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Images of Hamilton and Goddard Space Flight Center (GSFC)
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Hubble Catches Jupiter Chang
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| Title |
Hubble Catches Jupiter Changing Its Stripes |
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Hubble Catches Jupiter Chang
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| Title |
Hubble Catches Jupiter Changing Its Stripes |
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Hubble Catches Jupiter Chang
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| Title |
Hubble Catches Jupiter Changing Its Stripes |
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Hubble Catches Jupiter Chang
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| Title |
Hubble Catches Jupiter Changing Its Stripes |
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Hubble Catches Jupiter Chang
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| Title |
Hubble Catches Jupiter Changing Its Stripes |
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Updated Jakobshavn Glacier C
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| Title |
Updated Jakobshavn Glacier Calving Front Retreat from 2001 through 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, ocean sea levels raise. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. This animation is an update of and extension to animation ID #3374. In this version, a pause is added on the approach to the Jakobshavn glacier in order to highlight the meltwater lakes visible on the Greenland ice sheet. In addition, semi-transparent overlays and text indicate different regions of the glacier before the calving lines are shown. After the calving front retreat, an additional segment shows a zoom to a global view. During the pull out, historic calving front locations are shown followed by a color overlay showing regions of increase and decrease in the Greenland ice sheet. |
| Completed |
2007-07-20 |
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Updated Jakobshavn Glacier C
…
| Title |
Updated Jakobshavn Glacier Calving Front Retreat from 2001 through 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, ocean sea levels raise. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. This animation is an update of and extension to animation ID #3374. In this version, a pause is added on the approach to the Jakobshavn glacier in order to highlight the meltwater lakes visible on the Greenland ice sheet. In addition, semi-transparent overlays and text indicate different regions of the glacier before the calving lines are shown. After the calving front retreat, an additional segment shows a zoom to a global view. During the pull out, historic calving front locations are shown followed by a color overlay showing regions of increase and decrease in the Greenland ice sheet. |
| Completed |
2007-07-20 |
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Updated Jakobshavn Glacier C
…
| Title |
Updated Jakobshavn Glacier Calving Front Retreat from 2001 through 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, ocean sea levels raise. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. This animation is an update of and extension to animation ID #3374. In this version, a pause is added on the approach to the Jakobshavn glacier in order to highlight the meltwater lakes visible on the Greenland ice sheet. In addition, semi-transparent overlays and text indicate different regions of the glacier before the calving lines are shown. After the calving front retreat, an additional segment shows a zoom to a global view. During the pull out, historic calving front locations are shown followed by a color overlay showing regions of increase and decrease in the Greenland ice sheet. |
| Completed |
2007-07-20 |
|
Updated Jakobshavn Glacier C
…
| Title |
Updated Jakobshavn Glacier Calving Front Retreat from 2001 through 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, ocean sea levels raise. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. This animation is an update of and extension to animation ID #3374. In this version, a pause is added on the approach to the Jakobshavn glacier in order to highlight the meltwater lakes visible on the Greenland ice sheet. In addition, semi-transparent overlays and text indicate different regions of the glacier before the calving lines are shown. After the calving front retreat, an additional segment shows a zoom to a global view. During the pull out, historic calving front locations are shown followed by a color overlay showing regions of increase and decrease in the Greenland ice sheet. |
| Completed |
2007-07-20 |
|
Updated Jakobshavn Glacier C
…
| Title |
Updated Jakobshavn Glacier Calving Front Retreat from 2001 through 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, ocean sea levels raise. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. This animation is an update of and extension to animation ID #3374. In this version, a pause is added on the approach to the Jakobshavn glacier in order to highlight the meltwater lakes visible on the Greenland ice sheet. In addition, semi-transparent overlays and text indicate different regions of the glacier before the calving lines are shown. After the calving front retreat, an additional segment shows a zoom to a global view. During the pull out, historic calving front locations are shown followed by a color overlay showing regions of increase and decrease in the Greenland ice sheet. |
| Completed |
2007-07-20 |
|
Updated Jakobshavn Glacier C
…
| Title |
