by owlice » Sun Jan 08, 2012 10:46 am
________________________________________________________________
This is it! You've looked at APOD all year, voted in 64 APOW and APOM polls, and now, it's time to select the Astronomy Picture of the Year for 2011!
Please vote for the
THREE best APODs (image and text); there are 15 APODs in this poll selected from the winners of the APOM polls, plus three. All titles are clickable and link to the original APOD page.
Thank you!
________________________________________________________________
<< APOY 2010
What's happened to the Sun? Sometimes it looks like the Sun is being viewed through a large
lens. In the above case, however, there are actually millions of lenses:
ice crystals. As water freezes in the upper
atmosphere, small, flat, six-sided, ice crystals might be formed. As these
crystals flutter to the ground, much time is spent with their faces flat, parallel to the ground. An
observer may pass through the same plane as many of the falling ice crystals near sunrise or sunset. During this alignment, each crystal can act like a miniature lens, refracting sunlight into our
view and creating
phenomena like parhelia, the technical term for
sundogs. The above image was taken last year in
Stockholm,
Sweden. Visible in the image center is the Sun, while two bright
sundogs glow prominently from both the left and the right.
Also visible is the bright
22 degree halo -- as well as the rarer and much fainter
46 degree halo -- also created by
sunlight reflecting off of atmospheric ice
crystals.
Sometimes a morning sky can be a combination of serene and surreal. Such a sky perhaps existed before sunrise this past Sunday as
viewed from a snowy slope in eastern
Switzerland. Quiet clouds blanket the above scene, lit from beneath by lights from the village of
Trübbach. A snow covered mountain,
Mittlerspitz, poses dramatically on the upper left, hovering over the small town of
Balzers,
Liechtenstein far below.
Peaks from the
Alps can be seen across the far right, just below the freshly
rising Sun. Visible on the upper right are the
crescent Moon and the bright planet
Venus. Venus will remain in the
morning sky all month, although it will likely not be found in such a photogenic setting.
Credit & Copyright: Terje Sørgjerd; Music: Gladiator Soundtrack: Now we are Free
Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case earlier this month when one of the
largest auroral displays in recent years appeared over northern locations like the border between Norway and Russia. Pictured in the
above time-lapse movie, auroras flow over snow covered landscapes, trees, clouds, mountains and lakes found near
Kirkenes,
Norway. Many times the auroras are green, as high energy particles strike the
Earth's atmosphere, causing the air to glow as electrons recombine with their
oxygen hosts. Other
colors are occasionally noticeable as atmospheric nitrogen also becomes affected. In later sequences the Moon and rising stars are also visible. With the
Sun expected to become ever more active over the next few years, there may be many
opportunities to see similarly
spectacular auroras personally, even from areas much
closer to the equator.
The
spiky stars in the foreground of
this sharp cosmic portrait are well within our own
Milky Way Galaxy. The two eye-catching galaxies lie far
beyond the Milky Way, at a distance of over 300 million light-years. Their distorted appearance is due to gravitational tides as the pair engage
in close encounters. Cataloged
as Arp 273 (also as UGC 1810), the galaxies do look
peculiar, but interacting galaxies are now understood to be common in the universe. In fact, the nearby large spiral Andromeda Galaxy is known to be some 2 million light-years away and approaching the Milky Way. Arp 273 may offer an analog of their
far future encounter. Repeated galaxy encounters on a
cosmic timescale can ultimately result in a merger into a single galaxy of stars. From our perspective, the bright cores of the Arp 273 galaxies are separated by only a little over 100,000 light-years. The release of this
stunning vista celebrates the 21st anniversary of the Hubble Space Telescope in orbit.
Credit & Copyright: Daniel López, IAC; Music: Matti Paalanen, Angel's Tear (Aeon 2)
If you could sit back and watch clouds and the sky move all night and day, what might you see? One answer from the island of
Tenerife, captured over the
course of the year, includes sequences that are not only breathtaking but instructive. Visible in the
above time-lapse movie include clouds that seem to flow like water, a setting sun that shows numerous
green flashes, the Milky Way Galaxy rising behind towering plants, a colorful double
fogbow,
lenticular clouds that appear stationary near their mountain peaks, and colorful
moon coronas. The
above video was shot solely from the
Teide National Park on
Tenerife in the
Canary Islands of
Spain, off the north west coast of
Africa. The video also features an unusual type of plant in several scenes --
can you identify it?
