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As it arrived at Jupiter on
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| Description |
As it arrived at Jupiter on December 7, 1995, NASA's Galileo orbiter received a stream of data transmissions -- represented by the blue dots in this artist's depiction -- from the atmospheric probe that was descending through Jupiter's clouds. The orbiter had released the probe five months earlier. The wok-shaped probe sent information to the orbiter for 57.6 minutes as it dropped about 200 kilometers (125 miles) through the atmosphere, before succumbing to atmospheric pressure about 23 times greater than the average at Earth's sea level. The probe returned data about sunlight, heat flux, pressure, temperature, winds, lightning and atmospheric composition. About one hour after the end of the probe's transmissions, the orbiter fired its main engine to brake into orbit around Jupiter. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. |
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Stardust Trajectory
Stardust, a spacecraft desig
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11/22/95
| Date |
11/22/95 |
| Description |
Stardust, a spacecraft designed to gather samples of dust spewed from a comet and return the dust to Earth for detailed analysis, has been selected to become the fourth flight mission in NASA's Discovery program. The spacecraft, to be launched in February 1999, will also gather and return samples of interstellar dust encountered during its trip through the solar system to fly by Comet Wild-2 in January 2004. Comet Wild-2 is a "fresh comet" because its orbit was deflected from much farther out in the solar system by the gravitational attraction of Jupiter in 1974. Stardust will approach as close as 100 kilometers (62 miles) to the comet's nucleus, capturing cometary samples with an unusual material called aerogel. A return capsule carrying the captured dust samples would parachute to Earth in a landing on a dry Utah lake bed in January 2006. Stardust will also carry an optical camera that should return cometary images with 10 times the clarity of those taken of Halley's Comet by previous space missions. A mass spectrometer provided by Germany also will perform compositional analysis of the samples while in-flight. The Stardust mission team will be led by Principal Investigator Dr. Donald Brownlee of the University of Washington in Seattle, with Lockheed-Martin Astronautics, Denver, as the contractor building the spacecraft. NASA's Jet Propulsion Laboratory, Pasadena, CA, will manage the project for NASA's Office of Space Science, Washington, D.C. ##### |
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The Saturn-bound Cassini spa
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8/16/99
| Date |
8/16/99 |
| Description |
The Saturn-bound Cassini spacecraft will fly past the Earth Tuesday, August 17, at 8:28 p.m. Pacific Daylight Time (August 18 at 03:28 Universal Time). Launched in October 1997, Cassini will gain a boost in speed during its Earth flyby, which occurs at an altitude of 1,166 kilometers (725 miles) over the eastern South Pacific at -23.5 degrees latitude and 231.5 degrees longitude. Two successful flybys of Venus, next week's flyby of Earth, and a flyby of Jupiter in December 2000 all give Cassini the additional speed it needs to reach Saturn in 2004. Cassini is a joint endeavor of NASA, the European Space Agency and the Italian Space Agency, and is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory (JPL). JPL is a division of the California Institute of Technology, Pasadena, Calif. [Image for NASA-JPL was created by John Aiello of JPL.] |
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Jupiter Eye to Io
This image taken by NASA's C
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12/11/00
| Date |
12/11/00 |
| Description |
This image taken by NASA's Cassini spacecraft on Dec. 1, 2000, shows details of Jupiter's Great Red Spot and other features that were not visible in images taken earlier, when Cassini was farther from Jupiter. The picture is a color composite, with enhanced contrast, taken from a distance of 28.6 million kilometers (17.8 million miles). It has a resolution of 170 kilometers (106 miles) per pixel. Jupiter's closest large moon, Io, is visible at left. The edges of the Red Spot are cloudier with ammonia haze than the spot's center is. The filamentary structure in the center appears to spiral outward toward the edge. NASA's Galileo spacecraft has previously observed the outer edges of the Red Spot to be rotating rapidly counterclockwise, while the inner portion was rotating weakly in the opposite direction. Whether the same is true now will be answered as Cassini gets closer to Jupiter and interior cloud features become sharper. Cassini will make its closest approach to Jupiter, at a distance of about 10 million kilometers (6 million miles), on Dec. 30, 2000. The Red Spot region has changed in one notable way over the years: In images from NASA's Voyager and Galileo spacecraft, the area surrounding the Red Spot is dark, indicating relatively cloud-free conditions. Now, some bright white ammonia clouds have filled in the clearings. This appears to be part of a general brightening of Jupiter's cloud features during the past two decades. Jupiter has four large moons and an array of tiny ones. In this picture, Io is visible. The white and reddish colors on Io's surface are due to the presence of different sulfurous materials while the black areas are due to silicate rocks. Like the other large moons, Io always keeps the same hemisphere facing Jupiter, called the sub-Jupiter hemisphere. The opposite side, much of which we see here, is the anti-Jupiter hemisphere. Io has more than 100 active volcanoes spewing very hot lava and giant plumes of gas and dust. Its biggest plume, Pele, is near the bottom left edge of Io's disk as seen here. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona # # # # # |
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High Latitude Mottling on Ju
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The familiar banded appearan
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12/18/00
| Date |
12/18/00 |
| Description |
The familiar banded appearance of Jupiter at low and middle latitudes gradually gives way to a more mottled appearance at high latitudes in this striking true color image taken Dec. 13, 2000, by NASA's Cassini spacecraft. The intricate structures seen in the polar region are clouds of different chemical composition, height and thickness. Clouds are organized by winds, and the mottled appearance in the polar regions suggests more vortex-type motion and winds of less vigor at higher latitudes. The cause of this difference is not understood. One possible contributor is that the horizontal component of the Coriolis force, which arises from the planet's rotation and is responsible for curving the trajectories of ocean currents and winds on Earth, has its greatest effect at high latitudes and vanishes at the equator. This tends to create small, intense vortices at high latitudes on Jupiter. Another possibility may lie in that fact that Jupiter overall emits nearly as much of its own heat as it absorbs from the Sun, and this internal heat flux is very likely greater at the poles. This condition could lead to enhanced convection at the poles and more vortex-type structures. Further analysis of Cassini images, including analysis of sequences taken over a span of time, should help us understand the cause of equator-to-pole differences in cloud organization and evolution. By the time this picture was taken, Cassini had reached close enough to Jupiter to allow the spacecraft to return images with more detail than what's possible with the planetary camera on NASA's Earth-orbiting Hubble Space Telescope. The resolution here is 114 kilometers (71 miles) per pixel. This contrast- enhanced, edge-sharpened frame was composited from images take at different wavelengths with Cassini's narrow-angle camera, from a distance of 19 million kilometers (11.8 million miles). The spacecraft was in almost a direct line between the Sun and Jupiter, so the solar illumination on Jupiter is almost full phase. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona # # # # # |
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Io in Front of Jupiter
Jupiter's four largest satel
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12/20/00
| Date |
12/20/00 |
| Description |
Jupiter's four largest satellites, including Io, the golden ornament in front of Jupiter in this image from NASA's Cassini spacecraft, have fascinated Earthlings ever since Galileo Galilei discovered them in 1610 in one of his first astronomical uses of the telescope. Images from Cassini that will be released over the next several days capture each of the four Galilean satellites in their orbits around the giant planet. This true-color composite frame, made from narrow angle images taken on Dec. 12, 2000, captures Io and its shadow in transit against the disk of Jupiter. The distance of the spacecraft from Jupiter was 19.5 million kilometers (12.1 million miles). The image scale is 117 kilometers (73 miles) per pixel. The entire body of Io, about the size of Earth's Moon, is periodically flexed as it speeds around Jupiter and feels, as a result of its non-circular orbit, the periodically changing gravitational pull of the planet. The heat arising in Io's interior from this continual flexure makes it the most volcanically active body in the solar system, with more than 100 active volcanoes. The white and reddish colors on its surface are due to the presence of different sulfurous materials. The black areas are silicate rocks. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona # # # # # |
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Europa, Callisto and Jupiter
One moment in an ancient, or
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12/21/00
| Date |
12/21/00 |
| Description |
One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet. The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image. Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters. Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both Callisto and Europa. Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different, when Cassini finally reaches its destination in 2004. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona ##### |
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Still from Planetwide Movie