Updated Jakobshavn Glacier Calving Front Retreat from 2001 through 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, ocean sea levels raise. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. This animation is an update of and extension to animation ID #3374. In this version, a pause is added on the approach to the Jakobshavn glacier in order to highlight the meltwater lakes visible on the Greenland ice sheet. In addition, semi-transparent overlays and text indicate different regions of the glacier before the calving lines are shown. After the calving front retreat, an additional segment shows a zoom to a global view. During the pull out, historic calving front locations are shown followed by a color overlay showing regions of increase and decrease in the Greenland ice sheet. |
| Completed |
2007-07-20 |
|
Updated Jakobshavn Glacier C
…
| Title |
Updated Jakobshavn Glacier Calving Front Retreat from 2001 through 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, ocean sea levels raise. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. This animation is an update of and extension to animation ID #3374. In this version, a pause is added on the approach to the Jakobshavn glacier in order to highlight the meltwater lakes visible on the Greenland ice sheet. In addition, semi-transparent overlays and text indicate different regions of the glacier before the calving lines are shown. After the calving front retreat, an additional segment shows a zoom to a global view. During the pull out, historic calving front locations are shown followed by a color overlay showing regions of increase and decrease in the Greenland ice sheet. |
| Completed |
2007-07-20 |
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Updated Jakobshavn Glacier C
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| Title |
Updated Jakobshavn Glacier Calving Front Retreat from 2001 through 2006 with Blue/White Elevation Change over Greenland |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier gradually receded until about 1950, where it remained stable for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, ocean sea levels raise. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. This animation is an update of, and extension to, animation IDs #3374 and #3434. In this version, the pause on the approach to the Jakobshavn glacier where the meltwater lakes on the Greenland ice sheet are visible is shortened. In addition, the colors showing regions of elevation increase and decrease over the Greenland ice sheet are modified. |
| Completed |
2007-09-27 |
|
Updated Jakobshavn Glacier C
…
| Title |
Updated Jakobshavn Glacier Calving Front Retreat from 2001 through 2006 with Blue/White Elevation Change over Greenland |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier gradually receded until about 1950, where it remained stable for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, ocean sea levels raise. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. This animation is an update of, and extension to, animation IDs #3374 and #3434. In this version, the pause on the approach to the Jakobshavn glacier where the meltwater lakes on the Greenland ice sheet are visible is shortened. In addition, the colors showing regions of elevation increase and decrease over the Greenland ice sheet are modified. |
| Completed |
2007-09-27 |
|
Jakobshavn Glacier Flow in t
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| Title |
Jakobshavn Glacier Flow in the year 2000 and Calving Front Retreat from 2001 to 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, it raises sea levels. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. |
| Completed |
2006-09-12 |
|
Jakobshavn Glacier Flow in t
…
| Title |
Jakobshavn Glacier Flow in the year 2000 and Calving Front Retreat from 2001 to 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, it raises sea levels. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. |
| Completed |
2006-09-12 |
|
Jakobshavn Glacier Flow in t
…
| Title |
Jakobshavn Glacier Flow in the year 2000 and Calving Front Retreat from 2001 to 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, it raises sea levels. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. |
| Completed |
2006-09-12 |
|
Jakobshavn Glacier Flow in t
…
| Title |
Jakobshavn Glacier Flow in the year 2000 and Calving Front Retreat from 2001 to 2006 |
| Abstract |
Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2006, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. As more ice moves from glaciers on land into the ocean, it raises sea levels. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the glacier's flow in 2000, along with changes in the glacier's calving front between 2001 and 2006. |
| Completed |
2006-09-12 |
|
NGC 2440: Cocoon of a New Wh
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| Title |
NGC 2440: Cocoon of a New White Dwarf |
| Explanation |
Like a butterfly, a white dwarf star begins its life by casting off a cocoon that enclosed its former self. In this analogy, however, the Sun would be a caterpillar and the ejected shell of gas would become the prettiest of all! In the above cocoon [ http://hubblesite.org/newscenter/newsdesk/archive/releases/1999/35/image/e ], the planetary nebula designated NGC 2440, contains one of the hottest white dwarf stars known. The white dwarf [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html ] can be seen as the bright dot near the photo's center. Our Sun will eventually become a "white dwarf butterfly", but not for another 5 billion years. The above false color image [ http://heritage.stsci.edu/1999/38/ ] was post-processed by Forrest Hamilton [ http://heritage.stsci.edu/commonpages/infoindex/ourproject/f_hamilton.html ]. |
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NGC 2440: Cocoon of a New Wh
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| Title |
NGC 2440: Cocoon of a New White Dwarf |
| Explanation |
Like a butterfly, a white dwarf star begins its life by casting off a cocoon that enclosed its former self. In this analogy, however, the Sun would be a caterpillar and the ejected shell of gas would become the prettiest of all! The above cocoon, the planetary nebula designated NGC 2440, contains one of the hottest white dwarf stars known. The white dwarf [ http://www.sciencenet.org.uk/database/Physics/Stars/p01158c.html ] can be seen as the bright dot near the photo's center. Our Sun will eventually become a "white dwarf butterfly", but not for another 5 billion years. The above false color image [ http://presto.stsci.edu/apsb/doc/pep/public-proposals/6119.pro ] and was post-processed by Forrest Hamilton [ http://heritage.stsci.edu/public/commonpages/heritagebios.html#forrest ]. |
