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Hubble Space Telescope Finds …
Title Hubble Space Telescope Finds Stellar Graveyard
Hubble Zooms In on Heart of …
Title Hubble Zooms In on Heart of Mystery Comet
Hubble Zooms In on Heart of …
Title Hubble Zooms In on Heart of Mystery Comet
Hubble Zooms In on Heart of …
Title Hubble Zooms In on Heart of Mystery Comet
Hubble Zooms In on Heart of …
Title Hubble Zooms In on Heart of Mystery Comet
Mars: Closest Approach 2007
Title Mars: Closest Approach 2007
General Information What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. NASA's Hubble Space Telescope took this close-up of the red planet Mars when it was just 55 million miles ? 88 million kilometers ? away. This color image was assembled from a series of exposures taken within 36 hours of the Mars closest approach with Hubble's Wide Field and Planetary Camera 2. Mars will be closest to Earth on December 18, at 11:45 p.m. Universal Time (6:45 p.m. EST).
Hubble Finds Mysterious Disk …
Title Hubble Finds Mysterious Disk of Blue Stars Around Black Hole
First ESA Faint Object Camer …
Title First ESA Faint Object Camera Science Images Pluto - the "Double Planet
Hubble Sees Faintest Stars i …
Title Hubble Sees Faintest Stars in a Globular Cluster
Hubble Zooms In on Heart of …
Title Hubble Zooms In on Heart of Mystery Comet
Ionosphere Total Electron Co …
Title Ionosphere Total Electron Content - April 2001
Abstract A view of the ionospheric Total Electron Content (TEC) measured over North America during a storm in April 2001. Red is high electron counts, blue is low, grey where there is no data. From the pre-storm state, we see relatively low electron counts . As the storm intensity increases, so do the number of electrons. The increase will generate more interference for communications systems, GPS, etc.
Completed 2005-11-18
Ionosphere Total Electron Co …
Title Ionosphere Total Electron Content - November 2003
Abstract This movie displays plume formation for a space weather event in November 2003. In this visualization, the observer is fixed between the Sun and the Earth (slightly off the center line for better perspective). Blue represents low ionospheric electron counts, dark red is high electron counts.
Completed 2005-11-18
Ionosphere Total Electron Co …
Title Ionosphere Total Electron Content - November 2003
Abstract This movie displays plume formation for a space weather event in November 2003. In this visualization, the observer is fixed between the Sun and the Earth (slightly off the center line for better perspective). Blue represents low ionospheric electron counts, dark red is high electron counts.
Completed 2005-11-18
STS-88 Mission Insignia
Name of Image STS-88 Mission Insignia
Date of Image 1998-11-08
Full Description Designed by the STS-88 crew members, this patch commemorates the first assembly flight to carry United States-built hardware for constructing the International Space Station (ISS). This flight's primary task was to assemble the cornerstone of the Space Station: the Node with the Functional Cargo Block (FGB). The rising sun symbolizes the dawning of a new era of international cooperation in space and the beginning of a new program: the International Space Station. The Earth scene outlines the countries of the Station Partners: the United States, Russia, those of the European Space Agency (ESA), Japan, and Canada. Along with the Pressurized Mating Adapters (PMA) and the Functional Cargo Block, the Node is shown in the final mated configuration while berthed to the Space Shuttle during the STS-88/2A mission. The Big Dipper Constellation points the way to the North Star, a guiding light for pioneers and explorers for generations. In the words of the crew, These stars symbolize the efforts of everyone, including all the countries involved in the design and construction of the International Space Station, guiding us into the future.
Heat Wave in North America
Title Heat Wave in North America
Description Scorching summer sun, burning pavement, stinging sweat—normal for July. But in July 2006, temperatures climbed above average levels for the previous six years and stayed warm for several days. During mid-July, a heat wave settled over most of the United States, with air temperatures soaring past 100 degrees Fahrenheit (38 Celsius). Land surface temperatures climbed as well, as this image shows. Most of the United States and portions of Canada and Mexico were much warmer than they had been during the same period from 2000 to 2005. Deep red across the Midwest indicates that land surface temperatures were as much as 10 degrees Celsius warmer than the six-year average, and with the exception of the Pacific Northwest and a few other isolated region, the rest of the country was also warmer than average. The heat wave continued past the period shown here, through the end of July. In California alone, the heat killed at least 126 people, reported Reuters on July 29. This image was created from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Terra [ http://terra.nasa.gov/ ] satellite between July 12 and July 19, 2006. NASA image created by Jesse Allen, Earth Observatory, using data provided courtesy of Zhengming Wan, MODIS Land Surface Temperature Group, Institute for Computational Earth System Science [ http://www.icess.ucsb.edu/ ], University of California, Santa Barbara.
Massive Flare Erupts on Sun
Title Massive Flare Erupts on Sun
Description A massive solar flare erupted from the surface of the Sun at 9:51 UTC on October 28, 2003. The solar flare persisted for more than an hour, peaking at 11:10 UTC. Associated with the flare was an ejection of a billion tons or more of gas from the Sun?s tenuous outer atmosphere, or corona. Both the flare and the coronal mass ejection accelerated electrically charged particles to very high energies and hurled them at near the speed of light directly toward the Earth. It takes light roughly 8 minutes to travel from the Sun to Earth, and these particles made the trip in less than an hour. NOAA is predicting that the coronal mass ejection will hit the Earth?s magnetosphere sometime early tomorrow (Oct. 29), probably at or before 12 noon UTC. (Click to visit the NOAA Space Environment Center?s Space Weather [ http://sec.noaa.gov/today2.html ], Web site for more details.) The images above show the event from the perspective of three different satellite sensors. The top image was acquired by the Large Angle and Spectrometric Coronagraph (LASCO), aboard NASA?s Solar and Heliospheric Observatory (SOHO) satellite. In the center of the image is an occultation disc, which allows the sensor to focus on the scattering of light from the Sun?s surface off the free electrons in the Sun?s corona. This light appears as the orange halo seemingly radiating outward from the Sun. (The white circle on the occultation disc shows the actual size and location of the solar disc). Note the bright white features extending from beneath and to the left of the Sun. These are today?s coronal mass ejections, which appear to be heading directly toward the Earth. The bottom left image shows the Michelson Doppler Imager (MDI) view of the Sun?s visible surface. The dark patches are sunspots, which are a tepid 4,000 Kelvin?much cooler than the Sun?s typical surface temperature of 6,000 Kelvin. The bottom right scene shows the view from the Extreme Ultraviolet Imaging Telescope (EIT). This sensor shows the light from a single ionized species of iron that is formed at about 1.5 million Kelvin high in the Sun?s corona. Today?s solar flare appears as the bright green-white feature toward the bottom left of the solar disc. To put this event in perspective, NOAA predicts the impacts of the coronal mass ejection on the Earth?s magnetosphere will be a ?4? (severe) on a scale of 1 to 5. The flare is the third largest ever recorded in the 30 years since NOAA began observing soft X-ray emissions from the Sun. Today?s flare is listed as an X17.2, with an X20 being the most intense flare ever observed in that time. People living in Quebec, Canada, may recall that in March 1989 an X15 solar storm was strong enough to knock out the region?s power grid. Officials say it is possible that people in the Southern Hemisphere will see aurorae at much lower latitudes than usual on Oct. 29, when the coronal mass ejection reaches Earth. It is also possible that people could experience problems using telecommunications devices, such as satellite phones and pagers. In May 1998, for example, the commercial Galaxy IV satellite was damaged by a solar storm, knocking out its ability to support telecommunications. For more images from the SOHO mission, please see http://sohowww.nascom.nasa.gov/hotshots/2003_10_28/ [ http://sohowww.nascom.nasa.gov/hotshots/2003_10_28/ ]. To learn more about NASA?s ongoing studies of the Sun-Earth connection, please read A Violent Sun Affects the Earth?s Ozone [ http://earthobservatory.nasa.gov/Study/ProtonOzone/ ]. Images courtesy Solar & Heliospheric Observatory [ http://sohowww.nascom.nasa.gov/ ]
