Galerie de photos de la planète Jupiter

<h1>PIA01524: Jupiter's Equatorial Zone in Exaggerated Color</h1><div class="PIA01524" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This special color composite made from Voyager 2 narrow-angle frames taken on June 28, 1979, has been processed to exaggerate color differences within the naturally colorful Jovian atmosphere. Such processing makes detailed structure in the clouds more apparent. The dark belt across the upper portion of the photograph is the North Equatorial Belt. One of the largest of the long-lived dark features found along the northern edge of this belt is seen in the upper middle of the photograph. Jupiter's Equatorial Zone, which lies across the middle of the photograph, is characterized by a series of wisp-like plume features. The northern bluish edges of these plumes are thought to lie within deeper, warmer levels of the atmosphere. South of the Equatorial Zone lies the chaotic region of whiter clouds found west of the Great Red Spot. kilometers (6.4 million miles) from Jupiter. The smallest features visible in this photograph are about 190 kilometers (119 miles) across.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01524" onclick="window.open(this.href); return false;" title="Voir l'image PIA01524: Jupiter's Equatorial Zone in Exaggerated Color sur le site de la NASA">Voir l'image PIA01524: Jupiter's Equatorial Zone in Exaggerated Color sur le site de la NASA.</a></div>
PIA01524: Jupiter's Equatorial Zone in Exaggerated Color
<h1>PIA01594: Hubble Views Ancient Storm in the Atmosphere of Jupiter - Full Disk</h1><div class="PIA01594" lang="en" style="width:718px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">When 17th-century astronomers first turned their telescopes to Jupiter, they noted a conspicuous reddish spot on the giant planet. This Great Red Spot is still present in Jupiter's atmosphere, more than 300 years later. It is now known that it is a vast storm, spinning like a cyclone. Unlike a low-pressure hurricane in the Caribbean Sea, however, the Red Spot rotates in a counterclockwise direction in the southern hemisphere, showing that it is a high-pressure system. Winds inside this Jovian storm reach speeds of about 270 mph.<p>The Red Spot is the largest known storm in the Solar System. With a diameter of 15,400 miles, it is almost twice the size of the entire Earth and one-sixth the diameter of Jupiter itself.<p>The long lifetime of the Red Spot may be due to the fact that Jupiter is mainly a gaseous planet. It possibly has liquid layers, but lacks a solid surface, which would dissipate the storm's energy, much as happens when a hurricane makes landfall on the Earth. However, the Red Spot does change its shape, size, and color, sometimes dramatically. Such changes are demonstrated in high-resolution Wide Field and Planetary Cameras 1 & 2 images of Jupiter obtained by NASA's Hubble Space Telescope between 1992 and 1999(PIA01594 thru PIA01599 and PIA02400 thru PIA02402). This image was obtained in June 1999.<p>A montage representing the entire series of images was prepared by the Hubble Heritage Project team and is available at<a href="/catalog/PIA01593">PIA01593</a>.<p>Astronomers study weather phenomena on other planets in order to gain a greater understanding of our own Earth's climate. Lacking a solid surface, Jupiter provides us with a laboratory experiment for observing weather phenomena under very different conditions than those prevailing on Earth. This knowledge can also be applied to places in the Earth's atmosphere that are over deep oceans, making them more similar to Jupiter's deep atmosphere.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01594" onclick="window.open(this.href); return false;" title="Voir l'image PIA01594: Hubble Views Ancient Storm in the Atmosphere of Jupiter - Full Disk sur le site de la NASA">Voir l'image PIA01594: Hubble Views Ancient Storm in the Atmosphere of Jupiter - Full Disk sur le site de la NASA.</a></div>
PIA01594: Hubble Views Ancient Storm in the Atmosphere of Jupiter - Full Disk
<h1>PIA01636: Changing Lightning Storms on Jupiter</h1><div class="PIA01636" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This view shows lightning storms in three different locations (panels 1, 2, and 3) on Jupiter's night side. Each panel shows multiple lightning strikes, coming from different parts of the same storm. The lightning originates in Jupiter's water cloud, which is 50 to 75 kilometers (30 to 45 miles) below the ammonia cloud. The latter acts as a translucent screen, diffusing the light over an area comparable to the depth. The individual strikes are unresolved in these images, which have a resolution of 133 kilometers (80 miles) per picture element.</p><p>The brightest strikes emit as much light energy as 30 million 100-watt light bulbs burning for one second, which makes the strikes hundreds of times brighter than lightning on Earth. The bottom row shows the same three storms as the top row but the bottom-row images were taken two minutes later. The images were taken in the clear filter with an exposure time of 90 seconds. Clouds, illuminated by light reflected off Jupiter's moon Io, can be seen in the background. Moonlight on Jupiter is 100,000 times fainter than sunlight, and the lightning flashes would be undetectable on the day side of the planet.</p><p>North is at the top of the picture. The planetocentric latitudes and west longitudes (in degrees) of the storms in panels 1 through 3 are (34.4, 16.1), (23.4, 27.6), and (8.6, 15.6), respectively. The panels are 8,000 kilometers (5,000 miles) on a side. The images in the top row were taken on October 6, 1997 at Universal Times (in hours:minutes:seconds), of 00:15:01, 00:17:03, and 00:17:03, respectively, by the solid state imaging camera system onboard NASA's Galileo spacecraft. Distance from the planet to the spacecraft was 6.62 million kilometers (4.1 million miles).</p><p>JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC.</p><p>This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at <a href="http://galileo.jpl.nasa.gov"> http://galileo.jpl.nasa.gov</a>. Background information and educational context for the images can be found at <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01636" onclick="window.open(this.href); return false;" title="Voir l'image PIA01636: Changing Lightning Storms on Jupiter sur le site de la NASA">Voir l'image PIA01636: Changing Lightning Storms on Jupiter sur le site de la NASA.</a></div>
PIA01636: Changing Lightning Storms on Jupiter
<h1>PIA01638: Jovian Lightning and the Daytime Storm</h1><div class="PIA01638" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This picture highlights a convective storm (left panel) and the associated lightning (right panels) in Jupiter's atmosphere. The left image shows the dayside view. The right images show the area highlighted (box) in the dayside view as it appeared 110 minutes later during the night. Multiple lightning strikes are visible in the night side images, which were taken 3 minutes and 38 seconds apart. The bright, cloudy area in the dayside view is similar in appearance to a region of upwelling in Earth's atmosphere. The dark, clear region to the west (left) appears similar to a region of downwelling in Earth's atmosphere. The presence of lightning confirms that this is a site of moist convection.</p><p>The lightning originates below the visible ammonia cloud, which acts as a translucent screen, diffusing the light over a wider area. This apparent width can be used to infer the depth of approximately 75 kilometers (46 miles). This figure is consistent with the hypothesis that lightning originates in the Jovian water cloud at about 75 kilometers (46 miles) depth.