This single frame from a col
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12/27/00
| Date |
12/27/00 |
| Description |
This single frame from a color movie of Jupiter from NASA's Cassini spacecraft shows what it would look like to unpeel the entire globe of Jupiter, stretch it out on a wall into the form of a rectangular map. The image is a color cylindrical projection of the complete circumference of Jupiter, from 60 degrees south to 60 degrees north. It was produced from six images taken by Cassini's narrow- band camera on Oct. 31, 2000, in each of three filters: red, green and blue. The smallest visible features at the equator are about 600 kilometers (about 370 miles) across. In a map of this type, the most extreme northern and southern latitudes are unnaturally stretched out. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona # # # # # |
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The Main Ring of Jupiter (cl
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The ring system of Jupiter w
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1/17/97
| Date |
1/17/97 |
| Description |
The ring system of Jupiter was imaged by the Galileo spacecraft on November 9, 1996. In this image the west ansa of Jupiter's main ring is seen at a resolution of 24 kilometers per pixel. The ring clearly shows radial structure that had only been hinted at in the Voyager images. The plot of the brightness of ring as a function of location, going from the inner-most edge of the image to the outer-most through the thickest part of the ring, shows the "dips" in brightness due to perturbations from satellites. Two small satellites, Adrastea and Metis, which are not seen in this image, orbit through the outer portion of the ansa, their location relative to these radial features will be available after further data analysis. The ring's faint halo is seen to arise in the inner main ring just as it fades. Although most of Jupiter's ring is composed of small grains that should be highly perturbed by the strong Jovian magnetosphere, the ring's brightness drops abruptly at the outer edge. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo ##### |
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This is a composite of two i
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1/17/97
| Date |
1/17/97 |
| Description |
This is a composite of two images of Jupiter's icy moon Europa obtained from a range of 2119 miles (3410 kilometers) by the Galileo spacecraft during its fourth orbit around Jupiter and its first close pass of Europa. The mosaic spans 11 miles by 30 miles (17 km by 49 km) and shows features as small as 230 feet (70 meters) across. This mosaic is the first very high resolution image data obtained of Europa, and has a resolution more than 50 times better than the best Voyager coverage and 500 times better than Voyager coverage in this area. The mosaic shows the surface of Europa to be structurally complex. The sun illuminates the scene from the right, revealing complex overlapping ridges and fractures in the upper and lower portions of the mosaic, and rugged, more chaotic terrain in the center. Lateral faulting is revealed where ridges show offsets along their lengths (upper left of the picture). Missing ridge segments indicate obliteration of pre-existing materials and emplacement of new terrain (center of the mosaic). Only a small number of impact craters can be seen, indicating the surface is not geologically ancient. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo ##### |
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This image of Europa, an icy
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1/17/97
| Date |
1/17/97 |
| Description |
This image of Europa, an icy satellite of Jupiter, was obtained from a range of 39028 miles (62089 kilometers) by the Galileo spacecraft during its fourth orbit around Jupiter and its first close pass of Europa. The image spans an area 78 miles by 244 miles (126 km by 393 km), and shows features as small as a mile (1.6 km) across. Sun illumination is from the right, revealing several ridges crossing the scene, plateaus commonly several miles (10 km) across, and patches of smooth, low-lying darker materials. No prominent impact craters are visible, indicating the surface in this location is not geologically ancient. Some ridges have gaps, and subtle textural differences in these areas indicate that missing ridge segments probably were swept away by volcanic flows. The flow deposits are probably composed mainly of water ice, the chief constituent of the surface of Europa. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo ##### |
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Ridges on Europa
This is the highest resoluti
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1/17/97
| Date |
1/17/97 |
| Description |
This is the highest resolution picture ever taken of the Jupiter moon, Europa. The area shown is about 5.9 by 9.9 miles (9.6 by 16 kilometers) and the smallest visible feature is about the size of a football field. In this view, the ice-rich surface has been broken into a complex pattern by cross-cutting ridges and grooves resulting from tectonic processes. Sinuous rille- like features and knobby terrain could result from surface modifications of unknown origins. Small craters of possible impact origin range in size from less than 330 feet (100 meters) to about 1300 feet (400 meters) across are visible. This image was taken by the solid state imaging television camera aboard the Galileo during its fourth orbit around Jupiter, at adistance of 2060 miles (3340 kilometers). The picture is centered at 325 degrees West, 5.83 degrees North. North is toward the top of this image, with the sun shining from the right. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL ##### |
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This image of Europa, an icy
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1/17/97
| Date |
1/17/97 |
| Description |
This image of Europa, an icy satellite of Jupiter about the size of the Earth's Moon, was obtained from a range of 7415 miles (11933 kilometers) by the Galileo spacecraft during its fourth orbit around Jupiter and its first close pass of Europa. The image spans 30 miles by 57 miles (48 km by 91 km) and shows features as small as 800 feet (240 meters) across. The large circular feature centered in the upper middle of the image is called a macula, and could be the scar of a large meteorite impact. The surface of Europa is composed mostly of water ice, so large impact craters on Europa could look different from large bowl-shaped depressions formed by impact into rock, such as on the Moon. On Europa's icy surface, the original impact crater has been modified into a central zone of rugged topography surrounded by circular fractures which reflect adjustments to stress in the surrounding icy crust. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo ##### |
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This image of Jupiter's sate
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1/17/97
| Date |
1/17/97 |
| Description |
This image of Jupiter's satellite Europa was obtained from a range of 7364 miles (11851 km) by the Galileo spacecraft during its fourth orbit around Jupiter and its first close pass of Europa. The image spans 30 miles by 57 miles (48 km x 91 km) and shows features as small as 800 feet (240 meters) across, a resolution more than 150 times better than the best Voyager coverage of this area. The sun illuminates the scene from the right. The large circular feature in the upper left of the image could be the scar of a large meteorite impact. Clusters of small craters seen in the right of the image may mark sites where debris thrown from this impact fell back to the surface. Prominent doublet ridges over a mile (1.6 km) wide cross the plains in the right part of the image, younger ridges overlap older ones, allowing the sequence of formation to be determined. Gaps in ridges indicate areas where emplacement of new surface material has obliterated pre-existing terrain. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo ##### |
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Sulfuric Acid on Europa
Frozen sulfuric acid on Jupi
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9/1/99
| Date |
9/1/99 |
| Description |
Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain. This image is based on data gathered by Galileo's near infrared mapping spectrometer. Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks. Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA. ##### |
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Aurora Borealis on Jupiter
This image, taken by NASA's
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2/10/97
| Date |
2/10/97 |
| Description |
This image, taken by NASA's Galileo spacecraft, shows the dark side of Jupiter, the part not illuminated by sunlight. The curved line crossing from the lower left to the upper right is the auroral arc on the horizon. With north at the top of the image, the central part of the auroral arc has a latitude of 57 degrees north. When this same region was imaged 30 seconds later, the central part had changed. The left and right boxes below show a magnified view of the central region at the earlier and later times, respectively. The aurora is dynamic on Jupiter, just as it is here on Earth. The eerie, glowing light is created when molecules in the upper atmosphere are struck by charge particles from the space around Jupiter. Fluctuations in the charged particle flow cause variations in the auroral emission. This image was part of a multi-instrument set of observations made as Galileo flew through a region of space rich in charged particles. The particles follow the magnetic field and, in this case, the spacecraft was flying through the particular field line that was imaged. With these observations, scientists hope to learn more about the particles and their interaction with the molecules in the atmosphere. This image provides a severe test of the camera optics. The overexposed region at the lower right is the illuminated part of the planet, which is much brighter than the aurora. When light from this region is scattered into the telescope, it creates a diffuse background. The long exposure subjects the detector to more cosmic rays than usual. These create spikes, the bright dots that are sprinkled throughout the image. These images were taken in the clear filter of the solid state imaging (CCD) system aboard the Galileo spacecraft on Nov. 5, 1996. Each pixel subtends a square about 30 kilometers (18.5 miles) throughout the image. The range is 1.433 million kilometers (0.89 million miles). Launched in October 1989, Galileo entered orbit around Jupiter on Dec. 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and its magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are on the Galileo mission home page on the World Wide Web at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo. ##### |
