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More Images of Abell 1795
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More Images of Abell 1795 |
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Sputnik: Traveling Companion
| Title |
Sputnik: Traveling Companion |
| Explanation |
Sputnik means [ http://www.hq.nasa.gov/office/pao/History/sputnik/index.html ]"traveling companion". Despite the innocuous sounding name, the launch [ http://www.nytimes.com/partners/aol/special/sputnik/ launch.1.jpg.html ] of the Earth's first "artificial moon", Sputnik 1 [ http://www.nytimes.com/partners/aol/special/sputnik/ ], by the Soviet Union on October 4, 1957 shocked the free world, setting in motion events which resulted in the creation of NASA [ http://antwrp.gsfc.nasa.gov/apod/ap981001.html ] and the race to the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap970202.html ]. Sputnik 1 [ http://whyfiles.org/047sputnik/main1.html ] was a 184 pound, 22 inch diameter sphere with four whip antennas connected to battery powered transmitters. The transmitters broadcast a continuous "beeping" signal to an astounded [ http://www.sciam.com/explorations/100697sputnik/ hall1.html ] earthbound audience for 23 days. A short month later, on November 3, the Soviet Union followed this success by launching a dog [ http://ham.spa.umn.edu/kris/animals.html ] into orbit aboard Sputnik 2 [ http://asca.gsfc.nasa.gov/docs/StarChild/space_level2/laika.html ]. |
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SN 1006: Pieces of the Cosmi
…
| Title |
SN 1006: Pieces of the Cosmic Ray Puzzle |
| Explanation |
Research balloon flights [ http://lheawww.gsfc.nasa.gov/docs/balloon/ balloon_top.html ] conducted in 1912 by Austrian physicist Victor Hess revealed that the Earth was constantly bombarded by high energy radiation from space - which came to be called "Cosmic Rays" [ http://imagine.gsfc.nasa.gov/docs/features/topics/snr_group/ cosmic_rays.html ]. "What are Cosmic Rays and where do they come from?" They are now known to be mostly subatomic particles - predominantly protons and electrons - but their origin is a long standing mystery. After almost a century of study, this cosmic puzzle may have been at least partially solved by X-ray images and spectra [ http://heasarc.gsfc.nasa.gov/docs/astroe_lc/ ] from the ASCA satellite observatory [ http://heasarc.gsfc.nasa.gov/docs/asca/ascagof.html ]. Pieced together to show the region around a star observed to go supernova [ http://antwrp.gsfc.nasa.gov/apod/ap960612.html ] in 1006 AD, the overlapping X-ray snapshots above (seen in false color) reveal the bright rims of the exploded star's still expanding blast [ http://antwrp.gsfc.nasa.gov/apod/ap980618.html ] wave. These ASCA observations showed [ http://heasarc/docs/asca/science/graphics/09sep1996/docs/ snr_cosmic.html ] for the first time that the energy spectrum of the bright regions is like that produced by extremely high energy electrons streaming through a magnetic field at nearly the speed of light. If (as expected) [ http://heasarc.gsfc.nasa.gov/docs/asca/science/cosmic.html ] high energy protons are associated with these energetic electrons then supernova remnants like SN 1006 [ http://heasarc.gsfc.nasa.gov/docs/asca/science/science_snr.html ] are sources of Hess' puzzling Cosmic Rays [ http://www.cosmic-ray.org/ ]. |
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50th Anniversary of Sputnik:
…
| Title |
50th Anniversary of Sputnik: Traveling Companion |
| Explanation |