</p><p>To show details of the lightning, the nightside images have been expanded by a factor of two relative to the dayside image. The latitude and longitude scale is shown around the left panel. On Jupiter, one degree of latitude spans a distance of 1,200 kilometers (744 miles), so the highlighted area is approximately 2,400 kilometers (1,488 miles) on a side. The resolution is 23 kilometers (14 miles) per picture element. The dayside image was taken through the 727 nanometer filter with an exposure of 0.529 seconds at 23:03:03 Universal Time on November 7, 1997. The upper night side image was taken through the red filter with an exposure of 166.9 seconds in gain state 1 at 00:49:590 Universal Time on November 8, 1997. The bottom night side image was taken through the red filter with an exposure of 38.9 seconds in gain state 2 at 00:53:37 Universal Time on November 8, 1997. The signal to noise ratio is greater in the lower night side image because the gain state is higher. The images were taken by the solid state imaging camera system on NASA's Galileo spacecraft at a range of 1.1 million kilometers (680,000 miles).</p><p>JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC.</p><p>This image and other images and data received from Galileo are posted on the World Wide Web on the Galileo mission home page at <a href="http://www2.jpl.nasa.gov/galileo.jpl.nasa.gov">http://www.jpl.nasa.gov/galileo.jpl.nasa.gov</a>. Background information and educational context for the images can be found at <a href="http://www2.jpl.nasa.gov/galileo/sepo"><a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>.</a>.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01638" onclick="window.open(this.href); return false;" title="Voir l'image PIA01638: Jovian Lightning and the Daytime Storm sur le site de la NASA">Voir l'image PIA01638: Jovian Lightning and the Daytime Storm sur le site de la NASA.</a></div>
PIA01638: Jovian Lightning and the Daytime Storm
<h1>PIA01639: Water Cloud Thunderstorm Northwest of Great Red Spot</h1><div class="PIA01639" lang="en" style="width:592px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This false-color picture of a convective thunderstorm 10,000 kilometers (6,218 miles) northwest of Jupiter's Great Red Spot was obtained by NASA's Galileo spacecraft on June 26, 1996. The white cloud in the center is a tall, thick cloud 1,000 kilometers (620 miles) across, standing 25 kilometers (15 miles) higher than most of the surrounding clouds. Its base extends off to the left and appears red in this representation. This red color indicates that the cloud base is very deep in the atmosphere, about 50 kilometers (30 miles) below the surrounding clouds. Most of the wisps and features in Jupiter's clouds are thick and thin ammonia clouds, forming at a pressure just less than Earth's sea level pressure. On Jupiter, water is the only substance to form a cloud at a depth where the pressure is about five times the Earth's sea level pressure. The red base of this thunderstorm is so deep that it can only be a water cloud.</p><p>In 1979 NASA's Voyager spacecraft saw convective clouds of this type near the Great Red Spot. They erupted like this roughly once every 10 days and lasted a few days each. But Voyager's cameras could not allow the determination of the storms' altitude. It is thought that this storm is analogous to an Earth thunderstorm, with the cloud's high, bright, white portion comparable to the familiar anvil cloud on Earth. Whether any rain or snow is falling below this cloud is unknown, but there are indications that similar storms on Jupiter have lightning in them. The most dramatic difference between this storm and typical thunderstorms on Earth is the scale. The anvil of this storm is 1,000 km (620 miles) across and 75 km (46 miles) high. On Earth, the largest anvils are 200 km (124 miles) across and 18 km (11 miles) high.</p><p>Light at different wavelengths penetrates to different depths in Jupiter's atmosphere before being reflected by clouds. In this image, red represents data taken with the 756 nanometer (nm) filter, where Jupiter's atmospheric gases are mostly transparent and the light penetrates deeply. Blue and green represent data taken with the 889 and 727 nm filters, respectively, where the gases in Jupiter's atmosphere absorb strongly, so only high clouds can reflect the light. Thus, the blue and green areas depict higher clouds, while the red areas show deep clouds as well as higher clouds.</p><p>North is to the top of the picture, which was taken at a distance of 1.75 million kilometers (1.09 million miles) by Galileo's onboard solid state imaging camera system. The image covers an area approximately 9,000 by 7,000 kilometers (5,580 by 4,340 miles).</p><p>JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at <a href="http://solarsystem.nasa.gov/galileo/" target="_blank">http://solarsystem.nasa.gov/galileo/</a>. Background information and educational context for the images can be found at <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01639" onclick="window.open(this.href); return false;" title="Voir l'image PIA01639: Water Cloud Thunderstorm Northwest of Great Red Spot sur le site de la NASA">Voir l'image PIA01639: Water Cloud Thunderstorm Northwest of Great Red Spot sur le site de la NASA.</a></div>
PIA01639: Water Cloud Thunderstorm Northwest of Great Red Spot
<h1>PIA01650: Historic Merger of Storms on Jupiter</h1><div class="PIA01650" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Jupiter's white oval storms before (top) and after (bottom) their historic merger in February 1998. The three classic white ovals which formed in the 1930's have occupied the band from 31 to 35 degrees south planetocentric latitude ever since. The top panel shows two of the ovals with a pear-shaped region between them. Winds around the white ovals are counterclockwise (anticyclonic), indicating they are high-pressure systems. Winds around the pear-shaped region are clockwise (cyclonic), indicating that it is a low-pressure region. The two white ovals were named BC (right) and DE (left) shortly after they formed. The lower panel shows the merged oval, named BE. The pear-shaped cyclonic region is absent. The merger took place in February 1998 when Jupiter was behind the Sun and could not be seen from Earth.</p><p>The top and bottom panels show the features in the same viewing geometry. One might expect the area of the merged feature to equal the sum of the areas of the original features, but the oval might have lost some material during the merger or it might have stretched out in the vertical direction. Vertical stretching causes the ovals to spin faster, similar to what happens when figure skaters spin and pull their arms closer to their bodies. The images allow determination of both the areas of the storms and the related winds; this will help distinguish among the mechanisms involved.</p><p>The top mosaic combines images obtained using the Galileo imaging camera's three near-infrared filters (756, 727, and 889 nanometers displayed in red, green, and blue respectively) to show variations in cloud height and thickness. Light blue clouds are high and thin, reddish clouds are deep, and white clouds are high and thick. The clouds and haze over the white ovals are high, extending into Jupiter's stratosphere. There is a lack of high haze over the cyclonic pear-shaped feature between the ovals. Dark purple most likely represents a high haze overlying a clear deep atmosphere. Galileo is the first spacecraft to distinguish cloud layers on Jupiter. The bottom mosaic uses images obtained with the camera's 756 nanometer filter only.</p><p>North is at the top of these mosaics. The smallest resolved features are tens of kilometers in size. The top images were taken on February 19, 1997, while the bottom images were taken on September 25, 1998, all at ranges of about 1 million kilometers (620,000 miles) by the Solid State Imaging (CCD)system on NASA's Galileo spacecraft.</p><p>The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC.</p><p>This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL<a href="http://solarsystem.nasa.gov/galileo/" target="_blank">http://solarsystem.nasa.gov/galileo/</a>. Background information and educational context for the images can be found at <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01650" onclick="window.open(this.href); return false;" title="Voir l'image PIA01650: Historic Merger of Storms on Jupiter sur le site de la NASA">Voir l'image PIA01650: Historic Merger of Storms on Jupiter sur le site de la NASA.</a></div>
