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More Los Angeles Fire Images
Triple-digit temperatures, e …
9/1/09
Description Triple-digit temperatures, extremely low relative humidities, dense vegetation that has not burned in decades, and years of extended drought are all contributing to the explosive growth of wildfires throughout Southern California. The Station fire, which began Aug. 26, 2009, in La Canada/Flintridge, not far from NASA's Jet Propulsion Laboratory, had reportedly burned 105,000 acres (164 square miles) of the Angeles National Forest by mid-day Aug. 31, destroying at least 21 homes and threatening more than 12,000 others. It is one of four major fires burning in Southern California at the present time. This image was acquired mid-morning on Aug. 30 by the backward (northward)-viewing camera of the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. The image is shown in an approximate perspective view at an angle of 46 degrees off of vertical. The area covered by the image is 245 kilometers (152 miles) wide. Several pyrocumulus clouds, created by the Station Fire, are visible above the smoke plumes rising from the San Gabriel Mountains north of Los Angeles in the left-center of the image. Smoke from the Station fire is seen covering the interior valleys along the south side of the San Gabriel Mountains, along with parts of the City of Los Angeles and Orange County, and can be seen drifting for hundreds of kilometers to the east over the Mojave Desert. The accompanying plots are histograms that display the heights of the smoke plumes and wind speeds. In this data set, the plume is injecting smoke more than 7 kilometers (4.3 miles) above sea level. MISR observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. This image was generated from a portion of the imagery acquired during Terra orbit 51601. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, Md. The MISR data were obtained from the NASA Langley Research Center Atmospheric Science Data Center. JPL is a division of the California Institute of Technology. Image Credit: NASA/GSFC/LaRC/JPL, MISR Team
Date 9/1/09
LOS ALAMOS FIRE IMAGED BY NA …
The fire that has raged out …
5/19/00
Date 5/19/00
Description The fire that has raged out of control this month near Los Alamos, New Mexico, was captured in a series of images by the Multi-angle Imaging Spectro-Radiometer (MISR) on NASA's Terra satellite. The picture is available at http://www.jpl.nasa.gov/pictures/misr These true-color images covering north-central New Mexico capture the bluish-white smoke plume of the Los Alamos fire, just west of the Rio Grande river. The middle image is a downward-looking or "nadir" view taken by MISR. As the satellite flew from north to south, the instrument viewed the scene from nine different angles. The top image was taken by the MISR camera looking 60 degrees forward along its orbit, whereas the bottom image looks 60 degrees aft. The fire plume stands out more dramatically in the steep-angle views. Its color and brightness also change with angle. By comparison, a thin, white water cloud appears in the upper right portion of the scene, and is most easily detected in the top image. MISR scientists use these angle-to-angle differences to monitor particulate pollution and to identify different types of haze. Such observations allow scientists to study how airborne particles interact with sunlight, a measure of their impact on Earth's climate system. The images are about 400 km (250 miles) wide. The spatial resolution of the nadir image is 275 meters (300 yards), resolution is 1.1 kilometers (1,200 yards) for the off-nadir images. North is toward the top. MISR is managed by the Jet Propulsion Laboratory, a division of the California Institute of Technology, for NASA' s Office of Earth Science, Washington, D.C. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, Md. ##### Photo credit: NASA/GSFC/JPL, MISR Science Team.
Nicaraguan Volcanoes The tru …
Description Nicaraguan Volcanoes The true-color image at left is a downward-looking (nadir) view of the area around the San Cristobal volcano, which erupted the previous day. This image is oriented with east at the top and north at the left. The right image is a stereo anaglyph of the same area, created from red band multi-angle data taken by the 45.6-degree aftward and 70.5-degree aftward cameras on the Multi- angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. View this image through red/blue 3D glasses, with the red filter over the left eye. A plume from San Cristobal (approximately at image center) is much easier to see in the anaglyph, due to 3 effects: the long viewing path through the atmosphere at the oblique angles, the reduced reflection from the underlying water, and the 3D stereoscopic height separation. In this image, the plume floats between the surface and the overlying cumulus clouds. A second plume is also visible in the upper right (southeast of San Cristobal). This very thin plume may originate from the Masaya volcano, which is continually degassing at a slow rate. The spatial resolution is 275 meters (300 yards). MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. #####
Multi-Angle Views of the App …
Description Multi-Angle Views of the Appalachian Mountains The true-color image at left is a downward-looking (nadir) view of the eastern United States, stretching from Lake Ontario to northern Georgia, and spanning the Appalachian Mountains. The three images to the right are also in true-color, taken by the forward 45.6-degree, 60.0-degree, and 70.5-degree cameras, respectively, of the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. As the slant angle increases, the line- of-sight through the atmosphere grows longer, and a pall of haze over the Appalachians becomes progressively more apparent. You can see a similar effect by scanning from near-nadir to the horizon when standing on a mountain top or looking out an airplane window. MISR uses this multi-angle technique to monitor particulate pollution and to distinguish different types of haze. These observations reveal how airborne particles are interacting with sunlight, a measure of their impact on Earth's climate system. The images are about 400 km (250 miles) wide, and the spatial resolution is 1.1 kilometers (1,200 yards). North is toward the top. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. #####
Multi-Angle View of the Cana …
A multi-angle view of the Ca …
Description A multi-angle view of the Canary Islands in a dust storm, 29 February 2000. At left is a true-color image taken by the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. This image was captured by the MISR camera looking at a 70.5-degree angle to the surface, ahead of the spacecraft. The middle image was taken by the MISR downward- looking (nadir) camera, and the right image is from the aftward 70.5-degree camera. The images are reproduced using the same radiometric scale, so variations in brightness, color, and contrast represent true variations in surface and atmospheric reflectance with angle. Windblown dust from the Sahara Desert is apparent in all three images, and is much brighter in the oblique views. This illustrates how MISR's oblique imaging capability makes the instrument a sensitive detector of dust and other particles in the atmosphere. Data for all channels are presented in a Space Oblique Mercator map projection to facilitate their co-registration. The images are about 400 km (250 miles) wide, with a spatial resolution of about 1.1 kilometers (1,200 yards). North is toward the top. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. #####
Multi-angle Images of Hudson …
At left is a true-color imag …
Description At left is a true-color image from the downward-looking (nadir) camera on the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. The false-color image at right is a composite of red band data taken by the MISR forward 45.6-degree, nadir, and aftward 45.6-degree cameras, displayed in blue, green, and red colors, respectively. Color variations in the left image highlight spectral (true-color) differences, whereas those in the right image highlight differences in angular reflectance properties. The purple areas in the right image are low cloud, and light blue at the edge of the bay is due to increased forward scattering by the fast (smooth) ice. The orange areas are rougher ice, which scatters more light in the backward direction. This example illustrates how multi-angle viewing can distinguish physical structures and textures. Data for all channels are presented in a Space Oblique Mercator map projection to facilitate their co- registration. The images are about 400 km (250 miles) wide with a spatial resolution of about 275 meters (300 yards). North is toward the top. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. #####
Pine Island Glacier, Antarct …
These two images of Pine Isl …
4/3/01
Date 4/3/01
Description These two images of Pine Island Glacier in Antarctica show the recently discovered 25-kilometer (15-mile) long crack that scientists expect will turn into a large iceberg within the next 18 months. The views from NASA's Multi-angle Imaging SpectroRadiometer (MISR) on the Terra satellite also reveal differences in the ice sheet's surface texture, highlighting surface fractures and enabling distinction of rough crevasses from smooth blue ice. The image data shown was acquired on December 12, 2000, during Terra orbit 5246. At left is a conventional, true-color image from the downward-looking (nadir) camera. The false-color image at right is a composite of red-band data taken by the MISR forward 60-degree, nadir, and aftward 60-degree cameras, displayed in red, green and blue, respectively. Color variations in the true-color image at left highlight spectral differences. In the multi-angle composite, on the other hand, color variations act as a proxy for differences in the angular reflectance properties of the scene. In this representation, clouds show up as light purple. Blue to orange gradations on the surface indicate a transition in ice texture from smooth to rough. For example, the bright orange carrot-like features are rough crevasses on the glacier's tongue. In the conventional nadir view, the blue ice labeled "rough crevasses"' and "smooth blue ice" are similarly colored, but the multi-angle composite reveals their different textures, with the smoother ice appearing dark purple instead of orange. This could be an indicator of different mechanisms by which this ice is exposed. The multi-angle view also reveals subtle roughness variations on the frozen sea ice between the glacier and the open water in Pine Island Bay. To the left of the 'icebergs' label are chunks of floating ice. Smaller icebergs embedded in the frozen sea ice are visible below and to the right of the label. These small icebergs are associated with dark streaks. Analysis of the illumination geometry suggests that these streaks are surface features, not shadows. Wind-driven motion and thinning of the sea ice in the vicinity of the icebergs are a possible explanation. Recently, Robert Bindschadler, a glaciologist at the NASA Goddard Space Flight Center discovered in Landsat 7 imagery a newly-formed crack traversing the Pine Island Glacier. This crack is visible as an off-vertical dark line in the MISR nadir view. In the multi-angle composite, the crack and other stress fractures show up very clearly in bright orange. Radar observations of Pine Island Glacier in the 1990's showed the glacier to be shrinking, and the newly discovered crack is expected to eventually lead to the calving of a major iceberg. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calf., for NASA's Office of Earth Science, Washington, D.C. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, Md. JPL is a division of the California Institute of Technology. Image credit: NASA/JPL/GSFC/LaRC, MISR Team #####
Splendid Splinter
Title Splendid Splinter
Description The spiral galaxy NGC 5907, sometimes known as the "Splinter Galaxy" because of its unusual appearance, is located in the constellation Draco. It is fairly bright, and appears elongated because it has an edge-on alignment when viewed from Earth. It also has a strong set of dust lanes, visible in this image from NASA's Spitzer Space Telescope as red features. The central lane is so pronounced at visible light wavelengths, where it blocks our view of the starlight, that the galaxy was once mistaken for two objects and given two entries in the original New General Catalogue. The catalogue, published by J.L.E. Dreyer in 1888, was an attempt to collect a complete list of all nebulae and star clusters known at the time. NGC 5907's special orientation and close proximity to Earth have made it a popular target for observation by both professional and amateur astronomers. Over the last decade, ever-improving infrared instrumentation have allowed scientists to detect light from the galaxy that was until now hidden by dust. Recent observations using Spitzer's InfraRed Array Camera at infrared wavelengths from 3-10 microns resulted in the discovery of a significant and potentially massive thick stellar disk. This is the first time that a thick disk has been detected and characterized in the infrared. This image is composed of images obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). The contribution from starlight has been subtracted from the 5.8 and 8 micron images to enhance the visibility of the dust features.