Massive Solar Flare
Title Massive Solar Flare
Description A massive solar flare erupted from the surface of the Sun at 9:51 UTC on October 28, 2003. The solar flare persisted for more than an hour, peaking at 11:10 UTC. Associated with the flare was an ejection of a billion tons or more of gas from the Sun's tenuous outer atmosphere, or corona. Both the flare and the coronal mass ejection accelerated electrically charged particles to very high energies and hurled them at near the speed of light directly toward the Earth. It takes light roughly 8 minutes to travel from the Sun to Earth, and these particles made the trip in less than an hour. NOAA is predicting that the coronal mass ejection will hit the Earth's magnetosphere sometime early tomorrow (Oct. 29), probably at or before 12 noon UTC. (Click to visit the NOAA Space Environment Center's Space Weather [ http://sec.noaa.gov/today2.html ], Web site for more details.) The images above show the event from the perspective of three different satellite sensors. The top image was acquired by the Large Angle and Spectrometric Coronagraph (LASCO), aboard NASA's Solar and Heliospheric Observatory (SOHO) satellite. In the center of the image is an occultation disc, which allows the sensor to focus on the scattering of light from the Sun's surface off the free electrons in the Sun's corona. This light appears as the orange halo seemingly radiating outward from the Sun. (The white circle on the occultation disc shows the actual size and location of the solar disc). Note the bright white features extending from beneath and to the left of the Sun. These are today's coronal mass ejections, which appear to be heading directly toward the Earth. The bottom left image shows the Michelson Doppler Imager (MDI) view of the Sun's visible surface. The dark patches are sunspots, which are a tepid 4,000 Kelvin—much cooler than the Sun's typical surface temperature of 6,000 Kelvin. The bottom right scene shows the view from the Extreme Ultraviolet Imaging Telescope (EIT). This sensor shows the light from a single ionized species of iron that is formed at about 1.5 million Kelvin high in the Sun's corona. Today's solar flare appears as the bright green-white feature toward the bottom left of the solar disc. To put this event in perspective, NOAA predicts the impacts of the coronal mass ejection on the Earth's magnetosphere will be a "4" (severe) on a scale of 1 to 5. The flare is the third largest ever recorded in the 30 years since NOAA began observing soft X-ray emissions from the Sun. Today's flare is listed as an X17.2, with an X20 being the most intense flare ever observed in that time. People living in Quebec, Canada, may recall that in March 1989 an X15 solar storm was strong enough to knock out the region's power grid. Officials say it is possible that people in the Southern Hemisphere will see aurorae at much lower latitudes than usual on Oct. 29, when the coronal mass ejection reaches Earth. It is also possible that people could experience problems using telecommunications devices, such as satellite phones and pagers. In May 1998, for example, the commercial Galaxy IV satellite was damaged by a solar storm, knocking out its ability to support telecommunications. For more images from the SOHO mission, please see http://sohowww.nascom.nasa.gov/hotshots/2003_10_28/ [ http://sohowww.nascom.nasa.gov/hotshots/2003_10_28/ ]. To learn more about NASA's ongoing studies of the Sun-Earth connection, please read A Violent Sun Affects the Earth's Ozone [ http://earthobservatory.nasa.gov/Study/ProtonOzone/ ]. Images courtesy Solar & Heliospheric Observatory [ http://sohowww.nascom.nasa.gov/ ]
Monterrey, Mexico
Title Monterrey, Mexico
Description In northeastern Mexico's Nuevo Leon state, the Sierra Madre Oriental (Eastern Sierra Madres) cluster in densely packed rows of arcing ridgelines. Just to the southwest of the city of Monterrey, these west-to-east running ridges make a sharp bend toward the south. The mountains then continue southward roughly parallel to the Gulf Coast for hundreds of miles. This image of the region around Monterrey was captured by the Enhanced Thematic Mapper Plus sensor on NASA's Landsat satellite on November 28, 1999. The dry terrain at lower elevations in the image appear in shades of tan and brown, while on the sharp ridges, vegetation appears dull to deep green. The urban development of Monterrey makes a gray patch at the foothills of the mountains. A river winds its way through the ridges as a tan ribbon. This location is a key turning point in the migration route of the monarch butterfly, which returns from latitudes as far north as Canada to overwinter on mountain peaks several hundred miles southwest of Monterrey. The flight path of butterflies follows the ridgelines. The butterflies fly due east for a time, but when the ridges curve south-southeast, so do the insects. Scientists are still trying to understand what role various cues such as the angle of the Sun in the sky, the Earth's magnetic field, and physical or meteorological landmarks (such as dominant wind patterns) play in guiding the monarchs on their migrations. To read more about monarch butterfly migration, please visit the Journey North Website. [ http://www.learner.org/jnorth/tm/monarch/MapGoogleMexicoRoute.html ] NASA image created by Jesse Allen, Earth Observatory, using data obtained from the University of Maryland's Global Land Cover Facility. [ http://www.landcover.org/ ]
Mount Megantic Magnetic Stor …
Title Mount Megantic Magnetic Storm
Explanation Plasma from the Sun and debris from a comet both collided with planet Earth last Saturday morning triggering magnetic storms [ http://www.sec.noaa.gov/NOAAscales/ ] and a meteor shower in a dazzling atmospheric spectacle [ http://spacescience.com/headlines/y2000/ ast14aug_1.htm ]. The debris stream from comet Swift-Tuttle is anticipated [ http://antwrp.gsfc.nasa.gov/apod/ap000812.html ] yearly, and many skygazers [ http://www.imo.net/news/news.html ] already planned to watch the peak of the annual Perseids [ http://comets.amsmeteors.org/meteors/showers/ perseids.html ] meteor shower in the dark hours of August 11/12. But the simultaneous, widely reported [ http://www.globaldialog.com/~jrummel/Aurora/ Aurora.html ] auroras were [ http://www.infowest.com/personal/s/schmutz/ aurora.HTML ] triggered by the chance arrival of something much less predictable -- a solar coronal mass ejection [ http://science.nasa.gov/ssl/pad/solar/ cmes.htm ]. This massive bubble of energetic plasma was seen leaving the active Sun's surface on August 9, just in time to travel to Earth and disrupt the planet's magnetic field [ http://www-spof.gsfc.nasa.gov/Education/ Intro.html ] triggering extensive auroras [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/ apod_ts?aurora ] during the meteor shower's peak! Inspired by the cosmic light show, Sebastien Gauthier photographed the [ http://www.geocities.com/CapeCanaveral/Station/3622/ AlbumPhotoAstronomie/AlbumAstronomie3.htm ] colorful auroral displays above the dramatic dome of the Mount-Megantic [ http://astrolab.interlinx.qc.ca/ ] Popular Observatory [ http://astrolab.interlinx.qc.ca/Obs_pop/ OPMM/ob_pop_choix.htm ] in southern Quebec, Canada. Bright Jupiter and giant star Aldebaran can be seen peering through [ http://antwrp.gsfc.nasa.gov/apod/ap000504.html ] the shimmering northern lights at the upper right.