Sputnik means [ http://www.hq.nasa.gov/office/pao/History/sputnik/ index.html ]"traveling companion". Despite the innocuous sounding name, the launch [ http://www.nytimes.com/partners/aol/special/sputnik/ launch.1.jpg.html ] of planet Earth's first artificial moon, Sputnik 1 [ http://www.nytimes.com/partners/aol/special/sputnik/ ], by the Soviet Union on October 4, 1957, changed the world and set in motion events which resulted in the creation of NASA [ http://history.nasa.gov/ ] and the race [ http://www.nasm.si.edu/exhibitions/gal114/SpaceRace/sec300/ sec310.htm ] to the Moon. Sputnik 1 [ http://whyfiles.org/047sputnik/main1.html ] was a 184 pound, 22 inch diameter sphere with four whip antennas connected to battery powered transmitters. The transmitters broadcast a continuous "beeping" signal to an astounded [ http://www.airspacemag.com/issues/2007/august/ sputchev.php?page=1 ] earthbound audience for 23 days. A short month later, on November 3, the Soviet Union followed this success by launching a dog [ http://asca.gsfc.nasa.gov/docs/StarChild/space_level2/ laika.html ] into orbit aboard Sputnik 2 [ http://www.svengrahn.pp.se/histind/Sputnik2/ Sputnik2.htm ]. |
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Stars Without Galaxies
| Title |
Stars Without Galaxies |
| Explanation |
Galaxies are [ http://antwrp.gsfc.nasa.gov/apod/ap990322.html ] made up of stars, but are all stars [ http://antwrp.gsfc.nasa.gov/apod/ap010223.html ] found within galaxies? Using the Hubble Space Telescope, researchers exploring [ http://xxx.lanl.gov/abs/astro-ph/9801228 ] the Virgo Cluster [ http://bozo.lpl.arizona.edu/messier/more/virgo.html ] of galaxies have found about 600 red giant stars adrift in intergalactic space [ http://oposite.stsci.edu/pubinfo/PR/97/02/PR.html ]. Above is an artist's vision of the sky from a hypothetical planet of such a lonely sun. The night sky on a world orbiting an intergalactic star would be a stark contrast to Earth's - which features a spectacle of stars, all members of our own Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap010202.html ]. As suggested by the illustration, a setting red sun would leave behind a dark sky flecked only with faint, fuzzy, apparitions of Virgo Cluster galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap010126.html ]. Possibly ejected from their home galaxies during galaxy-galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap981219.html ] collisions, these isolated suns may well represent part of a large, previously unseen [ http://oposite.stsci.edu/pubinfo/background-text/ darkmatt.txt ] stellar population, filling the space between [ http://imagine.gsfc.nasa.gov/docs/features/exhibit/ asca_abundance.html ] Virgo Cluster galaxies. |
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An X-ray Hot Supernova in M8
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| Title |
An X-ray Hot Supernova in M81 |
| Explanation |
In 1993, a star in the galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950912.html ] M [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#messier ]81 exploded. Above is a picture of the hot material ejected by this supernova [ http://antwrp.gsfc.nasa.gov/apod/ap951122.html ] explosion. The picture was taken in X-rays [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#X-ray ] with the Advanced Satellite for Cosmology and Astrophysics [ http://heasarc.gsfc.nasa.gov/docs/asca/asca2.html ] (ASCA [ http://heasarc.gsfc.nasa.gov/0/docs/asca/ascagof.html ]). Since M81 is a relatively nearby galaxy, it can be examined in close detail by observatories on or near the Earth [ http://antwrp.gsfc.nasa.gov/apod/ap950622.html ]. Since the Earth's atmosphere [ http://antwrp.gsfc.nasa.gov/apod/ap951026.html ] protects the surface from interstellar X-radiation, the above photo [ http://pao.gsfc.nasa.gov/gsfc/lithos/snova/snova.htm ] was taken from space. Studying the nature and distribution of the X-rays has allowed astronomers to determine the composition and temperature of the expanding supernova gas. |
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ASCA X-Ray Observatory
| Title |
ASCA X-Ray Observatory |
| Explanation |