Thunderstorms almost spoiled this view of the spectacular June 15 total lunar eclipse. Instead, storm clouds parted for 10 minutes during the
total eclipse phase and
lightning bolts contributed to this dramatic skyview. Captured with a 30 second exposure, the scene also inspired what the editor considers may be the best title yet for a picture during the 16 year
history of Astronomy Picture of the Day. (Title credit to Chris K.) Of course, the lightning reference clearly makes sense, and the
shadow play of the dark lunar eclipse was
widely viewed across planet Earth in Europe, Africa, Asia, and Australia.
The picture itself, however. was shot from the Greek Ikaria island at Pezi. That area is known as "the planet of the goats" because of the rough terrain and strange looking rocks.
NGC 3314 is actually two large
spiral galaxies which just happen to almost exactly line up. The foreground spiral is viewed nearly
face-on, its pinwheel shape defined by young bright star clusters. But against the glow of the background galaxy, dark swirling lanes of
interstellar dust appear to dominate the face-on spiral's structure. The
dust lanes are surprisingly pervasive, and this remarkable
pair of overlapping galaxies is one of a small number of systems in which absorption of light from beyond a galaxy's own stars can be used to directly
explore its distribution of dust.
NGC 3314 is about 140 million light-years (background galaxy) and 117 million light-years (foreground galaxy) away in the multi-headed
constellation Hydra. The background galaxy would span nearly 70,000 light-years at its estimated distance. A synthetic third channel was created to construct this dramatic
new composite of the overlapping galaxies from two color image data in the Hubble Legacy Archive.
A quest to find planet Earth's darkest night skies led to this intriguing panorama. In projection, the mosaic view sandwiches the horizons visible in
all-sky images taken from the northern hemisphere's Canary Island of La Palma (top) and the south's high Atacama Desert between the two hemispheres of the Milky Way Galaxy. The photographers' choice of locations offered locally dark skies enjoyed by La Palma's
Roque de los Muchachos Observatory and
Paranal Observatory in Chile. But it also allowed the directions to
the Milky Way's north and south galactic poles to be placed near the local zenith. That constrained the faint, diffuse glow of the plane of the
Milky Way to the mountainous horizons. As a result, an even fainter S-shaped band of light, sunlight
scattered by dust along the solar system's
ecliptic plane, can be completely traced through both northern and southern hemisphere night skies.
Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact
groups of galaxies, now appropriately called
Hickson Compact Groups. The four prominent galaxies seen in this intriguing
telescopic skyscape are one such group, Hickson 44, about 100 million light-years distant toward the constellation Leo. The two spiral galaxies in the center of the image are edge-on NGC 3190 with its distinctive, warped dust lanes, and S-shaped NGC 3187. Along with the bright elliptical, NGC 3193 at the right, they are also known as Arp 316. The spiral in the upper left corner is NGC 3185, the 4th member of the Hickson group. Like other galaxies in Hickson groups, these show signs of distortion and
enhanced star formation, evidence of a gravitational tug of war that will eventually result in
galaxy mergers on a cosmic timescale. The merger process is now understood to be a normal part of the evolution of galaxies, including
our own Milky Way. For scale,
NGC 3190 is about 75,000 light-years across at the estimated distance of Hickson 44.
Gorgeous spiral galaxy
NGC 3521 is a mere 35 million light-years away, toward the
constellation Leo. Relatively bright in planet Earth's sky, NGC 3521 is easily visible in small telescopes but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like
M66 and M65. It's hard to overlook in
this colorful cosmic portrait, though. Spanning some 50,000 light-years the galaxy sports
characteristic patchy, irregular spiral arms laced with dust, pink star forming regions, and clusters of young, blue stars. Remarkably, this deep image also finds NGC 3521 embedded in gigantic bubble-like shells. The shells are likely tidal debris, streams of stars torn from satellite galaxies that have
undergone mergers with NGC 3521 in the distant past.