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Io Rotating
| Title |
Io Rotating |
| Explanation |
The surface of Io is continually changing. Jupiter's moon [ http://antwrp.gsfc.nasa.gov/apod/ap990920.html ] is the home to many powerful volcanoes [ http://antwrp.gsfc.nasa.gov/apod/ap991126.html ] so active they are effectively turning the moon inside out. The above time-lapse sequence [ http://solarviews.com/cap/jup/vio1.htm ] is a composite of images taken during two space missions that approached the violent moon: Voyager [ http://vraptor.jpl.nasa.gov/voyager/voyager_fs.html ] and Galileo [ http://www.jpl.nasa.gov/galileo/mission.html ]. The sequence shows Io [ http://www.seds.org/nineplanets/nineplanets/io.html ] during a complete rotation, which corresponds to a complete revolution around Jupiter [ http://www.jpl.nasa.gov/galileo/Jovian.html ] since Io [ http://cass.jsc.nasa.gov/pub/research/outerp/io.html ] always keeps the same face toward the giant planet. The rampant volcanism is thought to be caused by Jupiter's more distant Galilean Moons [ http://solarviews.com/eng/galdisc.htm ] (Europa [ http://www.seds.org/nineplanets/nineplanets/europa.html ], Ganymede [ http://www.seds.org/nineplanets/nineplanets/ganymede.html ], and Callisto [ http://www.seds.org/nineplanets/nineplanets/callisto.html ]) pulling on Io and continually distorting its shape, causing internal frictional [ http://www.cord.edu/dept/physics/p128/lecture99_12.html ] heating. Io is composed mostly of rock, with the yellow color originating from sulfur [ http://chemlab.pc.maricopa.edu/periodic/S.html ]. The causes of many of the other colors remain a topic of research [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999Icar..140..265G ]. |
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October Skylights
| Title |
October Skylights |
| Explanation |
With brilliant Venus [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ venusfact.html ] above the western horizon at sunset and Jupiter [ http://galileo.jpl.nasa.gov/ ] and Saturn [ http://www.jpl.nasa.gov/cassini/ ] high in the east by early evening, November's night sky is filled with bright planets. October's sky featured bright planets as well and, triggered by the active Sun, some lovely auroral displays [ http://www.exploratorium.edu/learning_studio/ auroras/ ]. This colorful aurora was recorded by astrophotographer Wade Clark in skies above Hamilton, Washington, USA on the night of October 4th. Through the shimmering northern lights [ http://climate.gi.alaska.edu/Curtis/aurora/ aurora.html ] Jupiter and Saturn are easy to spot [ http://antwrp.gsfc.nasa.gov/apod/ap000929.html ] flanking the V-shaped head of Taurus [ http://server.remc12.k12.mi.us/csplanet/myth/ taurus.html ] the Bull. Of course, just above lies the lovely Pleiades star cluster. Solar activity [ http://spaceweather.com/ ] will also produce auroral shows in November, particularly at high northern and southern latitudes. Plus, November skygazers can certainly anticipate a celestial performance on the evening of the 17th/18th -- the moonlit Leonid meteor shower [ http://spacescience.com/headlines/y2000/ast10oct_1.htm ]. |
|
Europa Rotating
| Title |
Europa Rotating |
| Explanation |
Evidence has been mounting that beneath the vast planes of ice that cover Europa [ http://antwrp.gsfc.nasa.gov/apod/ap961120.html ] lies water -- liquid oceans that might be home to alien life [ http://www.sciam.com/0497issue/0497scicit7.html ]. The smallest of Jupiter [ http://www.seds.org/nineplanets/nineplanets/jupiter.html ]'s Galilean Moons [ http://solarviews.com/eng/galdisc.htm ] (which include Io [ http://www.seds.org/nineplanets/nineplanets/io.html ], Ganymede [ http://www.seds.org/nineplanets/nineplanets/ganymede.html ], and Callisto [ http://www.seds.org/nineplanets/nineplanets/callisto.html ]), Europa's deep interior is composed of mostly of silicate rock [ http://windows.arc.nasa.gov/cgi-bin/tour_def/glossary/silicate_rock.html ]. Upon close inspection, many surface cracks [ http://antwrp.gsfc.nasa.gov/apod/ap980310.html ] stop abruptly only to continue on somewhere else -- indicating surface plates that might be sliding [ http://antwrp.gsfc.nasa.gov/apod/ap970410.html ]. The above time-lapse sequence [ http://www.solarviews.com/cap/jup/veuropa1.htm ] is a composite of images taken during the Voyager spacecraft [ http://vraptor.jpl.nasa.gov/voyager/voyager_fs.html ] flyby of the moon twenty years ago. Not all regions are resolved in high detail. The movie shows Europa [ http://www.seds.org/nineplanets/nineplanets/europa.html ] during a complete rotation, which corresponds to a complete revolution around Jupiter [ http://www.jpl.nasa.gov/galileo/Jovian.html ] since Europa [ http://cass.jsc.nasa.gov/pub/research/outerp/euro.html ] always keeps the same face toward the giant planet. The cause of many of the surface colors on Europa [ http://www.solarviews.com/eng/europa.htm ] also remains a topic of research [ http://antwrp.gsfc.nasa.gov/apod/ap010116.html http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1988Icar...75..437B ]. |
|
NGC 2440: Cocoon of a New Wh
…
| Title |
NGC 2440: Cocoon of a New White Dwarf |
| Explanation |
Like a butterfly, a white dwarf star begins its life by casting off a cocoon that enclosed its former self. In this analogy, however, the Sun would be a caterpillar and the ejected shell of gas would become the prettiest of all! The above cocoon, the planetary nebula designated NGC 2440, contains one of the hottest white dwarf stars known. The white dwarf [ http://www.sciencenet.org.uk/database/Physics/Stars/p01158c.html ] can be seen as the bright dot near the photo's center. Our Sun will eventually become a "white dwarf butterfly", but not for another 5 billion years. The above false color image [ http://presto.stsci.edu/apsb/doc/pep/public-proposals/6119.pro ] and was post-processed by Forrest Hamilton [ http://heritage.stsci.edu/public/commonpages/heritagebios.html#forrest ]. |