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Eyeing Ganymede
Jupiter casts a baleful eye
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12/5/00
| Date |
12/5/00 |
| Description |
Jupiter casts a baleful eye toward the moon Ganymede in this enhanced-contrast image from NASA's Cassini spacecraft. Jupiter's `eye', the Great Red Spot, was captured just before disappearing around the eastern edge of the planet. The furrowed eyebrow above and to the left of the spot is a turbulent wake region caused by westward flow that has been deflected to the north and around the Red Spot. The smallest features visible are about 240 kilometers (150 miles) across. Within the band south of the Red Spot are a trio of white ovals, high pressure counterclockwise-rotating regions that are dynamically similar to the Red Spot. The dark filamentary features interspersed between white ovals are probably cyclonic circulations and, unlike the ovals, are rotating clockwise. Jupiter's equatorial zone stretching across the planet north of the Spot appears bright white, with gigantic plume clouds spreading out from the equator both to the northeast and to the southeast in a chevron pattern. This zone looks distinctly different than it did during the Voyager flyby 21 years ago. Then, its color was predominantly brown and the only white plumes conspicuous against the darker material beneath them were oriented southwest-to-northeast. Ganymede is Jupiter's largest moon, about 50 percent larger than our own Moon and larger than the planet Mercury. The visible details in this image are different geological terrains. Dark areas tend to be older and heavily cratered, brighter areas are younger and less cratered. Cassini images of Ganymede and Jupiter's other large moons taken near closest approach on Dec. 30 will have resolutions about four times better than that seen here. This image is a color composite of ones taken with different filters by Cassini's narrow-angle camera on Nov. 18, 2000, processed to enhance contrast. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona # # # # # |
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Callisto Crater Chain Mosaic
This mosaic of three images
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2/10/97
| Date |
2/10/97 |
| Description |
This mosaic of three images shows an area within the Valhalla region on Jupiter's moon, Callisto. North is to the top of the mosaic and the Sun illuminates the surface from the left. The smallest details that can be discerned in this picture are knobs and small impact craters about 160 meters (175 yards) across. The mosaic covers an area approximately 45 kilometers (28 miles) across. It shows part of a prominent crater chain located on the northern part of the Valhalla ring structure. Crater chains can form from the impact of material ejected from large impacts (forming secondary chains) or by the impact of a fragmented projectile, perhaps similar to the Shoemaker-Levy 9 cometary impacts into Jupiter in July 1994. It is believed this crater chain was formed by the impact of a fragmented projectile. The images which form this mosaic were obtained by the solid state imaging system aboard NASA's Galileo spacecraft on Nov. 4, 1996 (Universal Time). Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo. ##### |
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False Color Mosaic of Jupite
…
This false color mosaic show
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2/10/97
| Date |
2/10/97 |
| Description |
This false color mosaic shows a belt-zone boundary near Jupiter's equator. The images that make up the four quadrants of this mosaic were taken within a few minutes of each other. Light at each of Galileo's three near-infrared wavelengths is displayed here in the visible colors red, green and blue. Light at 886 nanometers, strongly absorbed by atmospheric methane and scattered from clouds high in the atmosphere, is shown in red. Light at 732 nanometers, moderately absorbed by atmospheric methane, is shown in green. Light at 757 nanometers, scattered mostly from Jupiter's lower visible cloud deck, is shown in blue. The lower cloud deck appears bluish white, while the higher layer appears pinkish. The holes in the upper layer and their relationships to features in the lower cloud deck can be studied in the lower half of the mosaic. Galileo is the first spacecraft to image different layers in Jupiter's atmosphere. The edge of the planet runs along the right side of the mosaic. North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 280 degrees west. The smallest resolved features are tens of kilometers in size. These images were taken on Nov. 5, 1996, at a range of 1.2 million kilometers by the solid state imaging (CCD) system aboard NASA's Galileo spacecraft. Launched in October 1989, Galileo entered orbit around Jupiter on Dec. 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo. ##### |
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Asgard Scarp Mosaic
Low-resolution color data we
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2/10/97
| Date |
2/10/97 |
| Description |
Low-resolution color data were combined with a higher resolution mosaic to produce this infrared composite image of a pair of ancient multi-ringed impact basins on Jupiter's moon, Callisto. The region imaged is on the leading hemisphere of Callisto near 26 degrees north, 142 degrees west, and is almost 1,400 kilometers (860 miles) across. North is toward the top of the picture and the Sun illuminates the surface from the east. Dominating the scene is the impact structure, Asgard, centered on the smooth, bright region near the middle of the picture and surrounded by concentric rings up to 1,700 kilometers (about 1,050 miles) in diameter. A second ringed structure with a diameter of about 500 kilometers (310 miles) can be seen to the north of Asgard, partially obscured by the more recent, bright- rayed crater, Burr. The icy materials excavated by the younger craters contrast sharply with the darker and redder coatings on older surfaces of Callisto. Launched in October 1989, Galileo entered orbit around Jupiter on Dec. 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo. ##### |
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Jupiter Equatorial Region
True and false color views o
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6/5/97
| Date |
6/5/97 |
| Description |
True and false color views of Jupiter from NASA's Galileo spacecraft show an equatorial 'hotspot' on Jupiter. These images cover an area 34,000 kilometers by 11,000 kilometers (about 21,100 by 6,800 miles). The top mosaic combines the violet and near infrared continuum filter images to create an image similar to how Jupiter would appear to human eyes. Differences in coloration are due to the composition and abundances of trace chemicals in Jupiter's atmosphere. The bottom mosaic uses Galileo's three near-infrared wavelengths displayed in red, green, and blue) to show variations in cloud height and thickness. Bluish clouds are high and thin, reddish clouds are low, and white clouds are high and thick. The dark blue hotspot in the center is a hole in the deep cloud with an overlying thin haze. The light blue region to the left is covered by a very high haze layer. The multicolored region to the right has overlapping cloud layers of different heights. Galileo is the first spacecraft to distinguish cloud layers on Jupiter. North is at the top. The mosaic covers latitudes 1 to 10 degrees and is centered at longitude 336 degrees west. The smallest resolved features are tens of kilometers in size. These images were taken on December 17, 1996, at a range of 1.5 million kilometers (about 930,000 miles) by the Solid State Imaging camera system aboard Galileo. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo ##### |
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OUTWARD BOUND VOYAGER--A Tit
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| Description |
OUTWARD BOUND VOYAGER--A Titan-Centaur launch vehicle hurls Voyager 1 from Cape Canaveral toward its rendezvous with Jupiter and Saturn. The launch took place at 5:56 a.m. (PDT) September 5, 1977. Voyager 1 followed Voyager 2 away from Earth, but by the time they reach Jupiter it will be four months ahead of Voyager 2. Voyager 1 will reach Saturn nine months ahead of Voyager 2. The Voyager project is managed by Caltech's Jet Propulsion Laboratory for NASA's Office of Space Science. |
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S-1 C & BW -62
Voyager 1 looked back at Sat
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12/4/80
| Date |
12/4/80 |
| Description |
Voyager 1 looked back at Saturn on Nov. 16, 1980, four days after the spacecraft flew past the planet, to observe the appearance of Saturn and its rings from this unique perspective. A few of the spokelike ring features discovered by Voyager appear in the rings as bright patches in this image, taken at a distance of 5.3 million kilometers (3.3 million miles) from the planet. Saturn's shadow falls upon the rings, and the bright Saturn crescent is seen through all but the densest portion of the rings. From Saturn, Voyager 1 is on a trajectory taking the spacecraft out of the ecliptic plane, away from the Sun and eventually out of the solar system (by about 1990). Although its mission to Jupiter and Saturn is nearly over (the Saturn encounter ends Dec. 18, 1980), Voyager 1 will be tracked by the Deep Space Network as far as possible in an effort to determine where the influence of the Sun ends and interstellar space begins. Voyager 1's flight path through interstellar space is in the direction of the constellation Ophiuchus. Voyager 2 will reach Saturn on August 25, 1981, and is targeted to encounter Uranus in 1986 and possibly Neptune in 1989. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California. ##### |
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Jupiter's Main Ring and Halo
