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High Latitude Mottling on Ju …
The familiar banded appearan …
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 # # # # #
Highest resolution of lava f …
Lava flows similar to those …
4/19/00
Date 4/19/00
Description Lava flows similar to those found in Hawaii are seen in the black and white image at top, taken by NASA's Galileo spacecraft. It is one of the highest resolution images (7 meters or 23 feet per picture element) ever obtained of Jupiter's volcanic moon Io. The two horizontal black stripes are places where data were lost during transmission to Earth. The image shows the textures of lava flows on the floor of the caldera Chaac, which is shown in false color at lower resolution (185 meters or 607 feet per pixel element) in the bottom image. Calderas are depressions caused by collapse during volcanic eruptions. The one shown here is approximately 100 kilometers (63 miles) long and 30 kilometers (19 miles) across. Using shadow lengths from the new high-resolution observations, the northeastern (upper right) scarp, or line of cliffs, has been estimated to be 2.8 kilometers (9200 feet) high. The lava flows are similar in texture to lava flows within the caldera at Hawaii's Kilauea volcano. This suggests that the floor of Chaac has been covered by a combination of lava flows and lava lakes. The light-colored material surrounding the caldera may be composed of sulfur-dioxide frost or some other sulfur-rich material on the surface of Io. Galileo scientists believe that the greenish color on the caldera floor is a form of contaminated sulfur created when sulfur-rich material escaping from volcanic vents reacts chemically with warm lava flows. The high- resolution view shows numerous lava flows. The darkest flows are thought to be the most recent because they have not been covered by the sulfurous materials which coat most of Io's surface. The top image was acquired by Galileo on February 22, 2000. It was taken at a distance of 600 kilometers (370 miles) and is centered at 11.9 degrees north latitude and 157.6 degrees west longitude. North is to the top, and the Sun illuminates the surface from the right. The color image was created by combining a black and white image taken on February 22, 2000 at a distance of 18,800 kilometers (11,700 miles) from Io with lower-resolution (1.3 kilometers or 0.81 miles per picture element) color images taken on July 3, 1999 at a distance of 130,000 kilometers (81,000 miles). The image is centered at 11.6 degrees north latitude and 157.7 degrees west longitude. North is to the top and the Sun illuminates the surface from the left. 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 mission 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 . #####
Rifting at Hi'iaka Patera, I …
NASA's Galileo spacecraft ac …
5/18/00
Date 5/18/00
Description NASA's Galileo spacecraft acquired the images in this mosaic of Hi'iaka Patera (the irregularly shaped, dark depression at the center of the image) and two nearby mountains on November 25, 1999 during its 25th orbit. The sharp peak at the top of the image is about 11 kilometers (about 36,300 feet) high, and the two elongated plateaus to the west and south of the caldera are both about 3.5 kilometers (11,500 feet) high. The ridges on the northwestern mountain are often seen on Ionian mountains and are thought to be formed as surface material slides downslope due to gravity. At low resolution, many of the dark features, called pateras, appear to be calderas -- depressions formed by collapse into an empty magma chamber. However, higher resolution images such as this one suggest a different origin. In the case of Hi'iaka, the northern and southern margins of the pateras have very similar shapes which appear to fit together. This may indicate that the crust has been pulled apart here and the resulting depression has subsequently been covered by dark lava flows. Furthermore, the two mountains bordering Hi'iaka Patera also appear to fit together. However, the similar shapes and heights of the pateras' margins and mountains could be coincidental. Galileo scientists are currently investigating whether mountains and pateras are related to each other and what could cause the surface of Io to rift apart in such a manner. North is to the top of the mosaic and the sun is illuminating the surface from the left. The resolution is 260 meters (about 280 yards) per picture element. Galileo took the images at a distance of 26,000 kilometers (16,000 miles) from Io. The Jet Propulsion Laboratory, Pasadena, CA manages the 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 mission 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 . #####
Eruption at Tvashtar Catena, …
NASA's Galileo spacecraft ca …
5/18/00
Date 5/18/00
Description NASA's Galileo spacecraft caught this volcanic eruption in action on Jupiter's moon Io on November 25, 1999. This mosaic shows Tvashtar Catena, a chain of calderas, in enhanced color. It combines low resolution (1.3 kilometers, or .8 miles, per picture element) color images of Io taken on July 3, 1999 with the much higher resolution (180 meters, or 197 yards, per picture element) black and white images taken in November. The molten lava was hot enough, and therefore bright enough, to saturate, or overexpose, Galileo's camera (original image is inset in lower right corner). The bright lava curtain (a chain of lava fountains) and surface flows shown in the color image were assembled as an interpretive drawing by Galileo scientists, based on their knowledge of how the camera behaves when saturated. The lava appears to be producing fountains to heights of up to 1.5 kilometers (5,000 feet) above the surface. Several other lava flows can be seen on the floors of the calderas. The darkest flows are probably the most recent. The elongated caldera in the center of the image is almost surrounded by a mesa that is about 1 kilometer (.6 miles) high. In places the mesa's margins are scalloped, which is typical of an erosional process called sapping. This occurs when fluid escapes from the base of a cliff, causing the material above it to collapse. On Earth, sapping is caused by springs of groundwater. Similar features on Mars are one of the key pieces of evidence that water flowed on Mars' surface in the past. On Io, the fluid is believed to be sulfur dioxide, which should vaporize almost instantaneously when it reaches the near vacuum at Io's surface, blasting away material at the base of the cliffs. North is to the top of the image and the Sun illuminates the surface from the lower left. The high resolution black and white image was taken at a distance of 17,000 kilometers (11,000 miles). The Jet Propulsion Laboratory, Pasadena, CA manages the 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 mission 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 . #####
Ongoing Volcanic Eruption at …
An active volcanic eruption …
5/31/00
Date 5/31/00
Description An active volcanic eruption on Jupiter's moon Io was captured in this image taken on February 22, 2000 by NASA's Galileo spacecraft. Tvashtar Catena, a chain of giant volcanic calderas centered at 60 degrees north, 120 degrees west, was the location of an energetic eruption caught in action in November 1999. A dark, "L"shaped lava flow to the left of the center in this more recent image marks the location of the November eruption. White and orange areas on the left side of the picture show newly erupted hot lava, seen in this false color image because of infrared emission. The two small bright spots are sites where molten rock is exposed to the surface at the toes of lava flows. The larger orange and yellow ribbon is a cooling lava flow that is more than more than 60 kilometers (37 miles) long. Dark, diffuse deposits surrounding the active lava flows were not there during the November 1999 flyby of Io. This color mosaic was created by combining images taken in the near-infrared, clear, and violet filters from Galileo's camera. The range of wavelengths is slightly more than that of the human eye. The mosaic has been processed to enhance subtle color variations. The bright orange, yellow, and white areas at the left of the mosaic use images in two more infrared filters to show temperature variations, orange being the coolest and white the hottest material. This picture is about 250 kilometers (about 155 miles) across. North is toward the top and illumination from the Sun is from the west (left). The Jet Propulsion Laboratory, Pasadena, Calif., manages the mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission 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 . #####
An Ionian Caldera Up Close
Detail of one of the caldera …
5/31/00
Date 5/31/00
Description Detail of one of the calderas, or collapsed volcanic craters, on Jupiter's moon Io, is seen in these images acquired on February 22, 2000 by NASA's Galileo spacecraft. Taken from a distance of 700 to 800 kilometers (roughly 400 to 500 miles). The five partial images on the right comprise all of the data that could be returned from an eight-image mosaic. These are the highest resolution images of lava flows ever obtained from Io. The resolution of the close-up images varies from 7 to 8 meters (about 23 to 26 feet) per picture element. The boxes in the image to the left are approximate locations of the five partial images. They are shown superimposed on a lower resolution image of the entire Chaac caldera. The high-resolution snapshots highlight areas from both the southern and northern rims as well as areas on the floor of the caldera. They reveal fascinating similarities and differences between calderas on Io and Earth. Most puzzling is the texture of the material above the caldera rim. The plains surrounding Chaac are covered with alternating dark and light patches. The process that forms this surface is a complete mystery. By comparison, scientists analyzing the images say the floor of the caldera is amazingly familiar. The interwoven domes and pits form a surface essentially identical to many terrestrial calderas that erupt fluid lavas. For example, the similarity to the caldera on top of the Kilauea Volcano in Hawaii is striking. The southernmost Chaac image shows several raised plateaus and a deep, dark pit about 400 meters (about 440 yards) across. Although the Kilauea caldera is 10 times smaller than the Chaac caldera, the 1959 Kilauea eruption formed similar features to Chaac when a small volcanic crater was filled by erupting lava. The Hawaiian lava formed a pond that crusted over and then partially drained back down into the ground. Pieces of the pond crust that were left behind formed a perched plateau, and the hole the lava drained back into formed a deep pit. Scientists presume the same thing happened at Chaac in the recent past. The high-resolution images were taken at a distance of about 700- 800 kilometers (400-500 miles) and are centered around 12 degrees north latitude and 158 degrees west longitude. North is to the top and the sun illuminates the surface from the right. The lower resolution image was also taken on February 22, 2000 but from a distance of 18,800 kilometers (11,700 miles) from Io. The image is centered at 11.6 degrees north latitude and 157.7 degrees west longitude. North is to the top and the Sun illuminates the surface from the left. The Jet Propulsion Laboratory, Pasadena, Calif., manages the mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology, Pasadena, Calif. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission 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 . #####
