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The Hercules Cluster of Galaxies

Astronomy Picture of the Day - Dj, 16/07/2009 - 20:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/Abell-2151_LRGBhallas_2400.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/Abell-2151_LRGBhallas_800.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b The Hercules Cluster of Galaxies /b br b Credit a href="http://antwrp.gsfc.nasa.gov/apod/lib/about_apod.html#srapply"Copyright/a: /b a href="http://astrophoto.com/contact.htm"Tony Hallas/a P p b Explanation: /b These are galaxies of the a href="http://www.astr.ua.edu/gifimages/hercules.html"Hercules Cluster/a, an archipelago of a href="http://antwrp.gsfc.nasa.gov/apod/ap051222.html"island universes/a a mere 500 million a href="http://www.faqs.org/faqs/astronomy/faq/part8/ section-14.html"light-years away/a. Also known as a href="http://www.atlasoftheuniverse.com/superc/her.html"Abell 2151, this cluster/a is loaded with gas and dust rich, star-forming a href="http://antwrp.gsfc.nasa.gov/apod/ap070529.html"spiral/a galaxies but has relatively few a href="http://antwrp.gsfc.nasa.gov/apod/ap060520.html"elliptical/a galaxies, which lack gas and dust and the associated newborn stars. The colors in a href="http://www.qsimaging.com/gallery.html"this remarkably deep composite/a image clearly show the star forming galaxies with a blue tint and galaxies with older stellar populations with a yellowish cast. The sharp picture spans about 3/4 degree across the cluster center, corresponding to over 6 million light-years at the cluster's estimated distance. In the cosmic vista many galaxies seem to be a href="http://antwrp.gsfc.nasa.gov/apod/ap040612.html"colliding/a or a href="http://antwrp.gsfc.nasa.gov/apod/ap090618.html"merging/a while others seem a href="http://antwrp.gsfc.nasa.gov/apod/ap030607.html"distorted/a - clear evidence that a href="http://www.seds.org/messier/gal_clus.html"cluster galaxies/a commonly interact. In fact, the Hercules Cluster itself may be seen as the result of ongoing mergers of smaller galaxy clusters and is thought to be similar to a href="http://antwrp.gsfc.nasa.gov/apod/ap040226.html"young/a galaxy clusters in the much more distant, early a href="http://antwrp.gsfc.nasa.gov/apod/ap060323.html"Universe/a. p P script type="text/javascript" digg_url ='http://apod.nasa.gov/apod/ap090716.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

The Chameleon's Dark Nebulae

Astronomy Picture of the Day - Dc, 15/07/2009 - 18:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/chameleontis_kuznetsov1024.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/chameleontis_kuznetsov_c800.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b The Chameleon's Dark Nebulae /b br b Credit a href="http://antwrp.gsfc.nasa.gov/apod/lib/about_apod.html#srapply"Copyright/a: /b a href="mailto:Andrey.Kuznetsov at t-services dot ru"Andrey Kuznetsov/a P p b Explanation: /b The Chameleon is a small constellation near the a href="http://antwrp.gsfc.nasa.gov/apod/ap061202.html"south celestial pole/a. Boasting a href="http://hawastsoc.org/deepsky/cha/"no bright stars/a, it blends inconspicuously with the starry southern sky. But, taken in dark skies over Namibia, this image reveals a stunning aspect of the shy constellation -- a field of dusty nebulae and colorful stars. a href="http://antwrp.gsfc.nasa.gov/apod/ap090610.html"Blue reflection/a nebulae are scattered through the scene, but most eye-catching is the complex of silvery dust clouds that only faintly reflect starlight, punctuated by dense a href="http://antwrp.gsfc.nasa.gov/apod/ap090425.html"dark nebulae/a. The dark nebulae stand out because they block out background stars. This view of the a href="http://antwrp.gsfc.nasa.gov/apod/ap030706.html"cosmic dust/a clouds spans about 4 degrees on the sky. p P script type="text/javascript" digg_url ='http://apod.nasa.gov/apod/ap090715.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Moons and Jupiter

Astronomy Picture of the Day - Dm, 14/07/2009 - 16:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/lune-jupiter4_riou.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/lune-jupiter4_riou_c900.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Moons and Jupiter /b br b Credit a href="http://antwrp.gsfc.nasa.gov/apod/lib/about_apod.html#srapply"Copyright/a: /b a href="mailto:riou dot anne at neuf dot fr"Anne Riou/a P p b Explanation: /b Earth's Moon and a href="http://antwrp.gsfc.nasa.gov/apod/ap081106.html"planet Jupiter/a made a beautiful pairing in the night sky late last week. a href="http://www.astrosurf.com/ubb/Forum3/HTML/022397.html"This skyscape/a recorded on July 11 from Brittany in north western France captures the bright conjunction through a cloud bank. The clouds add a href="http://antwrp.gsfc.nasa.gov/apod/ap090430.html"drama/a and a href="http://antwrp.gsfc.nasa.gov/apod/ap080411.html"mystery/a to the scene but they were also positioned to reduce the intense moonlight. As a result, the exposure captures Jupiter's own a href="http://www2.jpl.nasa.gov/galileo/ganymede/discovery.html"Galilean moons/a (lower right) as tiny pinpricks of light, lined up and hugging both sides of the solar system's a href="http://antwrp.gsfc.nasa.gov/apod/ap001118.html"ruling gas giant/a. Later a href="http://www.skyandtelescope.com/observing/ ataglance"this week, the Moon/a is headed for a conjunction with Mars and Venus in the dawn sky. p P script type="text/javascript" digg_url ='http://apod.nasa.gov/apod/ap090714.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Erupting Volcano Anak Krakatau