PIA01650: Historic Merger of Storms on Jupiter
<h1>PIA02097: Cloud Features North of Jupiter's Equator</h1><div class="PIA02097" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Cloud features north of Jupiter's equator, in the region between 3 and 30 degrees north latitude, are shown in approximately true color (left mosaic) and in false color (right mosaic). The false color is used to reveal the heights and thicknesses of Jupiter's clouds. The left mosaic was taken about 40 minutes after the right mosaic, when the cloud features had rotated with the planet to Jupiter's curved limb. The images were taken by NASA's Galileo spacecraft.</p><p>Both mosaics show the characteristic banded nature of Jupiter's clouds that results from latitudinal changes in cloud abundance and height, ultimately due to upward convection and horizontal winds in the atmosphere. The top of the mosaics shows a "conveyor belt" counterclockwise vortex (burnt orange oblong feature in false color) perhaps similar to the "brown barges" seen at slightly lower latitudes during NASA's Voyager mission. This oblong vortex is analogous to a low pressure region on Earth, characterized by downwelling air and depressed cloud levels. Below this feature are what appear to be the remnants of two convective plumes of cloud material (whiter patches in false color), now being sheared apart high in the atmosphere by east-west winds. The lower third of the mosaics shows the relatively cloud-free region where thermal infrared "hot spots" appear. The Galileo Probe descended into a hot spot in December 1995.</p><p>The left mosaic combines violet (410 nanometers) and near-infrared continuum (756 nanometers) images to create a mosaic similar to how Jupiter would appear to human eyes. The different colors are due to the composition and abundance of trace chemicals in Jupiter's atmosphere. The right mosaic uses Galileo's camera's three near-infrared (beyond the visible range) wavelengths (756 nanometers, 727 nanometers, and 889 nanometers displayed in red, green, and blue) to show variations in cloud height and thickness. Light blue clouds are high and thin, reddish clouds are deep, and white clouds are high and thick.</p><p>The left mosaic has been projected on a spheroid. The right one was mapped using equal increments of latitude and longitude. The smallest resolved features are tens of kilometers in size. North is toward the top of the mosaics. The images used were taken on Nov. 5, 1997, at a range of 1.44 million kilometers (895,000 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during its eleventh orbit of Jupiter.</p><p>The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC.</p><p>This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL <a href="http://solarsystem.nasa.gov/galileo/" target="_blank">http://solarsystem.nasa.gov/galileo/</a>. Background information and educational context for the images can be found at URL <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02097" onclick="window.open(this.href); return false;" title="Voir l'image PIA02097: Cloud Features North of Jupiter's Equator sur le site de la NASA">Voir l'image PIA02097: Cloud Features North of Jupiter's Equator sur le site de la NASA.</a></div>
PIA02097: Cloud Features North of Jupiter's Equator
<h1>PIA02098: Clouds and Hazes of Jupiter's Southern Hemisphere</h1><div class="PIA02098" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>The clouds and hazes of Jupiter's southern hemisphere, in the region between 25 degrees south latitude and the pole, are shown in approximately true color (left mosaic) and in false color (right mosaic). The false color is used to reveal the heights and thicknesses of Jupiter's clouds. The images were taken by NASA's Galileo spacecraft.</p><p>The clouds visible in these mosaics are being folded and sheared by Jupiter's winds, like cream in a cup of coffee. The upper part of the mosaics sports a pair of vortices, one rotating clockwise (left) and one rotating counterclockwise (right). Each is about 3500 kilometers (2170 miles) in their north-south dimension. North is toward the top of the mosaics.</p><p>The bright spots near the top edge may be places where new cloud material is forming, perhaps analogous to huge convective storms on Earth, complete with lightning. Near Jupiter's pole, the cloud features become increasingly obscured by a "polar cap" of high-altitude haze thought to form from the chemical byproducts of auroral activity.</p><p>The left mosaic combines violet (410 nanometers) and near-infrared (756 nanometers) images to create a mosaic similar to how Jupiter would appear to human eyes. The different colors are due to the composition and abundance of trace chemicals in Jupiter's atmosphere. The right mosaic uses Galileo's camera's three near-infrared (beyond the visible range) wavelengths (756 nanometers, 727 nanometers, and 889 nanometers) displayed in red, green, and blue) to show variations in cloud height and thickness. Light blue clouds are high and thin, reddish clouds are deep, and white clouds are high and thick. Galileo's camera is the first to distinguish cloud heights on Jupiter.</p><p>The mosaics are projected on a spheroid. The smallest resolved features are tens of kilometers in size. The images used were taken on May 7, 1997, at a range of 1.2 million kilometers (746,000 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during its eighth orbit of Jupiter.</p><p>The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC.</p><p>This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL <a href="http://solarsystem.nasa.gov/galileo/" target="_blank">http://solarsystem.nasa.gov/galileo/</a>. Background information and educational context for the images can be found at URL <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02098" onclick="window.open(this.href); return false;" title="Voir l'image PIA02098: Clouds and Hazes of Jupiter's Southern Hemisphere sur le site de la NASA">Voir l'image PIA02098: Clouds and Hazes of Jupiter's Southern Hemisphere sur le site de la NASA.</a></div>
PIA02098: Clouds and Hazes of Jupiter's Southern Hemisphere
<h1>PIA02666: Cassini "First-Look" Images of Jupiter</h1><div class="PIA02666" lang="en" style="width:633px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This image of Jupiter was taken by the Cassini Imaging Science narrow angle camera through the blue filter (centered at 445nanometers) on October 1, 2000, 15:26 UTC at a distance of 84.1million km from Jupiter. The smallest features that can be seen are 500 kilometers across. The contrast between bright and dark features in this region of the spectrum is determined by the different light absorbing properties of the particles composing Jupiter's clouds. Ammonia ice particles are white, reflecting all light that falls on them. But some particles are red, and absorb mostly blue light. The composition of these red particles and the processes which determine their distribution are two of the long-standing mysteries of Jovian meteorology and chemistry. Note that the Great Red Spot contains a dark core of absorbing particles.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02666" onclick="window.open(this.href); return false;" title="Voir l'image PIA02666: Cassini "First-Look" Images of Jupiter sur le site de la NASA">Voir l'image PIA02666: Cassini "First-Look" Images of Jupiter sur le site de la NASA.</a></div>