Stereo Images of Tvashtar Ca …
This stereo image illustrate …
5/31/00
Date 5/31/00
Description This stereo image illustrates the topography of the Tvashtar Catena region on Jupiter's moon Io. It was created by combining two different views of Tvashtar taken by NASA's Galileo spacecraft on November 25, 1999 (shown in red) and February 22, 2000 (shown in blue). A raised plateau surrounds the volcanic depression, or caldera, in the center of the image. To the northeast of the main caldera, the plateau's inner and outer margins are scalloped, which may indicate that a process called sapping is eroding them. Sapping occurs when fluid escapes from the base of a cliff, causing the material above it to collapse. Smaller calderas have formed in the floor of the main caldera. This nesting of calderas is also observed on Earth, at Kilauea in Hawaii. (The two bright red regions toward the upper left of this image, which are roughly triangular in shape, are the areas where the earlier image was overexposed by the brightness of hot lava fountains). Galileo scientists are in the process of generating topographic maps from these images. Such maps will reveal the heights and slopes of different landforms in this region, which will help scientists determine the strength and other properties, of Io's surface materials. They will also be useful in understanding the processes of uplift and erosion on Io. The picture is centered at 59 degrees north latitude and 121 degrees west longitude. North is to the top of the picture and the Sun illuminates the surface from the lower left. The observations used to make the stereo image were made at ranges of 18,000 and 34,500 kilometers (11,400 and 21,600 miles) from Io. The resolution of the stereo image is about 320 meters (350 yards) per picture element. 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 mission 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 . #####
Colorized View of Zal Region …
This image shows one of many …
5/31/00
Date 5/31/00
Description This image shows one of many intriguing mountains on Jupiter's moon Io. The image was made by combining a recent high- resolution, black and white image with earlier low-resolution color data to provide a high-resolution, color view. NASA's Galileo spacecraft took both images. The 240-kilometer (150-mile) long mountain in the image is south of the volcanic hot spot named Zal. The black and white version of this image was useful for showing the shape of the mountain and the small fans of debris piled against the base of its tall, steep cliffs. However, when colorized the relationship between different types of materials becomes apparent. For example, the bright, red material is believed to contain a compound of sulfur that forms when sulfur is boiled at a high temperature. Active eruptions of molten rock (lava) are the most likely source for the heat. Thus we see red sulfur where lava reaches the surface. Other sulfur compounds cover the yellow areas, and the black areas are fresh silicate lava that has not yet been coated by the yellow sulfurous materials. The green patches are still somewhat mysterious, they appear to form when red sulfur lands on warm lava and the two react in a manner that is still unknown. In this image, it is clear that the red material has blown out of a long crack along the western side of the mountain. Lava has flowed from this crack and filled a depression (caldera). Some of the red sulfur close to the dark caldera appears to have been converted into green material. The fact that lava comes up along the faults that define the sides of the mountains provides important clues to how the mountains form and the state of the interior of Io. Scientists at the University of Arizona speculate that the formation of the mountains on Io may be related to plumes of hot material rising inside the fiery body of Io. North is to the top and the setting sun is shining from the west. The image is centered at about 33 degrees north, 72 degrees west. The high-resolution image was taken on February 22, 2000 by NASA's Galileo spacecraft. The image was taken by the Galileo's onboard camera from a range of 33,500 kilometers (20,800 miles) and has a resolution of 335 meters (1,100 feet) per picture element. The color images were taken on July 3, 1999. They have resolutions of 1.3 kilometers (0.81 miles) per picture element and are illuminated from almost directly behind the spacecraft. They were taken at a distance of about 130,000 kilometers (81,000 miles) from Io. The Jet Propulsion Laboratory, Pasadena, CA manages the 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 mission 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. #####
Shamshu Mons and Patera, Io
This mosaic of images taken …
5/31/00
Date 5/31/00
Description This mosaic of images taken by NASA's Galileo spacecraft on February 22, 2000 shows three mountains and two lava-filled depressions in the Shamshu region of Jupiter's moon Io. The dark oval feature on the left side of the image is a depression that has been resurfaced by lava flows. The rough terrain northeast of the depression is Shamshu Mons. A 10-kilometer (6-mile) wide canyon oriented in northeast to southwest direction cuts this mountain. The northwestern edge of the mountain has been scalloped by erosion, and it appears that the material has flowed along the canyon floor. Portions of two more mountains can be seen on the right side of the image. The depression between these mountains is Shamshu Patera, a volcanic hotspot. The dark patches within it are recent and active lava flows. The northernmost edge of Shamshu Patera appears to be cutting into the mountain to its northeast. North is to the top of the picture and the Sun illuminates the surface from the west. This mosaic has a resolution of about 345 meters (1,130 feet) per picture element and covers an area approximately 390 by 380 kilometers (240 by 235 miles) at its maximum dimensions. It is centered at about 9 degrees south latitude and 68 degrees west longitude. The images that make up this mosaic were acquired at a range of 34,500 kilometers (21,400 miles) by Galileo's onboard camera. The Jet Propulsion Laboratory, Pasadena, CA manages the 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 mission 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 . #####
Ganymede dark terrain at hig …
Impact craters dominate the …
12/16/00
Date 12/16/00
Description Impact craters dominate the surface down to the smallest features visible on the dark terrain of the Nicholson Regio region of Jupiter's moon Ganymede in this image taken by NASA's Galileo spacecraft. It is the highest resolution view ever obtained of Ganymede's dark terrain. Both the regional-scale image at the bottom and high- resolution image at the top were taken by Galileo during its May 20, 2000, flyby of Ganymede. The latter are the highest resolution images ever obtained of Ganymede's dark terrain, which makes up about one third of Ganymede's surface. Impact cratering is clearly the dominant mechanism of surface modification in this relatively ancient terrain, which is analogous to the cratered highlands of Earth's Moon. Small- scale craters seem to mimic larger-scale craters, as is apparent in the similarities between the high and medium resolution scenes. The bright spots are probably fresh ice-rich ejecta excavated by the most recent impact events. North is to the top of the images and the Sun illuminates the surface from the west. The medium-resolution image, centered at –15 degrees latitude and 337 degrees longitude, covers an area approximately 237 by 130 kilometers (147 by 81 miles) at a resolution of 125 meters (410 feet) per picture element. The high-resolution image is at 28 meters (92 feet) per picture element. This image and other images and data received from Galileo are posted on the 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 . 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. The images were produced by Arizona State University, Tempe, and Brown University, Providence, R.I.. Their websites are at http://europa.la.asu.edu/index.html and http://www.planetary.brown.edu/ . # # # # #
Region of Ganymede with mix …
The area of Nicholson Regio …
12/16/00
Date 12/16/00
Description The area of Nicholson Regio and Arbela Sulcus illustrates many of the diverse terrain types on Jupiter's moon Ganymede, as seen in this image taken by NASA's Galileo spacecraft. The bright terrain of Arbela Sulcus is the youngest terrain here, slicing north-south across the image. It is finely striated, and relatively lightly cratered. To the east (right) is the oldest terrain in this area, rolling and relatively densely cratered Nicholson Regio. To the west (left) is a region of highly deformed grooved terrain, intermediate in relative age. In this area of grooved terrain, stretching and normal faulting of Nicholson Regio has deformed it beyond recognition. North is to the top of the picture and the Sun illuminates the surface from the west. The image, centered at -15 degrees latitude and 347 degrees longitude, covers an area approximately 89 by 26 kilometers (55 by 16 miles). The resolution is 34 meters (112 feet) per picture element. The images were taken on May 20, 2000, at a range of 3,350 kilometers (2,082 miles). This image and other images and data received from Galileo are posted on the 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 . 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. This image was produced by DLR (German Aerospace Center), Berlin, and Brown University, Providence, R.I., http://solarsystem.dlr.de/ and http://www.planetary.brown.edu/ . # # # # #
Regional view of bright and …
This view of the Nicholson R …
12/16/00
Date 12/16/00
Description This view of the Nicholson Regio/Arbela Sulcus region on Jupiter's moon Ganymede, taken by NASA's Galileo spacecraft, shows the stark contrast between the smooth bright terrain and the surrounding highly fractured dark terrain. This observation was designed in part to distinguish between different models for how Arbela Sulcus and other groove lanes on Ganymede were formed. The volcanic model suggests that a relatively clean, water-rich lava filled a tectonic depression, then cooled to create a smooth surface. Tectonic models suggest that focused faulting and deformation of older dark terrain destroyed the pre-existing texture, which was brightened by exposure of underlying, clean ice. Analysis of these photos suggests a third and unexpected possibility: Arbela Sulcus may be similar to some bands on another of Jupiter's moons, Europa, formed by tectonic crustal spreading and renewal. North is to the upper left of the picture and the Sun illuminates the surface from the west. The image, centered at – 14 degrees latitude and 347 degrees longitude, covers an area approximately 258 by 116 kilometers (160 by 72 miles). The resolution is 133 meters (436 feet) per picture element. The images were taken on May 20, 2000, at a range of 13,100 kilometers (8,140 miles). This image and other images and data received from Galileo are posted on the 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 . 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. This image was produced by DLR (German Aerospace Center), Berlin, and Brown University, Providence, R.I., http://solarsystem.dlr.de/ and http://www.planetary.brown.edu/ . # # # # #