From Sagittarius to Carina, the Milky Way Galaxy shines in this dark night sky above planet Earth's lush island paradise of Mangaia. Familiar to denizens of the southern hemisphere, the gorgeous skyscape includes the bulging galactic center at the upper left and bright stars Alpha and Beta Centauri just right of center. About 10 kilometers wide, volcanic Mangaia is the southernmost of the Cook Islands. Geologists estimate that at 18 million years old it is the oldest island in the Pacific Ocean. Of course, the Milky Way is somewhat older, with the galaxy's oldest stars estimated to be over 13 billion years old.
(Editor's note: This image holds the distinction of being selected as winner in the Royal Observatory, Greenwich, Astronomy Photographer of the Year competition in the Earth and Space category.)
It's the bubble versus the cloud. NGC 7635, the
Bubble Nebula, is being pushed out by the
stellar wind of massive central star
BD+602522. Next door, though, lives a giant
molecular cloud, visible to the right. At this place in space, an
irresistible force meets an
immovable object in an interesting way. The
cloud is able to contain the expansion of the bubble gas, but gets blasted by the hot radiation from the
bubble's central star. The
radiation heats up dense regions of the
molecular cloud causing it to glow. The
Bubble Nebula,
pictured above in scientifically mapped colors to bring up contrast, is about 10
light-years across and part of a much
larger complex of stars and shells. The
Bubble Nebula can be seen with a small telescope towards the
constellation of the Queen of
Aethiopia (
Cassiopeia).
A fourth moon is visible on the
above image if you look hard enough. First -- and furthest in the background -- is
Titan, the largest moon of Saturn and one of the larger moons in the Solar System. The dark feature across the top of this perpetually cloudy world is the
north polar hood. The next most obvious moon is bright
Dione, visible in the foreground, complete with craters and long
ice cliffs. Jutting in from the left are several of Saturn's
expansive rings, including Saturn's A ring featuring the dark
Encke Gap. On the far right, just outside the rings, is
Pandora, a moon only 80-kilometers across that
helps shepherd Saturn's F ring. The fourth moon? If you look closely in the Encke Gap you'll find a speck that is actually
Pan. Although one of Saturn's smallest moons at 35-kilometers across, Pan is massive enough to help keep the
Encke gap relatively free of ring particles.
Each day can have a beautiful ending as the
Sun sets below the western horizon. This week, the setting Sun added naked-eye sunspots to its finale, as enormous active regions
rotated across the dimmed, reddened solar disc. Near the Sun's center in this closing telephoto view from November 7th are sunspots in
Active Region 1339. Responsible for a powerful
X-class flare on November 3rd, Active Region 1339 is larger than Jupiter. In the foreground, the ruined tower of a medieval castle stands in
dramatic silhouette. Located in Igersheim, Germany and traditionally known as
castle Neuhaus, it might be
named Sunspot Castle for this well-composed scene.
What's large and blue and can wrap itself around an entire galaxy? A
gravitational lens mirage.
Pictured above, the gravity of a luminous red galaxy (
LRG) has
gravitationally distorted the light from a much more distant blue galaxy. More typically, such light bending results in
two discernible images of the distant galaxy, but here the
lens alignment is so precise that the background galaxy is distorted into a horseshoe -- a nearly complete ring. Since such a
lensing effect was generally predicted in some detail by
Albert Einstein over
70 years ago, rings
like this are now known as
Einstein Rings. Although LRG 3-757 was discovered in 2007 in data from the
Sloan Digital Sky Survey (SDSS), the image shown above is a follow-up observation taken with the
Hubble Space Telescope's
Wide Field Camera 3. Strong gravitational lenses like LRG 3-757 are more than oddities -- their multiple properties allow astronomers to determine the mass and
dark matter content of the foreground galaxy lenses.
<< APOY 2010
[size=200][color=#FF0000]________________________________________________________________[/color][/size]
This is it! You've looked at APOD all year, voted in 64 APOW and APOM polls, and now, it's time to select the Astronomy Picture of the Year for 2011!
Please vote for the [b]THREE[/b] best APODs (image and text); there are 15 APODs in this poll selected from the winners of the APOM polls, plus three. All titles are clickable and link to the original APOD page.