Solstice And Season's Eclips …
Title Solstice And Season's Eclipse
Explanation Today the Sun reaches its southernmost point [ http://www-spof.gsfc.nasa.gov/stargaze/Sseason.htm ] in planet Earth's sky at 13:37 UT [ http://aa.usno.navy.mil/AA/faq/docs/UT.html ]. This celestial event is known as a solstice, marking the beginning of Summer [ http://antwrp.gsfc.nasa.gov/apod/ap951222.html ] in the Southern Hemisphere and Winter in the North. But this year, the solstice will be followed, on December 25th, by another geocentric celestial event [ http://aa.usno.navy.mil/AA/data/docs/EarthSeasons.html ] -- the last eclipse of the millennium [ http://www.usno.navy.mil/millennium/ ]! The Christmas day eclipse [ http://sunearth.gsfc.nasa.gov/eclipse/extra/ PSE2000Dec25.html ] will only be a partial one as the silhouetted disk of the Moon obscures the Sun's edge. Visible [ http://sunearth.gsfc.nasa.gov/eclipse/SEplot/ SE2000Dec25P.gif ] from much of Canada [ http://sunearth.gsfc.nasa.gov/eclipse/extra/ PSE2000Dec25city2/PSE2000Dec25city2.html ], The United States [ http://sunearth.gsfc.nasa.gov/eclipse/extra/ PSE2000Dec25city1/PSE2000Dec25city1.html ] and Mexico [ http://sunearth.gsfc.nasa.gov/eclipse/extra/ PSE2000Dec25city3/PSE2000Dec25city3.html ], the appearance of the partially eclipsed Sun might remind you of the last holiday cookie [ http://www.cs.cmu.edu/~mjw/recipes/cookies/cookie.html ] you took a bite from. Still, the exact timing and degree of the eclipse will depend very much on your location. This image, from an annular eclipse [ http://www.astrosurf.com/alphaweb/10mai94/ ] in 1994, shows the lunar disk covering around 55% of the Sun's diameter. It is representative of what could be seen from Washington D. C. during the December 25 eclipse maximum which, for that location, occurs at 12:41 PM ET. As always, if you view the eclipse be extremely careful [ http://www.mreclipse.com/Totality/ TotalityCh11.html#Intro ] to protect your eyes.
A Yukon Aurora
Title A Yukon Aurora
Explanation Last week was another good week for auroras [ http://www.pfrr.alaska.edu/~ddr/ASGP/STRSCOOP/AURORA/SUMMARY.HTM ]. The story began about two weeks ago when two large Coronal Mass Ejections [ http://antwrp.gsfc.nasa.gov/apod/ap000309.html ] exploded off the Sun [ http://www.nineplanets.org/sol.html ]. Waves of elementary particles [ http://sol.sci.uop.edu/~jfalward/elementaryparticles/elementaryparticles.html ] and ions [ http://www-istp.gsfc.nasa.gov/Education/wposion.html ] swept out past the Earth [ http://antwrp.gsfc.nasa.gov/apod/earth.html ] on September 28 and 29, causing many auroras [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?auroras ]. A week ago, a flapping sheet [ http://pluto.space.swri.edu/IMAGE/glossary/IMF.html ] that divides north and south regions of the Sun's magnetic field [ http://www-istp.gsfc.nasa.gov/Education/wimfproj.html ] passed the Earth, again causing auroras. Pictured above is a particularly good image of one of the October 1 northern lights [ http://www.spaceweather.com/aurora/gallery_01oct01.html ]. Taken in Canada [ http://www.cia.gov/cia/publications/factbook/geos/ca.html ]'s Yukon [ http://www.gov.yk.ca/ ], the city lights of Whitehorse [ http://www.city.whitehorse.yk.ca/ ] are seen below dark cloud [ http://antwrp.gsfc.nasa.gov/apod/ap960925.html ]s and a twisting green aurora [ http://antwrp.gsfc.nasa.gov/apod/ap000519.html ].
Aurora Over Winnipeg
Title Aurora Over Winnipeg
Explanation What's happening above that city? The city is Winnipeg [ http://www.city.winnipeg.mb.ca/ ], Canada [ http://www.cia.gov/cia/publications/factbook/geos/ca.html ], and the phenomenon is aurora [ http://www.pfrr.alaska.edu/~ddr/ASGP/STRSCOOP/AURORA/SUMMARY.HTM ]. These past few months have been active ones for our Sun [ http://antwrp.gsfc.nasa.gov/apod/ap010924.html ], producing several coronal mass ejections [ http://science.msfc.nasa.gov/ssl/pad/solar/cmes.htm ] (CMEs) of particles [ http://www-istp.gsfc.nasa.gov/Education/wposion.html ] that have swept past our Earth [ http://www.nineplanets.org/earth.html ] and caused many spectacular auroras [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?aurora ]. Specifically in this case, a CME that occurred on October 9 impacted the Earth on October 11 and 12, causing nearly 12 hours of auroras [ http://www.spaceweather.com/aurora/gallery_12oct01.html ]. The above-pictured aurora [ http://www.spaceweather.com/aurora/gallery_12oct01.html ] had to be very bright to be seen over the lights of Winnipeg, the city well below and in front of the cascading atmospheric airglow [ http://www.geo.mtu.edu/weather/aurora/ ]. Lights reflecting off of a slight haze [ http://www.concord.org/haze/causes.html ] cause an unrelated glow that emanates from some of the buildings.