Ganymede feature resembling …
This frame compares a high-r …
12/16/00
Date 12/16/00
Description This frame compares a high-resolution view of Arbela Sulcus on Jupiter's moon Ganymede (top) with the gray band Thynia Linea on another Jovian moon, Europa (bottom), shown to the same scale. Both images are from NASA's Galileo spacecraft. Arbela Sulcus is one of the smoothest lanes of bright terrain identified on Ganymede, but subtle striations are apparent here along its length. This section of Arbela contrasts markedly from highly fractured terrain to its west and dark terrain to its east. On Europa, gray bands such as Thynia Linea have formed by tectonic crustal spreading and renewal. Such bands have sliced through and completely separated pre-existing features in the surrounding bright, ridged plains. The younger prominent double ridge Delphi Flexus cuts across Thynia Linea. The scarcity of craters on Europa attests to the relative youth of its surface compared to Ganymede's. Unusual for Ganymede, it is possible that Arbela Sulcus has formed by complete separation of Ganymede's icy crust, like bands on Europa. Tests of this idea come from detailed comparisons of their internal shapes and the relationships to the surrounding structures. In the Ganymede image, north is to the top of the picture and the Sun illuminates the surface from the west. The image, centered at -15 degrees latitude and 347 degrees longitude, covers an area approximately 34 by 26 kilometers (21 by 16 miles). The resolution is 34 meters (112 feet) per picture element. The image was taken on May 20, 2000, at a range of 3,370 kilometers (2,094 miles). In the Europa image, north is to the upper-right of the picture and the Sun illuminates the surface from the northwest. The image, centered at -66 degrees latitude and 161 degrees longitude, covers an area approximately 44 by 46 kilometers (27 by 29 miles). The resolution is 45 meters (147 feet) per picture element. The image was taken on September 26, 1998, at a range of 3,817 kilometers (2,371 miles). This image and other images and data received from Galileo are posted on the 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 . 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. This image was produced by DLR (German Aerospace Center), Berlin, and Brown University, Providence, R.I., http://solarsystem.dlr.de/ and http://www.planetary.brown.edu/ . # # # # #
Comparison of Ganymede and E …
This image, taken by NASA's …
12/16/00
Date 12/16/00
Description This image, taken by NASA's Galileo spacecraft, shows a same-scale comparison between Arbela Sulcus on Jupiter's moon Ganymede (left) and an unnamed band on another Jovian moon, Europa (right). Arbela Sulcus is one of the smoothest lanes of bright terrain identified on Ganymede, and shows very subtle striations along its length. Arbela contrasts markedly from the surrounding heavily cratered dark terrain. On Europa, dark bands have formed by tectonic crustal spreading and renewal. Bands have sliced through and completely separated pre-existing features in the surrounding bright ridged plains. The scarcity of craters on Europa illustrates the relative youth of its surface compared to Ganymede's. Unusual for Ganymede, it is possible that Arbela Sulcus has formed by complete separation of Ganymede's icy crust, like bands on Europa. Prominent fractures on either side of Arbela appear to have been offset by about 65 kilometers (about 40 miles) along the length of the area of furrows and ridges, suggesting that strike-slip faulting was important in the formation of Arbela Sulcus. In the Ganymede image, north is to the upper left of the picture and the Sun illuminates the surface from the west. The image, centered at -14 degrees latitude and 347 degrees longitude, covers an area approximately 258 by 116 kilometers (160 by 72 miles.) The resolution is 133 meters (436 feet) per picture element. The images were taken on May 20, 2000, at a range of 13,100 kilometers (8,100 miles). In the Europa image, north is to the left of the picture and the Sun illuminates the surface from the east. The image, centered at -7 degrees latitude and 236 degrees longitude, covers an area approximately 275 by 424 kilometers (171 by 263 miles.) The resolution is 220 meters (about 720 feet) per picture element (re-sampled here to 133 meters, or 436 feet). The images were taken on Nov. 6, 1997, at a range of 21,500 kilometers (13,360 miles). The Jet Propulsion Laboratory, Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology in Pasadena. Images and data received from Galileo are posted on the 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 . Images were produced by Brown University, Providence, R.I., http://www.planetary.brown.edu/, DLR (German Aerospace Center) Berlin, http://solarsystem.dlr.de , and University of Arizona, Tempe, http://www.lpl.arizona.edu/. # # # # #
Perspective view of Arbela S …
This view of Arbela Sulcus, …
12/16/00
Date 12/16/00
Description This view of Arbela Sulcus, a 24-kilometer-wide (15-mile- wide) region of furrows and ridges on Jupiter's moon Ganymede, shows its relationship to the dark terrain surrounding it. NASA's Galileo spacecraft took these pictures during its May 20, 2000, flyby of Ganymede. Arbela Sulcus lies overall slightly lower than the dark terrain of Nicholson Regio, a 3,700 kilometers (3,300 mile) area in the southern hemisphere. However, along the eastern margin (bottom), a portion of the dark terrain (probably an ancient degraded impact crater) lies even lower than Arbela Sulcus. Scientists did not find bright icy material on Arbela Sulcus, indicating that this ridgy area was not created by watery volcanic activity. Instead, they found fine striations covering the surface, along with a series of broader highs and lows that resemble piano keys. This suggests that the movement of underlying tectonic plates deformed the surface. Combining images from two observations taken from different viewing perspectives provides stereo topographic information, giving valuable clues as to the geologic history of a region. North is to the right of the image. The Sun illuminates the surface from the west. The image, centered at –15 degrees latitude and 347 degrees longitude, covers an area approximately 89 by 26 kilometers (55 by 16 miles). The image resolution is 70 meters (230 feet) per picture element. The images were taken on May 20, 2000, at a range of 3,350 kilometers (2,100 miles). The Jet Propulsion Laboratory, Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . The images were produced by German Aerospace Center (DLR), http://solarsystem.dlr.de/ Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . # # # # #
Bright-Dark terrain boundary …
The boundary between the bri …
12/16/00
Date 12/16/00
Description The boundary between the bright terrain of Harpagia Sulcus (right) and dark terrain of Nicholson Regio (left) areas of Jupiter's moon Ganymede springs out when viewed through red/blue 3-D glasses, in this image taken by NASA's Galileo spacecraft as it flew by Ganymede on May 20, 2000. Details of the rough, ancient, heavily cratered dark terrain of Nicholson Regio are in stark contrast to the very smooth, bright, young terrain of Harpagia Sulcus. In the center lies the transition to the boundary between these two regions, providing evidence that extensional faulting marks the boundary. A series of steep slopes deform the dark terrain close to the boundary. In the bright terrain, a deep trough and flanking ridge delimit the boundary. North is to the top of the picture. The Sun illuminates the surface from the left. The imaged region, centered at –14 degrees latitude and 319 degrees longitude, covers an area approximately 25 by 10 kilometers (15.5 by 6 miles.) The resolutions of the two data sets are 20 meters (66 feet) per picture element and 121 meters (397 feet) per picture element. The higher resolution images were taken at a range of 2,000 kilometers (about 1,200 miles). The Jet Propulsion Laboratory, Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . The image was produced by the German Aerospace Center (DLR), http://solarsystem.dlr.de and Brown University, http://www.planetary.brown.edu/ . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . # # # # #
Bright-dark boundary and top …
These images, taken by NASA' …
12/16/00
Date 12/16/00
Description These images, taken by NASA's Galileo spacecraft on its May 20, 2000, flyby of Jupiter's moon Ganymede, illustrate the boundary and different elevations between the dark, ancient terrain of Nicholson Regio (left) and bright, younger terrain of Harpagia Sulcus (right.) The bottom image is a wide view of the boundary, and the top image is an enlargement of the colorized strip. An important goal of Galileo's Ganymede encounter was to understand the nature of the boundary between ancient, dark terrain and younger, bright terrain. The camera was aimed at the boundary to obtain both very high-resolution images (top) and medium-resolution context images (bottom). Color-coded elevations are indicated relative to the average elevation of the sampled area, with high elevation marked in red, and low in blue. Combining the two image mosaics allows scientists to derive a detailed description of the region from the overlap. The data shows that there are approximately 200 meters (about 650 feet) of topographic relief within the bright terrain here, and a deep depression marks the boundary between bright and dark terrains. North is to the top of the pictures. The Sun illuminates the surface from the left. The larger image, centered at –14 degrees latitude and 319 degrees longitude, covers an area approximately 213 by 97 kilometers (132 by 60 miles.) The resolution of the high-resolution image is 20 meters (about 65 feet) per picture element, and the context image is at 121 meters (397 feet) per picture element. The higher resolution image was taken at a range of 2000 kilometers (over 1,200 miles). The Jet Propulsion Laboratory, Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . The images were produced by the German Aerospace Center (DLR) http://solarsystem.dlr.de/ , and Brown University, http://www.planetary.brown.edu/ . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . # # # # #
Caldera-like depression on G …
The shallow, scalloped depre …
12/16/00
Date 12/16/00