Galactic Fossil Revealed in …
Title Galactic Fossil Revealed in Infrared Light
Description This animation demonstrates the power of infrared light to see what visible light cannot -- a newfound bundle of stars called a globular cluster. The movie shifts from a visible-light image to a near-infrared image to a new mid-infrared image from NASA's Spitzer Space Telescope. The visible-light image is from the California Institute of Technology's Digitized Sky Survey and the near-infrared image is from the NASA-funded Two Micron All-Sky Survey (2MASS). Globular clusters date back to the birth of our galaxy, 13 or so billion years ago. There are about 150 clusters sprinkled around the core of the galaxy like seeds in a pumpkin. Astronomers use these galactic "fossils" as tools for studying the age and formation of the Milky Way. Most clusters orbit around the center of the galaxy well above its dust-enshrouded disc, or plane, while making brief, repeated passes through the plane that each last about a million years. Spitzer, with infrared eyes that can see into the dusty galactic plane, first spotted the newfound cluster during its current pass. Astronomers then searched for past references to the cluster and found only one undocumented image from the Two Micron All-Sky Survey. Follow-up observations with the University of Wyoming Infrared Observatory helped set the distance of the new cluster at about 9,000 light-years from Earth -- closer than most clusters -- and set the mass at the equivalent of 300,000 Suns. The cluster's apparent size, as viewed from Earth, is comparable to a grain of rice held at arm's length. It is located in the constellation Aquila. Astronomers believe that this cluster may be one of the last in our galaxy to be uncovered. The Two Micron All-Sky Survey false-color image was obtained using near-infrared wavelengths ranging from 1.3 to 2.2 microns. The Spitzer false-color image composite was taken on April 21, 2004, by its infrared array camera. It is composed of images obtained at four mid-infrared wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). The true-color image from the Digitized Sky Survey was acquired with red and blue filters.
Spitzer Digs Up Galactic Fos …
Title Spitzer Digs Up Galactic Fossil
Description This false-color image taken by NASA's Spitzer Space Telescope shows a globular cluster previously hidden in the dusty plane of our Milky Way galaxy. Globular clusters are compact bundles of old stars that date back to the birth of our galaxy, 13 or so billion years ago. Astronomers use these galactic "fossils" as tools for studying the age and formation of the Milky Way. Most clusters orbit around the center of the galaxy well above its dust-enshrouded disc, or plane, while making brief, repeated passes through the plane that each last about a million years. Spitzer, with infrared eyes that can see into the dusty galactic plane, first spotted the newfound cluster during its current pass. A visible-light image (inset) shows only a dark patch of sky. The red streak behind the core of the cluster is a dust cloud, which may indicate the cluster's interaction with the Milky Way. Alternatively, this cloud may lie coincidentally along Spitzer's line of sight. Follow-up observations with the University of Wyoming Infrared Observatory helped set the distance of the new cluster at about 9,000 light-years from Earth -- closer than most clusters -- and set the mass at the equivalent of 300,000 Suns. The cluster's apparent size, as viewed from Earth, is comparable to a grain of rice held at arm's length. It is located in the constellation Aquila. Astronomers believe that this cluster may be one of the last in our galaxy to be uncovered. This image composite was taken on April 21, 2004, by Spitzer's infrared array camera. It is composed of images obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). The visible-light image is from the Digitized Sky Survey, California University of Technology, Pasadena, Calif.
Spitzer Digs Up Galactic Fos …
Title Spitzer Digs Up Galactic Fossil
Description This false-color image taken by NASA's Spitzer Space Telescope shows a globular cluster previously hidden in the dusty plane of our Milky Way galaxy. Globular clusters are compact bundles of old stars that date back to the birth of our galaxy, 13 or so billion years ago. Astronomers use these galactic "fossils" as tools for studying the age and formation of the Milky Way. Most clusters orbit around the center of the galaxy well above its dust-enshrouded disc, or plane, while making brief, repeated passes through the plane that each last about a million years. Spitzer, with infrared eyes that can see into the dusty galactic plane, first spotted the newfound cluster during its current pass. A visible-light image (inset) shows only a dark patch of sky. The red streak behind the core of the cluster is a dust cloud, which may indicate the cluster's interaction with the Milky Way. Alternatively, this cloud may lie coincidentally along Spitzer's line of sight. Follow-up observations with the University of Wyoming Infrared Observatory helped set the distance of the new cluster at about 9,000 light-years from Earth -- closer than most clusters -- and set the mass at the equivalent of 300,000 Suns. The cluster's apparent size, as viewed from Earth, is comparable to a grain of rice held at arm's length. It is located in the constellation Aquila. Astronomers believe that this cluster may be one of the last in our galaxy to be uncovered. This image composite was taken on April 21, 2004, by Spitzer's infrared array camera. It is composed of images obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). The visible-light image is from the Digitized Sky Survey, California University of Technology, Pasadena, Calif.
Spitzer Digs Up Galactic Fos …
Title Spitzer Digs Up Galactic Fossil
Description This false-color image taken by NASA's Spitzer Space Telescope shows a globular cluster previously hidden in the dusty plane of our Milky Way galaxy. Globular clusters are compact bundles of old stars that date back to the birth of our galaxy, 13 or so billion years ago. Astronomers use these galactic "fossils" as tools for studying the age and formation of the Milky Way. Most clusters orbit around the center of the galaxy well above its dust-enshrouded disc, or plane, while making brief, repeated passes through the plane that each last about a million years. Spitzer, with infrared eyes that can see into the dusty galactic plane, first spotted the newfound cluster during its current pass. A visible-light image (inset) shows only a dark patch of sky. The red streak behind the core of the cluster is a dust cloud, which may indicate the cluster's interaction with the Milky Way. Alternatively, this cloud may lie coincidentally along Spitzer's line of sight. Follow-up observations with the University of Wyoming Infrared Observatory helped set the distance of the new cluster at about 9,000 light-years from Earth -- closer than most clusters -- and set the mass at the equivalent of 300,000 Suns. The cluster's apparent size, as viewed from Earth, is comparable to a grain of rice held at arm's length. It is located in the constellation Aquila. Astronomers believe that this cluster may be one of the last in our galaxy to be uncovered. This image composite was taken on April 21, 2004, by Spitzer's infrared array camera. It is composed of images obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). The visible-light image is from the Digitized Sky Survey, California University of Technology, Pasadena, Calif.
Galactic Fossil Found Behind …
Title Galactic Fossil Found Behind Curtain of Dust
Description This image mosaic shows the same patch of sky in various wavelengths of light. While the visible-light image (left) shows a dark sky speckled with stars, infrared images (middle and right), reveal a never-before-seen bundle of stars, called a globular cluster. The left panel is from the California Institute of Technology's Digitized Sky Survey, the middle panel includes images from the NASA-funded Two Micron All-Sky Survey and the University of Wyoming Infrared Observatory (circle inset), and the right panel is from NASA's Spitzer Space Telescope. Globular clusters date back to the birth of our galaxy, 13 or so billion years ago. There are about 150 clusters sprinkled around the core of the galaxy like seeds in a pumpkin. Astronomers use these galactic "fossils" as tools for studying the age and formation of the Milky Way. Most clusters orbit around the center of the galaxy well above its dust-enshrouded disc, or plane, while making brief, repeated passes through the plane that each last about a million years. Spitzer, with infrared eyes that can see into the dusty galactic plane, first spotted the newfound cluster during its current pass. Astronomers then searched for past references to the cluster and found only one undocumented image from the Two Micron All-Sky Survey. Follow-up observations with the University of Wyoming Infrared Observatory helped set the distance of the new cluster at about 9,000 light-years from Earth -- closer than most clusters -- and set the mass at the equivalent of 300,000 Suns. The cluster's apparent size, as viewed from Earth, is comparable to a grain of rice held at arm's length. It is located in the constellation Aquila. Astronomers believe that this cluster may be one of the last in our galaxy to be uncovered. The Two Micron All-Sky Survey false-color image was obtained using near-infrared wavelengths ranging from 1.3 to 2.2 microns. The University of Wyoming Observatory false-color image was captured on July 31, 2004, at wavelengths ranging from 1.2 to 2.2 microns. The Spitzer false-color image composite was taken on April 21, 2004, by its infrared array camera. It is composed of images obtained at four mid-infrared wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).