|
The Mountains of Mars
| Title |
The Mountains of Mars |
| Explanation |
Volcanic activity on Mars has produced towering mountains. The largest one, Olympus Mons, is pictured here in this Viking Orbiter [ http://nssdc.gsfc.nasa.gov/planetary/viking.html ] image. Olympus Mons is a shield volcano nearly 15 miles high and over 300 miles wide at its base. By comparison, Earth's largest volcano, Mauna Loa in Hawaii, is just over 5 miles high and about 12 miles wide. For more information about volcanic mountains on Mars see Calvin J. Hamilton's Mars page. [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/marsvolc.html ] The exploration of Mars is chronicled by the Center For Mars Exploration. [ http://cmex-www.arc.nasa.gov/ ] |
|
The Face on Mars
| Title |
The Face on Mars |
| Explanation |
This image, showing what looks to be a human face sculpted on the martian surface, was produced using data from NASA's Viking 1 orbiter [ http://nssdc.gsfc.nasa.gov/planetary/viking.html ] in 1976. Described in a press release as a "face-like hill" it caused some to offer the sensational speculation that it was an artificial construct built by an intelligent civilization on Mars! As a result, this image was splashed across the covers of many grocery store tabloids at the time. A detailed analysis of multiple images of this feature reveals a natural looking martian hill whose illusory face-like appearance depends on viewing angle and angle of illumination. For more information about the picture see the NSSDC Photo Gallery of Mars. [ http://nssdc.gsfc.nasa.gov/photo_gallery/PhotoGallery-Mars.html#controversy ] For a detailed discussion of the "Face on Mars" see Calvin J. Hamilton's Face on Mars page. [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/face.html ] |
|
The Grand Canyon of Mars
| Title |
The Grand Canyon of Mars |
| Explanation |
The Mariner Valley, also known as the Valles Marineris canyon system, appears in this mosaic of images from NASA's Viking spacecraft [ http://nssdc.gsfc.nasa.gov/planetary/viking.html ] as a huge gouge across the red planet. This "Grand Canyon" of Mars is about 2500 miles long and up to 4 miles deep. By comparison, the Earth's Grand Canyon is less than 500 miles long and 1 mile deep. For more information about Mars see Calvin J. Hamilton's Mars Page. [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/mars.html ] The exploration of Mars is chronicled by the Center For Mars Exploration. [ http://cmex-www.arc.nasa.gov/ ] |
|
The Night Side of Saturn
| Title |
The Night Side of Saturn |
| Explanation |
This image of Saturn was made in November 1980 by the Voyager [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] 1 spacecraft as it flew past the ringed gas giant planet. From a spectacular vantage point, looking back toward the inner solar system, the robot spacecraft recorded this view of the night side of Saturn casting a sharp shadow across the bright rings. No Earth based telescope could ever take a similar picture. Since Earth is closer to the sun than Saturn, only the day side of the planet is visible from the Earth. For more information see Calvin J. Hamilton's Saturn Page. [ http://bang.lanl.gov/solarsys/saturn.htm ] |
|
Closeup of an Io Volcano
| Title |
Closeup of an Io Volcano |
| Explanation |
In 1979, one of NASA's Voyager [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] spacecraft made a spectacular and unexpected discovery. Io, [ http://antwrp.gsfc.nasa.gov/apod/ap950803.html ] the innermost Galilean moon of Jupiter, was covered with volcanoes and some of them were erupting! In all, Voyager 1 observed nine volcanic eruptions during its encounter with the moon. When Voyager 2 flew past four months later it was able to confirm that at least six of them were still erupting. This Voyager image of Ra Patera, a large shield volcano, shows colorful flows up to about 200 miles long emanating from the dark central volcanic vent. For more information about volcanism on Io, see Calvin J. Hamilton's Io page [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/io.html ] Tomorrow's picture: Geysers on Triton |
|
Neptune: Big Blue Giant
| Title |
Neptune: Big Blue Giant |
| Explanation |
This picture was taken by the Voyager 2 [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] spacecraft in 1986 - the only spacecraft ever to visit Neptune. Neptune [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/neptune.html ] will be the farthest planet from the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ] until 1999, when the elliptical orbit of Pluto will cause it to once again resume this status. Neptune [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/neptune.html ], like Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ], is composed mostly of liquid water, methane and ammonia, is surrounded by a thick gas atmosphere of mostly hydrogen and helium, and has many moons and rings. Neptune [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-neptune.html ]'s moon Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ] is unlike any other and has active volcanoes. The nature of Triton [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/triton.html ]'s unusual orbit around Neptune is the focus of much discussion and speculation. Tomorrow's picture: Pluto: The Frozen Planet |
|
Venus: Earth's Sister Planet
| Title |
Venus: Earth's Sister Planet |
| Explanation |