Description The shallow, scalloped depression in the center of this picture from NASA's Galileo spacecraft is a caldera-like feature 5 to 20 kilometers (3 to 12 miles) wide on Jupiter's largest moon, Ganymede. Calderas are surface depressions formed by collapse above a subsurface concentration of molten material. Some shallow depressions in bright, smooth areas of Ganymede have some overall similarities to calderas on Earth and on Jupiter's moon Io. On Ganymede, caldera-like depressions may serve as sources of bright, volcanic flows of liquid water and slush, an idea supported by a Ganymede photo obtained by Galileo during its seventh orbit and available at http://photojournal.jpl.nasa.gov/cgi- bin/PIAGenCatalogPage.pl?PIA01614 . In the more recent image here, from Galileo's 28th orbit, a tall scarp marks the western boundary of a caldera-like feature. The western scarp is aligned similarly to older tectonic grooves visible in the image, suggesting the feature has collapsed along older lines of weakness. The interior is mottled in appearance, yet smooth compared to most of Ganymede's bright terrain seen at high resolution. The eastern boundary of the caldera-like feature is cut by younger, grooved terrain. Small impact craters pepper the scene, but the lack of a raised rim argues against an impact origin for the caldera-like feature itself. Instead, water-rich icy lava may have once flowed out of it toward the east. If so, later tectonism could have erased any telltale evidence of volcanic flow fronts. Direct evidence for icy volcanism on Ganymede continues to be elusive. North is to the top of the picture and the Sun illuminates the surface from the left. The image, centered at -24 degrees latitude and 318 degrees longitude, covers an area approximately 162 by 119 kilometers (101 by 74 miles). The resolution is 43 meters (141 feet) per picture element. This image and other images and data received from Galileo are posted on the 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 . 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. This image was produced by Brown University, Providence, R.I., http://www.planetary.brown.edu/ . # # # # #
Not-so-smooth bright terrain …
The highest-resolution image …
12/16/00
Date 12/16/00
Description The highest-resolution images ever obtained of Jupiter's moon Ganymede show that even smooth-looking terrain has been deformed at a fine scale. The high-resolution image taken of the bright Harpagia Sulcus area by NASA's Galileo spacecraft during a May 20, 2000, flyby of Ganymede shows features as small as 16 meters (52 feet). This area was selected for a closer look because, in images taken by NASA's Voyager spacecraft about 20 years earlier, it looked as flat as a hockey rink. It appears smooth even in a medium-resolution Galileo image (at 116 meters or 380 feet per pixel) that is superimposed over a Voyager image in the top portion of this frame. But the closeup shot revealed that, instead of a hockey rink, the area has ups and downs that would be challenging for a cross-country skier. North is to the top of the picture and the Sun illuminates the surface from the left. The medium-resolution image mosaic is centered at -16 degrees latitude and 310 degrees longitude, and covers an area approximately 282 by 144 kilometers (175 by 89 miles). This image and other images and data received from Galileo are posted on the 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 . 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. This image was produced by DLR (German Aerospace Center), Berlin, and Brown University, Providence, R.I., http://solarsystem.dlr.de/ and http://www.planetary.brown.edu/ . # # # # #
Stair-step scarps in dark te …
NASA's Galileo spacecraft to …
12/16/00
Date 12/16/00
Description NASA's Galileo spacecraft took this image of dark terrain within Nicholson Regio, near the border with Harpagia Sulcus on Jupiter's moon Ganymede. The ancient, heavily cratered dark terrain is faulted by a series of scarps. The faulted blocks form a series of 'stair-steps' like a tilted stack of books. On Earth, similar types of features form when tectonic faulting breaks the crust and the intervening blocks are pulled apart and rotate. This image supports the notion that the boundary between bright and dark terrain is created by that type of extensional faulting. North is to the right of the picture and the Sun illuminates the surface from the west (top). The image is centered at -14 degrees latitude and 320 degrees longitude, and covers an area approximately 16 by 15 kilometers (10 by 9 miles). The resolution is 20 meters (66 feet) per picture element. The image was taken on May 20, 2000, at a range of 2,090 kilometers (1,299 miles). This image and other images and data received from Galileo are posted on the 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 . 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. This image was produced by Brown University, Providence, R.I., http://www.planetary.brown.edu/ . # # # # #
Description Jupiter Aurora
Full Description Solar Wind and Aurora at Jupiter March 8, 2001 For higher resolution image, click here. NASA's Earth-orbiting Hubble Space Telescope and Saturn-bound Cassini spacecraft recently provided scientists an opportunity to watch whether changes in Jupiter's glowing auroras correspond in timing to fluctuations in the solar wind reaching Jupiter. While Cassini passed near Jupiter in December 2000 and January 2001, the Hubble telescope obtained ultraviolet images of the ring-shaped aurora near Jupiter's north pole. The auroras, comparable to Earth's northern lights, are glows caused when charged particles steered by the planet's magnetic field excite gases high in the atmosphere. They give an indication of conditions in the invisible magnetic field. The Hubble images were taken at times when instruments on Cassini were measuring the solar wind approaching Jupiter. The solar wind is a fluctuating stream of particles speeding away from the Sun. The Cassini measurements allowed scientists to extrapolate the properties of the solar wind even closer to Jupiter, where it interacts with the planet's magnetic field. One example of these sets of data is presented in this pair of images. An image of Jupiter's northern aurora, taken by Hubble on Dec. 16, 2000, shows the aurora as a white loop against a blue background in the top frame. The bottom frame presents information that Cassini's plasma spectrometer and magnetometer instruments collected about the solar wind reaching Jupiter at the same time. It gives measurements of the solar wind's speed, density, pressure and magnetic-field direction. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA). It is managed for NASA by the Space Telescope Science Institute, Baltimore, Md. Cassini, on course to reach Saturn in 2004, is a cooperative mission of NASA, ESA and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C. More information about the studies of Jupiter while Cassini passed it available online at: http://www.jpl.nasa.gov/jupiterflyby . Credit: NASA/JPL/University of Michigan
Cassini Jupiter Portrait
Description Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn.
Full Description This true color mosaic of Jupiter was constructed from images taken by the narrow angle camera onboard NASA's Cassini spacecraft on December 29, 2000, during its closest approach to the giant planet at a distance of approximately 10 million kilometers (6.2 million miles). It is the most detailed global color portrait of Jupiter ever produced, the smallest visible features are approximately 60 kilometers (37 miles) across. The mosaic is composed of 27 images: nine images were required to cover the entire planet in a tic-tac-toe pattern, and each of those locations was imaged in red, green, and blue to provide true color. Although Cassini's camera can see more colors than humans can, Jupiter's colors in this new view look very close to the way the human eye would see them. Everything visible on the planet is a cloud. The parallel reddish-brown and white bands, the white ovals, and the large Great Red Spot persist over many years despite the intense turbulence visible in the atmosphere. The most energetic features are the small, bright clouds to the left of the Great Red Spot and in similar locations in the northern half of the planet. These clouds grow and disappear over a few days and generate lightning. Streaks form as clouds are sheared apart by Jupiter's intense jet streams that run parallel to the colored bands. The prominent dark band in the northern half of the planet is the location of Jupiter's fastest jet stream, with eastward winds of 480 kilometers (300 miles) per hour. Jupiter's diameter is eleven times that of Earth, so the smallest storms on this mosaic are comparable in size to the largest hurricanes on Earth. Unlike Earth, where only water condenses to form clouds, Jupiter's clouds are made of ammonia, hydrogen sulfide, and water. The updrafts and downdrafts bring different mixtures of these substances up from below, leading to clouds at different heights. The brown and orange colors may be due to trace chemicals dredged up from deeper levels of the atmosphere, or they may be byproducts of chemical reactions driven by ultraviolet light from the Sun. Bluish areas, such as the small features just north and south of the equator, are areas of reduced cloud cover, where one can see deeper. For more information, see the Cassini Project home page, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org. The imaging team is based at the Space Science Institute, Boulder, Colo. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Image Credit: NASA/JPL/Space Science Institute
Rings and More Rings
Description Rings and More Rings
Full Description This dramatic view of Saturn's rings draped by the shadow of Saturn, shows brightness variations that correspond to differences in the concentration of the ring particles as they orbit the planet. The planet's western limb is visible in the upper right corner. Three of Saturn¿s moons can be seen here: Bright Enceladus (499 kilometers, or 310 miles across) is visible near lower right, Epimetheus (116 kilometers, or 72 miles across) appears at center left, and interior to the F ring, near the top of the image, is Prometheus (102 kilometers, or 63 miles across). The F ring, the outermost ring shown here, displays several knot-like features near the left side of the image. The image was taken in visible light by the Cassini spacecraft wide angle camera on July 3, 2004, from a distance of 1.5 million kilometers (930,000 miles) from Saturn, at a Sun-Saturn-spacecraft, or phase, angle of about 108 degrees. This is the first processed wide angle camera image to be released since Cassini's encounter with Jupiter in 2000. The image scale is 87 kilometers (54 miles) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org . Image Credit: NASA/JPL/Space Science Institute
Tvashtar Catena, Io
title Tvashtar Catena, Io
date 02.22.2000
description An active volcanic eruption on Jupiter's moon Io was captured in this image taken on Feb. 22, 2000 by NASA's Galileo spacecraft. Tvashtar Catena, a chain of giant volcanic calderas centered at 60 degrees north, 120 degrees west, was the location of an energetic eruption caught in action in November 1999. A dark, "L"-shaped lava flow to the left of the center in this more recent image marks the location of the November eruption. White and orange areas on the left side of the picture show newly erupted hot lava, seen in this false color image because of infrared emission. The two small bright spots are sites where molten rock is exposed to the surface at the toes of lava flows. The larger orange and yellow ribbon is a cooling lava flow that is more than more than 60 kilometers (37 miles) long. Dark, diffuse deposits surrounding the active lava flows were not there during the November 1999 flyby of Io. This color mosaic was created by combining images taken in the near-infrared, clear, and violet filters from Galileo's camera. The range of wavelengths is slightly more than that of the human eye. The mosaic has been processed to enhance subtle color variations. The bright orange, yellow, and white areas at the left of the mosaic use images in two more infrared filters to show temperature variations, orange being the coolest and white the hottest material. This picture is about 250 kilometers (about 155 miles) across. North is toward the top and illumination from the Sun is from the west (left). *Image Credit*: NASA