PIA02666: Cassini "First-Look" Images of Jupiter
<h1>PIA02821: Jupiter's Great Red Spot in Cassini image</h1><div class="PIA02821" lang="en" style="width:528px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This true color image of Jupiter, taken by NASA's Cassini spacecraft, is composed of three images taken in the blue, green and red regions of the spectrum. All images were taken from a distance of 77.6 million kilometers (48.2 million miles) on Oct. 8, 2000.<p>Different chemical compositions of the cloud particles lead to different colors. The cloud patterns reflect different physical conditions -- updrafts and downdrafts -- in which the clouds form. The bluish areas are believed to be regions devoid of clouds and covered by high haze.<p>The Great Red Spot (below and to the right of center) is a giant atmospheric storm as wide as two Earths and over 300 years old, with peripheral winds of 483 kilometers per hour (300 miles per hour). This image shows that it is trailed to the north by a turbulent region, caused by atmospheric flow around the spot.<p>The bright white spots in this region are lightning storms, which were seen by NASA's Galileo spacecraft when it photographed the night side of Jupiter. Cassini will track these lightning storms and measure their lifetimes and motions when it passes Jupiter in late December and looks back on the darkside of the planet. Cassini is currently en route to its ultimate destination, Saturn.<p>The resolution is 466 kilometers (290 miles) per picture element.<p>Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02821" onclick="window.open(this.href); return false;" title="Voir l'image PIA02821: Jupiter's Great Red Spot in Cassini image sur le site de la NASA">Voir l'image PIA02821: Jupiter's Great Red Spot in Cassini image sur le site de la NASA.</a></div>
PIA02821: Jupiter's Great Red Spot in Cassini image
<h1>PIA02822: Jupiter in blue, ultraviolet and near infrared</h1><div class="PIA02822" lang="en" style="width:750px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>These three images of Jupiter, taken through the narrow angle camera of NASA's Cassini spacecraft from a distance of 77.6 million kilometers (48.2 million miles) on October 8, reveal more than is apparent to the naked eye through a telescope.<p>The image on the left was taken through the blue filter. The one in the middle was taken in the ultraviolet. The one on the right was taken in the near infrared.<p>The blue-light filter is within the part of the electromagnetic spectrum detectable by the human eye. The appearance of Jupiter in this image is, consequently, very familiar. The Great Red Spot (below and to the right of center) and the planet's well-known banded cloud lanes are obvious. The brighter bands of clouds are called zones and are probably composed of ammonia ice particles. The darker bands are called belts and are made dark by particles of unknown composition intermixed with the ammonia ice.<p>Jupiter's appearance changes dramatically in the ultraviolet and near infrared images. These images are near negatives of each other and illustrate the way in which observations in different wavelength regions can reveal different physical regimes on the planet.<p>All gases scatter sunlight efficiently at short wavelengths; this is why the sky appears blue on Earth. The effect is even more pronounced in the ultraviolet. The gases in Jupiter's atmosphere, above the clouds, are no different. They scatter strongly in the ultraviolet, making the deep banded cloud layers invisible in the middle image. Only the very high altitude haze appears dark against the bright background. The contrast is reversed in the near infrared, where methane gas, abundant on Jupiter but not on Earth, is strongly absorbing and therefore appears dark. Again the deep clouds are invisible, but now the high altitude haze appears relatively bright against the dark background. High altitude haze is seen over the poles and the equator.<p>The Great Red Spot, prominent in all images, is obviously a feature whose influence extends high in the atmosphere. As the Cassini cameras continue to return images of Jupiter, it will be possible to construct a three-dimensional picture of how clouds form and evolve by watching the changing appearance of Jupiter in different spectral regions.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02822" onclick="window.open(this.href); return false;" title="Voir l'image PIA02822: Jupiter in blue, ultraviolet and near infrared sur le site de la NASA">Voir l'image PIA02822: Jupiter in blue, ultraviolet and near infrared sur le site de la NASA.</a></div>
PIA02822: Jupiter in blue, ultraviolet and near infrared
<h1>PIA02823: Oval Storms Merging on Jupiter</h1><div class="PIA02823" lang="en" style="width:693px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>These four images of clouds in a portion of Jupiter's southern hemisphere show steps in the consolidation of three "white oval" storms into one over a three-year span of time. They were obtained on four dates, from Sept. 18, 1997, to Sept. 2, 2000, by NASA's Hubble Space Telescope. The widths of the white ovals range from about 8,000 kilometers to 12,000 kilometers (about 5,000 miles to 7,500 miles). North is up and east is to the right.<p>The top image shows three white oval storms, which had coexisted for about 60 years. They were nicknamed FA, DE and BC, in order from west to east. By mid-1998, as shown in the second image, the two easternmost storms had merged into one, called BE. By October 1999, as shown in the third image, the merged oval and the last of the original three were approaching each other, but they were separated by a dark storm, called o 1, between them. The two white oval storms later merged into a single storm, as shown in the final image from September 2000.<p>The Hubble Space Telescope is a facility of NASA and the European Space Agency. It is operated by the Space Telescope Science Institute, Baltimore, Md., which is managed for NASA by the Association of Universities for Research in Astronomy in Honolulu.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02823" onclick="window.open(this.href); return false;" title="Voir l'image PIA02823: Oval Storms Merging on Jupiter sur le site de la NASA">Voir l'image PIA02823: Oval Storms Merging on Jupiter sur le site de la NASA.</a></div>
PIA02823: Oval Storms Merging on Jupiter
<h1>PIA02825: Nine Frames as Jupiter Turns</h1><div class="PIA02825" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>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.<p>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.<p>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.<p>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.<p>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.<p>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.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02825" onclick="window.open(this.href); return false;" title="Voir l'image PIA02825: Nine Frames as Jupiter Turns sur le site de la NASA">Voir l'image PIA02825: Nine Frames as Jupiter Turns sur le site de la NASA.</a></div>
PIA02825: Nine Frames as Jupiter Turns