The top and bottom panels sh
…
9/15/98
| Date |
9/15/98 |
| Description |
The top and bottom panels show a mosaic of images of Jupiter's rings taken by NASA's Galileo spacecraft. Jupiter is to the right of this mosaic, and different brightness scales accent different parts of the ring system. Jupiter's ring system has three parts -- a flat main ring, a halo inside the main ring shaped like a double-convex lens, and the gossamer ring outside the main ring. In the top view, a faint mist of particles is seen above and below the main rings. This vertically extended "halo" is unusual in planetary rings, and is caused by electromagnetic forces pushing the smallest grains, which carry electric charges, out of the ring plane. Jupiter's main ring is a thin sheet of material encircling the planet. The near and far arms of this ring extend horizontally across the mosaic, joining together at the ring's ansa, the portion visible on the sides of Jupiter, on the figure's far left side. In the bottom view, some radial structure is visible across the ring's ansa. The diffuse innermost boundary begins at approximately 122,500 kilometers (about 76,100 miles). The main ring's outer radius is at about 128,940 kilometers (80,120 miles), very close to the orbit of the Jovian moon Adrastea (128,980 kilometers or 80,140 miles). The brightness of the main ring drops markedly at about 127,850 kilometers (79,440 miles), very near the orbit of another moon, Metis, at 127,978 kilometers (79,521 miles). Jupiter's four small satellites-Metis, Adrastea, Amalthea and Thebe, affect the structure of the huge planet's tenuous rings. These images were taken through the clear filter of Galileo's onboard solid state imaging camera system on November 9, 1996. The resolution is approximately 24 kilometers (14 miles) per picture element along Jupiter's rings. Because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened vertically. The images were obtained when Galileo was in Jupiter's shadow, peering back toward the Sun, when the ring was approximately 2.3 million kilometers (1.4 million miles) away. The view of Earth's moon in the explanatory graphics was created from images returned by the Clementine lunar orbiter, launched in 1994 by NASA and the Ballistic Missile Defense Organization.) JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC. The images are posted on the Internet at http://photojournal.jpl.nasa.gov/ and at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at: http://www.jpl.nasa.gov/galileo/sepo . ##### 9/9/98 JP |
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Shapes of the Small Inner Sa
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The upper series of images r
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9/15/98
| Date |
9/15/98 |
| Description |
The upper series of images represents the best yet of the four small inner satellites of Jupiter taken by the camera on NASA's Galileo spacecraft. From left to right, in order of decreasing distance to Jupiter, are Thebe, Amalthea (the largest moon), Adrastea (the smallest), and Metis. The images represent the first time that the shapes of Adrastea and Metis have been resolved by a spacecraft camera. The views are presented at a common scale but were taken at somewhat different original resolutions, ranging from 5.4 kilometers (3.3 miles) per picture element for Amalthea, to 7.5 kilometers (4.6 miles) per picture element for Thebe and Metis. Individual craters, 35 to 90 kilometers (20 to 55 miles) across, are visible on Thebe and Amalthea. While no craters are visible on Adrastea and Metis in these images, the overall irregular shape of Metis indicates it has suffered major collisions. Jupiter is to the right. Viewing positions are slightly different from the views of the models in the bottom row, which depict the shapes of the small satellites viewed from the direction of satellite motion ("leading sides") and presented at a common scale. These shape models have been calculated from the outlines of the satellites and locations of shadows in individual images, as well as from stereoscopic images taken by the Galileo's camera during different orbits. The models emphasize the highly irregular shapes caused by a history of impacts by fragments of small asteroids and comets. Jupiter's strong gravitational pull on these objects at relatively close distances accelerates the objects to very high velocities, making such impacts very energetic. JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC. The images are posted on the Internet at http://photojournal.jpl.nasa.gov/ and at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at: http://www.jpl.nasa.gov/galileo/sepo . ##### 9/9/98 JP |
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Jupiter's Inner Satellites a
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This schematic cut-away view
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9/15/98
| Date |
9/15/98 |
| Description |
This schematic cut-away view of the components of Jupiter's ring system shows the geometry of the rings in relation to Jupiter and to the small inner satellites, which are the source of the dust that forms the rings. The innermost and thickest ring, shown in gray shading, is the halo that ends at the main ring. The thin, narrow main ring, shown with red shading, is bounded by the 16-kilometer-wide (10-miles) satellite Adrastea and shows a marked decrease in brightness near the orbit of Jupiter's innermost moon, Metis. It is composed of fine particles knocked off Adrastea and Metis. Although the orbits of Adrastea and Metis are about 1,000 kilometers (about 600 miles) apart, that separation is not depicted in this drawing. Impacts by small meteoroids (fragments of asteroids and comets) into these small, low- gravity satellites feed material into the rings. Thebe and Amalthea, the next two satellites in increasing distance from Jupiter, supply dust which forms the thicker, disk-like "gossamer" rings. The gossamer rings, depicted with yellow and green shading, are thicker because the source satellites orbit Jupiter on inclined paths These small satellites all orbit closer to Jupiter than the four largest "Galilean" satellites, Io, Europa, Ganymede and Callisto, which were discovered nearly 400 years ago. The orbital distances of the moons are drawn relative to the size of Jupiter. The Jupiter image was created from a map based on data obtained by the Hubble Space Telescope. JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC. The images are posted on the Internet at http://photojournal.jpl.nasa.gov/ and at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at: http://www.jpl.nasa.gov/galileo/sepo . ##### 9/10/98 JP |
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GLL/EM15
This mosaic picture of the M
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12/22/92
| Date |
12/22/92 |
| Description |
This mosaic picture of the Moon was compiled from 18 images taken with a green filter by Galileo's imaging system during the spacecraft's flyby on December 7, 1992, some 11 hours before its Earth flyby at 1509 UTC (7:09 a.m. Pacific Standard Time) December 8. The north polar region is near the top part of the mosaic, which also shows Mare Imbrium, the dark area on the left, Mare Serenitatis at center, and Mare Crisium, the circular dark area to the right. Bright crater rim and ray deposits are from Copernicus, an impact crater 96 kilometers (60 miles) in diameter. Computer processing has exaggerated the brightness of poorly illuminated features near the day/night terminator in the polar regions, giving a false impression of high reflectivity there. The digital image processing was done by DLR the German aerospace research establishment near Munich, an international collaborator in the Galileo mission. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. ##### |
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Jupiter's Main and Gossamer
…
The schematic structures of
…
9/15/98
| Date |
9/15/98 |
| Description |
The schematic structures of Jupiter's main and gossamer rings are depicted here. Scientists studying data from NASA's Galileo spacecraft have found that the ring system is made up of impact debris created when meteoroids, which are fragments of comets and asteroids, slam into Jupiter's four smallest satellites. The top panel shows that the main ring (red) is formed mostly from meteoroid impact debris kicked up from the innermost moons, Metis (m) and Adrastea (a). Since both satellites orbit in paths not inclined to Jupiter's equator, the main ring appears as a narrow line. The middle panel shows the additional effect of dust ejected from the satellite Amalthea (A), responsible for producing one of the two moon components of the gossamer ring. Amalthea's orbit is inclined to Jupiter's equatorial plane, and at different times the satellite's vertical position can range anywhere between the two extreme limits shown. Dust ejected from Amalthea (orange) produces a ring whose thickness equals Amalthea's vertical projections beyond Jupiter's equatorial plane. The lower panel shows the additional effect of dust ejected from Thebe (T), which makes up the second component (shown in green) of the gossamer ring. Again, the two positions shown represent the maximum projections of Thebe from Jupiter's equatorial plane. This component of the gossamer ring is thicker than the component due to Amalthea's dust because Thebe's orbit is more inclined than that of Amalthea. The Jupiter image was created from a map based on data obtained by the Hubble Space Telescope. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC. The images are posted on the Internet at http://photojournal.jpl.nasa.gov/ and at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at: http://www.jpl.nasa.gov/galileo/sepo . ##### 9/9/98 JP |
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GLL/EM16
This view looking down on th
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| Description |
This view looking down on the north pole of the Moon was assembled from 18 images taken with a green filter by Galileo's imaging system as the spacecraft flew by the Moon on December 7, 1992. The part of the moon visible from Earth is toward the left and includes the dark, lava-filled Imbrium basin, upper left, Mare Serenitatis, middle left, Mare Tranquillitatis, lower left, and Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii basins, lower right. The Humboldtianum Basin, a 650-kilometer (400-mile) impact structure partly filled with dark volcanic deposits, is visible in the middle of the image. The Moon's north pole is located just inside the shadow zone about a third of the way from the top left of the lighted region. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. ##### |