An Eruption on Io
title An Eruption on Io
date 02.26.2007
description The first images returned to Earth by New Horizons during its close encounter with Jupiter feature the Galilean moon Io, snapped with the Long Range Reconnaissance Imager (LORRI) at 0840 UTC on February 26, while the moon was 2.5 million miles (4 million kilometers) from the spacecraft. Io is intensely heated by its tidal interaction with Jupiter and is thus extremely volcanically active. That activity is evident in these images, which reveal an enormous dust plume, more than 150 miles high, erupting from the volcano Tvashtar. The plume appears as an umbrella-shaped feature of the edge of Io's disk in the 11 o'clock position in the right image, which is a long-exposure (20-millisecond) frame designed specifically to look for plumes like this. The bright spots at 2 o'clock are high mountains catching the setting sun, beyond them the night side of Io can be seen, faintly illuminated by light reflected from Jupiter itself. The left image is a shorter exposure -- 3 milliseconds -- designed to look at surface features. In this frame, the Tvashtar volcano shows as a dark spot, also at 11 o'clock, surrounded by a large dark ring, where an area larger than Texas has been covered by fallout from the giant eruption. This is the clearest view yet of a plume from Tvashtar, one of Io's most active volcanoes. Ground-based telescopes and the Galileo Jupiter orbiter first spotted volcanic heat radiation from Tvashtar in November 1999, and the Cassini spacecraft saw a large plume when it flew past Jupiter in December 2000. The Keck telescope in Hawaii picked up renewed heat radiation from Tvashtar in spring 2006, and just two weeks ago the Hubble Space Telescope saw the Tvashtar plume in ultraviolet images designed to support the New Horizons flyby. Most of those images will be stored onboard the spacecraft for downlink to Earth in March and April. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Jupiter Portrait
title Jupiter Portrait
description This true color mosaic of Jupiter was constructed from images taken by the narrow angle camera onboard NASA's Cassini spacecraft on December 29, 2000, during its closest approach to the giant planet at a distance of approximately 10 million kilometers (6.2 million miles). It is the most detailed global color portrait of Jupiter ever produced, the smallest visible features are approximately 60 kilometers (37 miles) across. The mosaic is composed of 27 images: nine images were required to cover the entire planet in a tic-tac-toe pattern, and each of those locations was imaged in red, green, and blue to provide true color. Although Cassini's camera can see more colors than humans can, Jupiter's colors in this new view look very close to the way the human eye would see them. Everything visible on the planet is a cloud. The parallel reddish-brown and white bands, the white ovals, and the large Great Red Spot persist over many years despite the intense turbulence visible in the atmosphere. The most energetic features are the small, bright clouds to the left of the Great Red Spot and in similar locations in the northern half of the planet. These clouds grow and disappear over a few days and generate lightning. Streaks form as clouds are sheared apart by Jupiter's intense jet streams that run parallel to the colored bands. The prominent dark band in the northern half of the planet is the location of Jupiter's fastest jet stream, with eastward winds of 480 kilometers (300 miles) per hour. Jupiter's diameter is eleven times that of Earth, so the smallest storms on this mosaic are comparable in size to the largest hurricanes on Earth. Unlike Earth, where only water condenses to form clouds, Jupiter's clouds are made of ammonia, hydrogen sulfide, and water. The updrafts and downdrafts bring different mixtures of these substances up from below, leading to clouds at different heights. The brown and orange colors may be due to trace chemicals dredged up from deeper levels of the atmosphere, or they may be byproducts of chemical reactions driven by ultraviolet light from the Sun. Bluish areas, such as the small features just north and south of the equator, are areas of reduced cloud cover, where one can see deeper. For more information, see the Cassini Project home page, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org. The imaging team is based at the Space Science Institute, Boulder, Colo. A high-resolution TIFF version of this image is available at http://photojournal.jpl.nasa.gov/catalog/PIA04866. *Image Credit*: NASA/JPL/Space Science Institute
Hubble Discovers Missing Pie …
Title Hubble Discovers Missing Pieces of Comet Linear
IC 418: The "Spirograph" Neb …
Title IC 418: The "Spirograph" Nebula
General Information What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. Back to top [ #top ]
Astronomers Puzzled over Com …
Title Astronomers Puzzled over Comet LINEAR's Missing Pieces
Celestial Fireworks
Title Celestial Fireworks
General Information What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. Back to top [ #top ]
A Giant Hubble Mosaic of the …
Title A Giant Hubble Mosaic of the Crab Nebula
Los Angeles Faults
Title Los Angeles Faults
Description Los Angeles, Calif., is one of the world's largest metropolitan areas with a population of about 15 million people. The urban areas mostly cover the coastal plains and lie within the inland valleys. The intervening and adjacent mountains are generally too rugged for much urban development. This is in large part because the mountains are "young," meaning they are still building (and eroding) in this seismically active (earthquake prone) region. Earthquake faults commonly lie between the mountains and the lowlands. The San Andreas fault, the largest fault in California, likewise divides the very rugged San Gabriel Mountains from the low-relief Mojave Desert, thus forming a straight topographic boundary between the top center and lower right corner of the image. We present this perspective image from NASA's Shuttle Radar Topography Mission (SRTM) with a graphic overlay that maps faults that have been active in Late Quaternary times (white lines). The fault database was provided by the U.S. Geological Survey. The Landsat image used here was acquired on May 4, 2001, about seven weeks before the summer solstice, so natural terrain shading is not particularly strong. It is also not especially apparent given a view direction (northwest) nearly parallel to the sun illumination (shadows generally fall on the backsides of mountains). Consequently, topographic shading derived from the SRTM elevation model was added to the Landsat image, with a false sun illumination from the left (southwest). This synthetic shading enhances the appearance of the topography. Size: View width 134 kilometers (83 miles), view distance 150 kilometers (93 miles) Location: 34.3 degrees North latitude, 118.4 degrees West longitude Orientation: View west-northwest, 1.8 X vertical exaggeration Image Data: Landsat Bands 3, 2+4, 1 as red, green, blue, respectively Original Data Resolution: SRTM 1 arcsecond (30 meters or 98 feet), Landsat 30 meters (98 feet) Graphic Data: Earthquake faults active in Late Quaternary times Date Acquired: February 2000 (SRTM), May 4, 2001 (Landsat). Image Courtesy SRTM Team [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://www.jpl.nasa.gov/srtm/ ] NASA/JPL/NIMA and Landsat 7 Science Team [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://landsat7.usgs.gov/ ] NASA GSFC/USGS
Eros At Sunset
Title Eros At Sunset
Explanation Gleaming in the rays of the setting sun, boulders litter the rugged surface of asteroid 433 Eros [ http://near.jhuapl.edu/eros/ ]. The brightest boulder, at the edge of the large, shadowy crater near this picture's bottom center, is about 30 meters (100 feet) across. In orbit around Eros since February 2000, the NEAR Shoemaker [ http://near.jhuapl.edu/NEAR/ ] spacecraft's camera recorded the dramatic view [ http://near.jhuapl.edu/NEAR/iod/20000821/index.html ] earlier this month from an altitude of about 50 kilometers. Eros itself orbits [ http://www.fwkc.com/encyclopedia/low/articles/o/ o018000416f.html ] the Sun with a perihelion [ http://imagine.gsfc.nasa.gov/docs/ dictionary.html#perihelion ] of 1.13 Astronomical Units [ http://imagine.gsfc.nasa.gov/docs/ask_astro/ answers/980122b.html ] (AU) and aphelion [ http://imagine.gsfc.nasa.gov/docs/ dictionary.html#aphelion ] of 1.78 AU. Part of a class of near-Earth asteroids [ http://neo.jpl.nasa.gov/neo.html ], it spends much of its time between the orbits of Mars (at 1.5 AU) and Earth (at 1 AU) ... but it wasn't always that way. Eros and other near-Earth asteroids [ http://neo.planetary.org/ABCsOfNEOs/index.html ] originally orbited in the main asteroid belt [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ asteroids.html ], between Jupiter [ http://galileo.jpl.nasa.gov/jupiter/jupiter.html ] and Mars [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ marsfact.html ]. Over time, the gravitational influence of Jupiter and other planets perturbed their orbits sending them on trajectories closer [ http://antwrp.gsfc.nasa.gov/apod/ap000226.html ] to Earth.
Asteroid Eros Reconstructed
Title Asteroid Eros Reconstructed
Explanation Orbiting the Sun [ http://www.nineplanets.org/sol.html ] between Mars [ http://pds.jpl.nasa.gov/planets/welcome/mars.htm ] and Earth [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-earth.html ], asteroid 433 Eros was visited by the robot spacecraft NEAR-Shoemaker [ http://near.jhuapl.edu/intro/faq.html ] in 2000 February. High-resolution surface measurements made by NEAR [ http://near.jhuapl.edu/NEAR/ ]'s Laser Rangefinder (NLR [ http://near.jhuapl.edu/instruments/NLR/index.html ]) have been combined into the above visualization [ http://svs.gsfc.nasa.gov/imagewall/eros.html ] based on the derived 3D model [ http://svs.gsfc.nasa.gov/imagewall/ eros.html#eros ] of the tumbling space rock [ http://antwrp.gsfc.nasa.gov/apod/ap000210.html ]. NEAR allowed scientists to discover that Eros [ http://www.gsfc.nasa.gov/GSFC/SpaceSci/Near/eros.htm ] is a single solid body, that its composition is nearly uniform, and that it formed during the early years of our Solar System [ http://www.nineplanets.org/overview.html ]. Mysteries remain, however, including why some rocks on the surface have disintegrated. On 2001 February 12, the NEAR mission drew to a dramatic close as it was crash landed [ http://antwrp.gsfc.nasa.gov/apod/ap010212.html ] onto the asteroid's surface [ http://antwrp.gsfc.nasa.gov/apod/ap000803.html ], surviving well enough [ http://antwrp.gsfc.nasa.gov/apod/ap010213.html ] to return an analysis of the composition [ http://antwrp.gsfc.nasa.gov/apod/ap010305.html ] of the surface regolith [ http://antwrp.gsfc.nasa.gov/apod/ap000829.html ]. Unless re-awakened by NASA [ http://www.nasa.gov/ ], NEAR will likely remain on the asteroid [ http://antwrp.gsfc.nasa.gov/apod/ap000327.html ] for billions of years as a monument to human ingenuity at the turn of the third millennium [ http://antwrp.gsfc.nasa.gov/apod/ap010101.html ].