Astronomy Picture of the Day - Dll, 13/07/2009 - 14:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/krakatau_fulle_big.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/krakatau_fulle.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Erupting Volcano Anak Krakatau /b br b Credit a href="http://www.swisseduc.ch/stromboli/about/copyright-en.html" Copyright/a: /b a href="http://www.ts.astro.it/astro/gente2.html"Marco Fulle/a (Stromboli Online) P p b Explanation: /b A volcano on a href="http://en.wikipedia.org/wiki/Krakatoa"Krakatoa/a is still erupting. Perhaps most famous for the powerfully explosive a href="http://www.geology.sdsu.edu/how_volcanoes_work/Krakatau.html" eruption/a in 1883 that killed tens of thousands of people, ash from a a href="http://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa" violent eruption/a might also have temporarily altered Earth's climate as long as 1500 years ago. In 1927, eruptions caused smaller a href="http://en.wikipedia.org/wiki/Krakatoa#Anak_Krakatau" Anak Krakatau/a to rise from the sea, and the emerging volcanic island continues to grow at an average rate of 2 cm per day. The latest a href="http://www.youtube.com/watch?v=q8yuk8KUzjQ"eruption/a of Anak Krakatau started in 2008 April and continues today. a href="http://www.swisseduc.ch/stromboli/perm/krakatau/ krakatau-storm-stars-en.html"In this picture/a, Anak Krakatau is seen erupting from a href="http://www.britannica.com/EBchecked/topic/323164/Krakatoa" Rakata/a, the main island of the Krakatoai group. High above, stars including the a href="http://antwrp.gsfc.nasa.gov/apod/ap070108.html"Big Dipper/a are clearly apparent. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090713.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

A Cosmic Call to Nearby Stars

Astronomy Picture of the Day - Dg, 12/07/2009 - 12:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/message_dutil_big.gif" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/message_dutil.gif" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b A Cosmic Call to Nearby Stars /b br b Credit Copyright: /b a href="http://www3.sympatico.ca/stephane_dumas/CETI/biographies.html" Yuvan Dutil Stephane Dumas/a P p b Explanation: /b If Earth received this a href="http://web.media.mit.edu/~minsky/papers/AlienIntelligence.html" message from deep space/a, could we a href="http://www.youtube.com/watch?v=5vFwTJ44lFw"decode/a it? The people from the a href="http://www.matessa.org/~mike/dd-pr.html" Cosmic Call/a project sent the a href="http://www.matessa.org/~mike/dutil-dumas.html" above image/a as the first page of a longer message. The a href="http://en.wikipedia.org/wiki/Cosmic_Call"message/a was a href="http://www.matessa.org/~mike/inter-comm.html"broadcast/a toward a href="http://www.matessa.org/~mike/2001.html" local stars/a by a href="http://en.wikipedia.org/wiki/Radio_telescope"radio telescope/a during the summer of 1999. Another message was a href="http://www.cplire.ru/html/rasr/irm/report-1999.html"sent/a in 2003. The single-dish, 70-meter diameter telescope that send the a href="http://www.youtube.com/watch?v=LCjKBh8f1R8"messages/a is located in a href="http://en.wikipedia.org/wiki/Ukraine"Ukraine/a on the Crimean peninsula near the town of a href="http://en.wikipedia.org/wiki/Yevpatoria"Yevpatoria/a. This first page of the a href="http://www.matessa.org/~mike/dutil/p1.html"Cosmic Call 1999/a message, shown above, involves only numbers and so is easier for puzzle solvers to decode than a a href="http://antwrp.gsfc.nasa.gov/apod/ap000123.html"more famous message/a broadcast toward distant star cluster a href="http://antwrp.gsfc.nasa.gov/apod/ap090617.html"M13/a in 1974. (The solution is a href="http://library.thinkquest.org/C003763/pdf/interview01.pdf"here/a.) p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090712.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Noctilucent Cloud Storm Panorama

Astronomy Picture of the Day - Ds, 11/07/2009 - 23:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/NLCcloudsallover_heden.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/NLCcloudsallover_heden.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Noctilucent Cloud Storm Panorama /b br P-M Hedeacute;n (a href="http://www.clearskies.se/"Clear Skies/a, a href="http://www.twanight.org/"TWAN/a) P p b Explanation: /b Noctilucent or night-shining clouds lie near the a href="http://earthobservatory.nasa.gov/IOTD/view.php?id=7953"edge of space/a. From about 80 kilometers above Earth's surface, a href="http://www.nasa.gov/mission_pages/aim/index.html"the icy clouds/a can still reflect sunlight even though the Sun itself is below the horizon as a href="http://spaceweather.com/nlcs/gallery2009_page6.htm"seen from the ground/a. Usually occurring at high latitudes in summer months, the diaphanous apparitions are also known as a href=""polar mesospheric clouds/a and may be connected to a href="http://climate.jpl.nasa.gov/"global change/a in the lower atmosphere. This impressive 360 degree panorama made from 34 separate images captures an impressive display of noctilucent clouds all over the sky. It was recorded last month from Vallentuna, Sweden. The photographer reports that the display was like a noctilucent cloud storm, one of the best he's ever a href="http://antwrp.gsfc.nasa.gov/apod/ap060718.html"witnessed/a. p P script type="text/javascript" digg_url = http://apod.nasa.gov/apod/ap090711.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