Titan Sea and Lake Superior
Description Titan Sea and Lake Superior
Full Description This side-by-side image shows a Cassini radar image (on the left) of what is the largest body of liquid ever found on Titan's north pole, compared to Lake Superior (on the right). This close-up is part of a larger image (see Titan (T25) Viewed by Cassini's Radar - Feb. 22, 2007) and offers strong evidence for seas on Titan. These seas are most likely liquid methane and ethane. This feature on Titan is at least 100,000 square kilometers (39,000 square miles), which is greater in extent than Lake Superior (82,000 square kilometers or 32,000 square miles), which is one of Earth's largest lakes. The feature covers a greater fraction of Titan than the largest terrestrial inland sea, the Black Sea. The Black Sea covers 0.085 percent of the surface of the Earth, this newly observed body on Titan covers at least 0.12 percent of the surface of Titan. Because of its size, scientists are calling it a sea. The image on the right is from the SeaWiFS project, NASA's Goddard Space Flight Center, Greenbelt, Md. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. *Credit:* NASA/JPL/GSFC
Date March 13, 2007
Warm Fractures on Enceladus
Description Warm Fractures on Enceladus
Full Description This image shows the warmest places in the south polar region of Saturn's moon Enceladus. The unexpected temperatures were discovered by Cassini's composite infrared spectrometer during a close flyby on July 14, 2005. The image shows how these temperatures correspond to the prominent, bluish fractures dubbed "tiger stripes," first imaged by Cassini's imaging science subsystem cameras. Working together the two teams were able to pinpoint the exact location of the warmest regions on Enceladus. The composite infrared spectrometer instrument measured the infrared heat radiation from the surface at wavelengths between 9 and 16.5 microns within each of the 10 squares shown here. Each square is 6 kilometers (4 miles) across. The color of each square, and the number shown above it, describe the composite infrared spectrometer's measurement of the approximate average temperature of the surface within that square. The warmest temperature squares, at 91 and 89 degrees Kelvin (minus 296 and minus 299 degrees Fahrenheit), are located over one of the "tiger stripe" fractures. They contrast sharply with the surrounding temperatures, which are in the range 74 to 81 degrees Kelvin (minus 326 to minus 313 degrees Fahrenheit). The detailed composite infrared spectrometer data suggest that small areas near the fracture are at substantially higher temperatures, well over 100 degrees Kelvin (minus 279 degrees Fahrenheit). Such "warm" temperatures are unlikely to be due to heating of the surface by the feeble sunlight striking Enceladus' south pole. They are a strong indication that internal heat is leaking out of Enceladus and warming the surface along these fractures. Evaporation of this relatively warm ice probably generates the cloud of water vapor detected above Enceladus' south pole by several other Cassini instruments. Scientists are unsure how the internal heat reaches the surface. The process might involve liquid water, slushy brine, or soft but solid ice. The imaging science subsystem image is an enhanced color view with a pixel scale of 122 meters (400 feet) that was acquired at the same time as the composite infrared spectrometer data. It covers a region 125 kilometers (75 miles) across. The spacecraft's distance from Enceladus was 21,000 kilometers (13,000 miles). The broad bluer fractures that can be seen running from the upper left to the lower right of the image are 1 to 2 kilometers (0.6 to 1.2 miles) wide and more than 100 kilometers (60 miles) long. The fractures are thought to be bluer than the surrounding surface because coarser-grained ice (which has a blue color just as thick masses of ice, like glaciers and icebergs, do on Earth) has been exposed in the fractures. The color image was constructed using an ultraviolet filter (centered at 338 nanometers) in the blue channel, a clear filter in the green channel, and an infrared filter (centered at 930 nanometers) in the red channel. The Cassini-Huygens mission is a cooperative project of NASA,, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The composite infrared spectrometer team homepage is http://cirs.gsfc.nasa.gov/ . The imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/GSFC/Space Science Institute
Date July 29, 2005
Enceladus Temperature Map
Description Enceladus Temperature Map
Full Description This image shows the surprise that startled Cassini scientists on the composite infrared spectrometer team when they got their first look at the infrared (heat) radiation from the south pole of Saturn's moon Enceladus. There is a dramatic warm spot centered on the pole that is probably a sign of internal heat leaking out of the icy moon. The data were taken during the spacecraft's third flyby of this intriguing moon on July 14, 2005. Based on data from previous flybys, which did not show the south pole well, team members expected that the south pole would be very cold, as shown in the left panel. Enceladus is one of the coldest places in the Saturn system because its extremely bright surface reflects 80 percent of the sunlight that hits it, so only 20 percent is available to heat the surface. As on Earth, the poles should be even colder than the equator because the sun shines at such an oblique angle there. The right hand panel shows a global temperature image made from measurements of Enceladus' heat radiation at wavelengths between 9 and 16.5 microns. Cassini made the observation from a distance of 84,000 kilometers (52,000 miles) on the approach to Enceladus, and the image shows details as small as 25 kilometers (16 miles). Equatorial temperatures are much as expected, topping out at about 80 degrees Kelvin (-315 degrees Fahrenheit), but the south pole is occupied by a well-defined warm region reaching 85 Kelvin (-305 degrees Fahrenheit). That is 15 degrees Kelvin (27 degrees Fahrenheit) warmer than expected. The composite infrared spectrometer data further suggest that small areas of the pole are at even higher temperatures, well over 110 degrees Kelvin (-261 degrees Fahrenheit). Evaporation of this relatively warm ice probably generates the cloud of water vapor detected above Enceladus' south pole by several other Cassini instruments. The south polar temperatures are very difficult to explain if sunlight is the only energy source heating the surface, though exotic sunlight-trapping mechanisms have not yet been completely ruled out. It therefore seems likely that portions of the polar region are warmed by heat escaping from the interior of the moon. This would make Enceladus only the third solid body in the solar system, after Earth and Jupiter's volcanic moon Io, where hot spots powered by internal heat have been detected. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The composite infrared spectrometer team homepage is, http://cirs.gsfc.nasa.gov/ . Credit: NASA/JPL/GSFC
Date July 29, 2005
Phoebe Temperature Maps
Description Phoebe Temperature Maps
Full Description A montage of maps of Saturn's moon Phoebe shows surface temperatures at various times of day as determined by the composite infrared spectrometer onboard Cassini during the June 11, 2004, Phoebe flyby. The asterisk on each map shows the location of the subsolar point, where the Sun is directly overhead. This point moves across the surface as Phoebe rotates. It is morning in regions to the left of the subsolar point, and afternoon in regions to the right. Like a newspaper weather map, different colors indicate different temperatures, though Phoebe's temperatures are distinctly cooler than even the coldest January day on Earth. Equatorial temperatures peak in the early afternoon near 112 Kelvin (-257 Fahrenheit), plunging to 78 Kelvin (-319 Fahrenheit) before dawn, and are even colder at higher latitudes. The large day/night temperature contrasts imply that Phoebe's surface is covered in loose dust or ice particles that store little heat and thus cool off rapidly at night. Regions of Phoebe's surface that were not observed are shown in black. Most of the maps show the effect on surface temperatures of the large crater-like depression seen in Cassini's visible-wavelength images of Phoebe, which is located just left of center in these maps. Crater walls that are shadowed and cold in the early morning in the first map are sunlit and warm in the late afternoon in the final map. 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 was designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini composite infrared spectrometer home page at http://cirs.gsfc.nasa.gov/ . Image Credit: NASA/JPL/Goddard Space Flight Center
A Summer View of Russia's Le …
Title A Summer View of Russia's Lena Delta and Olenek River
Description These views of the Russian Arctic were acquired by NASA's Multi-angle Imaging SpectroRadiometer (MISR) instrument on July 11, 2004. The brief arctic summer had transformed the frozen tundra and the thousands of lakes, channels, and rivers of the Lena Delta into a fertile wetland, and the usual blanket of thick snow had melted from the vast plains and taiga forests. The images show an area in the northern part of the Sakha Republic in eastern Siberia. The Olenek River wends northeast from the bottom of the images to the upper left, and the delta through which the mighty Lena River empties into the Laptev Sea dominate the top portions of the images. Creating accurate maps of vegetation structure is essential for understanding the seasonal exchanges of energy and water at the Earth's surface and for preserving biodiversity. The left-hand image is a natural-color image from MISR's nadir (vertical-viewing) camera, in which the rivers appear murky due to sediment, and photosynthetically active vegetation appears green. The center image is also from MISR's nadir camera, but is a false-color view in which the predominant red color is due to the brightness of vegetation at near-infrared wavelengths. Apart from the Lena Delta, the most photosynthetically active regions are within the lower half of the image and throughout the great stretch of land that curves across the Olenek River.  The relatively barren ranges of the Volyoi Mountains appear as the pale tan-colored area to the right of image center. The right-hand image is a multiangle, false-color view made from the red band data of the 60-degree-backward, nadir, and 60-degree-forward cameras, displayed as red, green and blue, respectively. Water appears blue in this image because sun glint makes smooth, wet surfaces look brighter at the forward camera's view angle. Much of the landscape and many low clouds appear purple because these surfaces are both forward and backward scattering, and clouds that are further from the surface appear in a different spot for each view angle, creating a rainbow-like appearance. The highly vegetated region in the natural-color nadir image exhibits a faint greenish hue in the multi-angle composite. This subtle effect suggests that the nadir camera is observing more of the brighter, underlying surface than the oblique cameras, providing information about the distribution and density of trees and shrubs in this area. The Multiangle Imaging SpectroRadiometer observes the daylit Earth continuously, and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. The MISR Browse Image Viewer [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://eosweb.larc.nasa.gov/MISRBR/ ], provides access to low-resolution true-color versions of these images. These data products were generated from a portion of the imagery acquired during Terra orbit 24273. The panels cover an area of about 230 kilometers x 420 kilometers, and utilize data from blocks 30 to 34 within World Reference System-2 path 134. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. [ http://www-misr.jpl.nasa.gov/ ] Text by Clare Averill (Raytheon/JPL).
Angora Fire
Title Angora Fire
Description On the weekend of June 23, 2007, a wildfire broke out south of Lake Tahoe, which stretches across the California-Nevada border. By June 28, the Angora Fire [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14323 ] had burned more than 200 homes and forced some 2,000 residents to evacuate, according to The Seattle Times and the Central Valley Business Times. On June 27, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite captured this image of the burn scar left by the Angora fire. The burn scar is dark gray, or charcoal. Water bodies, including the southern tip of Lake Tahoe and Fallen Leaf Lake, are pale silvery blue, the silver color a result of sunlight reflecting off the surface of the water. Vegetation ranges in color from dark to bright green. Streets are light gray, and the customary pattern of meandering residential streets and cul-de-sacs appears throughout the image, including the area that burned. The burn scar shows where the fire obliterated some of the residential areas just east of Fallen Leaf Lake. According to news reports, the U.S. Forest Service had expressed optimism about containing the fire within a week of the outbreak, but a few days after the fire started, it jumped a defense, forcing the evacuation of hundreds more residents. Strong winds that had been forecast for June 27, however, did not materialize, allowing firefighters to regain ground in controlling the blaze. On June 27, authorities hoped that the fire would be completely contained by July 3. According to estimates provided in the daily report from the National Interagency Fire Center, [ http://www.nifc.gov/information.html ] the fire had burned 3,100 acres (about 12.5 square kilometers) and was about 55 percent contained as of June 28. Some mandatory evacuations remained in effect. You can download a 15-meter-resolution KMZ file of the Angora fire [ http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/tahoe_ast_2007178.kmz ] suitable for use with Google Earth. [ http://earth.google.com/ ] NASA image by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.
Cloud Heights of Frances and …
Title Cloud Heights of Frances and Ivan
Description NASA's Multi-angle Imaging SpectroRadiometer [ http://www-misr.jpl.nasa.gov ] (MISR) captured these images and cloud-top height retrievals of Hurricane Frances on September 4, 2004, when the eye sat just off the coast of eastern Florida, and Hurricane Ivan on September 5, after the storm had devastated Grenada and was heading toward the central and western Caribbean. Hurricane Frances made landfall in the early hours of September 5, and was downgraded to Tropical Storm status as it swept inland through the Florida panhandle and continued northward. Following on the heels of Frances is Hurricane Ivan, which is on record as the strongest tropical hurricane to form at such a low latitude in the Atlantic, and was the most powerful storm to have hit the Caribbean in nearly a decade. The ability of forecasters to predict the intensity and amount of rainfall associated with hurricanes still requires improvement, especially on the 24- to 48-hour timescale vital for disaster planning. To improve the operational models used to make hurricane forecasts, scientists need to better understand the multi-scale interactions at the cloud, mesoscale and synoptic scales that lead to hurricane intensification and dissipation, as well as the various physical processes that determine hurricane intensity and rainfall distributions. Because these uncertainties with regard to how to represent cloud processes still exist, it is vital that the model findings be evaluated against hurricane observations whenever possible. Two-dimensional maps of cloud height such as those shown here offer an unprecedented opportunity for comparing simulated cloud fields against actual hurricane observations. The lefthand panel in each image pair is a natural-color view from MISR's nadir camera. The righthand panels are cloud-top height retrievals produced by automated computer recognition of the distinctive spatial features between images acquired at different view angles. These results indicate that at the time that these images were acquired, clouds within Frances and Ivan had attained altitudes of 15-16 kilometers (9-10 miles) above sea level, respectively. The height fields pictured here are uncorrected for the effects of cloud motion. Wind-corrected heights (which have higher accuracy but coarser spatial coverage) are within about 1 kilometer of the heights shown here. (Visit the Earth Observatory's Natural Hazards Severe Storms [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?topic=storm ] section to view more recent images of Hurricanes Ivan and Frances.) The MISR observes the daylit Earth continuously and every 9 days views the entire globe between 82° north and 82° south latitude. These data products were generated from a portion of the imagery acquired during Terra [ http://terra.nasa.gov ], orbits 25081 and 25094. The panels cover an area of 380 kilometers x 924 kilometers, and utilize data from within blocks 65 to 87 within World Reference System-2 paths 14 and 222, respectively. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. NASA image courtesy GSFC/LaRC/JPL, MISR Team. [ http://www-misr.jpl.nasa.gov ] Text acknowledgment: Clare Averill (Raytheon/Jet Propulsion Laboratory) and Greg McFarquhar (University of Illinois at Urbana-Champaign).