<h1>PIA02826: Jupiter and Europa in Near Infrared</h1><div class="PIA02826" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>These two images, taken by NASA's Cassini spacecraft, show Jupiter in a near-infrared wavelength, and catch Europa, one of Jupiter's largest moons, at different phases.<p>Cassini's narrow-angle camera took both images, the upper one from a distance of 69.9 million kilometers (43.4 million miles) on Oct. 17, 2000, and the lower one from a distance of 65.1 million kilometers (40.4 million miles) on Oct. 22, 2000. Both were taken at a wavelength of 727 nanometers, which is in the near-infrared region of the electromagnetic spectrum.<p>The camera's 727-nanometer filter accepts only a narrow spectral range centered on a relatively strong absorption feature due to methane gas. In this spectral region, the amount of light reflected by Jupiter's clouds is only half that reflected in a nearby spectral region outside the methane band. The features that are brightest in these images are the highest and thickest clouds, such as the Great Red Spot and the band of clouds girding the equator, as these scatter sunlight back to space before it has a chance to be absorbed by the methane gas in the atmosphere. This stratigraphic effect can be seen even more prominently in an image released on Oct. 23, 2000, taken in the stronger methane band at 889 nanometers, in which the only bright features are the highest hazes over the equator, the poles and the Great Red Spot. By comparing images taken in the 727 nanometer filter with others taken at 889 nanometers and at a weaker methane band at 619 nanometers, researchers will probe the heights and thickness of clouds in Jupiter's atmosphere.<p>Europa, a satellite of Jupiter about the size of Earth's Moon, is visible to the left of Jupiter in the upper image, and in front of the planet in the lower image. Another of Jupiter's Galilean satellites, Ganymede, which is larger than the planet Mercury, is to the right in the upper image, with brightness variations visible across its surface. In the upper image, Europa is caught entering Jupiter's shadow, and hence appears as a bright crescent; in the lower image, it is seen about one-and-a-half orbits later, in transit across the face of the planet. Because there is neither methane nor any strong absorber in this spectral region on the surface of Europa, it appears strikingly white and bright compared to Jupiter.<p>Imaging observations of the moons Europa, Io and Ganymede entering and passing through Jupiter's shadow are planned for the two-week period surrounding Cassini's closest approach on Dec. 30, 2000. The purpose of these eclipse observations is to detect and measure the variability of emissions that arise from the interaction of the satellites' tenuous atmospheres with the charged particles trapped in Jupiter's magnetic field.<p>At the times these images were taken, Cassini was about 3.3 degrees above Jupiter's equatorial plane, and the Sun-Jupiter-spacecraft angle was about 20 degrees.<p>Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02826" onclick="window.open(this.href); return false;" title="Voir l'image PIA02826: Jupiter and Europa in Near Infrared sur le site de la NASA">Voir l'image PIA02826: Jupiter and Europa in Near Infrared sur le site de la NASA.</a></div>
PIA02826: Jupiter and Europa in Near Infrared
<h1>PIA02830: Still from Red Spot Movie</h1><div class="PIA02830" lang="en" style="width:400px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This image is one of seven from the narrow-angle camera on NASA's Cassini spacecraft assembled as a brief movie of cloud movements on Jupiter. It was taken with a blue filter. The smallest features visible are about 500 kilometers (about 300 miles) across.<p>Small bright clouds appear suddenly to the west of the Great Red Spot. Based on data from NASA's Galileo spacecraft, scientists suspect that these small white features are lightning storms, where falling raindrops create an electrical charge. The lightning storms eventually merge with the Red Spot and surrounding jets, and may be the main energy source for these large-scale features. Imaging observations of the darkside of the planet in the weeks following Cassini's closest approach to Jupiter on Dec. 30, 2000 will search for lightning storms like these.<p>This image was re-projected by cylindrical-map projection of an image taken in the first week of October 2000. It shows an area from 50 degrees north of Jupiter's equator to 50 degrees south, extending 100 degrees east west, about one quarter of Jupiter's circumference.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02830" onclick="window.open(this.href); return false;" title="Voir l'image PIA02830: Still from Red Spot Movie sur le site de la NASA">Voir l'image PIA02830: Still from Red Spot Movie sur le site de la NASA.</a></div>
PIA02830: Still from Red Spot Movie
<h1>PIA02832: Still from Processed Movie of Zonal Jets</h1><div class="PIA02832" lang="en" style="width:400px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This image is one frame from a movie clip of cloud motions on Jupiter, from the side of the planet opposite to the Great Red Spot. It was taken in the first week of October 2000 by the narrow-angle camera on NASA's Cassini spacecraft, with a blue filter.<p>A white oval visible in the lower left is the remains of a historic merger that began several years ago, when three white oval storms that had existed for 60 years merged into two, then one. Like the Great Red Spot, it is a high-pressure center in the southern hemisphere, but only half as large. The color difference between the white oval and the Red Spot is not well understood, but it is undoubtedly related to the updrafts and downdrafts that carry chemicals to different heights in the two structures.<p>The region shown reaches from 50 degrees north to 50 degrees south of Jupiter's equator, and extends 100 degrees east-to-west, about one-quarter of Jupiter's circumference. The smallest features are about 500 kilometers (about 300 miles) across.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02832" onclick="window.open(this.href); return false;" title="Voir l'image PIA02832: Still from Processed Movie of Zonal Jets sur le site de la NASA">Voir l'image PIA02832: Still from Processed Movie of Zonal Jets sur le site de la NASA.</a></div>
PIA02832: Still from Processed Movie of Zonal Jets
<h1>PIA02837: Eyeing Ganymede</h1><div class="PIA02837" lang="en" style="width:559px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Jupiter casts a baleful eye toward the moon Ganymede in this enhanced-contrast image from NASA's Cassini spacecraft.<p>Jupiter's "eye', the Great Red Spot, was captured just before disappearing around the eastern edge of the planet. The furrowed eyebrow above and to the left of the spot is a turbulent wake region caused by westward flow that has been deflected to the north and around the Red Spot. The smallest features visible are about 240 kilometers (150 miles) across.<p>Within the band south of the Red Spot are a trio of white ovals, high pressure counterclockwise-rotating regions that are dynamically similar to the Red Spot. The dark filamentary features interspersed between white ovals are probably cyclonic circulations and, unlike the ovals, are rotating clockwise.<p>Jupiter's equatorial zone stretching across the planet north of the Spot appears bright white, with gigantic plume clouds spreading out from the equator both to the northeast and to the southeast in a chevron pattern. This zone looks distinctly different than it did during the Voyager flyby 21 years ago. Then, its color was predominantly brown and the only white plumes conspicuous against the darker material beneath them were oriented southwest-to-northeast.<p>Ganymede is Jupiter's largest moon, about 50 percent larger than our own Moon and larger than the planet Mercury. The visible details in this image are different geological terrains. Dark areas tend to be older and heavily cratered; brighter areas are younger and less cratered. Cassini images of Ganymede and Jupiter's other large moons taken near closest approach on Dec. 30 will have resolutions about four times better than that seen here.<p>This image is a color composite of ones taken with different filters by Cassini's narrow-angle camera on Nov. 18, 2000, processed to enhance contrast. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02837" onclick="window.open(this.href); return false;" title="Voir l'image PIA02837: Eyeing Ganymede sur le site de la NASA">Voir l'image PIA02837: Eyeing Ganymede sur le site de la NASA.</a></div>