The Pillars of Eagle Castle

Astronomy Picture of the Day - Dv, 10/07/2009 - 21:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/m16_colognato_big.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/m16_colognato.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b The Pillars of Eagle Castle /b br b Credit Copyright: /b a href="http://www.backyardskies.com/BackyardSkies/About_Me.html" Emanuele Colognato/a Jim Wood (a href="http://www.backyardskies.com/"Backyard Skies/a) P p b Explanation: /b What lights up this a href="http://en.wikipedia.org/wiki/Castle"castle/a of star formation? The familiar a href="http://antwrp.gsfc.nasa.gov/apod/ap090208.html"Eagle Nebula/a glows bright in many colors at once. The a href="http://www.backyardskies.com/BackyardSkies/M16_Information.html" above image/a is a composite of three of these glowing gas colors. a href="http://antwrp.gsfc.nasa.gov/apod/ap070218.html"Pillars of dark dust/a nicely outline some of the denser a href="http://en.wikipedia.org/wiki/Tower"tower/as of a href="http://en.wikipedia.org/wiki/Star_formation"star formation/a. Energetic light from young massive stars causes the gas to glow and effectively a href="http://www.youtube.com/watch?v=kieGBkOdyMU" boils/a away part of the a href="http://antwrp.gsfc.nasa.gov/apod/ap961119.html"dust/a and gas from its birth pillar. Many of these stars will a href="http://www.youtube.com/watch?v=RgfbjHz_UTo" explode/a after several million years, returning most of their elements back to the nebula which formed them. This process is forming an a href="http://antwrp.gsfc.nasa.gov/apod/ap960903.html"open cluster/a of stars known as a href="http://seds.lpl.arizona.edu/messier/m/m016.html"M16/a. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090710.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Fermi's Gamma-ray Pulsars

Astronomy Picture of the Day - Dj, 09/07/2009 - 19:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/Fermi_pulsar_map_labels_2048.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/Fermi_pulsar_map_labels_900.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Fermi's Gamma-ray Pulsars /b br a href="http://www.nasa.gov/"NASA/a, a href="http://www.energy.gov/"DOE/a, a href="http://www.nasa.gov/mission_pages/GLAST/team/index.html"Fermi LAT Collaboration/a P p b Explanation: /b Born in supernovae, pulsars are spinning neutron stars, collapsed stellar cores left from the death explosions of massive stars. a href="http://www.aip.org/history/mod/pulsar/ pulsar1/01.html"Traditionally/a identified and studied by observing their regular a href="http://www.astro.cornell.edu/academics/courses/ astro201/pulsar.htm"radio pulsations/a, two dozen pulsars have now been a href="http://www.nasa.gov/mission_pages/GLAST/news/ pulsar_passel.html"detected at extreme gamma-ray energies/a by the a href="http://www.nasa.gov/mission_pages/GLAST/spacecraft/ index.html"Fermi Gamma-ray Space Telescope/a. The detections include 16 pulsars identified by their a href="http://svs.gsfc.nasa.gov/vis/a010000/a010400/a010426/ index.html"pulsed gamma-ray emission/a alone. This gamma-ray all-sky map, aligned with the plane of our Milky Way Galaxy, shows the pulsar positions, with the 16 new Fermi pulsars circled in yellow (8 previously known radio pulsars are in magenta). Bizarre stellar corpses, the a href="http://antwrp.gsfc.nasa.gov/apod/ap000609.html"Vela/a, Crab, and Geminga pulsars on the right are the brightest ones in the gamma-ray sky. Pulsars Taz, Eel, and Rabbit are named for the nebulae they are now known a href="http://antwrp.gsfc.nasa.gov/apod/ap010602.html"to power/a. The Gamma Cygni and a href="http://antwrp.gsfc.nasa.gov/apod/ap081021.html"CTA 1 pulsars/a at the left also reside within a href="http://antwrp.gsfc.nasa.gov/apod/ap011026.html"expanding supernova remnants/a of the same name. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090709.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