Day Fire in Southern Califor …
Title Day Fire in Southern California
Description While the outline of a fire may be hidden by thick smoke in a photo-like, "natural-color" image, "false-color" images that use visible as well as short-wave or near-infrared light observed by remote-sensing instruments can reveal details on the ground. This pair of images shows the Day Fire in southern California northwest of Los Angeles on September 19, 2006. The images are based on data collected by an aircraft-based sensor called MASTER, [ http://masterweb.jpl.nasa.gov/ ] a simulator for two sensors on NASA's Terra [ http://terra.nasa.gov ] satellite. (NASA uses airborne simulators to cross-check the accuracy of satellite data.) In the natural-color version (bottom), dingy white smoke hangs over most of the scene, hiding the outline of the fire. But in the infrared-enhanced version (top), the actively burning areas around the perimeter of the blaze are obvious as glowing pink and yellow spots, while the smoke fades into a transparent blue. Unburned vegetation appears green, while the burned area appears in shades of brown and gold. The MASTER instrument simulates the Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov ] and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensors on Terra. The instrument can be mounted on several different aircraft, including NASA's ER-2 [ http://www.nasa.gov/centers/dryden/news/FactSheets/FS-046-DFRC.html ] and WB-57 [ http://jsc-aircraft-ops.jsc.nasa.gov/wb57/index.html ] airplanes. NASA images created by Jesse Allen, Earth Observatory, using data provided by the ER-2/MASTER team.
Day Fire in Southern Califor …
Title Day Fire in Southern California
Description While the outline of a fire may be hidden by thick smoke in a photo-like, "natural-color" image, "false-color" images that use visible as well as short-wave or near-infrared light observed by remote-sensing instruments can reveal details on the ground. This pair of images shows the Day Fire in southern California northwest of Los Angeles on September 19, 2006. The images are based on data collected by an aircraft-based sensor called MASTER, [ http://masterweb.jpl.nasa.gov/ ] a simulator for two sensors on NASA's Terra [ http://terra.nasa.gov ] satellite. (NASA uses airborne simulators to cross-check the accuracy of satellite data.) In the natural-color version (bottom), dingy white smoke hangs over most of the scene, hiding the outline of the fire. But in the infrared-enhanced version (top), the actively burning areas around the perimeter of the blaze are obvious as glowing pink and yellow spots, while the smoke fades into a transparent blue. Unburned vegetation appears green, while the burned area appears in shades of brown and gold. The MASTER instrument simulates the Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov ] and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensors on Terra. The instrument can be mounted on several different aircraft, including NASA's ER-2 [ http://www.nasa.gov/centers/dryden/news/FactSheets/FS-046-DFRC.html ] and WB-57 [ http://jsc-aircraft-ops.jsc.nasa.gov/wb57/index.html ] airplanes. NASA images created by Jesse Allen, Earth Observatory, using data provided by the ER-2/MASTER team.
Hurricane Katrina
Title Hurricane Katrina
Description Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology. Images and movie courtesy of NASA/GSFC/LaRC/JPL, MISR Team. Caption details provided by Clare Averill (Raytheon ITSS/Jet Propulsion Laboratory), David J. Diner, Mike Garay and Ralph Kahn (Jet Propulsion Laboratory) and Greg McFarquhar (University of Illinois at Urbana-Champaign)., MISR stereo-height estimates (not shown here) indicate that the highest clouds reach 18-19 kilometers above the surface of the Earth. The stereo anaglyph shows relative height variations and enhances the appearance of thin clouds, such as those that mark the series of gravity waves north-east of the eyewall. Atmospheric gravity waves are caused by air displacements in an otherwise stable air layer. In this case, the gravity waves are above the hurricane arms in the upper troposphere, and were probably generated as the towering storm updraft tried to push into the stable air between the troposphere and the stratosphere (known as the tropopause). Some of Katrina's cloud tops were about 2 kilometers above the tropopause. Such high "overshooting tops" are also characteristic of strong and rapidly growing storms. The animation progresses from MISR's most forward-pointing camera, which views the scene first, to the most backward-pointing camera, which views the scene last. It was created by aligning the views from all 9 cameras using the high clouds within the eyewall as a reference point. North is at the top. The convective cloud towers, especially those along the eastern sides of the inner and outer eyewalls, attain the highest altitudes and indicate that the storm is strengthening. Those areas that do not exhibit cloud-top convection are clouds experiencing vertical wind shear, and tend to be lower than the towering cloud structures. The vertical and horizontal development of the convective clouds and the formation of an outer ring of growing clouds (referred to as an "eyewall replacement cycle") also indicate rapid strengthening. During this stage of hurricane development, an outer band of clouds may gradually move inward to replace the existing hurricane eyewall, causing the central pressure to increase and weaken the storm in the short term. However, eyewall replacement may sometimes be a forerunner for rapid strengthening in the longer term. This was the case with Hurricane Katrina, whose central pressure increased slightly on Saturday, but then dropped again significantly on Sunday when Katrina became a Category 5 storm. Observing the development of a concentric eyewall at this spatial and temporal resolution is a unique feature of these MISR observations. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82 degrees North and 82 degrees South latitude every nine days. The still images each cover an area of about 827 kilometers by 380 kilometers, and the animation covers an area of about 202 kilometers by 214 kilometers. The data products were generated from a portion of the imagery acquired during Terra orbit 30280 and utilize data from blocks 69 to 74 within World Reference System-2 path 17. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's, This image and animation from NASA's Multi-angle Imaging SpectroRadiometer (MISR) show the strong convective development of Hurricane Katrina on Saturday, August 27, as it moved west through the Gulf of Mexico. Over 7 minutes during which all 9 MISR cameras viewed Katrina, the animation captures the cloud-top sides, the counterclockwise rotation of the eyewall, and the bubbling growth of the towering cloud structures. At this time, Katrina was undergoing rapid development— it had just been upgraded to a Category 3 hurricane, and within 24 hours it would reach Category 5. On Monday morning when the eyewall made landfall over the United States, it was a Category 4 storm. Hurricane Katrina was one of the most powerful and destructive storms on record for the Atlantic Basin. The image above is a false-color view (near-infrared, red, and blue wavelengths of reflected light displayed as red, green and blue) from MISR's nadir (pointing straight down) camera. In the image above, north is up. The high resolution image linked above shows a wider view of this false-color image, with north to the left. The vegetated Alabama coast in the upper left-hand corner in this high-resolution image appears in red hues. The bottom panel in the high-resolution image is a 3-D stereo anaglyph created with red band data from MISR's 70-degree-forward-viewing and 60-degree-forward-viewing cameras, displayed as red and green/blue, respectively. To observe the height variations in 3-D, you will need to use red/blue glasses. [ http://photojournal.jpl.nasa.gov/Help/VendorList.html#Glasses ]
Hurricane Katrina
Title Hurricane Katrina
Description Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology. Images and movie courtesy of NASA/GSFC/LaRC/JPL, MISR Team. Caption details provided by Clare Averill (Raytheon ITSS/Jet Propulsion Laboratory), David J. Diner, Mike Garay and Ralph Kahn (Jet Propulsion Laboratory) and Greg McFarquhar (University of Illinois at Urbana-Champaign)., MISR stereo-height estimates (not shown here) indicate that the highest clouds reach 18-19 kilometers above the surface of the Earth. The stereo anaglyph shows relative height variations and enhances the appearance of thin clouds, such as those that mark the series of gravity waves north-east of the eyewall. Atmospheric gravity waves are caused by air displacements in an otherwise stable air layer. In this case, the gravity waves are above the hurricane arms in the upper troposphere, and were probably generated as the towering storm updraft tried to push into the stable air between the troposphere and the stratosphere (known as the tropopause). Some of Katrina's cloud tops were about 2 kilometers above the tropopause. Such high "overshooting tops" are also characteristic of strong and rapidly growing storms. The animation progresses from MISR's most forward-pointing camera, which views the scene first, to the most backward-pointing camera, which views the scene last. It was created by aligning the views from all 9 cameras using the high clouds within the eyewall as a reference point. North is at the top. The convective cloud towers, especially those along the eastern sides of the inner and outer eyewalls, attain the highest altitudes and indicate that the storm is strengthening. Those areas that do not exhibit cloud-top convection are clouds experiencing vertical wind shear, and tend to be lower than the towering cloud structures. The vertical and horizontal development of the convective clouds and the formation of an outer ring of growing clouds (referred to as an "eyewall replacement cycle") also indicate rapid strengthening. During this stage of hurricane development, an outer band of clouds may gradually move inward to replace the existing hurricane eyewall, causing the central pressure to increase and weaken the storm in the short term. However, eyewall replacement may sometimes be a forerunner for rapid strengthening in the longer term. This was the case with Hurricane Katrina, whose central pressure increased slightly on Saturday, but then dropped again significantly on Sunday when Katrina became a Category 5 storm. Observing the development of a concentric eyewall at this spatial and temporal resolution is a unique feature of these MISR observations. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82 degrees North and 82 degrees South latitude every nine days. The still images each cover an area of about 827 kilometers by 380 kilometers, and the animation covers an area of about 202 kilometers by 214 kilometers. The data products were generated from a portion of the imagery acquired during Terra orbit 30280 and utilize data from blocks 69 to 74 within World Reference System-2 path 17. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's, This image and animation from NASA's Multi-angle Imaging SpectroRadiometer (MISR) show the strong convective development of Hurricane Katrina on Saturday, August 27, as it moved west through the Gulf of Mexico. Over 7 minutes during which all 9 MISR cameras viewed Katrina, the animation captures the cloud-top sides, the counterclockwise rotation of the eyewall, and the bubbling growth of the towering cloud structures. At this time, Katrina was undergoing rapid development— it had just been upgraded to a Category 3 hurricane, and within 24 hours it would reach Category 5. On Monday morning when the eyewall made landfall over the United States, it was a Category 4 storm. Hurricane Katrina was one of the most powerful and destructive storms on record for the Atlantic Basin. The image above is a false-color view (near-infrared, red, and blue wavelengths of reflected light displayed as red, green and blue) from MISR's nadir (pointing straight down) camera. In the image above, north is up. The high resolution image linked above shows a wider view of this false-color image, with north to the left. The vegetated Alabama coast in the upper left-hand corner in this high-resolution image appears in red hues. The bottom panel in the high-resolution image is a 3-D stereo anaglyph created with red band data from MISR's 70-degree-forward-viewing and 60-degree-forward-viewing cameras, displayed as red and green/blue, respectively. To observe the height variations in 3-D, you will need to use red/blue glasses. [ http://photojournal.jpl.nasa.gov/Help/VendorList.html#Glasses ]