This picture in visible light was taken by the Galileo [ http://nssdc.gsfc.nasa.gov/planetary/galileo.html ] spacecraft. Venus [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/venus.html ] is very similar to Earth [ http://antwrp.gsfc.nasa.gov/apod/ap950622.html ] in size and mass - and so is sometimes referred to as Earth's sister planet - but Venus has a quite different climate. Venus' [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/venus.html ] thick clouds and closeness to the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ] (only Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap950814.html ] is closer) make it the hottest planet - much hotter than the Earth. Humans could not survive there, and no life of any sort has ever been found. When Venus [ http://nssdc.gsfc.nasa.gov/photo_gallery/PhotoGallery-Venus.html ] is visible it is usually the brightest object in the sky after the Sun and the Moon. More than 20 spacecraft have visited Venus including Venera 9, which landed on the surface, and Magellan [ http://stardust.jpl.nasa.gov/mveg/guide.html ], which used radar to peer through the clouds and make a map of the surface. There are still many things about Venus's unusual atmosphere that astronomers don't understand. Tomorrow's picture: Uranus: The Tilted Planet |
|
Geysers on Triton
| Title |
Geysers on Triton |
| Explanation |
In August of 1989 NASA's Voyager 2 [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] spacecraft passed by Neptune, the most distant of the solar system's gas giant planets. Its encounter with Neptune climaxed with its closest approach to Neptune's largest moon Triton. From a distance of about 24,000 miles the robot space probe surveyed Triton's surface, whose temperature averages nearly -400 degrees Fahrenheit, and discovered surprising evidence of a complex and active world. For example, the prominent dark streaks in this image seem to come from small volcanoes and may consist of nitrogen frost mixed with organic compounds ejected during geyser-like eruptions. For more information about Triton, see Calvin J. Hamilton's Triton page [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/triton.html ]. Tomorrow's picture: Liftoff of Space Shuttle Columbia. |
|
Ganymede: Moonquake World
| Title |
Ganymede: Moonquake World |
| Explanation |
Ganymede [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ganymede.html ] probably undergoes frequent ground shaking events not unlike terrestrial earthquakes. Ganymede [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/ganymede.html ], the largest moon of Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap950625.html ] and the Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap950819.html ], has a thick outer coating of water ice. Passing Voyager spacecraft found a large number of cracks and grooves in the ice so it is thought that Ganymede, like the Earth [ http://antwrp.gsfc.nasa.gov/apod/ap950622.html ], has large shifting surface masses called tectonic plates. Ganymede was discovered by Galileo [ http://galileo.imss.firenze.it/museo/4/index.html ] and Marius [ http://seds.lpl.arizona.edu/billa/tnp/help.html#M ] in 1610, and is larger than the planets Mercury and Pluto. The NASA spacecraft Galileo [ http://www.jpl.nasa.gov/galileo/ ] is scheduled to arrive at Jupiter is December of 1995. Tomorrow's picture: Europa: Ancient Water World |
|
Europa: Ancient Water World
| Title |
Europa: Ancient Water World |
| Explanation |
Beneath the cold icy surface of Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap950625.html ]'s moon Europa [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/europa.html ] are probably the only oceans of water in our Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap950819.html ] outside of Earth [ http://antwrp.gsfc.nasa.gov/apod/ap950622.html ]. These oceans, possibly 50 kilometers deep, might also be the most likely local place to find extra-terrestrial life. Europa [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/europa.html ]'s smooth surface is unlike any other known planet or moon, giving evidence for relatively few craters or mountains. Europa was discovered by Galileo [ http://galileo.imss.firenze.it/museo/4/index.html ] and Marius [ http://seds.lpl.arizona.edu/billa/tnp/help.html#M ] in 1610. The NASA spacecraft Galileo [ http://www.jpl.nasa.gov/galileo/ ] is scheduled to arrive at Jupiter in December of 1995. Tomorrow's picture: Callisto: Dark Smashed Iceball |
|
Atete Corona on Venus
| Title |
Atete Corona on Venus |
| Explanation |
What could cause a huge cylindrical mountain to rise from the surface of Venus [ http://www.nineplanets.org/venus.html ]? Such features that occur on Venus [ http://pdsmaps.wr.usgs.gov/PDS/public/explorer/html/fmapeasy.htm ] are known as coronas [ http://emma.la.asu.edu/~hamilton/abstracts/coronae.html ]. Pictured above [ http://photojournal.jpl.nasa.gov/cgi-bin/PIAGenCatalogPage.pl?PIA00096 ] in the foreground is 500-kilometer wide Atete Corona found in a region of Venus known as the Galindo [ http://wwwflag.wr.usgs.gov/USGSFlag/Space/GEOMAP/MapStatus/VenusStatus/V40.html ]. The image was created by combining multiple radar maps [ http://spaceplace.jpl.nasa.gov/srtm_makemap3.htm ] of the region to form a computer-generated three-dimensional perspective. The series of dark rectangles that crosses the image from top to bottom were created by the imaging procedure and are not real. The origin of massive coronas [ http://pds.jpl.nasa.gov/planets/captions/venus/vencor.htm ] remains a mystery although speculation [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999Icar..139..100S ] holds they result from some form of volcanism [ http://www.usgs.gov/education/learnweb/volcano/ ]. Studying Venusian coronas [ http://www.star.ucl.ac.uk/~idh/geology/g3613.htm ] help scientists better understand the inner structure [ http://www.windows.ucar.edu/tour/link=/venus/interior.html ] of both Venus and Earth [ http://scign.jpl.nasa.gov/learn/plate1.htm ]. |
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Saturn's Moon Dione
| Title |
Saturn's Moon Dione |
| Explanation |