Jupiter and Saturn Pas de De …
Title Jupiter and Saturn Pas de Deux
Explanation Viewed from [ http://space.jpl.nasa.gov/ ] Earth, the solar system's [ http://solarsystem.nasa.gov/features/planets/ planetsfeat.html ] planets do a cosmic dance that is hard to appreciate on any single night. But consider this well planned animated sequence combining 23 pictures taken at approximately 2 week intervals from June 2000 through May 2001. It reveals the graceful looping or retrograde motion [ http://alpha.lasalle.edu/~smithsc/Astronomy/ retrograd.html ] of bright wanderers [ http://spacekids.hq.nasa.gov/osskids/animate/ mac.html ] Jupiter (leftmost) and Saturn. Loitering among the background stars are the familiar Pleiades (above right) and V-shaped Hyades (below left) star clusters [ http://hou.lbl.gov/~vhoette/Explorations/ StarHop/hyades_pleiades.html ]. The planets didn't actually loop [ http://antwrp.gsfc.nasa.gov/apod/ap010601.html ] by reversing the direction of their orbits, though. Their apparent retrograde motion [ http://www.scienceu.com/observatory/articles/ retro/retro.html ] is a reflection of the motion [ http://faculty.fullerton.edu/cmcconnell/Planets.html ] of the Earth itself. Retrograde motion [ http://csep10.phys.utk.edu/astr161/lect/retrograde/ retrograde.html ] can be seen each time Earth overtakes and laps [ http://www.physics.uci.edu/~wtruppel/ AstroPage.html ] planets orbiting farther from the Sun, Earth moving more rapidly through its own relatively close-in orbit. Astronomer Tunc Tezel captured Jupiter and Saturn's "paired" retrograde loop in this remarkable series made after the close alignment [ http://antwrp.gsfc.nasa.gov/apod/ap000505.html ] of these gas giants in May 2000. The next opportunity to see these two planets dance such a pas de deux will be in the year 2020.
A Change of Seasons on Satur …
Title A Change of Seasons on Saturn - October, 2000
Description Looming like a giant flying saucer in our outer solar system, Saturn puts on a show as the planet and its magnificent ring system nod majestically over the course of its 29-year journey around the Sun. A series of Hubble Space Telescope images, captured from 1996 to 2000, show Saturn's rings open up from just past edge-on to nearly fully open as it moves from autumn towards winter in its Northern Hemisphere (for the composite view of all images seePIA03156 [ http://photojournal.jpl.nasa.gov/catalog/PIA03156 ]. Saturn's equator is tilted relative to its orbit by 27 degrees, very similar to the 23-degree tilt of the Earth. As Saturn moves along its orbit, first one hemisphere, then the other is tilted towards the Sun. This cyclical change causes seasons on Saturn, just as the changing orientation of Earth's tilt causes seasons on our planet. The first image in this sequence, on the lower left, was taken soon after the autumnal equinox in Saturn's Northern Hemisphere (which is the same as the spring equinox in its Southern Hemisphere). By the final image in the sequence, on the upper right, the tilt is nearing its extreme, or winter solstice in the Northern Hemisphere (summer solstice in the Southern Hemisphere). Astronomers are studying this set of images to investigate the detailed variations in the color and brightness of the rings. They hope to learn more about the rings' composition, how they were formed, and how long they might last. Saturn's rings are incredibly thin, with a thickness of only about 30 feet (10 meters). The rings are made of dusty water ice, in the form of boulder-sized and smaller chunks that gently collide with each other as they orbit around Saturn. Saturn's gravitational field constantly disrupts these ice chunks, keeping them spread out and preventing them from combining to form a moon. The rings, as shown here, have a slight pale reddish color due to the presence of organic material mixed with the water ice. Saturn is about 75,000 miles (120,000 km) across, and is flattened at the poles because of its very rapid rotation. A day is only 10 hours long on Saturn. Strong winds account for the horizontal bands in the atmosphere of this giant gas planet. The delicate color variations in the clouds are due to smog in the upper atmosphere, produced when ultraviolet radiation from the Sun shines on methane gas. Deeper in the atmosphere, the visible clouds and gases merge gradually into hotter and denser gases, with no solid surface for visiting spacecraft to land on. The Cassini/Huygens spacecraft, launched from Earth in 1997, is well on its way to the Saturn system. It will arrive in 2004 to land a probe on Titan, Saturn's largest moon, and to orbit the planet for four years for a detailed study of the entire Saturn system. These images of Saturn were taken with the Wide Field Planetary Camera 2 onboard Hubble.
Date 06.07.2001
Nine Frames as Jupiter Turns
Title Nine Frames as Jupiter Turns
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.
Date 11.06.2000
Collapsing Cliff at Telegonu …
Title Collapsing Cliff at Telegonus Mensa, Io
Description These images of an area called Telegonus Mensa on Jupiter's moon Io, taken by NASA's Galileo spacecraft on Oct. 16, 2001, reveal a complex interplay of geologic processes. Four small, high-resolution frames (9.6 meters, or 32 feet, per picture element) have been set into the larger context mosaic, which has a resolution of 42 meters (140 feet) per picture element. The illumination is from the upper right and north is to the top of the mosaic. A fracture runs northwest from the lower right corner of the mosaic into the amphitheater in the center of the frame. A high-resolution image along this fracture reveals that lava has erupted from it. The amphitheater itself is the site of extensive erosion, as the cliff has slumped southeastward under the influence of Io's gravity. High-resolution frames directly south of the amphitheater show another slumping cliff in detail. Flat tops of massive slump blocks -- up to 6 kilometers (3.7 miles) long and 0.5 kilometers (0.3 miles) across -- are illuminated by the Sun and cast shadows down the face of the cliff. Based on these shadows, Galileo scientists estimate that the cliff is 1 to 2 kilometers (3300 to 6600 feet) high. Just to the left of center a series of landslides can be seen, the longest of which extends 4 kilometers (2.5 miles). The mosaic is centered at 21.45 degrees south latitude and 124.8 degrees west longitude and is 67 kilometers (42 miles) across. 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. Additional information about Galileo and its discoveries is available on the Galileo mission home page athttp://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educationalcontext for the images can be found athttp://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].
Date 05.31.2000
Detailed View of Mountain an …
Title Detailed View of Mountain and Craters at Tohil, Io
Description Scientists pointed NASA's Galileo spacecraft camera at the Tohil region of Jupiter's moon Io to investigate the curious relationship between Io's mountains and its volcanoes. This mosaic of Galileo images taken Oct. 16, 2001, shows details of the mountain called Tohil Mons (lower left), a small dark-floored volcanic crater, or "patera," bordered by mountain walls (middle), and intricate patterns of dark lava flows intertwined with bright material on the floor of a larger crater, Tohil Patera (upper right). An earlierstereoobservation [ http://photojournal.jpl.nasa.gov/catalog/PIA02586 ]by Galileo revealed that Tohil Mons rises up to 6 kilometers (19,700 feet) above the surrounding plains. In contrast, shadows in the new images indicate the two paterae are only about 100 meters (330 feet) deep. The new images were taken soon after sunrise at Tohil, with a resolution of 50 meters (160 feet) per picture element to reveal details never seen before.Another view showing the entire mountain at lower resolution [ http://photojournal.jpl.nasa.gov/catalog/PIA03600 ]was also acquired. Despite Io's extremely high rate of volcanic activity, its mountains do not resemble volcanoes seen elsewhere in the solar system. Instead, the mountains appear to be formed by the uplift of large blocks of Io's crust. This image shows evidence of numerous landslides from the mountain (bottom left). However, one of the most surprising revelations from this observation is that despite the closeness of the small, dark-floored patera to the mountain walls, the patera floor is not covered with any landslide debris. This indicates that the patera floor has been resurfaced with lava more recently than any landslides have occurred. Another possibility is that this patera, likeothers on Io [ http://photojournal.jpl.nasa.gov/catalog/PIA02596 ]is actually a lava lake and completely consumes debris that falls into it from the mountain. Galileo's infrared-mapping instrument has detected heat from the patera, indicating an active or very recent eruption. North is to the top of the picture and the Sun illuminates the surface from the right. The mosaic is centered at 27.5 degrees south latitude and 160 degrees west longitude and covers 280 kilometers (170 miles) from upper right to lower left. 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. Additional information about Galileo and its discoveries is available on the Galileo mission home page athttp://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educationalcontext for the images can be found athttp://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].