Hurricane Katrina
Title Hurricane Katrina
Description Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology. Images and movie courtesy of NASA/GSFC/LaRC/JPL, MISR Team. Caption details provided by Clare Averill (Raytheon ITSS/Jet Propulsion Laboratory), David J. Diner, Mike Garay and Ralph Kahn (Jet Propulsion Laboratory) and Greg McFarquhar (University of Illinois at Urbana-Champaign)., MISR stereo-height estimates (not shown here) indicate that the highest clouds reach 18-19 kilometers above the surface of the Earth. The stereo anaglyph shows relative height variations and enhances the appearance of thin clouds, such as those that mark the series of gravity waves north-east of the eyewall. Atmospheric gravity waves are caused by air displacements in an otherwise stable air layer. In this case, the gravity waves are above the hurricane arms in the upper troposphere, and were probably generated as the towering storm updraft tried to push into the stable air between the troposphere and the stratosphere (known as the tropopause). Some of Katrina's cloud tops were about 2 kilometers above the tropopause. Such high "overshooting tops" are also characteristic of strong and rapidly growing storms. The animation progresses from MISR's most forward-pointing camera, which views the scene first, to the most backward-pointing camera, which views the scene last. It was created by aligning the views from all 9 cameras using the high clouds within the eyewall as a reference point. North is at the top. The convective cloud towers, especially those along the eastern sides of the inner and outer eyewalls, attain the highest altitudes and indicate that the storm is strengthening. Those areas that do not exhibit cloud-top convection are clouds experiencing vertical wind shear, and tend to be lower than the towering cloud structures. The vertical and horizontal development of the convective clouds and the formation of an outer ring of growing clouds (referred to as an "eyewall replacement cycle") also indicate rapid strengthening. During this stage of hurricane development, an outer band of clouds may gradually move inward to replace the existing hurricane eyewall, causing the central pressure to increase and weaken the storm in the short term. However, eyewall replacement may sometimes be a forerunner for rapid strengthening in the longer term. This was the case with Hurricane Katrina, whose central pressure increased slightly on Saturday, but then dropped again significantly on Sunday when Katrina became a Category 5 storm. Observing the development of a concentric eyewall at this spatial and temporal resolution is a unique feature of these MISR observations. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82 degrees North and 82 degrees South latitude every nine days. The still images each cover an area of about 827 kilometers by 380 kilometers, and the animation covers an area of about 202 kilometers by 214 kilometers. The data products were generated from a portion of the imagery acquired during Terra orbit 30280 and utilize data from blocks 69 to 74 within World Reference System-2 path 17. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's, This image and animation from NASA's Multi-angle Imaging SpectroRadiometer (MISR) show the strong convective development of Hurricane Katrina on Saturday, August 27, as it moved west through the Gulf of Mexico. Over 7 minutes during which all 9 MISR cameras viewed Katrina, the animation captures the cloud-top sides, the counterclockwise rotation of the eyewall, and the bubbling growth of the towering cloud structures. At this time, Katrina was undergoing rapid development— it had just been upgraded to a Category 3 hurricane, and within 24 hours it would reach Category 5. On Monday morning when the eyewall made landfall over the United States, it was a Category 4 storm. Hurricane Katrina was one of the most powerful and destructive storms on record for the Atlantic Basin. The image above is a false-color view (near-infrared, red, and blue wavelengths of reflected light displayed as red, green and blue) from MISR's nadir (pointing straight down) camera. In the image above, north is up. The high resolution image linked above shows a wider view of this false-color image, with north to the left. The vegetated Alabama coast in the upper left-hand corner in this high-resolution image appears in red hues. The bottom panel in the high-resolution image is a 3-D stereo anaglyph created with red band data from MISR's 70-degree-forward-viewing and 60-degree-forward-viewing cameras, displayed as red and green/blue, respectively. To observe the height variations in 3-D, you will need to use red/blue glasses. [ http://photojournal.jpl.nasa.gov/Help/VendorList.html#Glasses ]
Earthquake Raises Reefs in t …
Title Earthquake Raises Reefs in the Solomon Islands
Description When people talk about change happening on a geologic time scale, most of the time, they mean that the change happens over the course of millions of years: the Colorado River gradually cuts through the soft rock of the Colorado Plateau until it has made a 4,000-foot-deep chasm, the Grand Canyon, continents drift centimeters at a time, slowly changing the shape and position of landmasses on the Earth. Most of the time, change is slow, but sometimes, geologic change happens all at once. This was the case on Ranongga Island in the Solomon Islands. In the early morning hours of April 2, 2007, a magnitude 8.1 earthquake shook the Solomon Islands, its epicenter southwest of Ranongga Island. The huge quake pushed much of the island up, raising the coral reefs that ringed the island above the water. In the course of a few minutes, Ranongga Island acquired several meters of new beach. The newly exposed reef forms a gray rim along the eastern shore of the island in the left image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on April 12, 2007. In the right image, taken on March 31, 2006, the shallowly submerged reefs color the water a lighter shade of blue. The uplift may be more dramatic than the images show. When ASTER took the 2007 image, the tide was 29.4 centimeters higher than it was when the 2006 image was taken, and yet the uplift is still visible. The lush vegetation that covers the tropical island is bright red in this image, which is made from both visible and infrared light. Out of its aquatic environment, the reef died, becoming the foundation of new land. Such evolution is common in earthquake zones in the Pacific and Indian Oceans. During the December 26, 2004, earthquake that generated the massive Indian Ocean tsunami, Simeulue Island was lifted as much as 150 centimeters (4.9 feet), exposing the reef that surrounded it. A similar set of exposed fossilized reefs on the shores of Papua New Guinea, near the Solomon Islands, provided proof that wobbles in the Earth's orbit trigger ice ages. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ]Thanks to Aron Meltzner, California Institute of Technology, for help with image interpretation.
Earthquake Raises Reefs in t …
Title Earthquake Raises Reefs in the Solomon Islands
Description When people talk about change happening on a geologic time scale, most of the time, they mean that the change happens over the course of millions of years: the Colorado River gradually cuts through the soft rock of the Colorado Plateau until it has made a 4,000-foot-deep chasm, the Grand Canyon, continents drift centimeters at a time, slowly changing the shape and position of landmasses on the Earth. Most of the time, change is slow, but sometimes, geologic change happens all at once. This was the case on Ranongga Island in the Solomon Islands. In the early morning hours of April 2, 2007, a magnitude 8.1 earthquake shook the Solomon Islands, its epicenter southwest of Ranongga Island. The huge quake pushed much of the island up, raising the coral reefs that ringed the island above the water. In the course of a few minutes, Ranongga Island acquired several meters of new beach. The newly exposed reef forms a gray rim along the eastern shore of the island in the left image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on April 12, 2007. In the right image, taken on March 31, 2006, the shallowly submerged reefs color the water a lighter shade of blue. The uplift may be more dramatic than the images show. When ASTER took the 2007 image, the tide was 29.4 centimeters higher than it was when the 2006 image was taken, and yet the uplift is still visible. The lush vegetation that covers the tropical island is bright red in this image, which is made from both visible and infrared light. Out of its aquatic environment, the reef died, becoming the foundation of new land. Such evolution is common in earthquake zones in the Pacific and Indian Oceans. During the December 26, 2004, earthquake that generated the massive Indian Ocean tsunami, Simeulue Island was lifted as much as 150 centimeters (4.9 feet), exposing the reef that surrounded it. A similar set of exposed fossilized reefs on the shores of Papua New Guinea, near the Solomon Islands, provided proof that wobbles in the Earth's orbit trigger ice ages. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ]Thanks to Aron Meltzner, California Institute of Technology, for help with image interpretation.
Earthquake Raises Reefs in t …
Title Earthquake Raises Reefs in the Solomon Islands
Description When people talk about change happening on a geologic time scale, most of the time, they mean that the change happens over the course of millions of years: the Colorado River gradually cuts through the soft rock of the Colorado Plateau until it has made a 4,000-foot-deep chasm, the Grand Canyon, continents drift centimeters at a time, slowly changing the shape and position of landmasses on the Earth. Most of the time, change is slow, but sometimes, geologic change happens all at once. This was the case on Ranongga Island in the Solomon Islands. In the early morning hours of April 2, 2007, a magnitude 8.1 earthquake shook the Solomon Islands, its epicenter southwest of Ranongga Island. The huge quake pushed much of the island up, raising the coral reefs that ringed the island above the water. In the course of a few minutes, Ranongga Island acquired several meters of new beach. The newly exposed reef forms a gray rim along the eastern shore of the island in the left image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on April 12, 2007. In the right image, taken on March 31, 2006, the shallowly submerged reefs color the water a lighter shade of blue. The uplift may be more dramatic than the images show. When ASTER took the 2007 image, the tide was 29.4 centimeters higher than it was when the 2006 image was taken, and yet the uplift is still visible. The lush vegetation that covers the tropical island is bright red in this image, which is made from both visible and infrared light. Out of its aquatic environment, the reef died, becoming the foundation of new land. Such evolution is common in earthquake zones in the Pacific and Indian Oceans. During the December 26, 2004, earthquake that generated the massive Indian Ocean tsunami, Simeulue Island was lifted as much as 150 centimeters (4.9 feet), exposing the reef that surrounded it. A similar set of exposed fossilized reefs on the shores of Papua New Guinea, near the Solomon Islands, provided proof that wobbles in the Earth's orbit trigger ice ages. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ]Thanks to Aron Meltzner, California Institute of Technology, for help with image interpretation.