Today marks the third anniversary of the launch of the Advanced Satellite for Cosmology and Astrophysics (ASCA, renamed from Astro D when launched). ASCA [ http://heasarc.gsfc.nasa.gov/docs/heasarc/missions/asca.html ], seen here superposed on galaxy M31 [ http://antwrp.gsfc.nasa.gov/apod/ap950724.html ], is a Japanese satellite for which NASA has provided some scientific equipment. ASCA [ http://www.astro.isas.ac.jp/xray/mission/asca/ascaE.html ] carries four large-area X-ray telescopes. At the focus of two of the telescopes is a Gas Imaging Spectrometer (GIS [ http://heasarc.gsfc.nasa.gov/docs/asca/asca_gis.html ]), while a Solid-state Imaging Spectrometer (SIS [ http://heasarc.gsfc.nasa.gov/docs/asca/asca_sis.html ]) is at the focus of the other two. ASCA has provided recent evidence that high energy cosmic rays are formed in the expanding gas from a supernova [ http://heasarc.gsfc.nasa.gov/docs/asca/new_results.html ]. During ASCA's three years of operation, it has also yielded valuable data on quasars [ http://www.aas.org/ApJ/v458n2/5604/5604.html ], supernova remnants [ http://www.aas.org/ApJ/v459n1/5706/5706.html ], dwarf novae [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1994ApJ%2E%2E%2E436L%2E%2E19N&db_key=AST ], pulsars [ http://www.aas.org/ApJ/v449n1/5135/5135.html ], clusters of galaxies [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1994ApJ%2E%2E%2E436L%2E%2E63F&db_key=AST ], and the mysterious X-ray background [ http://xxx.lanl.gov/abs/astro-ph/9302004 ] radiation that appears to come from all directions. |
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Explanation: Research balloo
…
| Title |
Explanation: Research balloon flights conducted in 1912 by Austrian physicist Victor Hess revealed that the Earth was constantly bombarded by high energy radiation from space - which came to be called "Cosmic Rays" [ http://flaco.nmsu.edu:80/www/cosmicrays.html ]. "What are Cosmic Rays and where do they come from?" They are now known to be mostly subatomic particles - predominantly protons and electrons - but their origin is a long standing mystery [ http://ast.leeds.ac.uk/haverah/crs.html ]. After almost a century of study, this cosmic puzzle may have been at least partially solved by new X-ray images and spectra [ http://heasarc.gsfc.nasa.gov/docs/learning_center/basic/xray/ xray_information.html ] from the ASCA satellite observatory [ http://heasarc.gsfc.nasa.gov/docs/asca/asca2.html ]. Pieced together to show the region around a star observed to go supernova [ http://antwrp.gsfc.nasa.gov/apod/ap960612.html ] in 1006 AD, the overlapping X-ray snapshots above (seen in false color) reveal the bright rims of the exploded star's still expanding blast wave. These ASCA observations show [ http://heasarc/docs/asca/science/graphics/09sep1996/docs/ snr_cosmic.html ] for the first time that the energy spectrum of the bright regions is like that produced by extremely high energy electrons streaming through a magnetic field at nearly the speed of light. If (as expected) [ http://webhead.com/~sergio/cosmos95/0095.html ] high energy protons are associated with these energetic electrons then supernova remnants like SN 1006 [ http://heasarc.gsfc.nasa.gov/docs/asca/science/science_snr.html ] are sources of Hess' puzzling Cosmic Rays [ http://www.physics.adelaide.edu.au/astrophysics/cr.html ]. |
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Tomorrow's picture: Giant Cl
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| Title |
Tomorrow's picture: Giant Cluster Bends, Breaks Galaxy Images [ http://antwrp.gsfc.nasa.gov/apod/ap970503.html ] |
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Stars Without Galaxies
| Title |
Stars Without Galaxies |
| Explanation |