PIA02837: Eyeing Ganymede
<h1>PIA02838: Northern Belt of Jupiter</h1><div class="PIA02838" lang="en" style="width:400px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><a href="/figures/PIA02838bigfig.gif"></a><p>A four-panel frame shows a section of Jupiter's north equatorial belt viewed by NASA's Cassini spacecraft at four different wavelengths, and a separate reference frame shows the location of the belt on the planet.<p>A fascinating aspect of the images in the four-panel frame is the small bright spot in the center of each. The images come from different layers of the atmosphere, so the spot appears to be a storm penetrating upward through several layers. This may in fact be a "monster' thunderstorm, penetrating all the way into the stratosphere, as do some summer thunderstorms in the midwestern United States. These images were taken on Nov. 27, 2000, at a resolution of 192 kilometers (119 miles) per pixel. They have been contrast-enhanced to highlight features in the atmosphere.<p>The top panel of the four-panel frame is an image taken in a near-infrared wavelength at which the gases in Jupiter's atmosphere are relatively non-absorbing. Sunlight can penetrate deeply into the atmosphere at this wavelength and be reflected back out, providing a view of an underlying region of the atmosphere, the lower troposphere.<p>The second panel was taken in the blue portion of wavelengths detected by the human eye. At these wavelengths, gases in the atmosphere scatter a modest amount of sunlight, so the clouds we see tend to be at somewhat higher altitudes than in the top panel.<p>The third panel shows near-infrared reflected sunlight at a wavelength where the gas methane, an important constituent of Jupiter's atmosphere, absorbs strongly. Dark places are regions without high-level clouds and consequently large amounts of methane accessible to sunlight. Bright regions are locations with high clouds in the upper troposphere shielding the methane below.<p>The bottom panel was taken in the ultraviolet. At these very short wavelengths, the clear atmosphere scatters sunlight, and hazes in the stratosphere, above the troposphere, absorb sunlight. That makes it difficult to see into lower layers at all. The bright regions are generally free of high stratospheric hazes.<p>A small bright spot is visible near the center of each panel. Similar spots have been imaged in turbulent regions by the Galileo spacecraft, and they appear to be very energetic convective storms that move heat from the interior of Jupiter to higher altitudes. These storms are expected to penetrate to great heights, and so it is not surprising to see the storm in the first three images, which probe atmospheric altitudes from the lower to the upper troposphere. What is surprising is the appearance of the spot in the ultraviolet image. Higher resolution, time-lapse images to be captured by Cassini in coming weeks will shed more light on these spectacular features.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02838" onclick="window.open(this.href); return false;" title="Voir l'image PIA02838: Northern Belt of Jupiter sur le site de la NASA">Voir l'image PIA02838: Northern Belt of Jupiter sur le site de la NASA.</a></div>
PIA02838: Northern Belt of Jupiter
<h1>PIA02851: Still from High-Clouds Jupiter Movie</h1><div class="PIA02851" lang="en" style="width:400px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This image is one of seven from the narrow-angle camera on NASA's Cassini spacecraft assembled as a brief movie of high-altitude cloud movements on Jupiter. It was taken in early October 2000.<p>The images were taken at a wavelength that is absorbed by methane, one chemical in Jupiter's lower clouds. So, dark areas are relatively free of high clouds, and the camera sees through to the methane in a lower level. Bright areas are places with high, thick clouds that shield the methane below.<p>The area shown covers latitudes from 50 degrees north to 50 degrees south and a 100-degree sweep of longitude.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02851" onclick="window.open(this.href); return false;" title="Voir l'image PIA02851: Still from High-Clouds Jupiter Movie sur le site de la NASA">Voir l'image PIA02851: Still from High-Clouds Jupiter Movie sur le site de la NASA.</a></div>
PIA02851: Still from High-Clouds Jupiter Movie
<h1>PIA02852: Jupiter Eye to Io</h1><div class="PIA02852" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This image taken by NASA's Cassini spacecraft on Dec. 1, 2000, shows details of Jupiter's Great Red Spot and other features that were not visible in images taken earlier, when Cassini was farther from Jupiter.<p>The picture is a color composite, with enhanced contrast, taken from a distance of 28.6 million kilometers (17.8 million miles). It has a resolution of 170 kilometers (106 miles) per pixel. Jupiter's closest large moon, Io, is visible at left.<p>The edges of the Red Spot are cloudier with ammonia haze than the spot's center is. The filamentary structure in the center appears to spiral outward toward the edge. NASA's Galileo spacecraft has previously observed the outer edges of the Red Spot to be rotating rapidly counterclockwise, while the inner portion was rotating weakly in the opposite direction. Whether the same is true now will be answered as Cassini gets closer to Jupiter and interior cloud features become sharper. Cassini will make its closest approach to Jupiter, at a distance of about 10 million kilometers (6 million miles), on Dec. 30, 2000.<p>The Red Spot region has changed in one notable way over the years: In images from NASA's Voyager and Galileo spacecraft, the area surrounding the Red Spot is dark, indicating relatively cloud-free conditions. Now, some bright white ammonia clouds have filled in the clearings. This appears to be part of a general brightening of Jupiter's cloud features during the past two decades.<p>Jupiter has four large moons and an array of tiny ones. In this picture, Io is visible. The white and reddish colors on Io's surface are due to the presence of different sulfurous materials while the black areas are due to silicate rocks. Like the other large moons, Io always keeps the same hemisphere facing Jupiter, called the sub-Jupiter hemisphere. The opposite side, much of which we see here, is the anti-Jupiter hemisphere. Io has more than 100 active volcanoes spewing very hot lava and giant plumes of gas and dust. Its biggest plume, Pele, is near the bottom left edge of Io's disk as seen here.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02852" onclick="window.open(this.href); return false;" title="Voir l'image PIA02852: Jupiter Eye to Io sur le site de la NASA">Voir l'image PIA02852: Jupiter Eye to Io sur le site de la NASA.</a></div>
PIA02852: Jupiter Eye to Io
<h1>PIA02856: High Latitude Mottling on Jupiter</h1><div class="PIA02856" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>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.<p>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.<p>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.<p>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.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02856" onclick="window.open(this.href); return false;" title="Voir l'image PIA02856: High Latitude Mottling on Jupiter sur le site de la NASA">Voir l'image PIA02856: High Latitude Mottling on Jupiter sur le site de la NASA.</a></div>
PIA02856: High Latitude Mottling on Jupiter