Rice Cultivation in Northwes …
Title Rice Cultivation in Northwest Italy
Description The lowlands of Lombardy and Piedmont in northwest Italy are some of the most highly developed irrigation areas in the world. Irrigated lands cover at least 160,000 acres in this part of Italy, where rice is the most important crop. These views of the region were acquired on May 8, 2005, by NASA's Multi-angle Imaging SpectroRadiometer (MISR). The multiple viewing angles provided by MISR's nine cameras make it possible to tell wet surfaces, including flooded lands, from other surfaces, and they also make cities easy to locate. The left-hand image is a natural-color view acquired by MISR's downward-looking (nadir) camera, and the right-hand image is a combination of red band data from MISR's 60-degree-backward-, nadir, and 60-degree-forward-viewing cameras. (Red band is what scientists call the "channel" on the sensor that detects red light.) Color changes indicate surface texture, which is influenced by terrain, vegetation structure, soil type, and surface wetness. Wet surfaces or areas with standing water appear in blue or purple-blue hues. The purple-blue areas that dominate the center-left part of the image are part of the extensive irrigation network that exists throughout the plains and meadows of the region. Cities with tall buildings appear in red-orange hues. In this type of image, the city of Milan is the most obvious. The small orange area in the center of the purple inundated area indicates the location of Vercelli, and the larger city of Milan is the orange area to the northeast, on the other side of the Ticino River. To a lesser extent, the cities of Novara, Pavia, Galliate, Mortara, and Vigevano are also identifiable by their orange hues. MISR can tell various surface features like cities or irrigated areas apart because of the way surfaces reflect light. A smooth water surface tends to reflect sunlight away from the Sun. This effect is most apparent when a satellite views the surface with the Sun in front of the camera. Similarly, rough surfaces tend to reflect light back towards the Sun, and this "backward scattering" is most obvious when a satellites views a surface with the Sun behind the camera. Clouds present over the high country to the west of the Lago Maggiore (upper left corner) and along the coast of the Golfo di Genova (bottom) appear in a different spot for each view angle, creating a rainbow-like appearance. Mountains also have a "wavy" look in the multi-angle combination because, like clouds, their height above the surface makes them appear in a different spot in each camera's view angle. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82 degrees North and 82 degrees South latitude every nine days. This image covers an area of about 131 kilometers by 191 kilometers. These data products were generated from a portion of the imagery acquired during Terra orbit 28660 and utilize data from block 54 within World Reference System-2 path 193. MISR was, built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. [ http://www-misr.jpl.nasa.gov/ ] Text by Clare Averill (Raytheon ITSS/JPL)
San Miguel and Santa Rosa Is …
Title San Miguel and Santa Rosa Islands
Description Off the California coast lies a series of small islands, all part of the Channel Islands National Park. [ http://www.nps.gov/chis ] On May 29, 2005, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite captured this image of two of those islands: San Miguel and Santa Rosa. The westernmost island, San Miguel, is primarily a plateau, most of it with an elevation of approximately 150 meters (500 feet), although some hills on the island reach roughly 250 meters (800 feet). At just 9,500 acres (38 square kilometers), San Miguel faces a constant barrage of North Pacific winds. Strong stripes, resulting from linear sand dunes, cross this island from its northwestern beaches toward the southeast. In between the dunes, however, vegetation appears lush. According to the National Park Service, the island had been characterized as a "barren lump of sand" in the late nineteenth century, thanks to a century of overgrazing. Removal of the grazing animals eventually restored the island's flora. San Miguel's neighbor, Santa Rosa, sports no stripes, and seems slightly less lush. Santa Rosa is the second-largest island off the California coast, at 53,000 acres (214 square kilometers). Only its eastern neighbor, Santa Cruz, is larger. Santa Rosa has generally low elevation except for its central mountain range that reaches up to roughly 484 meters (1,589 feet). Like its elevation, Santa Rosa's coastline also varies, from wide sandy beaches to steep cliffs. In the water around the islands, kelp forests rise up from the ocean floor. You can download a 15-meter-resolution KMZ file of San Miguel Island [ http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/sanmiguel_ast_2005149.kmz ] for use with Google Earth. [ http://earth.google.com/download-earth.html ] NASA image created by Jesse Allen, using data provided courtesy NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.
Sierra Nevada Range, Mokelum …
Title Sierra Nevada Range, Mokelumne Wilderness
Description South of Lake Tahoe, in the Sierra Nevada mountain range in California, the boundaries of three national forests—Stanislaus, El Dorado, and Humboldt-Toiyabe—meet. At the intersection of these boundaries sits the Mokelumne Wilderness Area, [ http://www.fs.fed.us/r5/stanislaus/visitor/mokelumne.shtml ] which straddles the crest of the Sierra Nevada. On June 29, 2007, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov/ ] flying on NASA's Terra [ http://terra.nasa.gov/ ] satellite captured this image of the Mokelumne and surrounding forests. In this simulated true-color image, dark green indicates thick vegetation, pale green indicates sparse vegetation, dark blue indicates water, and beige and gray indicate bare ground. National Park boundaries appear in white. The terrain in the area is rugged, with steep mountain crags interspersed with occasional lakes with jagged contours. At high elevations, forests give way to alpine plants, and finally, to bare rock. A pale shoreline outlines Spicer Reservoir, near the bottom of the image, suggesting a dip in the lake's water level, consistent with warm, dry [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14393 ] conditions that predominated in the American West in the early summer of 2007. Not all national forests are wilderness area, many forests offer timber concessions. In Stanislaus National Forest, in the lower left corner of this image, tiny pale patches break the forest cover. In the high-resolution imagery, the precise geometric outlines of these patches are more obvious, such patterns are consistent with clear-cut logging. You can download a 15-meter-resolution KMZ file of the Mokelumne Wilderness [ http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/eldorado_ast_2007180.kmz ] suitable for use with Google Earth. [ http://earth.google.com/ ] NASA image by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.
Fires in Southern California
Title Fires in Southern California
Description browse image of orbit 20510 (430 kB JPEG) Large plumes of smoke rising from devastating wildfires burning near Los Angeles and San Diego on Sunday, October 26, 2003, are highlighted in this set of images from the Multi-angle Imaging SpectroRadiometer (MISR). These images include a natural color view from MISR's nadir camera (left) and an automated stereo height retrieval (right). The tops of the smoke plumes range in altitude from 500–3000 meters, and the stereo retrieval clearly differentiates the smoke from patches of high-altitude cirrus. Plumes are apparent from fires burning near the California-Mexico border, San Diego, Camp Pendleton, the foothills of the San Bernardino Mountains, and in and around Simi Valley. The majority of the smoke is coming from the fires near San Diego and the San Bernardino Mountains. The Multiangle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82° north and 82° south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 20510. The MISR Browse Image Viewer [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://eosweb.larc.nasa.gov/MISRBR/ ] provides access to low-resolution true-color versions of these images. The panels cover an area of 329 kilometers x 543 kilometers, and utilize data from blocks 62 to 66 within World Reference System-2 path 40. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://www-misr.jpl.nasa.gov/ ]
Fires in Southern California
Title Fires in Southern California
Description browse image of orbit 20510 (430 kB JPEG) Large plumes of smoke rising from devastating wildfires burning near Los Angeles and San Diego on Sunday, October 26, 2003, are highlighted in this set of images from the Multi-angle Imaging SpectroRadiometer (MISR). These images include a natural color view from MISR's nadir camera (left) and an automated stereo height retrieval (right). The tops of the smoke plumes range in altitude from 500–3000 meters, and the stereo retrieval clearly differentiates the smoke from patches of high-altitude cirrus. Plumes are apparent from fires burning near the California-Mexico border, San Diego, Camp Pendleton, the foothills of the San Bernardino Mountains, and in and around Simi Valley. The majority of the smoke is coming from the fires near San Diego and the San Bernardino Mountains. The Multiangle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82° north and 82° south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 20510. The MISR Browse Image Viewer [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://eosweb.larc.nasa.gov/MISRBR/ ] provides access to low-resolution true-color versions of these images. The panels cover an area of 329 kilometers x 543 kilometers, and utilize data from blocks 62 to 66 within World Reference System-2 path 40. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://www-misr.jpl.nasa.gov/ ]
Fires in Southern California
Title Fires in Southern California
Description Part of the firestorm that swept through Southern California in late October 2007, the Poomacha Fire east of Pauma Valley was still smoldering in a few interior locations as of November 8, according to the National Interagency Fire Center. This image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite on November 6 shows the burned landscape of the Poomacha Fire using a combination of visible and infrared light. The burned area in the center of the image is bright pink. Naturally bare (or thinly vegetated) land surfaces are lighter pink. Vegetation is bright green. The fire took its name from a street in a community on the reservation, La Jolla Amago, where at least 8 homes were destroyed. You can download a 15-meter-resolution KMZ file of the Poomacha fire scar [ http://earthobservatory.nasa.gov/NaturalHazards/Archive/Nov2007/scal_ast_2007310.kmz ] suitable for use with Google Earth. [ http://earth.google.com/ ] NASA image created by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ]
Tropical Cyclone Monty
Title Tropical Cyclone Monty
Description The Multi-angle Imaging SpectroRadiometer (MISR) acquired these natural color images and cloud top height measurements for Monty before and after the storm made landfall over the remote Pilbara region of Western Australia, on February 29 and March 2, 2004 (shown as the left and right-hand image sets, respectively). On February 29, Monty was upgraded to category 4 cyclone status. After traveling inland about 300 kilometers to the south, the cyclonic circulation had decayed considerably, although category 3 force winds were reported on the ground. Some parts of the drought-affected Pilbara region received more than 300 millimeters of rainfall, and serious and extensive flooding has occurred. The natural color images cover much of the same area, although the right-hand panels are offset slightly to the east. Automated stereoscopic processing of data from multiple MISR cameras was utilized to produce the cloud-top height fields. The distinctive spatial patterns of the clouds provide the necessary contrast to enable automated feature matching between images acquired at different view angles. The height retrievals are at this stage uncorrected for the effects of the high winds associated with cyclone rotation. Areas where heights could not be retrieved are shown in dark gray. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbits 22335 and 22364. The panels cover an area of about 380 kilometers x 985 kilometers, and utilize data from blocks 105 to 111 within World Reference System-2 paths 115 and 113. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. Image courtesy NASA/GSFC/LaRC/JPL MISR Team [ http://www-misr.jpl.nasa.gov/ ], caption courtesy Clare Averill, Raytheon/Jet Propulsion Laboratory.
Zaca Wildfire, Southern Cali …
Title Zaca Wildfire, Southern California
Description In early August 2007, the month-old Zaca Fire in Southern California was racing over the hilly terrain along the southwest margin of the Los Padres National Forest. Started accidentally on private ranch land near the forest in early July, the fire quickly got out of control in the hot, dry, windy conditions the area was experiencing in summer 2007. As of August 8, the fire had burned an estimated 72,050 acres and was about 68 percent contained. This image of the fire was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA'Terra [ http://terra.nasa.gov ] satellite on August 7. Unburned vegetation appears green, while the burned area appears charcoal-colored. Smoke hangs over the area. You can download a 15-meter-resolution KMZ file of the Zaca fire [ http://earthobservatory.nasa.gov/NaturalHazards/Archive/Aug2007/zaca_ast_2007218.kmz ] suitable for use with Google Earth. [ http://earth.google.com/ ] NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.
Zaca Wildfire, Southern Cali …
Title Zaca Wildfire, Southern California
Description In early August 2007, the month-old Zaca Fire in Southern California was racing over the hilly terrain along the southwest margin of the Los Padres National Forest. Started accidentally on private ranch land near the forest in early July, the fire quickly got out of control in the hot, dry, windy conditions the area was experiencing in summer 2007. As of August 8, the fire had burned an estimated 72,050 acres and was about 68 percent contained. This image of the fire was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA'Terra [ http://terra.nasa.gov ] satellite on August 7. Unburned vegetation appears green, while the burned area appears charcoal-colored. Smoke hangs over the area. You can download a 15-meter-resolution KMZ file of the Zaca fire [ http://earthobservatory.nasa.gov/NaturalHazards/Archive/Aug2007/zaca_ast_2007218.kmz ] suitable for use with Google Earth. [ http://earth.google.com/ ] NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.