Dueling Auroras
Title Dueling Auroras
Explanation Will it be curtains for one of these auroras? A quick inspection indicates that it is curtains for both, as the designation "curtains [ http://www.exploratorium.edu/learning_studio/auroras/auroraslook.html ]" well categorizes the type of aurora pattern pictured. Another (informal) type is the corona [ http://explorezone.com/snapshots/1999/09_09_aurora.htm ]. The above auroras [ http://www.spaceweather.com/aurora/gallery_01oct01.html ] resulted from outbursts of ionic particles [ http://www-istp.gsfc.nasa.gov/Education/Ielect.html ] from the Sun [ http://antwrp.gsfc.nasa.gov/apod/sun.html ] during the last week of September. A polarity change [ http://www.sciam.com/askexpert/geology/geology9/geology9.html ] in the solar magnetic field [ http://solar.physics.montana.edu/YPOP/Spotlight/Magnetic/ ] at the Earth [ http://antwrp.gsfc.nasa.gov/apod/ap010204.html ] then triggered auroras [ http://pluto.space.swri.edu/IMAGE/glossary/IMF.html ] over the next few days. The above picture [ http://www.spaceweather.com/aurora/gallery_01oct01.html ] was taken on October 3 as fleeting space radiation [ http://www.oulu.fi/~spaceweb/textbook/aurora/proton_aurora.html ] pelted the Earth's atmosphere [ http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.html ] high above the Yukon [ http://www.gov.yk.ca/ ] in Canada [ http://www.cia.gov/cia/publications/factbook/geos/ca.html ].
Stars and Planets in the Hal …
Title Stars and Planets in the Halo of the Moon
Explanation Photographed on [ http://www.photon-echoes.com/ ] March 13th from Caledon, Ontario, Canada, a bright Moon was surrounded by this lovely halo. Planet Jupiter and stars Procyon, Castor, and Pollux also appear within the circle of lunar light. Castor [ http://www.pantheon.org/articles/c/castor.html ] and Pollux, twins in Greek Mythology, are appropriately bright stars of the constellation Gemini [ http://www.astronomical.org/constellations/gem.html ] while Procyon [ http://www.astro.wisc.edu/~dolan/constellations/ hr/2943.html ] is the brightest star in Canis Minor [ http://www.astro.uiuc.edu/~kaler/sow/cmi-p.html ]. The circular halo is produced by six-sided ice crystals [ http://meteoros.de/arten/ee01e.htm ] in thin high-altitude clouds, which refract the moonlight and give the halo a characteristic radius of 22 degrees. For persistent skygazers such apparitions [ http://www.sundog.clara.co.uk/atoptics/phenom.htm ] are relatively easy to see when the Moon and Sun illuminate [ http://www.astro.uiuc.edu/~kaler/sow/atm/atm.html ] planet Earth's skies.
Aurora Over Edmonton
Title Aurora Over Edmonton
Explanation Northern and southern locales saw many a beautiful aurora [ http://antwrp.gsfc.nasa.gov/apod/ap020805.html ] over the last week, as particles [ http://www-spof.gsfc.nasa.gov/Education/Ielect.html ] from several large solar flares [ http://antwrp.gsfc.nasa.gov/apod/ap031029.html ] impacted the Earth. Many reported [ http://science.nasa.gov/spaceweather/aurora/gallery_01oct03_page8.html ] unusually red aurora [ http://antwrp.gsfc.nasa.gov/apod/ap031030.html ]s, although colors across the spectrum were also seen. Power grids and orbiting satellites braced for the onslaught [ http://www.space.com/scienceastronomy/power_outage_031031.html ], but little lasting damage was reported. Pictured above [ http://science.nasa.gov/spaceweather/aurora/gallery_01oct03_page2.html ], the Clover Bar Power Plant [ http://www.epcor.ca/Environment/Environmental+Commitment/Statements+and+Policies/Environmental+Statement+of+Clover+Bar+and+Rossdale+Generating+Stations.htm ] was photographed from the banks of the North Saskatchewan River [ http://www.chrs.ca/Rivers/NorthSask/NorthSask_e.htm ] in Edmonton [ http://www.gov.edmonton.ab.ca/ ], Alberta [ http://www.gov.ab.ca/ ], Canada [ http://www.cia.gov/cia/publications/factbook/geos/ca.html ]. A small pond in the foreground reflects predominantly green aurora [ http://antwrp.gsfc.nasa.gov/apod/ap010402.html ] light far in the distance. Two days ago, again unexpectedly, another large solar flare [ http://space.com/scienceastronomy/solar_flares_031103.html ] occurred from sunspot group 10486 [ http://antwrp.gsfc.nasa.gov/apod/ap031027.html ], the site of other recent major flares. This unusually active solar region is now rotating to the far side of the Sun.
Northern Lights, September S …
Title Northern Lights, September Skies
Explanation So far, the Aurora Borealis or Northern Lights [ http://www.exploratorium.edu/learning_studio/auroras/ ] have made some remarkable visits to September's skies [ http://www.spaceweather.com/aurora/ gallery_01sep05_page5.htm ]. The reason, of course, is the not-so-quiet Sun [ http://science.nasa.gov/headlines/y2005/ 15sep_solarminexplodes.htm ]. In particular, a large solar active region now crossing the Sun's disk has produced multiple, intense flares and a large coronal mass ejection (CME [ http://helios.gsfc.nasa.gov/cme.html ]) that triggered wide spread auroral activity just last weekend. This colorful example [ http://www.geocities.com/photo_geo/nouv.html ] of spectacular curtains of aurora was captured with a fish-eye lens in skies over Quebec, Canada on September 11. Also featured is the planet Mars [ http://science.nasa.gov/headlines/y2005/ 07jul_marshoax.htm ], the brightest object above and left of center. Seen near Mars (just below and to the right) is the tightly knit Pleiades [ http://antwrp.gsfc.nasa.gov/apod/ap050414.html ] star cluster. Although they can appear to be quite close, the northern lights actually originate at extreme altitudes, 100 kilometers or so above the Earth's surface.
Biggest Solar Flare on Recor …
nasa, nasaimageofthedaygalle …
View an eoimages.gsfc.nasa.g …
superflarecombo
mediatype IMAGE
mediatype image
date 2001-04-02
creator NASA -- Images courtesy sohowww.nascom.nasa.gov/ SOHO Project , NASA's Goddard Space Flight Center
identifier superflarecombo
Heat Wave in North America: …
nasa, nasanaturalhazards
Scorching summer sun, burnin …
nalstanom_tmo_2006193
mediatype IMAGE
mediatype image
date 2006-07-19
creator NASA -- NASA Image Of The Day
identifier nalstanom_tmo_2006193
Heat Wave in North America: …
nasa, nasanaturalhazards
Scorching summer sun, burnin …
nalstanom_tmo_2006193
mediatype IMAGE
mediatype image
date 2006-07-19
creator NASA -- NASA Image Of The Day
identifier nalstanom_tmo_2006193
Heat Wave across the United …
nasa, nasaimageofthedaygalle …
The first full week of Augus …
namerica_ceres_2007220
mediatype IMAGE
mediatype image
date 2007-08-08
creator NASA -- NASA image by Jesse Allen, using data provided courtesy of the CERES team at NASA Langley Research Center. Caption courtesy Denise Stefula, NASA Langley.