Date 05.31.2000
Rotten Egg Nebula
Title Rotten Egg Nebula
Description Violent gas collisions that produced supersonic shock fronts in a dying star are seen in a new, detailed image from NASA's Hubble Space Telescope. The picture, taken by Hubble's Wide Field and Planetary Camera 2, is online at http://www.jpl.nasa.gov/images/wfpc . The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Stars like our Sun will eventually die and expel most of their material outward into shells of gas and dust. These shells eventually form some of the most beautiful objects in the universe, called planetary nebulae."This new image gives us a rare view of the early death throes of stars like our Sun. For the first time, we can see phenomena leading to the formation of planetary nebulae. Until now, this had only been predicted by theory, but had never been seen directly," said Dr. Raghvendra Sahai, research scientist and member of the science team at JPL for the Wide Field and Planetary Camera 2. The object is sometimes called the Rotten Egg Nebula, because it contains a lot of sulphur, which would produce an awful odor if one could smell in space. The object is also known as the Calabash Nebula or by the technical name OH231.8+4.2. The densest parts of the nebula are composed of material ejected recently by the central star and accelerated in opposite directions. This material, shown as yellow in the image, is zooming away at speeds up to one and a half million kilometers per hour (one million miles per hour). Most of the star's original mass is now contained in these bipolar gas structures. A team of Spanish and American astronomers used NASA's Hubble Space Telescope to study how the gas stream rams into the surrounding material, shown in blue. They believe that such interactions dominate the formation process in planetary nebulae. Due to the high speed of the gas, shock-fronts are formed on impact and heat the surrounding gas. Although computer calculations have predicted the existence and structure of such shocks for some time, previous observations have not been able to prove the theory. This new Hubble image used filters that only let through light from ionized hydrogen and nitrogen atoms. Astronomers were able to distinguish the warmest parts of the gas heated by the violent shocks and found that they form a complex double-bubble shape. The bright yellow-orange colors in the picture show how dense, high-speed gas is flowing from the star, like supersonic speeding bullets ripping through a medium in opposite directions. The central star itself is hidden in the dusty band at the center. Much of the gas flow observed today seems to stem from a sudden acceleration that took place only about 800 years ago. The astronomers believe that 1,000 years from now, the Calabash Nebula will become a fully developed planetary nebula, like a butterfly emerging from its cocoon. The Calabash Nebula is 1.4 light years (more than 8 trillion miles) long and located some 5,000 light years (2,900 trillion, miles) from Earth in the constellation Puppis. The image was taken in December 2000 by the Wide Field and Planetary Camera 2. The image was originally released by the Hubble European Space Agency Information Centre, with a website at http://sci.esa.int/hubble. Additional information about the Hubble Space Telescope is online at http://www.stsci.edu . More information about the Wide Field and Planetary Camera 2 is at http://wfpc2.jpl.nasa.gov . Other scientists on the team include Valentin Bujarrabal and Javier Alcolea of Observatorio Astronomico Nacional, Spain, and Carmen Sanchez Contreras of JPL. The Space Telescope Science Institute, Baltimore, Md., manages space operations for Hubble for NASA's Office of Space Science, Washington, D.C. The institute is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. JPL is a division of the California Institute of Technology in Pasadena.
Date 12.02.1999
Doradus Nebula
Title Doradus Nebula
Description A panoramic view of a vast, sculpted area of gas and dust where thousands of stars are being born has been captured by NASA's Hubble Space Telescope. The image, taken by Hubble's Wide Field and Planetary Camera 2, is online at http://oposite.stsci.edu/pubinfo/pr/2001/21 and http://www.jpl.nasa.gov/images/wfpc . The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. The photo offers an unprecedented, detailed view of the entire inner region of the fertile, star-forming 30 Doradus Nebula. The mosaic picture shows that ultraviolet radiation and high-speed material unleashed by the stars in the cluster, called R136 (the large blue blob left of center), are weaving a tapestry of creation and destruction, triggering the collapse of looming gas and dust clouds and forming pillar-like structures that incubate newborn stars. The 30 Doradus Nebula is in the Large Magellanic Cloud, a satellite galaxy of the Milky Way located 170,000 light-years from Earth. Nebulas like 30 Doradus are signposts of recent star birth. High-energy ultraviolet radiation from young, hot, massive stars in R136 causes surrounding gaseous material to glow. Previous Hubble telescope observations showed that R136 contains several dozen of the most massive stars known, each about 100 times the mass of the Sun and about 10 times as hot. These stellar behemoths formed about 2 million years ago. The stars in R136 produce intense "stellar winds," streams of material traveling at several million miles an hour. These winds push the gas away from the cluster and compress the inner regions of the surrounding gas and dust clouds (seen in the image as the pinkish material). The intense pressure triggers the collapse of parts of the clouds, producing a new star formation around the central cluster. Most stars in the nursery are not visible because they are still encased in cocoons of gas and dust. This mosaic image of 30 Doradus consists of five overlapping pictures taken between January 1994 and September 2000 by the Wide Field and Planetary Camera 2. Several color filters enhance important details in the stars and the nebula. Blue corresponds to the hot stars. The greenish color denotes hot gas energized by the central cluster of stars. Pink depicts the glowing edges of the gas and dust clouds facing the cluster, which are being bombarded by winds and radiation. Reddish-brown represents the cooler surfaces of the clouds, which are not receiving direct radiation from the central cluster. Additional information about the Hubble Space Telescope is at http://www.stsci.edu . More information about the Wide Field and Planetary Camera 2 is at http://wfpc2.jpl.nasa.gov . The Space Telescope Science Institute, Baltimore, Md., manages space operations for Hubble for NASA's Office of Space Science, Washington, D.C. The institute is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract with the Goddard Space Flight, Center, Greenbelt, Md. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. JPL is a division of the California Institute of Technology in Pasadena.
Date 12.01.1999
Galileo's Best View of Loki …
Title Galileo's Best View of Loki Volcano on Io
Description Light from the setting Sun falls across the Loki volcanic region on Jupiter's moon Io in this image taken by NASA's Galileo spacecraft on Oct. 16, 2001. The image was taken to examine the relative depths and heights of features in the region. The Sun illuminates the surface from the right. Galileo's camera caught the large volcanic crater, or "patera" of Loki near the boundary between night and day. The image also shows several smaller craters plus shadows cast by the high peaks of several mountains. Shadows cast by the low sun should reveal any topography associated with Loki, such as a plateau in the center of the patera or high patera walls. The near absence of shadows in this region surprised Galileo scientists, as they had expected much more pronounced topography near Loki. Another surprising aspect of this image is that features that have been black in previousVoyager [ http://photojournal.jpl.nasa.gov/catalog/PIA00375 ]andGalileo [ http://photojournal.jpl.nasa.gov/catalog/PIA02588 ]images of Loki, such as the dark lava flows inside the patera, are here brighter than their surroundings. The best explanation is that the shiny, glassy surfaces of chilled lava flows look extremely dark when the Sun is directly overhead, but they reflect the Sun's light comparatively well when it shines at a low angle, in a similar manner to the reflective surfaces of bodies of water. Other volcanic paterae in this image show the same unusual reflectance as seen at Loki. Some of them are being viewed at such an angle that these reflections from lava flows are the brightest features in the image. This image tells us that lava flows on Io chill quickly and form glassy surfaces, not unlike recently cooled lava flows in Hawaii. The image has a resolution of 1.1 kilometers (0.7 miles) per picture element. North is to the top of the picture. 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. Additional information about Galileo and its discoveries is available on the Galileo mission home page athttp://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].
Date 05.31.2000
Two Very Different Asteroids
Title Two Very Different Asteroids
Description The NEAR Shoemaker spacecraft has scored two important firsts in the exploration of asteroids: it's the first to orbit an asteroid, Eros, and the first to encounter a denizen of the outer reaches of the asteroid belt, the C-type asteroid Mathilde. In a scheme that reflects how they have historically been a topic for astronomy, not geology, asteroids are classified into groups based on their colors as observed through telescopes. The two major classes of asteroids are called S-types and C-types. S-types, whose colors are consistent with "stony" or rocky compositions, prevail among asteroids that orbit closer to the Sun than the mid-point of the asteroid belt. Eros and the two asteroids encountered briefly by the Galileo spacecraft on its way to Jupiter -- Gaspra and Ida -- are all S-types. C-types like Mathilde have a dark gray color consistent with a "carbonaceous" composition, rich in carbon compounds and other dark materials. They prevail in the outer part of the asteroid belt. In this montage, Mathilde (at left) and Eros (at right) are shown at the same scale, as they were imaged by NEAR Shoemaker from about 1,800 kilometers (1,116 miles) on June 27, 1997, and February 12, 2000, respectively. Mathilde is 56 kilometers (35 miles) across, and Eros is 33 kilometers (21 miles) long and 13 kilometers (8 miles) wide. However, Mathilde's brightness is greatly exaggerated for viewing purposes -- it's actually six times darker than Eros, with about the same reflectivity as soot! Built and managed by The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, NEAR was the first spacecraft launched in NASA's Discovery Program of low-cost, small-scale planetary missions. See the NEAR web page at http://near.jhuapl.edu for more details.
Date 03.30.2000
Jovian Ring System Mosaic
Title Jovian Ring System Mosaic
Description NASA's Galileo spacecraft acquired this mosaic of Jupiter's ring system (top) when the spacecraft was in Jupiter's shadow looking back toward the Sun. Jupiter's ring system (inset diagram) is composed of three parts: an outermost gossamer ring, a flat main ring, and an innermost donut-shaped halo. These rings are made up of dust-sized particles that are blasted off of the nearby inner satellites by small impacts. This image was taken on November 9, 1996 at a distance of 2.3 million kilometers (1.4 million miles).
Date 09.24.2000
Jupiter small satellite mont …
Title Jupiter small satellite montage
Description A montage of images of the small inner moons of Jupiter from the camera onboard NASA's Galileo spacecraft shows the best views obtained of these moons during Galileo's 11th orbit around the giant planet in November 1997. At that point, Galileo was completing its first two years in Jupiter orbit--known as the Galileo "prime mission"--and was about to embark on a successful two-year extension, called the Galileo Europa Mission. The top two images show the moon Thebe. Thebe rotates by approximately 50 degrees between the time these two images were taken, so that the same prominent impact crater is seen in both views, this crater, which has been given the provisional name Zethus, is near the point on Thebe that faces permanently away from Jupiter. The next two images show the moon Amalthea, they were taken with the Sun directly behind the observer, an alignment that emphasizes patterns of intrinsically bright or dark surface material. The third image from the top is a view of Amalthea's leading side, the side of the moon that "leads" as Amalthea moves in its orbit around Jupiter. This image looks "noisy" because it was obtained serendipitously during an observation of the Jovian satellite Io (Amalthea and Io shared the same camera frame but the image was exposed for bright Io rather than for the much darker Amalthea). The fourth image from the top emphasizes prominent "spots" of relatively bright material that are located near the point on Amalthea that faces permanently away from Jupiter. The bottom image is a view of the tiny moon Metis. In all the images, north is approximately up, and the moons are shown in their correct relative sizes. The images are, from top to bottom: Thebe taken on November 7, 1997 at a range of 504,000 kilometers (about 313,000 miles), Thebe on November 7, 1997 at a range of 548,000 kilometers (about 340,000 miles), Amalthea on November 6, 1997 at a range of about 650,000 kilometers (about 404,000 miles), Amalthea on November 7, 1997 at a range of 475,000 kilometers (about 295,000 miles), Metis on November 7, 1997 at a range of 637,000 kilometers (about 396,000 miles).