Sky and Planets
Title Sky and Planets
Explanation On February 10th, an evocative [ http://www.jps.net/ssumner/ ] evening sky above Rocklin, California, USA inspired astrophotographer Steve Sumner to record this remarkable sight - five planets and the Moon. Near its first quarter phase, the bright Moon [ http://lunar.arc.nasa.gov/ ] was intentionally overexposed but Saturn [ http://www.jpl.nasa.gov/cassini/ ], Jupiter [ http://galileo.jpl.nasa.gov/ ], Mars [ http://mars.jpl.nasa.gov/ ], and Mercury [ http://sd-www.jhuapl.edu/MESSENGER/ ] (and, of course, planet Earth's [ http://www.earth.nasa.gov/ ] horizon) are all clearly visible in the deepening twilight. Notably absent in this grouping of naked-eye planets is Venus [ http://antwrp.gsfc.nasa.gov/apod/ap990903.html ] which is still putting in an early appearance as the morning star [ http://ispec.scibernet.com/station/morn_star.html ]. This month, Mercury has joined Venus in the dawn twilight while Saturn, Jupiter, and Mars still shine brightly in the western sky at nightfall [ http://www.skypub.com/sights/sights.shtml ] making another gorgeous close grouping with the crescent Moon [ http://www.inconstantmoon.com/ ].
Earth's San Andreas Fault
Title Earth's San Andreas Fault
Explanation The Earth's surface is broken. Cracks in the Earth's crust known as faults [ http://www.seismo.berkeley.edu/seismo/faq/fault_0.html ] can run for hundreds of kilometers. These faults are frequently [ http://www.seismo.berkeley.edu/seismo/faq/ ] the sites of major [ http://wwwneic.cr.usgs.gov/neis/eqlists/10maps_world.html ] earthquakes [ http://www.worldbook.com/fun/bth/earthquake/html/what_is.htm ] as the tectonic plates [ http://www.seismo.unr.edu/ftp/pub/louie/class/100/plate-tectonics.html ] that cover the surface of the Earth shift. Pictured above [ http://photojournal.jpl.nasa.gov/cgi-bin/PIAGenCatalogPage.pl?PIA02786 ] is San Andreas Fault in California [ http://www.state.ca.us/ ], one of the longest and most active faults [ http://ghtmaps01.cr.usgs.gov/wsfaults.html ]. Visible [ http://epod.usra.edu/archive/epodviewer.php3?oid=40480 ] as the linear feature to the right of the mountains, San Andreas Fault [ http://pubs.usgs.gov/gip/earthq3/safaultgip.html ] reaches 15 kilometers deep and is about 20 million years old. The above exaggerated-height image [ http://www.jpl.nasa.gov/pictures/srtm/ ] was created by combining radar deployed by the Space Shuttle Endeavour [ http://www.ksc.nasa.gov/shuttle/resources/orbiters/endeavour.html ] in February [ http://antwrp.gsfc.nasa.gov/apod/calendar/ca0002.html ] with a true-color Landsat [ http://geo.arc.nasa.gov/sge/landsat/landsat.html ] picture. Along San Andreas Fault [ http://www.agu.org/sci_soc/trehu.html ], the titanic Pacific Plate [ http://www.geol.ucsb.edu/~atwater/Animations/Pacificmovie-preview.html ] is shifting [ http://www.earth.nwu.edu/people/seth/demos/PLATE/plate.html ] relative to the huge North American Plate [ http://www.geol.ucsb.edu/~atwater/Animations/ ] by an average of a few centimeters per year. At that rate, in a few million years, the Earth's surface [ http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/Maps/map_plate_tectonics_world.html ] will look quite different [ http://antwrp.gsfc.nasa.gov/apod/ap001002.html ] than it does today.
Comet Hale-Bopp Over Indian …
Title Comet Hale-Bopp Over Indian Cove
Explanation Comet Hale-Bopp, the Great Comet of 1997 [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?great+comet+1997 ], was quite a sight. No comets [ http://www.nineplanets.org/comets.html ] of comparable brightness have graced the skies of Earth [ http://antwrp.gsfc.nasa.gov/apod/ap010204.html ] since then. During this next month, however, even besides the fleeting Comet Bradfield [ http://antwrp.gsfc.nasa.gov/apod/ap040419.html ], "two" comets have a slight chance of rivaling Hale-Bopp [ http://www2.jpl.nasa.gov/comet/ ] and a good chance of putting on a memorable [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/comet.html ] sky show. Unfortunately, most of the show will be confined to sky gazers in Earth's southern hemisphere [ http://antwrp.gsfc.nasa.gov/apod/ap021222.html ]. Both comets are already visible [ http://encke.jpl.nasa.gov/RecentObs.html#02T7 ] to the unaided eye from there. The first, Comet C/2002 T7 (LINEAR) [ http://cometography.com/lcomets/2002t7.html ], should be at its best before dawn during the first weeks of May from the south. The second, Comet C/2001 Q4 (NEAT) [ http://cometography.com/lcomets/2001q4.html ], should be visible in early May from all over the Earth. Both comets [ http://www.space.com/spacewatch/comet_double_040319.html ] appear to be approaching [ http://skyandtelescope.com/observing/objects/comets/article_1037_1.asp ] the inner Solar System [ http://www.nineplanets.org/overview.html ] for the first time and so it is very hard to predict [ http://www.exploratorium.edu/exploring/space/kohoutek.html ] how bright each will become. In the above photograph [ http://www2.jpl.nasa.gov/comet/pach17.html ] taken 1997 April 6, Comet Hale-Bopp was imaged from the Indian Cove Campground in the Joshua Tree National Forest [ http://www.nps.gov/jotr/ ] in California [ http://www.state.ca.us/ ], USA [ http://www.cia.gov/cia/publications/factbook/geos/us.html ]. A flashlight [ http://www.geocities.com/~stuarts1031/flashlight.html ] was used to momentarily illuminate foreground rocks during this six minute exposure.
Aura Launch
Title Aura Launch
Explanation In this alluring time exposure, star trails arc [ http://antwrp.gsfc.nasa.gov/apod/ap000715.html ] across the night sky above Monterey Bay and the lights of Santa Cruz, California, USA. But since the exposure began around 3:01am PDT on July 15 it also records the long trail of a Delta II rocket [ http://www.boeing.com/defense-space/space/delta/delta2/ delta2.htm ] lofting NASA's Aura [ http://www.jpl.nasa.gov/news/ news.cfm?release=2004-181 ] spacecraft into Earth orbit. Watching from a vantage point about 200 miles north of the Vandenberg Air Force Base [ http://www.vandenberg.af.mil/ ] launch site, photographer Rick Baldridge reports that the trail represents the first five minutes of the rocket's powered [ http://www.grc.nasa.gov/WWW/K-12/TRC/Rockets/ history_of_rockets.html ] flight with the ignition of additional solid fuel strap-on motors visible after liftoff, near the beginning of the track. The rocket trail ends at first stage shutdown. Seen under the rocket's path, the two brightest star trails mark the alpha and beta stars of the high-flying constellation Grus [ http://www.hawastsoc.org/deepsky/gru/ index.html ]. The Aura spacecraft's [ http://www.nasa.gov/mission_pages/aura/spacecraft/ index.html ] goal is a comprehensive study of planet Earth's nurturing atmosphere [ http://www.nasa.gov/missions/ earth/f-ozone.html ].
An Inner Neptune for 55 Canc …
Title An Inner Neptune for 55 Cancri
Explanation Is our Solar System [ http://www.nineplanets.org/overview.html ] unique? The discovery [ http://arXiv.org/abs/astro-ph/0408585 ] of a Neptune [ http://www.nineplanets.org/neptune.html ]-mass planet in an sub-Mercury orbit around nearby Sun [ http://antwrp.gsfc.nasa.gov/apod/sun.html ]-like star 55 Cancri [ http://antwrp.gsfc.nasa.gov/apod/ap020614.html ], announced [ http://planetquest.jpl.nasa.gov/index.html ] yesterday along with the discovery of other similar systems, gives a new indication that planetary systems [ http://exoplanets.org/exoplanets_pub.html ] as complex as our own Solar System [ http://space.jpl.nasa.gov/ ] likely exist elsewhere. The planet, discovered [ http://mcdonaldobservatory.org/news/releases/2004/0831.html ] in data from the Hobby-Eberly telescope [ http://www.as.utexas.edu/mcdonald/het/het.html ] in Texas, the Lick Observatory [ http://www.ucolick.org/ ] in California, and the orbiting Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap010806.html ], is one of four planets now known to orbit 55 Cancri [ http://exoplanets.org/esp/55cnc/55cnc.shtml ] -- the others being similar in mass to Jupiter. The finding involved noting subtle changes in the speed [ http://exoplanets.org/doppframe.html ] of the star caused by its orbiting planets. The above drawing [ http://planetquest.jpl.nasa.gov/news/ssu_images.html ] depicts what this planet might look like, assuming a mass similar to Neptune [ http://antwrp.gsfc.nasa.gov/apod/neptune.html ], but a composition similar [ http://www.solstation.com/stars/4planets.htm ] to Earth. The star 55 Cancri [ http://www.astro.uiuc.edu/~kaler/sow/55cnc.html ], only 40 light-years distant, is visible [ http://irtfweb.ifa.hawaii.edu/Science/GalleryOfImages/55cancri.html ] with binoculars [ http://www.birdwatching.com/optics/binoculars1.html ] towards the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Cancer [ http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=12 ].
Toutatis Nears Planet Earth
Title Toutatis Nears Planet Earth
Explanation On Wednesday, September 29, asteroid Toutatis [ http://www.astrosurf.com/maury/asteroides/toutatis.html ] came within one million miles of Earth -- the closest predicted aproach of a sizable asteroid or comet to our fair planet in this century. Coming within [ http://neo.jpl.nasa.gov/news/news144.html ] one million miles or about 4 times the Earth-Moon distance, Earth would have appeared to be nearly the size of the full moon in the asteroid's sky [ http://antwrp.gsfc.nasa.gov/apod/ap041001.html ]. In Earth's sky, Toutatis appeared [ http://echo.jpl.nasa.gov/asteroids/4179_Toutatis/ toutatis.html ] only as a faint, starlike, but rapidly moving object. Even so, asteroid 4179 [ http://www.eecs.wsu.edu/~hudson/Research/ Asteroids/4179/ ] Toutatis was still bright enough to see in small telescopes. Astronomers John Chumack, observing near Dayton Ohio, and Juergen Wolf from near Palo Alto, California, offer these composite images showing the progress of the asteroid (seen as a series of dots) against a background of distant stars. Their multiple exposures span a two hour period on two different days about a week before the asteroid's record close approach [ http://skyandtelescope.com/news/article_1360_1.asp ], which tracked through night skies south [ http://www.rasnz.org.nz/MinorP/ ToutatisNZ.htm ] of the celestial equator.