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GLL/EM17
This false-color mosaic was
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12/22/92
| Date |
12/22/92 |
| Description |
This false-color mosaic was constructed from a series of 53 images taken through three spectral filters by Galileo's imaging system as the spacecraft flew over the northern regions of the Moon on December 7, 1992. The part of the Moon vlsible from Earth is on the left side in this view. The color mosaic shows compositional variations in parts of the Moon's northern hemisphere. Bright pinkish areas are highlands materials, such as those surrounding the oval lava-filled Crisium impact basin toward the bottom of the picture. B1ue to orange shades indicate volcanic lava flows. To the left of Crisium, the dark blue Mare Tranquillitatis is richer in titanium than the green and orange maria above it. Thin mineral-rich soils associated with relatively recent impacts are represented by light blue colors, the youngest craters have prominent blue rays extending from them. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. ##### |
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This composite image shows t
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5/25/94
| Date |
5/25/94 |
| Description |
This composite image shows the asteroid 243 Ida as seen from the Galileo spacecraft during its approach on August 28, 1993. The six views were shuttered through the camera's green filter and show Ida's rotation over a period of about 3 hours 18 minutes. The asteroid makes a complete rotation every 4 hours 38 minutes, therefore, this set of images spans about 3/4 of Ida's rotation period and shows most of Ida's surface. By combining the information in these views with that from the highest resolution images returned from the spacecraft in September 1993, the size and shape of this irregular body can now be determined accurately The asteroid appears to be about 58 kilometers (36 miles) long and about 23 kilometers wide, with a very irregular shape and volume of some 16,000 cubic kilometers. The images are arranged in chronological order from a time 3 hours 51 minutes before closest approach (upper left), through upper right, middle left, middle right lower left and lower right (33 minutes before closest approach). The six images show ida at the same scale throughout. Ida's rotation axis is roughly vertical in these images, and the rotation causes the right-hand end of Ida to move toward the viewer as time progresses. The first image was taken from a range of about 171,000 km (106,000 miles) and provides an inage resolution of about 1,700 meters per pixel (the highest resolution achieved for Ida is about 25 meters per pixel). The second, taken 70 minutes later, is fromOn 119,000 kilometers, followed by 102,000 kilometers, 85,000 kilometers, 50,000 kilometers, and 25,000 kilometers. The features on Ida are less sharp in the earlier views because of the greater distances. Prominent in the middle three views is a deep depression across the short axis of the Asteroid. This feature tends to support the idea that Ida may have originally been formed from two or more separate large objects that collided softly and stuck together. Also visible in the lower left view is an apparent linear albedo or reflectance boundary. Color images yet to be returned from the Galileo spacecrart may help resolve the question of whether or not the two ends of Ida are made of different materials. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. |
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GALILEO
The Galileo imaging system c
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5/25/94
| Date |
5/25/94 |
| Description |
The Galileo imaging system captured this picture of the limb of the asteroid 243 Ida about 46 seconds after its closest approach on August 28, 1993, from a range of only 2480 kilometers. It is the highest-resolution image of an asteroid's surface ever captured and shows detail at a scale of about 25 meters per pixel. This image is one frame of a mosaic of 15 frames shuttered near Galileo's closest approach to Ida. Since the exact location of Ida in space was not well-known prior to the Galileo flyby, this mosaic was estimated to have only about a 50 percent chance of capturing Ida. Fortunately, this single frame did successfully image a part of the sunlit side of Ida. The area seen in this frame shows some of the same territory seen in a slightly lower resolution full-disk mosaic of Ida returned from the spacecraft in September, 1993, but from a different perspective. Prominent in this view is a 2-kilometer- deep "valley" seen in profile on the limb. This limb profile and the stereoscopic effect between this image and the full-disk mosaic will permit detailed refinement of Ida's shape in this region. This high-resolution view shows many small craters and some grooves on the surface of Ida, which give clues to understanding the history of this heavily impacted object. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory. ##### |
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GALILEO
This image is the most detai
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6/22/94
| Date |
6/22/94 |
| Description |
This image is the most detailed picture of the recently discovered natural satellite of asteroid 243 Ida taken by the Galileo Solid-State Imaging camera during its encounter with the asteroid on August 28, 1993. Shuttered through the camera's broadband clear filter as part of a 30-frame mosaic designed to image the asteroid itself, this frame fortuitously captured the previously unknown moon at a range of about 3,900 kilometers (2,400 miles), just over 4 minutes before the spacecraft's closest approach to Ida. Each picture element spans about 39 meters (125 feet) on the surface of the moon. More than a dozen craters larger than 80 meters (250 feet) in diameter are clearly evident, indicating that the moon has suffered numerous collisions from smaller Solar System debris during its history. The larger crater on the terminator is about 300 meters (1,000 feet) across. The satellite is approximately egg-shaped, measuring about 1.2 x 1.4 x 1.6 kilometers (0.75 x 0.87 x 1 mile). At the time this image was shuttered, Ida was about 90 kilometers (56 miles) away from the moon, outside this frame to the left and slightly below center. This image was relayed to Earth from Galileo on June 8, 1994. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory. ##### |
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Europa: Sea Salts or Battery
…
This composite image of the
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4/19/00
| Date |
4/19/00 |
| Description |
This composite image of the Jupiter-facing hemisphere of Europa was obtained on November 25, 1999 by two instruments onboard NASA's Galileo spacecraft. The global black-and-white view, by the spacecraft's camera, provides the highest resolution view ever obtained of this side of Europa. The superimposed false-color image, obtained by Galileo's near-infrared mapping spectrometer instrument, reveals the presence of materials with differing compositions on Europa's surface. In this image, blue areas represent the cleanest, brightest icy surfaces, while the reddest areas have the highest concentrations of darker, non-ice materials. The mixture of colors seen here is most likely the result of both variations in the ages and composition of surface materials. The dark materials are believed to fade with the passage of time. This area is highly unusual compared to many other areas on Europa because of its high concentration of fresh-appearing bright ridges and fractures. On other parts of Europa, the darker areas appear to be the most recently formed, but here the ridges and fractures appear to "overprint" the underlying darker mottled terrain. Scientists disagree about the chemical makeup of the dark materials, both sulfuric acid (common battery acid) and salty minerals, perhaps from a subsurface ocean, have been suggested. Analysis of images like this one may help to resolve this controversy. Surprisingly, either material could help to produce conditions below the surface that could be favorable to the formation of living organisms. The colored area is centered near the intersection of the equator and the Europan "prime meridian," where the longitude is assigned the value of 0 degrees. This is the sub-Jupiter point, where Jupiter always appears to be almost directly overhead. This phenomenon occurs because Europa takes the same period of time to rotate as it does to orbit around Jupiter (3.55 days). The area imaged in color is about 400 by 400 kilometers (250 by 250 miles), an area of about 160,000 square kilometers (about 62,000 square miles). The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology, Pasadena, CA. This image and other images and data received from Galileo are posted on the Galileo home page at http://galileo.jpl.nasa.gov . Background information and educational context for the images can be found at http://galileo.jpl.nasa.gov/images/io/ioimages.html . ##### |
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Galileo and Cassini Image: T
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Two Giant Plumes on Io ,Two
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3/29/01
| Date |
3/29/01 |
| Description |