Dione [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/dione.html ], one of Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap950705.html ]'s larger moons, is remarkable for its bright surface streaks. These streaks run across some of Dione's many craters, which indicate that the process which created the streaks occurred later than the process which created the craters. Dione [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/dione.html ] is made of mostly water ice but its relatively high density indicates that it contains much rock inside. Dione was discovered by Giovanni Cassini in 1684. NASA's Cassini mission [ http://newproducts.jpl.nasa.gov/calendar/cassini.html ] to Saturn is currently scheduled for launch in October 1997. Dione's orbit is remarkable it that it also houses the much smaller moon Helene [ http://antwrp.gsfc.nasa.gov/apod/ap951010.html ]. This moon, once designated "Dione B", precedes Dione by about 1/6th of an orbit. |
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Jupiter's Moon Amalthea
| Title |
Jupiter's Moon Amalthea |
| Explanation |
Amalthea is Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap951013.html ]'s fifth largest moon, much smaller than the four Galilean [ http://bang.lanl.gov/video/stv/arshtml/arstoc.html ] satellites Io [ http://antwrp.gsfc.nasa.gov/apod/ap950803.html ], Europa [ http://antwrp.gsfc.nasa.gov/apod/ap950905.html ], Ganymede [ http://antwrp.gsfc.nasa.gov/apod/ap950904.html ], and Callisto [ http://antwrp.gsfc.nasa.gov/apod/ap950906.html ]. The orbit of Amalthea [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/amalthea.html#amalthea ] is inside of these moons, and with its long axis always pointing toward Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap950625.html ]. It's dark surface color is probably due to sulfur being expelled from Io [ http://antwrp.gsfc.nasa.gov/apod/ap950804.html ]. Amalthea is not massive enough for its internal gravity to make it spherical. Amalthea [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/amalthea.html ] was discovered in 1892 by Edward Barnard. |
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Iapetus: Saturn's Disappeari
…
| Title |
Iapetus: Saturn's Disappearing Moon |
| Explanation |
Iapetus [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/iapetus.html ] has an unusual surface, one half of which is very dark, the other half very light. This caused it's discoverer Cassini [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/help.html#cassini ] to remark that Iapetus [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/iapetus.html ] could only be seen when on one side of Saturn but not the other. The reason for the difference between hemispheres is presently unknown. Iapetus is the third largest of Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap950705.html ]'s moon behind Titan [ http://antwrp.gsfc.nasa.gov/apod/ap950923.html ] and Rhea [ http://antwrp.gsfc.nasa.gov/apod/ap951014.html ]. Iapetus is composed predominantly of water ice. |
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Rhea: Saturn's Second Larges
…
| Title |
Rhea: Saturn's Second Largest Moon |
| Explanation |
Rhea [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/rhea.html ] is the second largest moon of Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap950705.html ], behind Titan [ http://antwrp.gsfc.nasa.gov/apod/ap950923.html ], and the largest without an atmosphere. It is composed mostly of water ice, but has a small rocky core. Rhea [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/rhea.html ]'s rotation and orbit are locked together (just like Earth's Moon) so that one side always faces Saturn. A consequence of this is that one side always leads the other. Rhea's leading surface is much more heavily cratered than its trailing surface. The above photograph was taken with the Voyager 1 spacecraft in 1980. |
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Saturn's Moon Tethys
| Title |
Saturn's Moon Tethys |
| Explanation |
Tethys is one of the larger and closer moons of Saturn. It was visited by both Voyager spacecraft [ http://voyager.jpl.nasa.gov/ ] - Voyager 1 in November 1980 and by Voyager [ http://antwrp.gsfc.nasa.gov/apod/ap960629.html ] 2 in August 1981. Tethys [ http://www.nineplanets.org/tethys.html ] is now known to be composed almost completely of water ice. Tethys [ http://www.solarviews.com/eng/tethys.htm ] shows a large impact crater [ http://antwrp.gsfc.nasa.gov/apod/ap990711.html ] that nearly circles the planet. That the impact that caused this crater did not disrupt the moon is taken as evidence that Tethys [ http://sse.jpl.nasa.gov/features/planets/saturn/tethys.html ] was not completely frozen in its past. Two smaller moons, Telesto [ http://www.nineplanets.org/tethys.html#telesto ] and Calypso [ http://www.nineplanets.org/tethys.html#calypso ], orbit Saturn [ http://antwrp.gsfc.nasa.gov/apod/saturn.html ] just ahead of and behind Tethys. Giovanni Cassini [ http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Cassini.html ] discovered Tethys in 1684. In 1997, NASA [ http://www.nasa.gov/ ] launched [ http://antwrp.gsfc.nasa.gov/apod/ap971016.html ] a spacecraft named Cassini [ http://saturn.jpl.nasa.gov/cassini/english/spacecraft/ ] to Saturn that will arrive in 2004. |
|
Saturn's Moon Tethys
| Title |
Saturn's Moon Tethys |
| Explanation |
Tethys [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/tethys.html ] is one of the larger and closer moons of Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap951018.html ]. It was visited by both Voyager spacecraft - Voyager 1 in November 1980 and by Voyager 2 in August 1981. Tethys [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/tethys.html ] is now known to be composed almost completely of water ice. Tethys shows a large impact crater that nearly circles the planet. That the impact that caused this crater did not disrupt the moon is taken as evidence that Tethys was not completely frozen in its past. Tethys has two moons named Telesto [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/tethys.html#telesto ] and Calypso [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/tethys.html#calypso ] that orbit just ahead of it and behind it. Tethys was originally discovered in 1684 by Giovanni Cassini. |