identifier namerica_ceres_2007220
Anaglyph, North America
PIA03378
Sol (our sun)
C-Band Interferometric Radar
Title Anaglyph, North America
Original Caption Released with Image This anaglyph (stereoscopic view) of North America was generated with data from the Shuttle Radar Topography Mission (SRTM). It is best viewed at or near full resolution with anaglyph glasses. For this broad view the resolution of the data was first reduced to 30 arcseconds (about 928 meters north-south and 736 meters east-west in central North America), matching the best previously existing global digital topographic data set called GTOPO30. The data were then resampled to a Mercator projection with approximately square pixels (about one kilometer, or 0.6 miles, on each side). Even at this decreased resolution the variety of landforms comprising the North American continent is readily apparent. Active tectonics (structural deformation of the Earth's crust) along and near the Pacific North American plate boundary creates the great topographic relief seen along the Pacific coast. Earth's crustal plates converge in southern Mexico and in the northwest United States, melting the crust and producing volcanic cones. Along the California coast, the plates are sliding laterally past each other, producing a pattern of slices within the San Andreas fault system. And, where the plates are diverging, the crust appears torn apart as one huge tear along the Gulf of California (northwest Mexico), and as the several fractures comprising the Basin and Range province (in and around Nevada). Across the Great Plains, erosional patterns dominate, with stream channels surrounding and penetrating the remnants of older smooth slopes east of the Rocky Mountains. This same erosion process is exposing the bedrock structural patterns of the Black Hills in South Dakota and the Ozark Mountains in Arkansas. Lateral erosion and sediment deposition by the Mississippi River has produced the flatlands of the lower Mississippi Valley and the Mississippi Delta. To the north, evidence of the glaciers of the last ice age is widely found, particularly east of the Canadian Rocky Mountains and around the Great Lakes. From northeastern British Columbia, across Alberta, Saskatchewan, and Manitoba to North Dakota and Minnesota, huge striations clearly show the flow pattern of the glaciers. And southwest of Lakes Michigan, Huron, and Erie, arcing ridges of sediment, called terminal moraines, show where glaciers dumped sediment at their melting ends. In eastern Canada, New York, and New England, the terrain has been scoured by glaciers, and eroded by streams, particularly along fractures in the bedrock. In Labrador and Quebec, the Mistastin, Manicougan, and Clearwater Lakes meteor impact craters can also be seen. Further south, narrow curving ridges of upturned and eroded layered rocks form most of the Appalachian Mountains. In contrast, around the Caribbean Sea region (Yucatan, Florida, and the Bahamas), flat-lying, stable limestone platforms are common, while the most eastern islands of the Caribbean include active volcanoes along another convergence zone of tectonic plates. This, anaglyph was created by deriving a shaded relief image from the SRTM data, draping it back over the SRTM elevation model, and then generating two differing perspectives, one for each eye. Illumination is from the north (top). When viewed through special glasses, the anaglyph is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter. Elevation data used in this image were acquired by the SRTM aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. Location: 15 to 60 degrees North latitude, 50 to 130 degrees West longitude Orientation: North toward the top, Mercator projection Image Data: Shaded SRTM elevation model Original Data Resolution: SRTM 1 arcsecond (about 30 meters or 98 feet) Date Acquired: February 2000
Shaded Relief with Height as …
PIA03377
Sol (our sun)
C-Band Interferometric Radar
Title Shaded Relief with Height as Color, North America
Original Caption Released with Image This image of North America was generated with data from the Shuttle Radar Topography Mission (SRTM). For this broad view the resolution of the data was first reduced to 30 arcseconds (about 928 meters north-south and 736 meters east-west in central North America), matching the best previously existing global digital topographic data set called GTOPO30. The data were then resampled to a Mercator projection with approximately square pixels (about one kilometer, or 0.6 miles, on each side). Even at this decreased resolution the variety of landforms comprising the North American continent is readily apparent. Active tectonics (structural deformation of the Earth's crust) along and near the Pacific -- North American plate boundary creates the great topographic relief seen along the Pacific coast. Earth's crustal plates converge in southern Mexico and in the northwest United States, melting the crust and producing volcanic cones. Along the California coast, the plates are sliding laterally past each other, producing a pattern of slices within the San Andreas fault system. And, where the plates are diverging, the crust appears torn apart as one huge tear along the Gulf of California (northwest Mexico), and as the several fractures comprising the Basin and Range province (in and around Nevada). Across the Great Plains, erosional patterns dominate, with streams channels surrounding and penetrating the remnants of older smooth slopes east of the Rocky Mountains. This same erosion process is exposing the bedrock structural patterns of the Black Hills in South Dakota and the Ozark Mountains in Arkansas. Lateral erosion and sediment deposition by the Mississippi River has produced the flatlands of the lower Mississippi Valley and the Mississippi Delta. To the north, evidence of the glaciers of the last ice age is widely found, particularly east of the Canadian Rocky Mountains and around the Great Lakes. From northeastern British Columbia, across Alberta, Saskatchewan, and Manitoba to North Dakota and Minnesota, huge striations clearly show the flow pattern of the glaciers. And southwest of Lakes Michigan, Huron, and Erie, arcing ridges of sediment, called terminal moraines, show where glaciers dumped sediment at their melting ends. In eastern Canada, New York, and New England, the terrain has been scoured by glaciers, and eroded by streams, particularly along fractures in the bedrock. In Labrador and Quebec, the Mistastin, Manicougan, and Clearwater Lakes meteor impact craters can also be seen. Further south, narrow curving ridges of upturned and eroded layered rocks form most of the Appalachian Mountains. In contrast, around the Caribbean Sea region (Yucatan, Florida, and the Bahamas), flat-lying, stable limestone platforms are common, while the most eastern islands of the Caribbean include active volcanoes along another convergence zone of tectonic plates. Two visualization methods were combined to produce the image: shading and color coding of, topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. Location: 15 to 60 degrees North latitude, 50 to 130 degrees West longitude Orientation: North toward the top, Mercator projection Image Data: shaded and colored SRTM elevation model Original Data Resolution: SRTM 1 arcsecond (about 30 meters or 98 feet) Date Acquired: February 2000
Stereo Pair, with Topographi …
PIA03384
Sol (our sun)
C-Band Interferometric Radar
Title Stereo Pair, with Topographic Height as Color, Manicouagan Crater, Quebec, Canada
