging artifacts jitter within the scene, a result of the high phase angle and faintness of the G ring. Stars slide across the background from upper left to lower right. The images in this movie were taken on Sept. 19 and 20 at a distance of approximately 2.1 to 2.2 million kilometers (1.3 to 1.4 million miles) from Saturn and at a Sun-G ring-spacecraft, or phase, angle that ranged from 167 to 164 degrees. Image scale is about 13 kilometers (8 miles) per pixel in the radial (outward from Saturn) direction. 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted October 11, 2006 Author #25 Share Posted October 11, 2006 Moon-Made Rings October 11, 2006 This view, acquired with the sun almost directly behind Saturn, reveals a previously unknown faint ring of material coincident with the orbit of the small moon Pallene. Another new, diffuse ring seen here was previously announced (see The Janus/Epimetheus Ring), and is coincident with the orbits of Saturn's moons Janus and Epimetheus. This viewing geometry makes microscopic, icy ring particles brighten substantially. Cassini spent nearly 12 hours in Saturn's shadow on Sept. 15, 2006, making observations like this one. The new Pallene ring is a faint narrow band, about 2,500 kilometers (about 1,550 miles) across, between the E ring and the G ring. The Janus/Epimetheus ring is visible between the G ring and the bright main rings and is about 5,000 kilometer (3,100 miles) wide. A labeled version of this view shows the locations of these features. Pallene, discovered by Cassini's imaging cameras earlier in the mission, is 4 kilometers (2.5 miles) across. Pallene orbits Saturn between the moons Mimas and Enceladus. The bright dot in the Pallene ring is not the tiny moon, but rather is a background star. While it is not unexpected that impact events on Janus, Epimetheus, and Pallene might kick particles off the moons' surfaces and inject them into Saturn orbit, it is, however, surprising that these structures are so well-defined. The view looks down from about 15 degrees above the dark side of the rings. Some faint spokes can also be spotted in the main rings, made visible by sunlight diffusing through the B ring. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Sept. 15, 2006, at a distance of approximately 2.2 million kilometers (1.3 million miles) from Saturn and at a Sun-Saturn-spacecraft angle of almost 179 degrees. Image scale is approximately 250 kilometers (155 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 Source: NASA/JPL - Cassini Link to comment Share on other sites More sharing options...
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