Galaxies are made up [ http://antwrp.gsfc.nasa.gov/apod/ap961009.html ] of stars, but are all stars found within galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap970125.html ]? Using the Hubble Space Telescope, researchers exploring the Virgo Cluster of galaxies [ http://bozo.lpl.arizona.edu/messier/more/virgo.html ] have now found about 600 red giant stars adrift in intergalactic space [ http://oposite.stsci.edu/pubinfo/PR/97/02/A.html ]. Above is an artist's vision of the sky from a hypothetical planet of such a lonely sun. The night sky on a world orbiting an intergalactic star would be a stark contrast to Earth's - which features a spectacle of stars, all members of our own Milky Way galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap971229.html ]. As suggested by the illustration, a setting swollen red sun would leave behind a dark sky flecked only with faint, fuzzy, apparitions of Virgo Cluster galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap960419.html ]. Possibly ejected from their home galaxies during galaxy-galaxy collisions [ http://antwrp.gsfc.nasa.gov/apod/ap971022.html ], these isolated suns may well represent part of a large, previously unseen [ http://oposite.stsci.edu/pubinfo/background-text/darkmatt.txt ] stellar population, filling the space between [ http://imagine.gsfc.nasa.gov/docs/features/exhibit/ asca_abundance.html ] Virgo Cluster galaxies. |
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Ultra-Fast Pulsar
| Title |
Ultra-Fast Pulsar |
| Explanation |
Pulsars are rotating neutron stars [ http://astro.uchicago.edu/home/web/miller/nstar.html ], born in the violent crucibles of supernova explosions [ http://antwrp.gsfc.nasa.gov/apod/ap961114.html ]. Like cosmic lighthouses [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/pulsars.html ], beams of radiation from surface hotspots sweep past our viewpoint creating pulses which reveal the rotation rates of these incredibly dense stellar corpses [ http://antwrp.gsfc.nasa.gov/apod/ap970926.html ]. The most famous pulsar of all is found in the nearby supernova remnant, the Crab Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap980208.html ]. The Crab's young pulsar is fast. Rotating at 33 times a second, its radiation energizes the surrounding [ http://antwrp.gsfc.nasa.gov/apod/ap960531.html ] gaseous stellar debris [ http://antwrp.gsfc.nasa.gov/apod/ap960909.html ]. But using archival observations from orbiting X-ray telescopes [ http://xxx.lanl.gov/abs/astro-ph/9708087 ], astronomers have recently identified another "Crab-like" pulsar that is even faster. Located in the Large Magellanic Cloud (LMC) [ http://antwrp.gsfc.nasa.gov/apod/ap980124.html ], X-ray pulses from this newly discovered pulsar, in the supernova remnant N157B [ http://www.astro.nwu.edu/astro/wqd/newpage1.htm ], indicate an even faster rotation rate - 62 times a second - making it the fastest known pulsar associated with a supernova remnant [ http://www.skypub.com/news/jan3098.html ]. This contoured, false color X-ray image of a portion of the LMC [ http://antwrp.gsfc.nasa.gov/apod/ap971224.html ] shows the location of N157B along with the core of the nearby hot star cluster R136 [ http://antwrp.gsfc.nasa.gov/apod/ap971004.html ], and the site of another Crab-like pulsar in SNR 0540-69.3 (rotating a mere 20 times a second). The image is about 1,500 light-years across. |
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The Perseus Cluster of Galax
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| Title |
The Perseus Cluster of Galaxies |
| Explanation |
Here is one of the largest objects [ http://www.actden.com/sky_den/cluster.htm ] that anyone will ever see on the sky. Each of the fuzzy blobs in the above picture is a galaxy, together making up the Perseus Cluster, one of the closest clusters of galaxies [ http://crux.astr.ua.edu/white/mug/cluster/clusters.html ]. We view the cluster through the foreground of faint stars in our own Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap970315.html ]. It takes light roughly 300 million years to get here from this region of the Universe [ http://antwrp.gsfc.nasa.gov/apod/ap980302.html ], so we see this cluster as it existed before the age of the dinosaurs [ http://www.wf.carleton.ca/Museum/extinction/homepg.html ]. Also known as Abell 426 [ http://users.ox.ac.uk/~jgodwin/tx426.htm ], the center of the Perseus Cluster is a prodigious source of X-ray radiation [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html ], and so helps astronomers explore [ http://lheawww.gsfc.nasa.gov/users/public_html/kaa/ asca_perseus/apjlett.html ] how clusters formed and how gas [ http://antwrp.gsfc.nasa.gov/apod/ap960419.html ] and dark matter interact [ http://physics.hallym.ac.kr/education/stellar/darkmatter/essay.html ]. The Perseus Cluster of Galaxies is part of the Pisces-Perseus [ http://aps.umn.edu/Papers/juan/mapspp.html ] supercluster of galaxies [ http://astrowww.phys.uvic.ca/rsocs/hudson/threed.html ], which spans over 15 degrees and contains over 1000 galaxies. |