Thank you!
[size=200][color=#FF0000]________________________________________________________________[/color][/size]
[url=http://asterisk.apod.com/viewtopic.php?f=29&t=22695][b]<< APOY 2010[/b][/url]
[hr][/hr]
[c][url=http://apod.nasa.gov/apod/ap110110.html][size=150][b]A Sun Halo Beyond Stockholm (2011 Jan 10)[/b][/size][/url][/c]
[float=left][img6="Credit & Copyright: Peter Rosén"]http://apod.nasa.gov/apod/image/1101/sunhalo_rosen.jpg[/img6][hr][/hr][/float] What's happened to the Sun? Sometimes it looks like the Sun is being viewed through a large [url=http://www.opticalres.com/optics_for_kids/kidoptx_p2.html]lens[/url]. In the above case, however, there are actually millions of lenses: [url=http://www.its.caltech.edu/~atomic/snowcrystals/halos/halos.htm]ice crystals[/url]. As water freezes in the upper [url=http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.html]atmosphere[/url], small, flat, six-sided, ice crystals might be formed. As these [url=http://en.wikipedia.org/wiki/Ice_crystal]crystals[/url] flutter to the ground, much time is spent with their faces flat, parallel to the ground. An [url=http://www.youtube.com/watch?v=RLYg5jptvCc]observe[/url]r may pass through the same plane as many of the falling ice crystals near sunrise or sunset. During this alignment, each crystal can act like a miniature lens, refracting sunlight into our [url=http://apod.nasa.gov/apod/ap100208.html]view[/url] and creating [url=http://www.atoptics.co.uk/halo/parhelia.htm]phenomena like parhelia[/url], the technical term for [url=http://apod.nasa.gov/apod/ap990823.html]sundogs[/url]. The above image was taken last year in [url=http://en.wikipedia.org/wiki/Stockholm]Stockholm[/url], [url=http://en.wikipedia.org/wiki/Sweden]Sweden[/url]. Visible in the image center is the Sun, while two bright [url=http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/opt/ice/sd.rxml]sundogs[/url] glow prominently from both the left and the right. [url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/halo.html]Also visible[/url] is the bright [url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/halo22.html]22 degree halo[/url] -- as well as the rarer and much fainter [url=http://www.atoptics.co.uk/halo/46hal.htm]46 degree halo[/url] -- also created by [url=http://www.atoptics.co.uk/halo/circular.htm]sunlight reflecting[/url] off of atmospheric ice [url=http://apod.nasa.gov/apod/ap080618.html]crystals[/url].
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[c][url=http://apod.nasa.gov/apod/ap110202.html][size=150][b]Moon and Venus Over Switzerland (2011 Feb 02)[/b][/size][/url][/c]
[float=left][img6="Credit & Copyright: David Kaplan"]http://apod.nasa.gov/apod/image/1102/moonvenus_kaplan_900.jpg[/img6][hr][/hr][/float] Sometimes a morning sky can be a combination of serene and surreal. Such a sky perhaps existed before sunrise this past Sunday as [url=http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=47%C2%B004%2756.30%22+N+9%C2%B026%2753.21%22+E&sll=37.0625,-95.677068&sspn=36.642161,66.445312&ie=UTF8&ll=47.076727,9.438457&spn=0.030804,0.064888&t=h&z=14]viewed from[/url] a snowy slope in eastern [url=http://en.wikipedia.org/wiki/Switzerland]Switzerland[/url]. Quiet clouds blanket the above scene, lit from beneath by lights from the village of [url=http://en.wikipedia.org/wiki/Tr%C3%Bcbbach]Trübbach[/url]. A snow covered mountain, [url=http://en.wikipedia.org/wiki/Mittlerspitz]Mittlerspitz[/url], poses dramatically on the upper left, hovering over the small town of [url=http://en.wikipedia.org/wiki/Balzers]Balzers[/url], [url=http://en.wikipedia.org/wiki/Liechtenstein]Liechtenstein[/url] far below. [url=http://www.youtube.com/watch?v=pTR93Hf9gjI]Peaks[/url] from the [url=http://en.wikipedia.org/wiki/Alps]Alps[/url] can be seen across the far right, just below the freshly [url=http://apod.nasa.gov/apod/ap091223.html]rising Sun[/url]. Visible on the upper right are the [url=http://apod.nasa.gov/apod/ap070320.html]crescent Moon[/url] and the bright planet [url=http://apod.nasa.gov/apod/ap101020.html]Venus[/url]. Venus will remain in the [url=http://www.skyandtelescope.com/observing/ataglance/]morning sky[/url] all month, although it will likely not be found in such a photogenic setting.