The Dark River to Antares

Astronomy Picture of the Day - Dj, 09/07/2009 - 06:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/RhoOphregion_jennings_r.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/RhoOphregion_jennings800.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b The Dark River to Antares /b br b Credit a href="http://antwrp.gsfc.nasa.gov/apod/lib/about_apod.html#srapply"Copyright/a: /b a href="http://cosmicphotos.com/"Jason Jennings/a P p b Explanation: /b Connecting the a href="http://antwrp.gsfc.nasa.gov/apod/ap090522.html"Pipe Nebula/a to the colorful region near bright star Antares is a dark cloud dubbed the a href="http://www.astropix.com/HTML/D_SUM_S/PIPE.HTM"Dark River/a, flowing from the picture's left edge. Murky looking, the a href="http://antwrp.gsfc.nasa.gov/apod/ap030928.html"Dark River/a's appearance is caused by a href="http://antwrp.gsfc.nasa.gov/apod/ap030706.html"dust/a obscuring background starlight, although the dark nebula contains mostly a href="http://periodic.lanl.gov/elements/1.html"hydrogen/a and molecular gas. Surrounded by dust, a href="http://www.astro.uiuc.edu/~kaler/sow/antares.html"Antares/a, a red supergiant star, creates an unusual bright yellowish reflection nebula. Above it, bright blue double star a href="http://www.astro.illinois.edu/~jkaler/sow/rhooph.html"Rho Ophiuchi/a is embedded in one of the more typical a href="http://antwrp.gsfc.nasa.gov/apod/ap090521.html"bluish reflection/a nebulae, while a href="http://antwrp.gsfc.nasa.gov/apod/ap080424.html"red emission/a nebulae are also scattered around the region. Globular star a href="http://antwrp.gsfc.nasa.gov/apod/ap000523.html"cluster M4/a is just seen above and right of Antares, though it lies far behind the colorful clouds, at a distance of some 7,000 light-years. The Dark River itself is about 500 a href="http://chandra.harvard.edu/photo/ cosmic_distance.html"light years/a away. a href="http://cosmicphotos.com/gallery/ image.php?fld_image_id=181fld_album_id=9"The colorful skyscape/a is a mosaic of telescopic images spanning nearly 10 degrees (20 Full Moons) across the sky in the constellation Scorpius. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090708.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

The Trifid Nebula in Stars and Dust

Astronomy Picture of the Day - Dm, 07/07/2009 - 15:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/m20_block_big.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/m20_block.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b The Trifid Nebula in Stars and Dust /b br b Credit a href="http://antwrp.gsfc.nasa.gov/apod/lib/about_apod.html#srapply"Copyright/a: /b a href="http://www.caelumobservatory.com/index.html"Adam Block/a, a href="http://skycenter.arizona.edu/"Mt. Lemmon SkyCenter/a, a href="http://www.as.arizona.edu/"U. Arizona/a P p b Explanation: /b Unspeakable beauty and unimaginable bedlam can be found together in the a href="http://www.seds.org/messier/m/m020.html"Trifid Nebula/a. Also known as M20, a href="http://skycenter.arizona.edu/m20.html" this photogenic nebula/a is a href="http://antwrp.gsfc.nasa.gov/apod/ap011229.html"visible/a with good binoculars towards the a href= "http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html" constellation/a of a href= "http://www.astro.wisc.edu/~dolan/constellations/constellations/Sagittarius.html" Sagittarius/a. The energetic processes of a href="http://antwrp.gsfc.nasa.gov/apod/ap030816.html"star formation/a create not only the colors but the a href="http://en.wikipedia.org/wiki/Chaos_%28physics%29"chaos/a. The a href="http://antwrp.gsfc.nasa.gov/apod/ap980828.html"red-glowing gas/a results from high-energy starlight striking interstellar a href="http://periodic.lanl.gov/elements/1.html"hydrogen/a gas. The dark a href="http://antwrp.gsfc.nasa.gov/apod/ap030706.html"dust/a a href="http://antwrp.gsfc.nasa.gov/apod/ap010928.html"filaments/a that lace a href="http://antwrp.gsfc.nasa.gov/apod/ap970828.html"M20/a were created in the atmospheres of cool a href="http://www.astro.keele.ac.uk/workx/starlife/StarpageS_26M.html" giant stars/a and in the a href="http://antwrp.gsfc.nasa.gov/apod/ap990803.html"debris/a from a href="http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html" supernovae/a explosions. Which bright young stars light up the blue a href="http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html"reflection nebula/a is still a href="http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1986AJ.....92.1125L" being investigated/a. The light from a href="http://en.wikipedia.org/wiki/Trifid_Nebula"M20/a we see today left perhaps 3,000 years ago, although the exact distance remains unknown. Light takes about 50 years to cross a href="http://www.youtube.com/watch?v=aolbM62bfNA"M20/a. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090707.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Unknown Dark Material on Mercury

Astronomy Picture of the Day - Dll, 06/07/2009 - 13:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/darkmercury_messenger_big.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/darkmercury_messenger.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Unknown Dark Material on Mercury /b br b Credit: /b a href="http://messenger.jhuapl.edu/who_we_are/teams.html"MESSENGER/a, a href="http://www.nasa.gov/"NASA/a, a href="http://www.jhuapl.edu/"JHU APL/a, a href="http://www.ciw.edu/"CIW/a P p b Explanation: /b What is that strange material on Mercury? When a href="http://www.youtube.com/watch?v=hq4rA9vYKBw"flying by Mercury/a last October, the robotic a href="http://en.wikipedia.org/wiki/MESSENGER"MESSENGER spacecraft/a imaged much of the solar system's a href="http://en.wikipedia.org/wiki/Mercury_(planet)"innermost planet/a in unprecedented detail. As common in science, new data bring new mysteries. a href="http://photojournal.jpl.nasa.gov/catalog/PIA11389" Pictured above/a on the lower right, a large crater -- about 100 kilometers across -- has unusual dark material of unknown composition near its center. The material's darkness does not appear to be caused by a href="http://antwrp.gsfc.nasa.gov/apod/ap070610.html"shadow/as, as the Sun was near a href="http://en.wikipedia.org/wiki/Zenith"zenith/a when the image was taken. One origin hypothesis is that the a href="http://antwrp.gsfc.nasa.gov/apod/ap090118.html"dark material/a was uncovered from beneath Mercury's surface during the impact that created the surrounding crater. If so, the composition of the dark mound might be similar to the composition of some a href="http://photojournal.jpl.nasa.gov/catalog/PIA11357"mysterious/a a href="http://photojournal.jpl.nasa.gov/catalog/PIA11763"dark ring/as also recently discovered on Mercury. Alternatively, the dark material could be related to an unusual composition of the a href="http://antwrp.gsfc.nasa.gov/apod/ap090328.html"impacting rock/a. MESSENGER will a href="http://www.youtube.com/watch?v=7bESWV_oKqI" buzz past/a Mercury again later this year before entering orbit in 2011. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090706.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Genesis Mission's Hard Impact