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Mercury's Faults
| Title |
Mercury's Faults |
| Explanation |
The surface [ http://antwrp.gsfc.nasa.gov/apod/ap960120.html ] of the planet Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap950814.html ] is not without fault. In this case, however, "fault" refers to unusual surface features that are the topic of much speculation. The above fault line is called Santa Maria Rupes, and runs through many prominent craters. The meandering feature is thought to be the result of huge forces of compression on Mercury [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/mercury.html ]'s surface. Such rupes probably originate from large impacts [ http://antwrp.gsfc.nasa.gov/apod/ap950924.html ] and a general shrinking of Mercury [ http://bang.lanl.gov/solarsys/mercury.htm ]'s crust, which in turn causes parts of the crust to push above other parts. |
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Uranus' Moon Ariel: Valley W
…
| Title |
Uranus' Moon Ariel: Valley World |
| Explanation |
What formed Ariel [ http://bang.lanl.gov/solarsys/ariel.htm ]'s valleys? This question presented itself when Voyager [ http://vraptor.jpl.nasa.gov/voyager/voyager.html ] 2 passed this satellite of Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ] in January 1986. Speculation [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1990Icar%2E%2E%2E87%2E%2E110T&db_key=AST ] includes that heating caused by the ancient tides of Uranus caused moonquakes and massive shifting of the moon's surface. In any event, a huge network of sunken valleys was found to cover this frozen moon, and some unknown material now coats the bottoms of many of these channels. Ariel [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ariel.html ] is the second closest to Uranus outside of Miranda [ http://antwrp.gsfc.nasa.gov/apod/ap951224.html ], and is composed of roughly half water ice and half rock. Ariel was discovered by William Lassell [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/help.html#lassell ] in 1851. |
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Uranus' Largest Moon: Titani
…
| Title |
Uranus' Largest Moon: Titania |
| Explanation |
Titania's tortured terrain is a mix of valleys and craters. NASA's interplanetary robot spacecraft Voyager [ http://spacelink.msfc.nasa.gov/NASA.Projects/Planetary.Probes/Voyager/Mission.Summary ] 2 passed this moon of Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ] in 1986 and took the above photograph. The photograph was then transmitted back to earth by radio [ http://www.science.uwaterloo.ca/physics/p13news/number_2/maxnew-2.html ]. The valleys of Titania [ http://bang.lanl.gov/solarsys/titania.htm ] resemble those on Ariel [ http://antwrp.gsfc.nasa.gov/apod/ap960303.html ] indicate that Titania underwent some unknown tumultuous resurfacing event in its distant past. Although Titania [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/titania.html ] is Uranus' largest moon, it is still much smaller than Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ] - the largest moon of Uranus' sister planet Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap950817.html ]. Titania is essentially a large dirty iceball that orbits Uranus - it is composed of about half water-ice and half rock. Titania was discovered by William Hershel [ http://www.dsi.unimi.it/Users/Students/amoroso/sun/fortunes/life-e.html ] in 1787. |
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Uranus's Moon Oberon: Impact
…
| Title |
Uranus's Moon Oberon: Impact World |
| Explanation |
Oberon is the most distant and second largest moon of Uranus. Discovered by William Herschel [ http://www.adventure.com/library/encyclopedia/space/herschls.html ] in 1787, the properties of the world remained relatively unknown until the robot spacecraft Voyager [ http://vraptor.jpl.nasa.gov/voyager/voyager.html ] 2 passed it during its flyby of Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ] in January 1986. Compared to Uranus' moons Ariel [ http://antwrp.gsfc.nasa.gov/apod/ap960303.html ], Titania [ http://antwrp.gsfc.nasa.gov/apod/ap960304.html ], and Miranda [ http://antwrp.gsfc.nasa.gov/apod/ap951224.html ], Oberon [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/oberon.html ] is heavily cratered, and in this way resembles Umbriel [ http://antwrp.gsfc.nasa.gov/apod/ap960407.html ]. Like all of Uranus' large moons, Oberon [ http://bang.lanl.gov/solarsys/oberon.htm ] is composed of roughly half ice and half rock. Note that Oberon has at least one large mountain, visible on the limb at the lower left, that rises 6 km off the surface. |
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Uranus's Moon Umbriel: A Mys
…
| Title |
Uranus's Moon Umbriel: A Mysterious Dark World |
| Explanation |
Why is Umbriel so dark? This dark moon reflects only half the light of other Uranus' [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ] moons such as Ariel [ http://antwrp.gsfc.nasa.gov/apod/ap960303.html ]. And what is that bright ring at the top? Unfortunately, nobody yet knows. These questions presented themselves when Voyager [ http://vraptor.jpl.nasa.gov/voyager/voyager.html ] 2 passed this satellite of Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ] in January 1986. Voyager found an old surface with unusually large craters, and determined Umbriel [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/umbriel.html ]'s composition to be about half ice and half rock. Umbriel [ http://bang.lanl.gov/solarsys/umbriel.htm ] is the fourth largest and third most distant of Uranus' five large moons. Umbriel was discovered in 1851 by William Lassell [ http://www.ast.cam.ac.uk/~naw96/lassell/lassell.htm ]. |
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NGC 3393: A Super Spiral?