Original Caption Released with Image Manicouagan Crater is one of the world's largest and oldest known impact craters and perhaps the one most readily apparent to astronauts in orbit. The age of the impact is estimated at 214 million years before present. Since then erosion has removed about one kilometer (0.6 miles) of rock from the region and has created a topographic pattern that follows the structural pattern of the crater. A ring depression (prominently seen as green) encloses a central peak. The ring depression now hosts the Manicouagan Reservoir and so appears as a distinct ring lake to astronauts and as a smooth and flat feature in this topographic visualization. A fine pattern of topographic striations trending south-southeast, most prominent within the crater itself, indicates the flow direction of glaciers that covered this area during the last ice age. Three visualization methods were combined to produce this image: shading, color coding, and synthetic stereoscopy. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to blue at the highest elevations. The stereoscopic effect was then created by generating two differing perspectives, one for each eye. The image can be seen in 3-D by viewing the left image with the right eye and the right image with the left eye (cross-eyed viewing) or by downloading, printing, and splitting the image pair and viewing them with a stereoscope. When stereoscopically merged, the result is a vertically exaggerated view of Earth's surface in its full three dimensions. Total topographic relief from the ring lake level to the central crater peak is about 600 meters (2000 feet). Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. Size: 222 by 138 kilometers (138 by 87 miles) Location: 50 to 52 degrees North latitude, 68 to 70 degrees West longitude Orientation: North toward the top Image Data: Shaded and colored SRTM elevation model Date Acquired: February 2000
Anaglyph, Manicouagan Crater …
PIA03385
Sol (our sun)
C-Band Interferometric Radar
Title Anaglyph, Manicouagan Crater, Quebec, Canada
Original Caption Released with Image Manicouagan Crater is one of the world's largest and oldest known impact craters and perhaps the one most readily apparent to astronauts in orbit. The age of the impact is estimated at 214 million years before present. Since then erosion has removed about one kilometer (0.6 miles) of rock from the region and has created a topographic pattern that follows the structural pattern of the crater. A ring depression (prominently seen as dark gray) encloses a central peak. The ring depression now hosts the Manicouagan Reservoir and so appears as a distinct ring lake to astronauts and as a smooth and flat feature in this topographic visualization. A fine pattern of topographic striations trending south-southeast, most prominent within the crater itself, indicates the flow direction of glaciers that covered this area during the last ice age. This anaglyph is derived entirely from the SRTM elevation model. First a gray image was created that uses image brightness to represent a mix of topographic height (higher elevations are brighter) and topographic orientation (northern slopes are brighter). The stereoscopic effect was then created by generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter. Total topographic relief from the ring lake level to the central crater peak is about 600 meters (2000 feet). Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. Size: 222 by 138 kilometers (138 by 87 miles) Location: 50 to 52 degrees North latitude, 68 to 70 degrees West longitude Orientation: North toward the top Image Data: SRTM elevation model as brightness and shading Date Acquired: February 2000
MISR View of Georgian Bay, O …
PIA02615
Sol (our sun)
Multi-angle Imaging SpectroR …
Title MISR View of Georgian Bay, Ontario, Canada
Original Caption Released with Image MISR images of the southeast portion of Georgian Bay in Ontario, Canada, acquired on March 6, 2000, during Terra orbit 1155. The color image is from the nadir (vertical) camera, and highlights a cloud to the southwest of Christian Island. In this view, the shadow cast by the cloud on the water is visible just north of the cloud itself. Bright areas in the image are either cloud or ice, an example of the latter is the frozen Lake Simcoe. The eight monochrome images are red band data from the off-nadir cameras. Starting with the one in the upper right and moving counterclockwise, the images progress from the most forward-viewing to the most aftward-viewing camera. Thus, the top (bottom) row of monochrome images are views acquired forward (aftward) of vertical. The apparent displacement of the cloud from south to north as the view progresses from forward to aftward is primarily a geometric parallax effect due to the cloud's elevation above the surface. In each image in the top row, a fainter feature with the same shape as the cloud is visible within Georgian Bay. The feature and the cloud itself approach one another as the view angle becomes less oblique. The feature is present only in the water, and disappears over the land surface of Christian Island. What is it? We are observing reflections of the cloud in the water. Their positions are dictated by the law of reflection, which states that the angle relative to the vertical of the reflected rays is the same as the angle of the incident rays. Therefore, the apparent location of a reflection relative to the cloud changes as a function of camera view angle. Unlike water, land does not act as a good mirror. Also, in the aftward views the reflections are less visible because they are blocked by the southern extension of the cloud. Reflections of this sort are not visible in conventional vertical imagery because in that case they lie directly underneath the cloud, and are consequently obscured. 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. For more information: http://www-misr.jpl.nasa.gov
Space Radar Image of Prince …
PIA01702
Sol (our sun)
Title Space Radar Image of Prince Albert, Canada
3-D Perspective View, Miquel …
PIA02739
Sol (our sun)
C-Band Interferometric Radar …
Title 3-D Perspective View, Miquelon and Saint Pierre Islands
Original Caption Released with Image This image shows Miquelon and Saint Pierre Islands, located south of Newfoundland, Canada. These islands, along with five smaller islands, are a self-governing territory of France. North is in the top right corner of the image. The island of Miquelon, in the background, is divided by a thin barrier beach into Petite Miquelon on the left, and Grande Miquelon on the right. Saint Pierre Island is seen in the foreground. The maximum elevation of this land is 240 meters (787 feet). The land mass of the islands is about 242square kilometers (94 square miles) or 1.5 times the size of Washington, DC. This three-dimensional perspective view is one of several still photographs taken from a simulated flyover of the islands. It shows how elevation data collected by the Shuttle Radar Topography Mission (SRTM) can be used to enhance other satellite images. Color and natural shading are provided by a Landsat 7 image taken on September 7, 1999. The Landsat image was draped over the SRTM data. Terrain perspective and shading are from SRTM. The vertical scale has been increased six times to make it easier to see the small features. This also makes the sea cliffs around the edges of the islands look larger. In this view the capital city of Saint Pierre is seen as the bright area in the foreground of the island. The thin bright line seen in the water is a breakwater that offers some walled protection for the coastal city. Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense(DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, DC. Size: 34 km (21 miles) by 44 km (27 miles) Location: 46.8 degrees north latitude, 56.3 degrees west longitude Orientation: Looking west Original Data Resolution: 30 meters (about 33 yards) per pixel Date Acquired: February 12, 2000 Credit: NASA/JPL/NIMA
New Gullies on Martian Sand …
PIA04290
Sol (our sun)
Mars Orbiter Camera
Title New Gullies on Martian Sand Dune
Original Caption Released with Image ), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2
New Gullies on Martian Sand …
PIA04290
Sol (our sun)
Mars Orbiter Camera
Title New Gullies on Martian Sand Dune
Original Caption Released with Image ), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2
New Gullies on Martian Sand …
PIA04290
Sol (our sun)
Mars Orbiter Camera
Title New Gullies on Martian Sand Dune
Original Caption Released with Image ), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2
New Gullies on Martian Sand …
PIA04290
Sol (our sun)
Mars Orbiter Camera
Title New Gullies on Martian Sand Dune
Original Caption Released with Image ), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2
New Gullies on Martian Sand …
PIA04290
Sol (our sun)
Mars Orbiter Camera
Title New Gullies on Martian Sand Dune
Original Caption Released with Image ), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2
Multi-angle Images of Hudson …
PIA02603
Sol (our sun)
Multi-angle Imaging SpectroR …
Title Multi-angle Images of Hudson Bay and James Bay, Canada, 24 February 2000
Original Caption Released with Image 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.