Astronomy Picture of the Day - Dg, 05/07/2009 - 11:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/genesisimpact_nasa_big.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/genesisimpact_nasa.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Genesis Mission's Hard Impact /b br b Credit: /b a href="http://genesismission.jpl.nasa.gov/"Genesis Mission/a, a href="http://www.nasa.gov/"NASA/a P p b Explanation: /b A flying saucer from outer space crash-landed in the Utah desert in 2004 after being tracked by radar and chased by helicopters. No a href="http://www.daviddarling.info/encyclopedia/S/SFafter1940.html" space aliens/a were involved, however. The saucer, a href= "http://www.nasa.gov/mission_pages/genesis/multimedia/genesisrecov090804-2.html" pictured above/a, was the Genesis sample return capsule, part of a human-made robot a href="http://www.jpl.nasa.gov/news/features.cfm?feature=635" Genesis spaceship/a launched in 2001 by NASA itself to study the Sun. The unexpectedly a href="http://www.youtube.com/watch?v=U2H-UkMBZ68"hard landing/a at over 300 kilometers per hour occurred because the parachutes did not open as planned. The a href="http://en.wikipedia.org/wiki/Genesis_(spacecraft)" Genesis mission/a had been orbiting the a href="http://www.nineplanets.org/sol.html"Sun/a collecting a href="http://antwrp.gsfc.nasa.gov/apod/ap970217.html"solar wind/a particles that are usually deflected away by a href="http://csep10.phys.utk.edu/astr161/lect/earth/magnetic.html" Earth's magnetic field/a. Despite the crash landing, many return samples remained in good enough condition to analyze and research is a href="http://adsabs.harvard.edu/abs/2009LPI....40.1373B"ongoing/a. So far, discoveries include new details about the a href="http://genesismission.jpl.nasa.gov/gm2/news/features/closer.htm" composition/a of the a href="http://antwrp.gsfc.nasa.gov/apod/ap070624.html"Sun/a and the a href="http://adsabs.harvard.edu/abs/2009NIMPB.267.1101C" effects of the solar wind on unprotected material/a. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090705.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Mount Rushmore's Starry Night

Astronomy Picture of the Day - Ds, 04/07/2009 - 09:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/Rushmore-Pan-c03-850wp.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/Rushmore-Pan-c03-850wp.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Mount Rushmore's Starry Night/b br b Credit a href="http://antwrp.gsfc.nasa.gov/apod/lib/about_apod.html#srapply"Copyright/a: /b a href="http://www.astropics.com/"Wally Pacholka/a (a href= "http://www.twanight.org/"TWAN/a) P p b Explanation: /b This starry night sky sparkles above the Black Hills of South Dakota and the United States' a href="http://www.nps.gov/moru/"Mount Rushmore National Park/a. The historic site features enormous sculptures of a href="http://www.nps.gov/moru/historyculture/why-these-four.htm"four US presidents/a; George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln, carved into the southeast face of granite cliffs. Above the monumental symbols of the a href="http://memory.loc.gov/ammem/today/jul04.html"country's independence/a and early history, the night features stars and constellations familiar to northern a href="http://www.twanight.org/newTWAN/index.asp"skygazers around the world/a. Most noticeable are the stars of Ursa Major and the a href="http://homepage.mac.com/kvmagruder/bcp/aster/ general/asterism.htm"asterism/a known as the Big Dipper, almost resting upright along the cliff edge near picture center. a href="http://www.space.com/spacewatch/ arcturus_bootes_020510.html"Follow the arc/a of the Big Dipper's handle to get to iArc/iturus, the bright yellowish star in the lower left corner. Of course, a line extending a href="http://antwrp.gsfc.nasa.gov/apod/ap070108.html"through the dipper's/a two right most stars points to the upper right toward Polaris, planet Earth's North Star. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090704.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Perihelion and Aphelion

Astronomy Picture of the Day - Dv, 03/07/2009 - 07:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/PerihelionAphelion_cervignon.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/PerihelionAphelion_cervignon800.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Perihelion and Aphelion /b br b Credit a href="http://antwrp.gsfc.nasa.gov/apod/lib/about_apod.html#srapply"Copyright/a: /b a href="http://www.ascensionrecta.com/"Enrique Luque Cervigoacute;n/a P p b Explanation: /b This year Aphelion, the point in Earth's a href="http://www.windows.ucar.edu/tour/link=/physical_science/ physics/mechanics/orbit/ellipse.htmledu=high"elliptical orbit/a when it is farthest from the Sun, occurs tomorrow, July 4th. Of course, that doesn't a href="http://csep10.phys.utk.edu/astr161/lect/time/ seasons.html"affect the seasons/a on a href="http://eol.jsc.nasa.gov/"our fair planet/a. Those are determined by the tilt of Earth's axis of rotation and not Earth's distance from the Sun, so July is still winter in the south and summer in northern hemisphere. But it does mean that on July 4th the Sun will be at its smallest apparent size. This composite neatly compares two pictures of the Sun taken with the same telescope and camera a href="http://aa.usno.navy.mil/data/docs/EarthSeasons.php"on the dates of/a Perihelion (closest approach) and Aphelion in 2008. The image labels include Earth's distance in kilometers from the Sun on the two dates. Otherwise difficult a href="http://www.sungazer.net/"to notice/a, the change in the Sun's apparent diameter between a href="http://www.windows.ucar.edu/tour/link=/physical_science/ physics/mechanics/orbit/perihelion_aphelion.htmledu=high"Perihelion and Aphelion/a is clear. The difference amounts to a little over 3 percent. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090703.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Lyman Alpha Blob