<h1>PIA02859: Jupiter's Main Ring and 2 Satellites</h1><div class="PIA02859" lang="en" style="width:317px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Jupiter's main ring is a narrow structure about 6,000 kilometers (about 3,700 miles) in width and about 100,000 times fainter than the planet it encircles. These are the first pictures that NASA's Cassini spacecraft has taken of the ring, a portion of which appears in each frame as an arc opening toward the right.<p>Image processing helped make the ring easier to see in these frames taken with Cassini's narrow-angle camera during a 39.5-hour period beginning Dec. 11, 2000. The distance between the spacecraft and Jupiter narrowed during those hours, from 20.3 million kilometers (12.6 million miles) to 19 million kilometers (11.8 million miles). Also, Cassini's movement took it from 3.3 degrees above the plane of the rings to 2.98 degrees above the plane. The frames are in sequence from upper left to lower right. The image of the ring's arc grows longer, as the spacecraft approaches the planet.<p>Resolution is about 230 kilometers (143 miles) per pixel. The 10 frames shown here are each a small section of several separate narrow-angle images taken through the camera's clear filter and spanning the entire 39.5 hour period. The scattered light background has been removed, and the images have been contrast-stretched to enhance the ring. The contours in the image, as well as the small variations in brightness of the ring from one frame to the next, are a result of the image processing and background removal.<p>This image sequence also shows the motions of two satellites embedded in Jupiter's ring. The moon Adrastea is the fainter of the two, and Metis the brighter. Images such as these will be used to refine the orbits of the two bodies. This image sequence also shows the motions of two satellites embedded in Jupiter's ring. The moon Adrastea is the fainter of the two, and Metis the brighter. Images such as these will be used to refine the orbits of the two bodies.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02859" onclick="window.open(this.href); return false;" title="Voir l'image PIA02859: Jupiter's Main Ring and 2 Satellites sur le site de la NASA">Voir l'image PIA02859: Jupiter's Main Ring and 2 Satellites sur le site de la NASA.</a></div>
PIA02859: Jupiter's Main Ring and 2 Satellites
<h1>PIA02860: Io in Front of Jupiter</h1><div class="PIA02860" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Jupiter's four largest satellites, including Io, the golden ornament in front of Jupiter in this image from NASA's Cassini spacecraft, have fascinated Earthlings ever since Galileo Galilei discovered them in 1610 in one of his first astronomical uses of the telescope.<p>Images from Cassini that will be released over the next several days capture each of the four Galilean satellites in their orbits around the giant planet.<p>This true-color composite frame, made from narrow angle images taken on Dec. 12, 2000, captures Io and its shadow in transit against the disk of Jupiter. The distance of the spacecraft from Jupiter was 19.5 million kilometers (12.1 million miles). The image scale is 117 kilometers (73 miles) per pixel.<p>The entire body of Io, about the size of Earth's Moon, is periodically flexed as it speeds around Jupiter and feels, as a result of its non-circular orbit, the periodically changing gravitational pull of the planet. The heat arising in Io's interior from this continual flexure makes it the most volcanically active body in the solar system, with more than 100 active volcanoes. The white and reddish colors on its surface are due to the presence of different sulfurous materials. The black areas are silicate rocks.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02860" onclick="window.open(this.href); return false;" title="Voir l'image PIA02860: Io in Front of Jupiter sur le site de la NASA">Voir l'image PIA02860: Io in Front of Jupiter sur le site de la NASA.</a></div>
PIA02860: Io in Front of Jupiter
<h1>PIA02861: Europa and Callisto under the watchful gaze of Jupiter</h1><div class="PIA02861" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet.<p>The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image.<p>Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters.<p>Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both worlds.<p>Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different when Cassini finally reaches its destination in 2004. <p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02861" onclick="window.open(this.href); return false;" title="Voir l'image PIA02861: Europa and Callisto under the watchful gaze of Jupiter sur le site de la NASA">Voir l'image PIA02861: Europa and Callisto under the watchful gaze of Jupiter sur le site de la NASA.</a></div>
PIA02861: Europa and Callisto under the watchful gaze of Jupiter
<h1>PIA02862: Ganymede and Jupiter</h1><div class="PIA02862" lang="en" style="width:747px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>The solar system's largest moon, Ganymede, is captured here alongside the planet Jupiter in a color picture taken by NASA's Cassini spacecraft on Dec. 3, 2000.<p>Ganymede is larger than the planets Mercury and Pluto and Saturn's largest moon, Titan. Both Ganymede and Titan have greater surface area than the entire Eurasian continent on our planet. Cassini was 26.5 million kilometers (16.5 million miles) from Ganymede when this image was taken. The smallest visible features are about 160 kilometers (about 100 miles) across.<p>The bright area near the south (bottom) of Ganymede is Osiris, a large, relatively new crater surrounded by bright icy material ejected by the impact, which created it. Elsewhere, Ganymede displays dark terrains that NASA's Voyager and Galileo spacecraft have shown to be old and heavily cratered. The brighter terrains are younger and laced by grooves. Various kinds of grooved terrains have been seen on many icy moons in the solar system. These are believed to be the surface expressions of warm, pristine, water-rich materials that moved to the surface and froze.<p>Ganymede has proven to be a fascinating world, the only moon known to have a magnetosphere, or magnetic environment, produced by a convecting metal core. The interaction of Ganymede's and Jupiter's magnetospheres may produce dazzling variations in the auroral glows in Ganymede's tenuous atmosphere of oxygen.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02862" onclick="window.open(this.href); return false;" title="Voir l'image PIA02862: Ganymede and Jupiter sur le site de la NASA">Voir l'image PIA02862: Ganymede and Jupiter sur le site de la NASA.</a></div>
PIA02862: Ganymede and Jupiter
<h1>PIA02864: Still from Planetwide Movie</h1><div class="PIA02864" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This single frame from a color movie of Jupiter from NASA's Cassini spacecraft shows what it would look like to unpeel the entire globe of Jupiter, stretch it out on a wall into the form of a rectangular map.<p>The image is a color cylindrical projection of the complete circumference of Jupiter, from 60 degrees south to 60 degrees north. It was produced from six images taken by Cassini's narrow-band camera on Oct. 31, 2000, in each of three filters: red, green and blue.<p>The smallest visible features at the equator are about 600 kilometers (about 370 miles) across. In a map of this type, the most extreme northern and southern latitudes are unnaturally stretched out.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02864" onclick="window.open(this.href); return false;" title="Voir l'image PIA02864: Still from Planetwide Movie sur le site de la NASA">Voir l'image PIA02864: Still from Planetwide Movie sur le site de la NASA.</a></div>
PIA02864: Still from Planetwide Movie