Date 04.24.2000
Mars and Earth Dust Storms
title Mars and Earth Dust Storms
Description seasonal meteorology [ http://www.thirdworld.org/role.html ] and the health of biological communities [ http://catbert.er.usgs.gov/african_dust/ ]. Photo Credit: NASA/JPL/Malin Space Science Systems, Spring on Mars...in either hemisphere...is a time for local and regional dust storms. These storms arise as the seasonal carbon dioxide frost cap, which can extend almost half-way to the equator, sublimes in the warming spring environment. Several factors promote these dust storms: * the atmospheric pressure is increasing as carbon dioxide frost (CO2) sublimes--higher pressure allows more dust to be suspended, and for a longer time, * the temperature contrast between the frost covered surface and immediately adjacent, recently defrosted surfaces is quite high, creating thermally-generated winds that circulate onto and off of the frost cap edge, * similar, temperature-driven winds arise as sublimation of frost covering sun-facing slopes and dark sandy surfaces deep within the polar region creates intense slope winds away from the higher-standing layered deposits and permanent cap. The roughly circular, polar orbit of the Mars Global Surveyor (MGS) spacecraft affords a view not unlike that seen by low Earth-orbiting environmental satellites. Mars is roughly 6800 km (4226 mi) in diameter, and a 370 km (230 mi) average altitude gives a diameter to altitude ratio for MGS of 18.4:1. For comparison, the SeaStar spacecraft in Earth orbit follows a very similar orbit: it's the diameter to altitude ratio is 17.5:1 (12,760 km or 7,928 mi diameter relative to a 705 km or 438 mi altitude). Each spacecraft covers the entire planet in 12 orbits. In this figure, we compare a recent dust storm on Mars with one that occurred earlier this year on Earth. The top image shows a martian north polar dust storm observed on 29 August 2000. This image is part of the Mars Orbiter Camera (MOC) daily global map--a low resolution, two-color view of Mars acquired from pole to pole every orbit. The storm is moving as a front, outward from a central "jet," and marginal "vortices" can be seen. In this image it extends about 900 km (560 mi) out from the north polar seasonal frost cap. The region on the right side of the Mars picture includes the north pole. The bottom image shows a terrestrial dust storm, seen in a SeaWiFS image [ http://seawifs.gsfc.nasa.gov/SEAWIFS/IMAGES/SEAWIFS_GALLERY.html ], acquired on 26 February 2000. This storm extends about 1800 km (1100 mi) off the coast of northwest Africa near the Earth's equator. Both images are shown at the same scale, 4 km (2.5 mi) per pixel. Dust storms play an important role in governing the climate of Mars. The rare, global storms alter the planet's total heat balance and promote variations in seasonal frost formation and dissipation, and greatly affect the distribution of water vapor. Local and regional storms, especially those in the polar regions, affect the rate at which seasonal frost evolves, and control local and regional weather patterns. On Earth, dust storms are also being recognized as contributing to environmental change, potentially influencing
Changes Over a Martian Year …
title Changes Over a Martian Year -- New Dark Slope Streaks in Lycus Sucli
Description Now in its Extended Mission, Mars Global Surveyor (MGS) is into its second Mars year of systematic observations of the red planet. With the Extended Mission slated to run through April 2002, the Mars Orbiter Camera (MOC) is being used, among other things, to look for changes that have occurred in the past martian year. Because Mars is farther from the Sun than Earth, its year is longer---about 687 Earth days. The two pictures shown here cover the same portion of Lycus Sulci, a rugged, ridged terrain north of the giant Olympus Mons volcano. The interval between the pictures span 92% of a martian year (August 2, 1999 to April 27, 2001). Dark streaks considered to result from the avalanching of dry, fine, bright dust are seen in both images. The disruption of the surface by the avalanching materials is thought to cause them to appear darker than their surroundings, just as the 1997 bouncing of Mars Pathfinder's airbags and the tire tracks made by the Sojourner rover left darkened markings indicating where the martian soil had been disrupted and disturbed. The arrows in the April 2001 picture indicate eight new streaks that formed on these slopes in Lycus Sulci since August 1999. These observations suggest that a new streak forms approximately once per martian year per kilometer (about 0.62 miles) along a slope. In both images, north is toward the top/upper right and sunlight illuminates each from the left. Dark (as well bright) slope streaks are most common in the dust-covered martian regions of Tharsis, Arabia, and Elysium. Additional examples of dark slope streaks can be seen in the following earlier MOC image media releases: * "Recent Movements: New Landslides in Less than 1 Martian Year," March 12, 2000 [ http://www.msss.com/mars_images/moc/lpsc2000/3_00_massmovement/ ] * "Dark Slope Streaks on Elysium Basin Buttes," July 19, 1999 [ http://www.msss.com/mars_images/moc/7_19_99_fifthMars/18_slopes/ ] Images Credit: NASA/JPL/Malin Space Science Systems
Description Cydonia comparison In July of 1976 the Viking 1 Orbiter imaged an area of the Cydonia region located in the northern latitudes of Mars. NASA released an image of a surface feature that due to sun angle and shadows gave the appearance of a human "face." The feature is 1.5 kilometers (one mile) across. It was imaged from a range of range of 1,873 kilometers (1,164 miles) with a resolution of 30 meters (98 feet) per pixel. Data transmission drop-out errors produced the speckled appearance of the image. NASA contended that the feature was formed by natural geological processes, however, other groups speculated that the feature was an artifact formed by intelligent means. The Mars Global Surveyor mission has imaged the Cydonia area multiple times in an effort to resolve the public debate over the origin of features in this region. In 2001 the Mars Global Surveyor mission succeeded in imaging Cydonia from altitude of 450 km (280 miles) with a resolution of approximately 2 m (6.5 feet) per pixel. Below are links to MGS pages giving more information on Cydonia. Highest Resolution MOC Images of Cydonia Region Released in May 2001:http://www.msss.com/mars_images/moc/extended_may2001/face/index.html [ http://www.msss.com/mars_images/moc/extended_may2001/face/index.html ] Compilation of MGS MOC Images of Cydonia Released in April 2000:http://mars.jpl.nasa.gov/mgs/msss/camera/images/4_5_00_cydonia/index.html [ http://mars.jpl.nasa.gov/mgs/msss/camera/images/4_5_00_cydonia/index.html ] First MGS MOC Images of Cydonia Released in April 1998:http://mars.jpl.nasa.gov/mgs/msss/camera/images/face.html [ http://mars.jpl.nasa.gov/mgs/msss/camera/images/face.html ]http://mars.jpl.nasa.gov/mgs/target/index.html [ http://mars.jpl.nasa.gov/mgs/target/index.html ]
ASTER Andes
PIA02654
Sol (our sun)
ASTER
Title ASTER Andes
Original Caption Released with Image In this image of the Andes along the Chile-Bolivia border, the visible and infrared data have been computer enhanced to exaggerate the color differences of the different materials. The scene is dominated by the Pampa Luxsar lava complex, occupying the upper right two-thirds of the scene. Lava flows are distributed around remnants of large dissected cones, the largest of which is Cerro Luxsar. On the middle left edge of the image are the Olca and Parumastrato volcanoes, which appear in blue due to a lack of vegetation (colored red in this composite). This image covers an area 60 kilometers (37 miles) wide and 60 kilometers (37 miles) long in three bands of the reflected visible and infrared wavelength region. It was acquired on April 7, 2000. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader, Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface. The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial advances and retreats, potentially active volcanoes, thermal pollution, and coral reef degradation, identifying crop stress, determining cloud morphology and physical properties, evaluating wetlands, mapping surface temperature of soils and geology, and measuring surface heat balance.
ASTER Images San Francisco B …
PIA02606
Sol (our sun)
ASTER
Title ASTER Images San Francisco Bay Area
Original Caption Released with Image This image of the San Francisco Bay region was acquired on March 3, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters about 50 to 300 feet ), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet. Image: This image covers an area 60 kilometers (37 miles) wide and 75 kilometers (47 miles) long in three bands of the reflected visible and infrared wavelength region. The combination of bands portrays vegetation in red, and urban areas in gray. Sediment in the Suisun Bay, San Pablo Bay, San Francisco Bay, and the Pacific Ocean shows up as lighter shades of blue. Along the west coast of the San Francisco Peninsula, strong surf can be seen as a white fringe along the shoreline. A powerful rip tide is visible extending westward from Daly City into the Pacific Ocean. In the lower right corner, the wetlands of the South San Francisco Bay National Wildlife Refuge appear as large dark blue and brown polygons. The high spatial resolution of ASTER allows fine detail to be observed in the scene. The main bridges of the area (San Mateo, San Francisco-Oakland Bay, Golden Gate, Richmond-San Rafael, Benicia-Martinez, and Carquinez) are easily picked out, connecting the different communities in the Bay area. Shadows of the towers along the Bay Bridge can be seen over the adjacent bay water. With enlargement the entire road network can be easily mapped, individual buildings are visible, including the shadows of the high-rises in downtown San Francisco. Inset: This enlargement of the San Francisco Airport highlights the high spatial resolution of ASTER. With further enlargement and careful examination, airplanes can be seen at the terminals. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader, Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface. The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example, applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance.
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