Astronomy Picture of the Day - Dj, 02/07/2009 - 18:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/labs2048_multiCXC.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/labs900_multiCXC.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Lyman Alpha Blob /b br b Credit: /b a href="http://www.nasa.gov/"NASA/a / a href="http://www.esa.int/esaCP/index.html"ESA/a, CXC, JPL-Caltech, STScI, a href="http://www.nao.ac.jp/E/index.html"NAOJ/a, J.E. Geach (Univ. Durham) a href="http://arxiv.org/abs/0904.0452"et al./a br b Illustration: /b a href="http://chandra.harvard.edu/photo/2009/labs/"NASA/CXC/M.Weiss/a P p b Explanation: /b Dubbed a Lyman-alpha blob, an enormous cloud of hydrogen gas spans several hundred thousand light-years in a href="http://chandra.harvard.edu/photo/2009/labs/"this remarkable image/a (left), a composite of a href="http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ multiwavelength_astronomy/multiwavelength_astronomy/"x-ray, optical, and infrared/a data from space and ground based observatories. The gigantic, amoeba-like structure is seen as it was when a href="http://antwrp.gsfc.nasa.gov/apod/ap060323.html"the universe was/a a a href="http://www.astro.ucla.edu/~wright/CosmoCalc.html"mere/a 2 billion years old (about 12 billion a href="http://map.gsfc.nasa.gov/universe/uni_age.html"years ago/a). Lyman-alpha blobs are so called because they strongly emit radiation due to the a href="http://en.wikipedia.org/wiki/Lyman_series"Lyman-alpha emission/a line of hydrogen gas. Normally, Lyman-alpha emission is in the ultraviolet part of the spectrum, but Lyman-apha blobs are so distant, their light is redshifted to (longer) optical a href="http://hyperphysics.phy-astr.gsu.edu/hbase/ ems1.html"wavelengths/a. X-ray data (blue) a href="http://arxiv.org/abs/0904.0452"indicates/a the presence of a a href="http://chandra.harvard.edu/xray_sources/ blackholes_sm.html"supermassive black hole/a feeding at the center of an active galaxy embedded in the blob. Illustrated close up in the right hand panel, radiation and outflows from the active galaxy are thought to be a source for energizing and heating the blob's hydrogen gas. In fact, Lyman-alpha blobs could represent an early phase in galaxy formation where the heating is so great it begins to limit further rapid growth of a href="http://chandra.harvard.edu/xray_sources/quasars.html"active galaxies/a and their supermassive black holes. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090702.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Three Galaxies in Draco

Astronomy Picture of the Day - Dc, 01/07/2009 - 16:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0907/NGC5982_benintende_h.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0907/NGC5982_benintende.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Three Galaxies in Draco /b br b Credit a href="http://antwrp.gsfc.nasa.gov/apod/lib/about_apod.html#srapply"Copyright/a: /b a href="http://www.astrogb.com/"Giovanni Benintende/a P p b Explanation: /b This intriguing trio of galaxies is sometimes called the Draco Group, located in the northern constellation of (you guessed it) a href="http://www.hawastsoc.org/deepsky/dra/index.html"Draco/a. From left to right are a href="http://antwrp.gsfc.nasa.gov/apod/ap010510.html"edge-on spiral/a NGC 5981, a href="http://antwrp.gsfc.nasa.gov/apod/ap060520.html"elliptical galaxy/a NGC 5982, and a href="http://antwrp.gsfc.nasa.gov/apod/ap040410.html"face-on spiral/a NGC 5985 -- all within this single telescopic field of view spanning a little more than half the width of the full moon. While the group is far too small to be a a href="http://www.seds.org/messier/gal_clus.html"galaxy cluster/a and has not been a href="http://www.astro.ubc.ca/people/hickson/hcg/"cataloged/a compact group, these galaxies all do lie roughly 100 million light-years from planet Earth. On close examination with a href="http://imagine.gsfc.nasa.gov/docs/ science/how_l1/spectral.html"spectrographs/a, the bright core of the striking face-on spiral NGC 5985 shows prominent emission in specific wavelengths of light, prompting astronomers to classify it as a a href="http://www.seds.org/~spider/spider/ScholarX/ seyferts.html"Seyfert/a, a type of active galaxy. Not as well known as other tight a href="http://antwrp.gsfc.nasa.gov/apod/ap090313.html"groupings of galaxies/a, the contrast in visual appearance makes this triplet an attractive subject for astrophotographers. This a href="http://www.astrogb.com/ngc5982.htm"impressively deep exposure/a of the region also reveals faint and even more distant a href="http://www.noao.edu/outreach/aop/observers/ bggalaxies.html"background galaxies/a. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090701.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