Leonids 1998: A Safe Meteor …
Title Leonids 1998: A Safe Meteor Storm
Explanation You're in no danger. During the meteor storm [ http://science.msfc.nasa.gov/newhome/headlines/ast10nov98_1.htm ] occurring tonight and tomorrow, thousands of bits of ice and rock [ http://www.seds.org/nineplanets/nineplanets/meteorites.html ] will likely rain onto the Earth [ http://antwrp.gsfc.nasa.gov/apod/ap980904.html ]. Few, if any, will hit the ground [ http://antwrp.gsfc.nasa.gov/apod/ap971117.html ]. Touted as potentially the most active meteor shower [ http://ssd.jpl.nasa.gov/leonids.html ] since 1966 [ http://antwrp.gsfc.nasa.gov/apod/ap981113.html ], the Leonids of 1998 [ http://www-space.arc.nasa.gov/%7Eleonid/index.html ] will be tracked by observers [ http://leonid.arc.nasa.gov/ ] the world over. The meteor storm [ http://george.arc.nasa.gov:80/dx/basket/storiesetc/96_08.html ] is caused by the Earth moving through the leftover debris of Comet Temple-Tuttle [ http://www-space.arc.nasa.gov/~leonid/comet.html ]. The peak of the storm [ http://www.skypub.com/sights/meteors/3showers.html ] will be best visible [ http://www-space.arc.nasa.gov/~leonid/1998.html ] tomorrow from Asia [ http://www.lib.utexas.edu/Libs/PCL/Map_collection/asia.html ], though increased activity should be visible globally over many hours. It is even possible to monitor the storm live [ http://www.leonidslive.com/ ] on the web. Pictured above is a Perseid 1997 [ http://medicine.wustl.edu/~kronkg/perseids.html ] meteor streaking across the sky behind an illuminated California desert.
A Leonid Fireball From 1966
Title A Leonid Fireball From 1966
Explanation This bright fireball meteor [ http://www.qsl.net/w7ftt/66leonid1.html ] was photographed from Table Mountain Observatory [ http://www.qsl.net/w7ftt/sunset1.html ] during the peak of the annual Leonid meteor shower [ http://science.msfc.nasa.gov/newhome/headlines/ast10nov98_1.htm ] on November 17, 1966. That was [ http://www-space.arc.nasa.gov/~leonid/history.html ] a good year for Leonid meteor watchers [ http://www-space.arc.nasa.gov/~leonid/ ] - a meteor "storm" was produced as the Earth swept through a dense swarm of dusty debris from the tail of comet Tempel-Tuttle [ http://antwrp.gsfc.nasa.gov/apod/ap980130.html ]. Observer Jim Young reported a peak rate for the 1966 shower of about 50 meteors "per second" and recorded 22 otherwise extremely rare, bright fireballs [ http://antwrp.gsfc.nasa.gov/apod/ap960226.html ] like this one in the span of 90 minutes from his California mountain top location. Predictions are uncertain [ http://see.msfc.nasa.gov/see/mod/leonids.html ], but this year might also produce an intense apparition of the Leonids shower [ http://www.skypub.com/sights/meteors/leonids/98preview.html ] which should again peak on the 17th. You may need to be well placed [ http://ssd.jpl.nasa.gov/leonids.html ] and a little lucky [ http://www.skypub.com/sights/meteors/3showers.html ] to see the shower at its maximum, but Leonid meteors [ http://www.skypub.com/sights/meteors/changedworld.html ] should be easy to see in dark skies - particularly in early morning hours - for two or so days before and after the peak. How do you watch a meteor shower [ http://antwrp.gsfc.nasa.gov/apod/ap980810.html ]? Get a comfortable lawn chair and a warm jacket ... go outside and look up!
Solar System Object Larger t …
Title Solar System Object Larger than Pluto Discovered
Explanation Is that a tenth planet? A faint, slowly moving dot discovered by computer [ http://www.astro.caltech.edu/~pick/survey.html ] shows clear signs of being a deep Solar System [ http://www.nineplanets.org/overview.html ] object at least as large as Pluto [ http://antwrp.gsfc.nasa.gov/apod/ap010319.html ]. The object, designated 2003 UB313, is currently situated nearly 100 times the Earth-Sun distance [ http://en.wikipedia.org/wiki/Astronomical_unit ] -- over twice the average Pluto-Sun distance. That far out, the only way a single round object could be as bright as 2003 UB313 would be if it is at least as large as Pluto and completely reflective [ http://en.wikipedia.org/wiki/Albedo ]. Since 2003 UB313 is surely not completely reflective [ http://gemini.edu/index.php?option=content&task=view&id=142 ], it could be substantially larger. One of the discovery frames [ http://www.jpl.nasa.gov/news/news.cfm?release=2005-126 ] is shown above digitally expanded and artificially brightened. 2003 UB313 was identified [ http://www.astro.caltech.edu/~pick/survey.html ] initially on frames taken by the automated 1.2-meter Samuel Oschin Telescope [ http://www.astro.caltech.edu/palomarnew/sot.html ] at Palomar Observatory in California [ http://en.wikipedia.org/wiki/California ], USA [ http://www.cia.gov/cia/publications/factbook/geos/us.html ].
Iridium 52: Not A Meteor
Title Iridium 52: Not A Meteor
Explanation While hunting for meteors [ http://leonid.arc.nasa.gov/meteor.html ] in the night sky above the White Mountains near Bishop, California, astrophotographer James Young instead captured this brilliant celestial apparition [ http://www.qsl.net/w7ftt/photos.html ]. Recorded near twilight on August 13, the bright streak is not the flash [ http://antwrp.gsfc.nasa.gov/apod/ap981113.html ] of a meteor trail but sunlight glinting from a satellite [ http://www.sat-tracks.com ]. The satellite, Iridium 52, is one of a constellation of Iridium digital communication satellites in Earth orbit known for producing stunning, predictable [ http://www.heavens-above.com/ ]"flares" as they momentarily reflect sunlight [ http://www2.satellite.eu.org/sat/vsohp/iridium.html ] from shiny antenna surfaces. For well placed observers, the peak brightness of this Iridium satellite flare [ http://antwrp.gsfc.nasa.gov/apod/ap980402.html ] reached about -6 magnitude [ http://www2.satellite.eu.org/sat/vsohp/magnitude.html ], not quite as bright as the half illuminated moon. At magnitude 2.5, the bright star at the left is Alpha [ http://www.astro.uiuc.edu/~kaler/sow/greek.html ] Pegasi, a star in the constellation Pegasus [ http://www.astro.wisc.edu/~dolan/constellations/constellations/ Pegasus.html ].
Ant nebula
Title Ant nebula
Description A new Hubble Space Telescope image of a celestial object called the Ant Nebula may shed new light on the future demise of our Sun. The image is available at http://www.jpl.nasa.gov/pictures/wfpc . The nebula, imaged on July 20, 1997, and June 30, 1998, by Hubble's Wide Field and Planetary Camera 2, was observed by Drs. Raghvendra Sahai and John Trauger of NASA's Jet Propulsion Laboratory, Pasadena, Calif., Bruce Balick of the University of Washington in Seattle, and Vincent Icke of Leiden University in the Netherlands. JPL designed and built the camera. The Ant Nebula, whose technical name is Mz3, resembles the head and thorax of an ant when observed with ground-based telescopes. The new Hubble image, with 10 times the resolution revealing 100 times more detail, shows the "ant's" body as a pair of fiery lobes protruding from a dying, Sun- like star. The Ant Nebula is located between 3,000 and 6,000 light years from Earth in the southern constellation Norma. The image challenges old ideas about what happens to dying stars. This observation, along with other pictures of various remnants of dying stars called planetary nebulae, shows that our Sun's fate will probably be much more interesting, complex and dramatic than astronomers previously believed. Although the ejection of gas from the dying star in the Ant Nebula is violent, it does not show the chaos one might expect from an ordinary explosion, but instead shows symmetrical patterns. One possibility is that the central star has a closely orbiting companion whose gravitational tidal forces shape the outflowing gas. A second possibility is that as the dying star spins, its strong magnetic fields are wound up into complex shapes like spaghetti in an eggbeater. Electrically charged winds, much like those in our Sun's solar wind but millions of times denser and moving at speeds up to 1,000 kilometers per second (more than 600 miles per second) from the star, follow the twisted field lines on their way out into space. The Space Telescope Science Institute, Baltimore, Md., manages space operations for the Hubble Space Telescope 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 NASA's 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. Additional information about the Hubble Space Telescope is available at http://www.stsci.edu . More information about the Wide Field and Planetary Camera 2 is available at http://wfpc2.jpl.nasa.gov.
Date 12.10.1999
Cold Hole Over Jupiter's Pol …
Title Cold Hole Over Jupiter's Pole
Description Observations with two NASA telescopes show that Jupiter has an arctic polar vortex similar to a vortex over Earth's Antarctica that enables depletion of Earth's stratospheric ozone. These composite images of Jupiter's north polar region from the Hubble Space Telescope (right) and the Infrared Telescope Facility (left) show a quasi-hexagonal shape that extends vertically from the stratosphere down into the top of the troposphere. A sharp temperature drop, compared to surrounding air masses, creates an eastward wind that tends to keep the polar atmosphere, including the stratospheric haze, isolated from the rest of the atmosphere. The linear striations in the composite projections are artifacts of the image processing. The area closest to the pole has been omitted because it was too close to the edge of the planet in the original images to represent the planet reliably. The composite on the right combines images from the Wide Field and Planetary Camera 2 of the Hubble Space Telescope taken at a wavelength of 890 nanometers, which shows stratospheric haze particles. The sharp boundary and wave-like structure of the haze layer suggest a polar vortex and a similarity to Earth's stratospheric polar clouds. Images of Jupiter's thermal radiation clinch that identification. The composite on the left, for example, is made from images taken with Jet Propulsion Laboratory's Mid-Infrared Large-Well Imager at NASA's Infrared Telescope Facility at a wavelength of 17 microns. It shows polar air mass that is 5 to 6 degrees Celsius (9 to 10 degrees Fahrenheit) colder than its surroundings, with the same border as the stratospheric haze. Similar observations at other infrared wavelengths show the cold air mass extends at least as high as the middle stratosphere down to the top of the troposphere. These images were taken Aug. 11 through Aug. 13, 1999, near a time when Jupiter's north pole was most visible from Earth. Other Infrared Telescope Facility images at frequencies sensitive to the polar haze were taken at frequent intervals from June to October 1999. They show that the quasi-hexagonal structure rotates slowly eastward at 1.2 degrees of longitude per day, a rate consistent with the average wind speeds measured from movement of visible clouds. Scientists studying the Earth's atmosphere are interested in these results because Jupiter's atmosphere provides a natural laboratory in which models of the polar vortex phenomenon can be studied under different conditions - for example, without the interference of topography. Of particular interest but yet unknown is how deep into Jupiter's troposphere the phenomenon extends. The answer to this question might be supplied by instrumentation on a polar orbiter mission at Jupiter. These images were taken as part of a program to support NASA's Galileo spacecraft reconnaissance of Jupiter. The Infrared Telescope Facility is on the summit of Hawaii's Mauna Kea and is operated by the University of Hawaii under a, cooperative agreement with NASA. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. The telescope is managed by the Space Telescope Science Institute, Baltimore, which 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 California Institute of Technology, Pasadena manages JPL for NASA.
Date 10.08.2002
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
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