Two Giant Plumes on Io ,Two tall volcanic plumes and the rings of red material they have deposited onto surrounding surface areas appear in images taken of Jupiter's moon Io by NASA's Galileo and Cassini spacecraft in late December 2000 and early January 2001. One plume, from the volcano Pele, shoots upward nearly 400 kilometers (250 miles) from the surface near Io's equator. The plume has been active for at least four years and, until now, had been far larger than any other plume seen on Io. The images also show a second plume about the same size, closer to Io's north pole. This plume had never been seen before. It is associated with a fresh eruption from the Tvashtar Catena volcanic area. The observations were made during joint studies of the Jupiter system while Cassini was passing Jupiter on its way to Saturn. Galileo passed closer to Io for higher-resolution images, and Cassini acquired images at ultraviolet wavelengths, better for detecting active volcanic plumes. The Cassini ultraviolet images, upper right, reveal two gigantic, actively erupting plumes of gas and dust. Near the equator, just the top of Pele's plume is visible where it projects into sunlight. None of it would be illuminated if it were less than 240 kilometers (150 miles) high. These images indicate a total height for Pele of 390 kilometers (242 miles). The Cassini image at far right shows a bright spot over Pele's vent. Although the Pele hot spot has a high temperature, silicate lava cannot be hot enough to explain a bright spot in the ultraviolet, so the origin of this bright spot is a mystery, but it may indicate that Pele was unusually active when the picture was taken. Also visible is a plume near Io's north pole. Although 15 active plumes over Io's equatorial regions have been detected in hundreds of images from NASA's Voyager and Galileo spacecraft, this is the first image ever acquired of an active plume over a polar region of Io. The plume projects about 150 kilometers (about 90 miles) over the limb, the edge of the globe. If it were erupting from a point on the limb, it would be only slightly larger than a typical Ionian plume, but the image does not reveal whether the source is actually at the limb or beyond it, out of view. A distinctive feature in Galileo images since 1997 has been a giant red ring of Pele plume deposits about 1,400 kilometers (870 miles) in diameter. The Pele ring is seen again in one of the new Galileo images, lower left. When the new Galileo images were returned this month, scientists were astonished to see a second giant red ring on Io, centered around Tvashtar Catena at 63 degrees north latitude. (To see a comparison from before the ring was deposited, see images PIA-01604 or PIA-02309.) Tvashtar was the site of an active curtain of high-temperature silicate lava imaged by Galileo in November 1999 and February 2000 (image PIA- 02584). The new ring shows that Tvashtar must be the vent for the north polar plume imaged by Cassini from the other side of Io. This means the plume is actually about 385 kilometers (239 miles) high, just like Pele. The uncertainty in estimating the height is about 30 kilometers (19 miles), so the plume could be anywhere from 355 to 415 kilometers (221 to 259 miles) high. If this new plume deposit is just one millimeter (four one- hundredths of an inch) thick, then the eruption produced more ash than the 1980 eruption of Mount St. Helens in Washington. NASA recently approved a third extension of the Galileo mission, including a pass over Io's north pole in August 2001. The spacecraft's trajectory will pass directly over Tvashtar at an altitude of 200 kilometers (124 miles). Will Galileo fly through an active plume? That depends on whether this eruption is long- lived like Pele or brief, and it also depends on how high the plume is next August. Two Pele-sized plumes are inferred to have erupted in 1979 during the four months between Voyager 1 and Voyager 2 flybys, as indicated by new Pele-sized rings in Voyager 2 images. Those eruptions, both from high-latitude locations, were shorter-lived than Pele, but their actual durations are unknown. In May, Galileo will get another, more distant look at Tvashtar. It has been said that Io is the heartbeat of the jovian magnetosphere. The two giant plumes evidenced in these images may have had significant effects on the types, density and distribution of neutral and charged particles in the Jupiter system during the joint observations of the system by Galileo and Cassini from November 2000 to March 2001. These Cassini images were acquired on Jan. 2, 2001, except for the frame at the far right, which was acquired a day earlier. The Galileo images were acquired on Dec. 30 and 31, 2000. Cassini was about 10 million kilometers (6 million miles) from Io, 10 times farther than Galileo. More information about the Cassini and Galileo joint observations of the Jupiter system is available online at http://www.jpl.nasa.gov/jupiterflyby . Cassini 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 Galileo and Cassini missions for NASA's Office of Space Science, Washington, D.C. |
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Jupiter's Great Red Spot in
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This true color image of Jup
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10/23/00
| Date |
10/23/00 |
| Description |
This true color image of Jupiter, taken by NASA's Cassini spacecraft, is composed of three images taken in the blue, green and red regions of the spectrum. All images were taken from a distance of 77.6 million kilometers (48.2 million miles) on Oct. 8, 2000. Different chemical compositions of the cloud particles lead to different colors. The cloud patterns reflect different physical conditions -- updrafts and downdrafts -- in which the clouds form. The bluish areas are believed to be regions devoid of clouds and covered by high haze. The Great Red Spot (below and to the right of center) is a giant atmospheric storm as wide as two Earths and over 300 years old, with peripheral winds of 483 kilometers per hour (300 miles per hour). This image shows that it is trailed to the north by a turbulent region, caused by atmospheric flow around the spot. The bright white spots in this region are lightning storms, which were seen by NASA's Galileo spacecraft when it photographed the night side of Jupiter. Cassini will track these lightning storms and measure their lifetimes and motions when it passes Jupiter in late December and looks back on the dark side of the planet. Cassini is currently en route to its ultimate destination, Saturn. The resolution is 466 kilometers (290 miles) per picture element. Cassini 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, Calif., manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona ##### |
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Jupiter in blue, ultraviolet
…
These three images of Jupite
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10/23/00
| Date |
10/23/00 |
| Description |
These three images of Jupiter, taken through the narrow angle camera of NASA's Cassini spacecraft from a distance of 77.6 million kilometers (48.2 million miles) on October 8, reveal more than is apparent to the naked eye through a telescope. The image on the left was taken through the blue filter. The one in the middle was taken in the ultraviolet. The one on the right was taken in the near infrared. The blue-light filter is within the part of the electromagnetic spectrum detectable by the human eye. The appearance of Jupiter in this image is, consequently, very familiar. The Great Red Spot (below and to the right of center) and the planet's well-known banded cloud lanes are obvious. The brighter bands of clouds are called zones and are probably composed of ammonia ice particles. The darker bands are called belts and are made dark by particles of unknown composition intermixed with the ammonia ice. Jupiter's appearance changes dramatically in the ultraviolet and near infrared images. These images are near negatives of each other and illustrate the way in which observations in different wavelength regions can reveal different physical regimes on the planet. All gases scatter sunlight efficiently at short wavelengths, this is why the sky appears blue on Earth. The effect is even more pronounced in the ultraviolet. The gases in Jupiter's atmosphere, above the clouds, are no different. They scatter strongly in the ultraviolet, making the deep banded cloud layers invisible in the middle image. Only the very high altitude haze appears dark against the bright background. The contrast is reversed in the near infrared, where methane gas, abundant on Jupiter but not on Earth, is strongly absorbing and therefore appears dark. Again the deep clouds are invisible, but now the high altitude haze appears relatively bright against the dark background. High altitude haze is seen over the poles and the equator. The Great Red Spot, prominent in all images, is obviously a feature whose influence extends high in the atmosphere. As the Cassini cameras continue to return images of Jupiter, it will be possible to construct a three-dimensional picture of how clouds form and evolve by watching the changing appearance of Jupiter in different spectral regions. JPL manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. JPl is a division of the California Institute of Technology in Pasadena. Credit: NASA/JPL/University of Arizona. ##### |
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Nine Frames as Jupiter Turns
This sequence of nine true-c
…
11/6/00
| Date |
11/6/00 |
| Description |
This sequence of nine true-color, narrow-angle images shows the varying appearance of Jupiter as it rotated through more than a complete 360-degree turn. The smallest features seen in this sequence are no bigger than about 380 kilometers (about 236 miles). Rotating more than twice as fast as Earth, Jupiter completes one rotation in about 10 hours. These images were taken on Oct. 22 and 23, 2000. From image to image (proceeding left to right across each row and then down to the next row), cloud features on Jupiter move from left to right before disappearing over the edge onto the nightside of the planet. The most obvious Jovian feature is the Great Red Spot, which can be seen moving onto the dayside in the third frame (below and to the left of the center of the planet). In the fourth frame, taken about 1 hour and 40 minutes later, the Great Red Spot has been carried by the planet's rotation to the east and does not appear again until the final frame, which was taken one complete rotation after the third frame. Unlike weather systems on Earth, which change markedly from day to day, large cloud systems in Jupiter's colder, thicker atmosphere are long-lived, so the two frames taken one rotation apart have a very similar appearance. However, when this sequence of images is eventually animated, strong winds blowing eastward at some latitudes and westward at other latitudes will be readily apparent. The results of such differential motions can be seen even in the still frames shown here. For example, the clouds of the Great Red Spot rotate counterclockwise. The strong westward winds northeast of the Great Red Spot are deflected around the spot and form a wake of turbulent clouds downstream (visible in the fourth image), just as a rock in a rapidly flowing river deflects the fluid around it. The equatorial zone