The North America and Pelican Nebulae

Astronomy Picture of the Day - Dm, 30/06/2009 - 14:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0906/northpelican_russell_big.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0906/northpelican_russell.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b The North America and Pelican Nebulae /b br b Credit Copyright: /b a href="mailto: stargazzzer at prodigy dot net"Danny Lee Russell/a P p b Explanation: /b Here are some familiar shapes in unfamiliar locations. This a href="http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html"emission nebula/a on the left is famous partly because it resembles Earth's continent of a href="http://en.wikipedia.org/wiki/North_America"North America/a. To the right of the a href="http://en.wikipedia.org/wiki/North_America_Nebula" North America Nebula/a, cataloged as NGC 7000, is a less luminous nebula that resembles a a href="http://en.wikipedia.org/wiki/Pelican"pelican/a dubbed the a href="http://antwrp.gsfc.nasa.gov/apod/ap020829.html"Pelican Nebula/a. The two emission a href="http://en.wikipedia.org/wiki/Nebula"nebula/a measure about 50 light-years across, are located about 1,500 a href= "http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html" light-years/a away, and are separated by a a href="http://antwrp.gsfc.nasa.gov/apod/dark_nebulae.html"dark absorption/a cloud. This spectacular image captures the nebulas, bright a href="http://antwrp.gsfc.nasa.gov/apod/ap000703.html"ionization fronts/a, and fine details of the dark dust. The a href="http://www.youtube.com/watch?v=LtKUuAM3zDY"nebulae can be seen/a with binoculars from a dark location. Look for a a href="http://antwrp.gsfc.nasa.gov/apod/ap971009.html"small nebular patch/a north-east of bright star a href="http://www.astro.wisc.edu/~dolan/constellations/hr/7924.html" Deneb/a in the constellation of a href="http://www.astro.wisc.edu/~dolan/constellations/constellations/Cygnus.html" Cygnus/a. It is still unknown which star or stars ionize the red-glowing a href="http://periodic.lanl.gov/elements/1.html" hydrogen/a gas. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090630.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Kaguya Spacecraft Crashes into the Moon

Astronomy Picture of the Day - Dm, 30/06/2009 - 01:10
object width="741" height="600"param name="movie" value="http://www.youtube.com/v/AxDNWXZpC3g"/paramparam name="allowFullScreen" value="true"/paramparam name="allowscriptaccess" value="always"/paramembed src="http://www.youtube.com/v/AxDNWXZpC3g" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="741" height="600"/embed/object P P b Kaguya Spacecraft Crashes into the Moon /b br b Credit a href="http://jda.jaxa.jp/jda/service_e.html"Copyright/a: /b a href="http://www.selene.jaxa.jp/en/members/members_e.htm"SELENE Team/a, a href="http://www.jaxa.jp/"JAXA/a, a href="http://www.nhk.or.jp/english/"NHK/a P p b Explanation: /b Japan's Kaguya spacecraft crashed into the Moon last week, as planned. Officially named the a href="http://en.wikipedia.org/wiki/Selenology"Selenological/a and Engineering Explorer (SELENE)/a, the spacecraft was given the nickname Kaguya after the princess in the Japanese folklore story a href="http://en.wikipedia.org/wiki/Tale_of_the_Bamboo_Cutter" The Tale of the Bamboo Cutter/a. a href="http://www.jaxa.jp/press/2009/06/20090619_kaguya_hdtv_e.html" Pictured above/a is a movie taken by Kaguya during the last orbit of its twenty-month lunar mission. A a href="http://antwrp.gsfc.nasa.gov/apod/ap031109.html"desolate/a, hilly, and cratered terrain passes underneath as the spacecraft barely clears a few peaks. At a href="http://www.jaxa.jp/press/2009/06/20090619_kaguya_hdtv_e.html" the movie/a's end, the spacecraft disappears into darkness a href="http://www.jaxa.jp/press/2009/06/20090611_kaguya_e.html" near Gill crater/a. Robotic a href="http://www.jaxa.jp/projects/sat/selene/index_e.html" SELENE/a carried thirteen scientific instruments and two a href="http://en.wikipedia.org/wiki/HDTV"HDTV/a cameras. The a href="http://en.wikipedia.org/wiki/Pun"groundbreaking/a mission took data on lunar topology and composition that are being used to better understand the origin and history of Earth's a href="http://en.wikipedia.org/wiki/Moon"unique and ancient companion/a. Data and images from a href="http://en.wikipedia.org/wiki/SELENE"Kaguya/a and the recently launched a href="http://lro.gsfc.nasa.gov/"Lunar Reconnaissance Orbiter/a could be used to choose good locations to land future a href="http://antwrp.gsfc.nasa.gov/apod/ap051217.html"Moon-exploring astronauts/a. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090629.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script