<h1>PIA02865: Jupiter Clouds in Depth</h1><div class="PIA02865" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><a href="/figures/PIA02865figa.tif"></a><br>619 nm<a href="/tiff/PIA02865.tif"></a><br>727 nm<a href="/figures/PIA02865figc.tif"></a><br>890 nm<p>Images from NASA's Cassini spacecraft using three different filters reveal cloud structures and movements at different depths in the atmosphere around Jupiter's south pole.<p>Cassini's cameras come equipped with filters that sample three wavelengths where methane gas absorbs light. These are in the red at 619 nanometer (nm) wavelength and in the near-infrared at 727 nm and 890 nm. Absorption in the 619 nm filter is weak. It is stronger in the 727 nm band and very strong in the 890 nm band where 90 percent of the light is absorbed by methane gas. Light in the weakest band can penetrate the deepest into Jupiter's atmosphere. It is sensitive to the amount of cloud and haze down to the pressure of the water cloud, which lies at a depth where pressure is about 6 times the atmospheric pressure at sea level on the Earth). Light in the strongest methane band is absorbed at high altitude and is sensitive only to the ammonia cloud level and higher (pressures less than about one-half of Earth's atmospheric pressure) and the middle methane band is sensitive to the ammonia and ammonium hydrosulfide cloud layers as deep as two times Earth's atmospheric pressure.<p>The images shown here demonstrate the power of these filters in studies of cloud stratigraphy. The images cover latitudes from about 15 degrees north at the top down to the southern polar region at the bottom. The left and middle images are ratios, the image in the methane filter divided by the image at a nearby wavelength outside the methane band. Using ratios emphasizes where contrast is due to methane absorption and not to other factors, such as the absorptive properties of the cloud particles, which influence contrast at all wavelengths.<p>The most prominent feature seen in all three filters is the polar stratospheric haze that makes Jupiter bright near the pole. The equatorial band is also very bright in the strong 890-nm (right) image and to a lesser extent in the 727 band (middle image) but is subdued in the weak 619-nm image on the left. These are high, thin, haze layers that are nearly transparent at wavelengths outside the methane absorption bands. Another prominent feature is the Great Red Spot. About a third of it appears at the right-hand edge of the frame. It is a bright feature in methane absorption because it has extensive cloud cover reaching to high altitude. A wisp of high thin cloud can be seen trailing off its western rim in the middle and right images.<p>Features mentioned above have been seen from ground-based telescopes, from NASA's Hubble Space Telescope and from NASA's Galileo spacecraft. This is the first high-resolution image in all three methane bands, and a comparison of all three reveals some interesting features. Chief among these is the very dark patch seen in the left (weak methane) image near the top-middle of the frame. It is almost invisible in the right image and it appears to be composed of strands of bright clouds in the middle image. This is a region similar to the hot spot where the Galileo Probe entered Jupiter's atmosphere in 1995. These images indicate that cloud cover is present at the higher altitudes but absent from the lower altitudes. This is also what the Galileo Probe found when it entered Jupiter's atmosphere.<p>To the northwest (above and to the left) of the dark feature is a small cloud that is bright in the 619-nm (left) image but has no contrast at the other wavelengths. This is the signature expected for a thick water cloud. Another feature seen only in the weak-methane (left image) ratio is a dark ring near the center of the image. This feature is probably a counter-clockwise rotating, upwelling core surrounded by a sinking perimeter with diminished cloudiness. The fact that it is seen only in the weak methane ratio indicates the effects of a lower-level circulation that does not penetrated to the upper ammonia cloud level and may be confined to the deeper water cloud.<p>The opposite behavior is evident in an oval storm that appears dark in the middle and right images but is absent in the weak, 619-nm image. It is located to the southwest of the Great Red Spot. Further to the west at slightly more northerly latitudes are a series of small spots that are dark at all wavelengths. These and a myriad of other contrast features at many latitudes reveal much about Jupiter's complicated cloud structure and meteorology.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02865" onclick="window.open(this.href); return false;" title="Voir l'image PIA02865: Jupiter Clouds in Depth sur le site de la NASA">Voir l'image PIA02865: Jupiter Clouds in Depth sur le site de la NASA.</a></div>
PIA02865: Jupiter Clouds in Depth
<h1>PIA02866: 3-D Atmosphere Movie</h1><div class="PIA02866" lang="en" style="width:720px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><br><a href="/figures/PIA02866.mov">Quicktime file</a> (45k)<br><a href="/figures/PIA02866.avi">Larger AVI file</a> (151k)<p>NASA's Cassini spacecraft took narrow-angle images of Jupiter's outer atmosphere, showing the giant planet as if it were constantly bathed in sunlight. To make this 3-D movie sequence (of which the release image is a still frame), projections of the movement of the atmosphere were inserted between frames, then projected on to a globe matching Jupiter's size and shape. The interpolated data came from studies by a previous mission to Jupiter, NASA's Voyager spacecraft. The movie shows one frame every 1.1 hours, over 10 days, from October 31 to November 9, 2000.<p>Cassini is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02866" onclick="window.open(this.href); return false;" title="Voir l'image PIA02866: 3-D Atmosphere Movie sur le site de la NASA">Voir l'image PIA02866: 3-D Atmosphere Movie sur le site de la NASA.</a></div>
PIA02866: 3-D Atmosphere Movie
<h1>PIA02867: 2-D Atmosphere Movie</h1><div class="PIA02867" lang="en" style="width:720px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><br><a href="/figures/PIA02867.mov">Quicktime file</a> (120k)<br><a href="/figures/PIA02867.avi">Larger AVI file</a> (453k)<p>NASA's Cassini spacecraft took narrow-angle images of Jupiter's outer atmosphere, showing the giant planet as if it were constantly bathed in sunlight. To make this smooth movie sequence (of which the release image is a still frame), projections of the movement of the atmosphere were inserted between frames, using data from a previous mission to Jupiter, NASA's Voyager spacecraft. The movie shows one frame every 1.1 hours, over 10 days, from October 31 to November 9, 2000.<p>Cassini is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02867" onclick="window.open(this.href); return false;" title="Voir l'image PIA02867: 2-D Atmosphere Movie sur le site de la NASA">Voir l'image PIA02867: 2-D Atmosphere Movie sur le site de la NASA.</a></div>
PIA02867: 2-D Atmosphere Movie
<h1>PIA02868: Turbulent Region Near Great Red Spot</h1><div class="PIA02868" lang="en" style="width:720px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><br><a href="/figures/PIA02868.mov">Quicktime file</a> (156k)<br><a href="/figures/PIA02868.avi">Larger AVI file</a> (506k)<p>This movie clip (of which the release image is a still frame), created from images taken by NASA's Cassini spacecraft, shows a turbulent region west of Jupiter's Great Red Spot. The small, bright white spots are believed to be thunderstorms.<p>Cassini is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02868" onclick="window.open(this.href); return false;" title="Voir l'image PIA02868: Turbulent Region Near Great Red Spot sur le site de la NASA">Voir l'image PIA02868: Turbulent Region Near Great Red Spot sur le site de la NASA.</a></div>
PIA02868: Turbulent Region Near Great Red Spot