A Change in the Weather
PIA09346
Sol (our sun)
CRISM
Title A Change in the Weather
Original Caption Released with Image These two Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) images were acquired over the northern plains of Mars near one of the possible landing sites for NASA's Phoenix mission, set to launch in August 2007. The lower right image was acquired first, on Nov. 29, 2006, at 0720 UTC (2:20 a.m. EST), while the upper left image was acquired about one month later on Dec. 26, 2006, at 0030 UTC (or Dec. 25, 2006, at 7:30 p.m. EST). The CRISM data were taken in 544 colors covering the wavelength range from 0.36-3.92 micrometers, and show features as small as about 20 meters (66 feet) across. The images shown above are red-green-blue color composites using wavelengths 0.71, 0.6, and 0.53 micrometers, respectively (or infrared, red, and green light), and are overlain on a mosaic of Mars Odyssey Thermal Emission Imaging System (THEMIS) visible data. Each image covers a region about 11 kilometers (6.6 miles) wide at its narrowest, and they overlap near 71.0 degrees north latitude, 252.8 degrees east longitude The Earth equivalent to the season and latitude of this site is late summer in northern Canada, above the Arctic Circle. At that season and latitude, Martian weather conditions are transitioning from summer with generally clear skies, occasional weather fronts, and infrequent dust storms, to an autumn with pervasive, thick water-ice clouds. The striking difference in the appearance of the images is caused by the seasonal development of water-ice clouds. The earlier (lower right) image is cloud-free, and surface features can clearly be seen - like the small crater in the upper left. However, the clouds and haze in the later (upper left) image make it hard to see the surface. There are variations in the thickness and spacing of the clouds, just like clouds on Earth. On other days when nearby sites were imaged, the cloud cover varied day-to-day, but as the seasons change the trend is more and thicker clouds. With the onset of autumn the clouds will gradually cover the area and, just as with autumn on Earth, the Martian day is getting shorter at these high northern latitudes. In a few more months this area will settle into winter darkness and be covered in a layer of frost and carbon dioxide snow. CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials -- leading to new understanding of the climate. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.
Global View of the Arctic Oc …
PIA02970
Sol (our sun)
Imaging Radar
Title Global View of the Arctic Ocean
Original Caption Released with Image NASA researchers have new insights into the mysteries of Arctic sea ice, thanks to the unique abilities of Canada's Radarsat satellite. The Arctic is the smallest of the world's four oceans, but it may play a large role in helping scientists monitor Earth's climate shifts. Using Radarsat's special sensors to take images at night and to peer through clouds, NASA researchers can now see the complete ice cover of the Arctic. This allows tracking of any shifts and changes, in unprecedented detail, over the course of an entire winter. The radar-generated, high-resolution images are up to 100 times better than those taken by previous satellites. Using this new information, scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., can generate comprehensive maps of Arctic sea ice thickness for the first time. "Before we knew only the extent of the ice cover," said Dr. Ronald Kwok, JPL principal investigator of a project called Sea Ice Thickness Derived From High Resolution Radar Imagery. "We also knew that the sea ice extent had decreased over the last 20 years, but we knew very little about ice thickness.""Since sea ice is very thin, about 3 meters (10 feet) or less,"Kwok explained, "it is very sensitive to climate change." Until now, observations of polar sea ice thickness have been available for specific areas, but not for the entire polar region. The new radar mapping technique has also given scientists a close look at how the sea ice cover grows and contorts over time. "Using this new data set, we have the first estimates of how much ice has been produced and where it formed during the winter. We have never been able to do this before, " said Kwok. "Through our radar maps of the Arctic Ocean, we can actually see ice breaking apart and thin ice growth in the new openings. " RADARSAT gives researchers a piece of the overall puzzle every three days by creating a complete image of the Arctic. NASA scientists then put those puzzle pieces together to create a time-lapsed view of this remote and inhospitable region. So far, they have processed one season's worth of images."We can see large cracks in the ice cover, where most ice grows, " said Kwok. "These cracks are much longer than previously thought, some as long as 2,000 kilometers (1,200 miles)," Kwok continued. "If the ice is thinning due to warming, we'll expect to see more of these long cracks over the Arctic Ocean. " Scientists believe this is one of the most significant breakthroughs in the last two decades of ice research. "We are now in a position to better understand the sea ice cover and the role of the Arctic Ocean in global climate change, " said Kwok. Radar can see through clouds and any kind of weather system, day or night, and as the Arctic regions are usually cloud-covered and subject to long, dark winters, radar is proving to be extremely useful. However, compiling these data into extremely detailed pictures of the Arctic is a challenging task."This is truly, a major innovation in terms of the quantities of data being processed and the novelty of the methods being used, " said Verne Kaupp, director of the Alaska SAR Facility at the University of Alaska, Fairbanks. The mission is a joint project between JPL, the Alaska SAR Facility, and the Canadian Space Agency. Launched by NASA in 1995, the Radarsat satellite is operated by the Canadian Space Agency. JPL manages the Sea Ice Thickness Derived From High Resolution Radar Imagery project for NASA's Earth Science Enterprise, Washington, DC. The Earth Science Enterprise is dedicated to studying how natural and human-induced changes affect our global environment.