on Jupiter is currently bright white, indicating the presence of clouds much like cirrus clouds on Earth, but made of ammonia instead of water ice. This is very different from Jupiter's appearance 20 years ago, when the equatorial zone was more of a brownish cast similar to the region just to its north. At the northern edge of the equatorial zone, local regions colored a dark grayish-blue are places where the ammonia clouds have cleared allowing a view to deeper levels in Jupiter's atmosphere. Interrupting these relatively clear regions is a series of bright arrow-shaped equatorial plumes. The most obvious one is visible just above and to the right of center in the third and ninth frames. These plumes resemble the `anvil' clouds that accompany common summer thunderstorms on Earth, although the Jovian plumes are much bigger, and their somewhat regular spacing around the planet suggests an association with a planetary-scale wave motion. The southwest-northeast tilt of these plumes suggests that the winds in this region act to help maintain the eastward winds at this latitude. In the dark belt north of the equatorial zone, a turbulent region with a white filamentary cloud is visible in the sixth frame, indicating rapidly changing wind direction. Several white ovals are visible at higher southern latitudes (toward the bottom of the fourth, fifth, and sixth frames, for example). These ovals, like the Great Red Spot, rotate counterclockwise and are similar in some respects to high-pressure systems on Earth. When these images were taken, Cassini was about 3.3 degrees above Jupiter's equatorial plane, and the Sun-Jupiter-spacecraft angle was about 20 degrees. JPL manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. JPl is a division of the California Institute of Technology in Pasadena. Credit: NASA/JPL/University of Arizona. ##### |
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Jupiter and Europa in Near I
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These two images, taken by N
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11/6/00
| Date |
11/6/00 |
| Description |
These two images, taken by NASA's Cassini spacecraft, show Jupiter in a near-infrared wavelength, and catch Europa, one of Jupiter's largest moons, at different phases. Cassini's narrow-angle camera took both images, the upper one from a distance of 69.9 million kilometers (43.4 million miles) on Oct. 17, 2000, and the lower one from a distance of 65.1 million kilometers (40.4 million miles) on Oct. 22, 2000. Both were taken at a wavelength of 727 nanometers, which is in the near-infrared region of the electromagnetic spectrum. The camera's 727-nanometer filter accepts only a narrow spectral range centered on a relatively strong absorption feature due to methane gas. In this spectral region, the amount of light reflected by Jupiter's clouds is only half that reflected in a nearby spectral region outside the methane band. The features that are brightest in these images are the highest and thickest clouds, such as the Great Red Spot and the band of clouds girding the equator, as these scatter sunlight back to space before it has a chance to be absorbed by the methane gas in the atmosphere. This stratigraphic effect can be seen even more prominently in an image released on Oct. 23, 2000, taken in the stronger methane band at 889 nanometers, in which the only bright features are the highest hazes over the equator, the poles and the Great Red Spot. By comparing images taken in the 727 nanometer filter with others taken at 889 nanometers and at a weaker methane band at 619 nanometers, researchers will probe the heights and thickness of clouds in Jupiter's atmosphere. Europa, a satellite of Jupiter about the size of Earth's Moon, is visible to the left of Jupiter in the upper image, and in front of the planet in the lower image. Another of Jupiter's Galilean satellites, Ganymede, which is larger than the planet Mercury, is to the right in the upper image, with brightness variations visible across its surface. In the upper image, Europa is caught entering Jupiter's shadow, and hence appears as a bright crescent, in the lower image, it is seen about one-and-a-half orbits later, in transit across the face of the planet. Because there is neither methane nor any strong absorber in this spectral region on the surface of Europa, it appears strikingly white and bright compared to Jupiter. Imaging observations of the moons Europa, Io and Ganymede entering and passing through Jupiter's shadow are planned for the two-week period surrounding Cassini's closest approach on Dec. 30, 2000. The purpose of these eclipse observations is to detect and measure the variability of emissions that arise from the interaction of the satellites' tenuous atmospheres with the charged particles trapped in Jupiter's magnetic field. At the times these images were taken, Cassini was about 3.3 degrees above Jupiter's equatorial plane, and the Sun-Jupiter- spacecraft angle was about 20 degrees. Cassini 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, Calif., manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona ##### |
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Still from Red Spot Movie
This image is one of seven f
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11/20/00
| Date |
11/20/00 |
| Description |
This image is one of seven from the narrow-angle camera on NASA's Cassini spacecraft assembled as a brief movie of cloud movements on Jupiter. It was taken with a blue filter. The smallest features visible are about 500 kilometers (about 300 miles) across. Small bright clouds appear suddenly to the west of the Great Red Spot. Based on data from NASA's Galileo spacecraft, scientists suspect that these small white features are lightning storms, where falling raindrops create an electrical charge. The lightning storms eventually merge with the Red Spot and surrounding jets, and may be the main energy source for these large-scale features. Imaging observations of the dark side of the planet in the weeks following Cassini's closest approach to Jupiter on Dec. 30, 2000 will search for lightning storms like these. This image was re-projected by cylindrical-map projection of an image taken in the first week of October 2000. It shows an area from 50 degrees north of Jupiter's equator to 50 degrees south, extending 100 degrees east-west, about one quarter of Jupiter's circumference. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona # # # # # |
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Galileo at Jupiter
This artist's rendering show
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7/11/95
| Date |
7/11/95 |
| Description |
This artist's rendering shows the Galileo orbiter arriving at Jupiter on Dec. 7, 1995. A few hours before arrival, the orbiter will have flown within about 1,000 kilometers (600 miles) of Jupiter's moon lo, shown as the crescent to the left of the spacecraft. The sun is visible between Io and the spacecraft, near the spacecraft's long magnetometer. Jupiter is to the right. A faint white streak above the planet's clouds shows the atmospheric probe beginning to decelerate before it deploys a parachute for its scientific mission to collect data as it descends into the atmosphere and relay that data to the orbiter. About an hour after the probe's mission is over, the orbiter will brake with its rocket engine to go into orbit around Jupiter for a two-year, 11-orbit study of Jupiter, its satellites and its magnetosphere. The Galileo mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C. The Galileo probe is managed by NASA's Ames Research Center, Moffett Field. Calif. |
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Jupiter Clouds, True Color a
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These two frames of composit
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1/23/01
| Date |
1/23/01 |
| Description |
These two frames of composited images taken by NASA's Cassini spacecraft show the same cloud patterns on Jupiter both in natural color (left) and in a false-color combination (right) selected to show differences in clouds' height. The white spots in the right frame are storms high in the atmosphere. Each frame is a combination of images taken by Cassini's narrow- angle camera through different filters on Dec. 31, 2000, one day after Cassini's closest approach to the planet. The smallest features are roughly 60 kilometers (40 miles) across. The left frame shows the colors Jupiter would have if seen by the naked eye. The right frame is composed of three images. Two were taken through filters centered on regions of the spectrum where the gaseous methane in Jupiter's atmosphere absorbs light, and the third was taken in a red continuum region of the spectrum, where Jupiter has no absorptions. The combination yields an image whose colors denote the height of the clouds. Red regions are deep water clouds, bright blue regions are high haze (like the blue covering the Great Red Spot). Small, bright white spots are energetic lightning storms that have risen to a height where there is no opportunity for absorption of light, so the clouds reflect all light equally. The darkest blue regions , such as the long linear regions bordering the northern part of the equatorial zone, are the very deep `hot spots' from which Jovian thermal emission is free to escape to space. This is the first time that global images of Jupiter in all the methane and appropriate continuum filters have been acquired by a spacecraft. From images like these, the dynamics of the layers within Jupiter's atmosphere will be determined. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona # # # # # |
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Io Above Clouds on New Year'
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The moon Io floats above the
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1/23/01
| Date |
1/23/01 |
| Description |
The moon Io floats above the cloudtops of Jupiter in this image captured by NASA's Cassini spacecraft on the dawn of the new millennium, Jan. 1, 2001, two days after Cassini's closest approach to Jupiter. The image is deceiving: There is room for two and a half Jupiters between Io and Jupiter's clouds. Io is the size of our Moon. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona # # # # # |
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Jupiter Night-Side Auroras,
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Oval-shaped auroras glow in