Fresh Tiger Stripes on Saturn's Enceladus

Astronomy Picture of the Day - Dg, 28/06/2009 - 23:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0906/enceladusstripes_cassini_big.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0906/enceladusstripes_cassini.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Fresh Tiger Stripes on Saturn's Enceladus /b br b Credit: /b a href="http://ciclops.org/"Cassini Imaging Team/a, a href="http://www.spacescience.org/"SSI/a, a href="http://www.jpl.nasa.gov/"JPL/a, a href="http://www.esa.int/"ESA/a, a href="http://www.nasa.gov/"NASA/a P p b Explanation: /b Do underground oceans vent through the tiger stripes on Saturn's moon Enceladus? Long features dubbed tiger stripes are known to be a href="http://antwrp.gsfc.nasa.gov/apod/ap071013.html"spewing ice/a from the moon's icy interior into space, creating a cloud of fine ice particles over the moon's South Pole and creating Saturn's mysterious a href= "http://antwrp.gsfc.nasa.gov/apod/ap070327.html"E-ring/a. Evidence for this has come from the a href="http://saturn.jpl.nasa.gov/mission/presentposition/" robot Cassini spacecraft/a now orbiting a href="http://en.wikipedia.org/wiki/Saturn"Saturn/a. a href="http://photojournal.jpl.nasa.gov/catalog/PIA06254"Pictured above/a, a high resolution image of Enceladus is shown from a close flyby. The unusual surface features dubbed a href="http://en.wikipedia.org/wiki/Tiger" tiger/a stripes are visible in false-color blue. Why a href="http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?enceladus" Enceladus/a is active remains a mystery, as the neighboring moon a href="http://antwrp.gsfc.nasa.gov/apod/ap090517.html"Mimas/a, approximately the same size, appears a href="http://www.davidpbrown.co.uk/jokes/monty-python-parrot.html" quite dead/a. Most recently, an a href="http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20090624/" analysis of dust/a captured by a href="http://www.youtube.com/watch?v=0BzXC4qfV44" Cassini found evidence/a for sodium as expected in a deep salty ocean. Conversely however, recent Earth-based observations of ice ejected by Enceladus into Saturn's E-Ring showed no a href="http://www.universetoday.com/2009/06/24/does-enceladus-harbor-a-liquid-ocean-reasonable-minds-disagree/"evidence/a of the expected a href="http://en.wikipedia.org/wiki/Sodium"sodium/a. Such research is particularly interesting since such an ocean would be a candidate to a href="http://www1.nasa.gov/mission_pages/cassini/media/enceladus-f20080326.html"contain life/a. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090628.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

Saharan Starry Night

Astronomy Picture of the Day - Ds, 27/06/2009 - 21:10
DIV ALIGN=CENTERa href="http://antwrp.gsfc.nasa.gov/apod/image/0906/Tassili-Lines_tafreshi.jpg" IMG SRC="http://antwrp.gsfc.nasa.gov/apod/image/0906/Tassili-Lines_tafreshi.jpg" alt="See Explanation. Clicking on the picture will download the highest resolution version available."/a /DIV DIV STYLE="max-width:40em"P P b Saharan Starry Night /b br b Credit a href="http://antwrp.gsfc.nasa.gov/apod/lib/about_apod.html#srapply"Copyright/a: /b a href="http://www.twanight.org/newtwan/ photographers_about.asp?photographer=Babak%20A.%20Tafreshi"Babak Tafreshi/a (a href="http://www.twanight.org/"TWAN/a) P p b Explanation: /b This panoramic image of a starry night looks across a dry, desolate landscape. a href="http://antwrp.gsfc.nasa.gov/apod/image/0906/Tassili_tafreshi.jpg"The magnificent view/a was recorded from a href="http://whc.unesco.org/en/list/179"Tassili National Park/a, in the heart of the Sahara desert in southern Algeria. Rising above a href="http://www.dreamview.net/dv/new/ photos.asp?id=101903cat=Nature"eroded sandstone cliffs/a, the celestial menagerie of constellations includes a href="http://www.windows.ucar.edu/tour/link=/mythology/ draco_dragon.htmledu=high"Draco/a the Dragon, a href="http://www.windows.ucar.edu/tour/link=/mythology/ cygnus.htmledu=high"Cygnus/a the Swan, a href="http://www.windows.ucar.edu/tour/link=/the_universe/ Constellations/summer/aquila.htmledu=high"Aquila/a the Eagle, and a href="http://www.windows.ucar.edu/tour/link=/mythology/ scorpius.html"Scorpius/a the Scorpion. Ruling planet Jupiter shines through clouds very close to the horizon near picture center, while star clouds of the Milky Way arc a href="http://antwrp.gsfc.nasa.gov/apod/ap070711.html"through Sagittarius/a above the rocks at the far right. Bright blue stars a href="http://antwrp.gsfc.nasa.gov/apod/ap070920.html"Deneb/a, in Cygnus, and a href="http://www.astro.illinois.edu/~jkaler/sow/altair.html"Altair/a, in Aquila, also shine in the starry night along with Scorpius' bright yellowish star a href="http://antwrp.gsfc.nasa.gov/apod/ap080603.html"Antares/a, the rival of Mars. Prehistoric skygazers surely witnessed a similar sky. In addition to dramatic sandstone formations, a href="http://en.wikipedia.org/wiki/Tassili_n%27Ajjer"the Tassili region/a is noted for a href="http://www.metmuseum.org/toah/hd/tass/hd_tass.htm"rock art/a and archaeological sites dating to a href="http://en.wikipedia.org/wiki/Neolithic"Neolithic times/a when the local climate was wetter. p P script type="text/javascript" digg_url = 'http://apod.nasa.gov/apod/ap090627.html'; digg_skin = 'compact'; /script script src="http://digg.com/tools/diggthis.js" type="text/javascript"/script /DIV

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