Comparative Views of Arctic …
PIA02971
Sol (our sun)
Imaging Radar
Title Comparative Views of Arctic Sea Ice Growth
Original Caption Released with Image NASA researchers have new insights into the mysteries of Arctic sea ice, thanks to the unique abilities of Canada's Radarsat satellite. The Arctic is the smallest of the world's four oceans, but it may play a large role in helping scientists monitor Earth's climate shifts. Using Radarsat's special sensors to take images at night and to peer through clouds, NASA researchers can now see the complete ice cover of the Arctic. This allows tracking of any shifts and changes, in unprecedented detail, over the course of an entire winter. The radar-generated, high-resolution images are up to 100 times better than those taken by previous satellites. The two images above are separated by nine days (earlier image on the left). Both images represent an area (approximately 96 by 128 kilometers, 60 by 80 miles)located in the Baufort Sea, north of the Alaskan coast. The brighter features are older thicker ice and the darker areas show young, recently formed ice. Within the nine-day span, large and extensive cracks in the ice cover have formed due to ice movement. These cracks expose the open ocean to the cold, frigid atmosphere where sea ice grows rapidly and thickens. Using this new information, scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., can generate comprehensive maps of Arctic sea ice thickness for the first time. "Before we knew only the extent of the ice cover," said Dr. Ronald Kwok, JPL principal investigator of a project called Sea Ice Thickness Derived From High Resolution Radar Imagery. "We also knew that the sea ice extent had decreased over the last 20 years, but we knew very little about ice thickness.""Since sea ice is very thin, about 3 meters (10 feet) or less,"Kwok explained, "it is very sensitive to climate change." Until now, observations of polar sea ice thickness have been available for specific areas, but not for the entire polar region. The new radar mapping technique has also given scientists a close look at how the sea ice cover grows and contorts over time. "Using this new data set, we have the first estimates of how much ice has been produced and where it formed during the winter. We have never been able to do this before," said Kwok. "Through our radar maps of the Arctic Ocean, we can actually see ice breaking apart and thin ice growth in the new openings." RADARSAT gives researchers a piece of the overall puzzle every three days by creating a complete image of the Arctic. NASA scientists then put those puzzle pieces together to create a time-lapsed view of this remote and inhospitable region. So far, they have processed one season's worth of images."We can see large cracks in the ice cover, where most ice grows," said Kwok. "These cracks are much longer than previously thought, some as long as 2,000 kilometers (1,200 miles)," Kwok continued. "If the ice is thinning due to warming, we'll expect to see more of these long cracks over the Arctic Ocean." Scientists believe this is one of the most, significant breakthroughs in the last two decades of ice research. "We are now in a position to better understand the sea ice cover and the role of the Arctic Ocean in global climate change," said Kwok. Radar can see through clouds and any kind of weather system, day or night, and as the Arctic regions are usually cloud-covered and subject to long, dark winters, radar is proving to be extremely useful. However, compiling these data into extremely detailed pictures of the Arctic is a challenging task."This is truly a major innovation in terms of the quantities of data being processed and the novelty of the methods being used," said Verne Kaupp, director of the Alaska SAR Facility at the University of Alaska, Fairbanks. The mission is a joint project between JPL, the Alaska SAR Facility, and the Canadian Space Agency. Launched by NASA in 1995, the Radarsat satellite is operated by the Canadian Space Agency. JPL manages the Sea Ice Thickness Derived From High Resolution Radar Imagery project for NASA's Earth Science Enterprise, Washington, DC. The Earth Science Enterprise is dedicated to studying how natural and human-induced changes affect our global environment.
Green Summer and Icy Winter …
PIA02645
Sol (our sun)
Multi-angle Imaging SpectroR …
Title Green Summer and Icy Winter in James Bay
Original Caption Released with Image One year ago, in late February 2000, MISR began acquiring Earth imagery. Its "first light" images showed a frozen James Bay in the Ontario-Quebec region of Canada. These more recent nadir-camera views of the same area illuminate stark contrasts between summer and winter. The left-hand image was acquired on August 9, 2000 (Terra orbit 3427), and the right-hand image is from January 16, 2001 (Terra orbit 5757). James Bay lies at the southern end of Hudson Bay. It is named for the English explorer Thomas James, who first explored the area in 1631 while searching for the Northwest Passage. Visible in these images are some of the many rivers that flow into the bay, starting at the southern tip and moving clockwise on the western side are the Harricana, Moose, Albany, and Attawapiskat. The latter enters the bay just to the west of the large, crescent-shaped Akimiski Island. 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.
Atlantic Ocean Surface Winds …
PIA01347
Sol (our sun)
SeaWinds Scatterometer
Title Atlantic Ocean Surface Winds from QuikScat
Original Caption Released with Image This image shows wind speeds and direction in the Atlantic Ocean on August 1, 1999, gathered by the Seawinds radar instrument flying onboard the QuikScat satellite. This image was released in conjunction with PIA01346 [ http://photojournal.jpl.nasa.gov/catalog/PIA01346 ]. Please refer to that image for more details about the Pacific region. The intense surface winds of Typhoon Olga, represented by yellow spirals, can be seen moving around South Korea in the China Sea.QuikScat tracks its birth as a tropical depression in the Philippines and its northward journey in the western Pacific to its landfall in Korea. The eastern North Pacific is dominated by a persistent high-pressure system, whose anticyclonic (clockwise) flow creates strong winds blowing parallel to the coast of Canada and the United States. Three groups of very intense winter storm scan be seen around Antarctica, which are associated with the season of maximum sea ice in that region of the world.
Pacific Ocean Surface Winds …
PIA01346
Sol (our sun)
SeaWinds Scatterometer
Title Pacific Ocean Surface Winds from QuikScat
Original Caption Released with Image This image shows wind speeds and direction in the Pacific Ocean on August 1, 1999, gathered by the Seawinds radar instrument flying onboard the QuikScat satellite. This image was released in conjunction with PIA01347 [ http://photojournal.jpl.nasa.gov/catalog/PIA01347 ]. The caption released for these images mostly details the Pacific region. The intense surface winds of Typhoon Olga, represented by yellow spirals, can be seen moving around South Korea in the China Sea. QuikScat tracks its birth as a tropical depression in the Philippines and its northward journey in the western Pacific to its landfall in Korea. The eastern North Pacific is dominated by a persistent high-pressure system, whose anticyclonic (clockwise) flow creates strong winds blowing parallel to the coast of Canada and the United States. Three groups of very intense winter storm scan be seen around Antarctica, which are associated with the season of maximum sea ice in that region of the world.
Pasadena, California Anaglyp …
PIA02721
Sol (our sun)
C-Band Interferometric Radar
Title Pasadena, California Anaglyph with Aerial Photo Overlay
Original Caption Released with Image This anaglyph shows NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. Red-blue glasses are required to see the 3-D effect. The surrounding residential areas of La Canada-Flintridge (to the left) and Altadena/Pasadena (to the right) are also shown. JPL is located at the base of the San Gabriel Mountains, an actively growing mountain range, seen towards the top of the image. The large canyon coming out of the mountains (top to bottom of image) is the Arroyo Seco, which is a major drainage channel for the mountains. Sand and gravel removal operations in the lower part of the arroyo (bottom of image) are removing debris brought down by flood and mudflow events. Old landslide scars (lobe-shaped features) are seen in the arroyo, evidence that living near steep canyon slopes in tectonically active areas can be hazardous. The data can also be utilized by recreational users such as hikers enjoying the natural beauty of these rugged mountains. This anaglyph was generated using topographic data from the Shuttle Radar Topography Mission to create two differing perspectives of a single image, one perspective for each eye. The detailed aerial image was provided by U. S. Geological Survey digital orthophotography. Each point in the image is shifted slightly, depending on its elevation. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter. The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI) space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, DC. Size: 2.2 km (1.4 miles) x 2.4 km (1.49 miles) Location: 34.16 deg. North lat., 118.16 deg. West lon. Orientation: looking straight down at land Original Data Resolution: SRTM, 30 meters, Aerial Photo, 3 meters. Date Acquired: February 16, 2000 Image: NASA/JPL/NIMA
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