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2/5/01
| Date |
2/5/01 |
| Description |
Oval-shaped auroras glow in night-side areas near Jupiter's north and south poles in these images taken by NASA's Cassini spacecraft on Jan. 13, 2001. The lower frame is the first to capture the southern aurora on the planet's night side. Blue lines of longitude and latitude have been added in each frame to indicate position of the glows. Jupiter's auroral ovals are similar to Earth's auroras, often called the northern lights or southern lights, although fluctuations in solar activity play a more important role in the auroras at Earth than at Jupiter. Energetic particles are constantly streaming towards Jupiter on magnetic field lines that intersect the planet's atmosphere on a ring around the magnetic pole. Where the energetic particles hit the upper atmosphere, they cause emission of light, similar to the glow in a fluorescent bulb. In the north (upper image), the magnetic pole is offset from the rotational pole, which is where the blue longitude lines converge, just to the left of the imaged area. The auroral oval appears like a draped necklace that is carried around by the rotation of the planet. In the south (lower image), the magnetic and rotational poles are nearly coincident, so no significant offset is visible. Cassini had passed its closest to Jupiter about two weeks before taking these pictures, so it was in position to see the night side of the planet. It was about 16.5 million kilometers (10.3 million miles) from the planet and about 2.5 degrees below the plane of Jupiter's equator. The smallest features visible are about 100 kilometers (about 60 miles) across. The images were taken by Cassini's narrow-band camera through a filter centered on a light-wave frequency at which hydrogen emits light when it is excited. They have been processed to remove scattered light from the overexposed sunlit crescent of the planet. Hydrogen is a major ingredient of Jupiter's atmosphere. It is not understood why the auroral oval rings are so thin. Cassini images will help scientists figure out what brings about the narrow nature and other features of the auroras, such as the break in the northern oval visible in the upper image. Cassini 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 mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona # # # # # |
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Jupiter in color, by Cassini
This color image of Jupiter
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10/9/00
| Date |
10/9/00 |
| Description |
This color image of Jupiter was taken by the camera onboard NASA's Cassini spacecraft when it was 81.3 million kilometers (50.5 million miles) from the planet. It is composed of images taken in the blue, green, and red regions of the spectrum and is therefore close to the true color of Jupiter that one would see through an Earth-based telescope. The image is remarkably similar to images taken by NASA's Voyager 1 and 2 spacecraft more than 21 years ago, illustrating the stability of Jupiter's weather patterns. The parallel dark and bright bands and many other large-scale features are quasi- permanent structures that survive despite the intense small-scale activity ongoing in the atmosphere. The longevity of the large- scale features is an intrinsic property of the atmospheric flows on a gaseous planet such as Jupiter, with no solid surface. Smaller features, such as those in the dark bands north and south of the equator, are observed to form and disappear in a few days. Everything visible on the planet is a cloud. Unlike Earth, where only water condenses to form clouds, Jupiter has several cloud-forming substances in its atmosphere. The updrafts and downdrafts bring different mixtures of these substances up from below, leading to clouds of different colors. The bluish features just north of the equator are regions of reduced cloud cover, similar to the place where the Galileo atmospheric probe entered in 1995. They are called "hot spots" because the reduced cloud cover allows heat to escape from warmer, deeper levels in the atmosphere. Jupiter's moon Europa is seen at the right, casting a shadow on the planet. Scientists believe Europa holds promise of a liquid ocean beneath its surface. Cassini 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, Calif., manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona |
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Mini Solar System in the Mak
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| Title |
Mini Solar System in the Making |
| Description |
This artist's concept shows a brown dwarf surrounded by a swirling disk of planet-building dust. NASA's Spitzer Space Telescope spotted such a disk around a surprisingly low-mass brown dwarf, or "failed star."Ê The brown dwarf, called OTS 44, is only 15 times the size of Jupiter, making it the smallest brown dwarf known to host a planet-forming, or protoplanetary disk. Astronomers believe that this unusual system will eventually spawn planets. If so, they speculate that OTS 44's disk has enough mass to make one small gas giant and a few Earth-sized rocky planets. OTS 44 is about 2 million years old. At this relatively young age, brown dwarfs are warm and appear reddish in color. With age, they grow cooler and darker. |
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Riding a Trail of Debris
| Title |
Riding a Trail of Debris |
| Description |
This image taken by NASA's Spitzer Space Telescope shows the comet Encke riding along its pebbly trail of debris (long diagonal line) between the orbits of Mars and Jupiter. This material actually encircles the solar system, following the path of Encke's orbit. Twin jets of material can also be seen shooting away from the comet in the short, fan-shaped emission, spreading horizontally from the comet. Encke, which orbits the Sun every 3.3 years, is well traveled. Having exhausted its supply of fine particles, it now leaves a long trail of larger more gravel-like debris, about one millimeter in size or greater. Every October, Earth passes through Encke's wake, resulting in the well-known Taurid meteor shower. This image was captured by Spitzer's multiband imaging photometer when Encke was 2.6 times farther away than Earth is from the Sun. It is the best yet mid-infrared view of the comet at this great distance. The data are helping astronomers understand how rotating comets eject particles as they circle the Sun. |
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'Mini-Me' Solar System
| Title |
'Mini-Me' Solar System |
| Description |
This artist's conception shows the relative size of a hypothetical brown dwarf-planetary system (below) compared to our own solar system. A brown dwarf is a cool or "failed" star, which lacks the mass to ignite and shine like our Sun. NASA's Spitzer Space Telescope set its infrared eyes on an extraordinarily low-mass brown dwarf called OTS 44 and found a swirling disk of planet-building dust. At only 15 times the mass of Jupiter, OTS 44 is the smallest known brown dwarf to host a planet-forming, or protoplanetary, disk. Astronomers believe that this unusual system will eventually spawn planets. If so, they speculate that OTS 44's disk has enough mass to make one small gas giant and a few Earth-sized rocky planets. Examples of these possible planets are depicted at the bottom of this picture, circling a low-mass brown dwarf. Above, the bodies of our own solar system have been drawn to the same scale. In each system, the terrestrial planets have been enlarged and the distances between the planets and their parent bodies have been scaled down for easier viewing. |
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A Distant Solar System
| Title |
A Distant Solar System |
| Description |
This animation portrays an artist's concept of a distant hypothetical solar system, about the same age as our own. It begins close to the star, and then moves out past a number of planets. Though "extrasolar" planets are too small to be seen with telescopes, astronomers have detected more than 100 gas giants like Jupiter via their gravitational tug on their parent stars. The view pulls back to reveal the outer fringes of the system and a ring of dusty debris that circles the star. This debris is all that remains of the planet-forming disk from which the planets evolved. Planets are formed when dusty material in a large disk surrounding a young star clumps together. Leftover material is eventually blown out by solar wind or pushed out by gravitational interactions with planets. Billions of years later, only an outer disk of debris remains. These outer debris disks are too faint to be imaged directly by visible-light telescopes. They are washed out by the glare of the Sun. However, NASAÕs Spitzer Space Telescope can detect their heat, or excess thermal emission, in infrared light. This allows astronomers to study the aftermath of planet building in distant solar systems like our own. |
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Planets May leave Tracks in
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| Title |
Planets May leave Tracks in Dust |
| Description |
Astronomers using NASA's Spitzer Space Telescope have gathered the most detailed data yet on a gap in a protoplanetary, or planet-forming, disk surrounding a young star. This artist's concept illustrates one interpretation of the data, which attributes the disk gap to planet formation. At the center lies a young star that is pulling in material from an inner disk of dust and gas. The gap between this inner disk and the thick outer disk is believed to be occupied by developing gas giant planets. The putative planets prevent the outer disk material from naturally falling in toward the star, thereby creating the gap. The inner disk is roughly the size of our inner solar system, or the distance between the Sun and Jupiter. The gap would span orbits equivalent to those of Jupiter and Saturn. The Saturn-like rings around the planets hint that they are very young and still surrounded by debris left over from their own formation. (Note: the planets in this illustration are exaggerated in size.) At the edges of the solar system, the thick disk is expected to coalesce into asteroids, comets and possibly more planets. The bipolar flow, or dim jets of material, shooting out of the star's north and south poles, is a characteristic typical of young stars that are not yet fully formed. |
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