| Title |
NGC 3393: A Super Spiral? |
| Explanation |
A bird? A plane? No, but pictured here is something physically much larger, flying much higher, and moving much faster than either of these. It is, in fact, a Seyfert type 2 spiral galaxy [ http://antwrp.gsfc.nasa.gov/apod/lib/spirals.html ]. The "S" is actually a lane of stars, gas and dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] circling the core. Designated NGC 3393, the bright core makes this galaxy a Seyfert [ http://msowww.anu.edu.au/~mga/seyfert.html ] and the infrared glow of central dust help distinguish it as "type 2." Seyfert galaxies [ http://praxis.pha.jhu.edu/papers/papers/afdscirev_b/node9.html ] have extremely energetic nuclei similar to more powerful quasars [ http://www.ph.unimelb.edu.au/~bholman/qso/qso1.html ]. Seyferts [ http://www-astronomy.mps.ohio-state.edu/~pogge/agn.html ] are thought to have black holes [ http://cossc.gsfc.nasa.gov/htmltest/rjn_bht.html ] in their centers. Most of the lines and small spots in this image are due to cosmic rays [ http://www.ngdc.noaa.gov/stp/SOLAR/COSMIC_RAYS/cosmic.html ] striking the imager and are unrelated to structure in the galaxy. |
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Arp 230: Two Spirals in One?
| Title |
Arp 230: Two Spirals in One? |
| Explanation |
Is this one galaxy or two? Analysis of Arp 230 [ http://adsabs.harvard.edu/cgi-bin/nph-article_query?bibcode=1990AJ%2E%2E%2E%2E100%2E1073M&page=1&plate_select=NO&type=GIF ] has shown evidence that this seemingly single spiral galaxy [ http://antwrp.gsfc.nasa.gov/apod/lib/spirals.html ] is actually the result of the recent collision of two spiral galaxies [ http://sdsc.edu/IOTW/week47/iotw.html ]. The slow motion collision [ http://antwrp.gsfc.nasa.gov/apod/ap951228.html ] took place over about 100 million years and induced a burst of star formation [ http://antwrp.gsfc.nasa.gov/apod/ap951107.html ] that has begun to subside. The collision apparently had many similarities to the colliding galaxy sequence in the IMAX movie "Cosmic Voyage [ http://zeus.ncsa.uiuc.edu:8080/Summers/scicomp.html ]." |
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Europa's Surface
| Title |
Europa's Surface |
| Explanation |
Voyager spacecraft [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-voyager.html ] images of Europa's surface [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/europa.html ], like the one above, are suggestive of sea ice on Earth [ http://antwrp.gsfc.nasa.gov/apod/ap951118.html ]. The criss-crossing dark streaks may indeed be cracks in its ice-covered surface caused by Jupiter's tidal stresses accompanied by the freezing and expansion of an underlying layer of water [ http://antwrp.gsfc.nasa.gov/apod/ap960806.html ]. This tantalizing prospect of oceans of liquid water [ http://antwrp.gsfc.nasa.gov/apod/ap950905.html ] beneath its frozen surface has helped make the smallest of the Galilean [ http://galileo.imss.firenze.it/museo/4/index.html ] moon's of Jupiter a planned focus of the Galileo spacecraft's ongoing mission to explore the Jovian system. New Europa images and results [ http://newproducts.jpl.nasa.gov/galileo/index.html ] from the Galileo mission were released today revealing [ ftp://ftp.hq.nasa.gov/pub/pao/pressrel/1996/96-164.txt ] details which further suggest that Europa's icy surface was once - and may still be - supported on slush or liquid water. |
|
A Close-Up of the Lagoon's H
…
| Title |
A Close-Up of the Lagoon's Hourglass |
| Explanation |
In the central part of the Lagoon Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap960807.html ] lies the above pictured Hourglass Nebula [ http://seds.lpl.arizona.edu/messier/more/m008_det.html ]. In this region of recent star formation, obscuring dark lanes of dust [ http://adsabs.harvard.edu/cgi-bin/nph-article_query?bibcode=1979AJ%2E%2E%2E%2E%2E84%2E1328T&page=1&plate_select=NO&type=GIF ] permeate the red-glowing hydrogen gas. Blocking some of the gas cloud from our view, they chance to create a glowing shape that appears from our vantage point like an hourglass [ http://www.skab.se/~riccard/BIGhourglass.html ]. In the upper right of this picture [ http://scivax.stsci.edu/~hamilton/nuggets/HST_NUGGETS.HTML ] from the Hubble Space Telescope [ http://www.stsci.edu/pubinfo/HSToverview.html ] is a bright young blue star from the open cluster NGC 6530 [ http://antwrp.gsfc.nasa.gov/apod/ap960127.html ] - visible below center in yesterday's APOD [ http://antwrp.gsfc.nasa.gov/apod/ap960820.html ]. A recent study of the Lagoon Nebula [ http://adsabs.harvard.edu/cgi-bin/nph-article_query?bibcode=1990ApJ%2E%2E%2E357%2E%2E502M&page=1&plate_select=NO&type=GIF ] (M [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#messier ]8), has shown that this emission nebula [ http://antwrp.gsfc.nasa.gov/apod/lib/emission.html ] houses large magnetic fields [ http://polaris.phys.ualberta.ca/users/greeniaus/Phys238B1/MagneticField/MagneticFieldTopic1.html ] and unusually large dust particles [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ]. |
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