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Sputnik: Traveling Companion
| Title |
Sputnik: Traveling Companion |
| Explanation |
Sputnik means [ http://www.hq.nasa.gov/office/pao/History/sputnik/index.html ]"traveling companion". Despite the innocuous sounding name, the launch of the Earth's first "artificial moon", Sputnik 1 [ http://history.msfc.nasa.gov/history/hr/34.html ], by the Soviets on October 4, 1957 shocked the free world, setting in motion events which resulted in the creation of NASA [ http://antwrp.gsfc.nasa.gov/apod/ap981001.html ] and the race to the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap970202.html ]. Sputnik 1 [ http://history.msfc.nasa.gov/history/mm/lk_sputdoc.html ] was a 184 pound, 22 inch diameter sphere with four whip antennas connected to battery powered transmitters. The transmitters broadcast a continuous "beeping" signal to an astounded earthbound audience for 23 days. A short month later, on November 3, the Soviet Union followed this success by launching a dog [ http://www.reston.com/sts69/laika.html ] into orbit aboard Sputnik 2 [ http://asca.gsfc.nasa.gov/docs/StarChild/space_level2/laika.html ]. |
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![Explanation: Research balloon flights conducted in 1912 by Austrian physicist Victor Hess revealed that the Earth was constantly bombarded by high energy radiation from space - which came to be called "Cosmic Rays" [ http://flaco.nmsu.edu:80/www/cosmicrays.html ]. "What are Cosmic Rays and where do they come from?" They are now known to be mostly subatomic particles - predominantly protons and electrons - but their origin is a long standing mystery [ http://ast.leeds.ac.uk/haverah/crs.html ]. After almost a century of study, this cosmic puzzle may have been at least partially solved by new X-ray images and spectra [ http://heasarc.gsfc.nasa.gov/docs/learning_center/basic/xray/ xray_information.html ] from the ASCA satellite observatory [ http://heasarc.gsfc.nasa.gov/docs/asca/asca2.html ]. Pieced together to show the region around a star observed to go supernova [ http://antwrp.gsfc.nasa.gov/apod/ap960612.html ] in 1006 AD, the overlapping X-ray snapshots above (seen in false color) reveal the bright rims of the exploded star's still expanding blast wave. These ASCA observations show [ http://heasarc/docs/asca/science/graphics/09sep1996/docs/ snr_cosmic.html ] for the first time that the energy spectrum of the bright regions is like that produced by extremely high energy electrons streaming through a magnetic field at nearly the speed of light. If (as expected) [ http://webhead.com/~sergio/cosmos95/0095.html ] high energy protons are associated with these energetic electrons then supernova remnants like SN 1006 [ http://heasarc.gsfc.nasa.gov/docs/asca/science/science_snr.html ] are sources of Hess' puzzling Cosmic Rays [ http://www.physics.adelaide.edu.au/astrophysics/cr.html ].](http://mm04.nasaimages.org/MediaManager/srvr?mediafile=/Size1/NVA2-4-NA/8077/sn1006_asca1_big.jpg&userid=1&username=admin&resolution=1&servertype=JVA&cid=4&iid=NVA2&vcid=NA&usergroup=NASA_Astronomy_Picture_of_the_Day_Collecti-4-Admin&profileid=16)
![Tomorrow's picture: Giant Cluster Bends, Breaks Galaxy Images [ http://antwrp.gsfc.nasa.gov/apod/ap970503.html ]](http://mm04.nasaimages.org/MediaManager/srvr?mediafile=/Size1/NVA2-4-NA/8247/ic443_asca_orig.jpg&userid=1&username=admin&resolution=1&servertype=JVA&cid=4&iid=NVA2&vcid=NA&usergroup=NASA_Astronomy_Picture_of_the_Day_Collecti-4-Admin&profileid=16)