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[c][url=http://apod.nasa.gov/apod/ap110328.html][size=150][b]Time-Lapse Auroras Over Norway (2011 Mar 28)[/b][/size][/url][/c]
[float=left][vimeo6]http://vimeo.com/21294655[/vimeo6][c][size=80]Credit & Copyright: Terje Sørgjerd; Music: Gladiator Soundtrack: Now we are Free[/size][/c][hr][/hr][/float]Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case earlier this month when one of the [url=http://spaceweather.com/aurora/gallery_01mar11.htm]largest auroral displays[/url] in recent years appeared over northern locations like the border between Norway and Russia. Pictured in the [url=http://vimeo.com/21294655]above time-lapse movie[/url], auroras flow over snow covered landscapes, trees, clouds, mountains and lakes found near [url=http://en.wikipedia.org/wiki/Kirkenes]Kirkenes[/url], [url=http://en.wikipedia.org/wiki/Norway]Norway[/url]. Many times the auroras are green, as high energy particles strike the [url=http://www.nasa.gov/audience/forstudents/9-12/features/912_liftoff_atm.html]Earth's atmosphere[/url], causing the air to glow as electrons recombine with their [url=http://periodic.lanl.gov/8.shtml]oxygen[/url] hosts. Other [url=http://en.wikipedia.org/wiki/Aurora_%28astronomy%29#Auroral_mechanism]colors[/url] are occasionally noticeable as atmospheric nitrogen also becomes affected. In later sequences the Moon and rising stars are also visible. With the [url=http://apod.nasa.gov/apod/ap071203.html]Sun[/url] expected to become ever more active over the next few years, there may be many [url=http://www.swapmeetdave.com/Humor/Cats/Curious.jpg]opportunities to see[/url] similarly [url=http://apod.nasa.gov/apod/ap101124.html]spectacular auroras[/url] personally, even from areas much [url=http://apod.nasa.gov/apod/ap031113.html]closer to the equator[/url].
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[c][url=http://apod.nasa.gov/apod/ap110421.html][size=150][b]Peculiar Galaxies of Arp 273 (2011 Apr 21)[/b][/size][/url][/c]
[float=left][img6="Credit: NASA, ESA, and the Hubble Heritage Team (STScI / AURA)"]http://apod.nasa.gov/apod/image/1104/arp273_hst900.jpg[/img6][hr][/hr][/float]The [url=http://spider.ipac.caltech.edu/staff/kaspar/obs_mishaps/images/int_reflection2.html]spiky[/url] stars in the foreground of [url=http://heritage.stsci.edu/2011/11/index.html]this sharp cosmic portrait[/url] are well within our own [url=http://www.atlasoftheuniverse.com/galaxy.html]Milky Way Galaxy[/url]. The two eye-catching galaxies lie far [url=http://apod.nasa.gov/apod/ap070712.html]beyond the Milky Way[/url], at a distance of over 300 million light-years. Their distorted appearance is due to gravitational tides as the pair engage [url=http://burro.cwru.edu/JavaLab/GalCrashWeb/backgrnd.html]in close encounters[/url]. Cataloged [url=http://www.noao.edu/image_gallery/html/im0011.html]as Arp 273[/url] (also as UGC 1810), the galaxies do look [url=http://nedwww.ipac.caltech.edu/level5/Arp/frames.html]peculiar[/url], but interacting galaxies are now understood to be common in the universe. In fact, the nearby large spiral Andromeda Galaxy is known to be some 2 million light-years away and approaching the Milky Way. Arp 273 may offer an analog of their [url=http://hubblesite.org/newscenter/archive/releases/galaxy/2002/09/]far future encounter[/url]. Repeated galaxy encounters on a [url=http://apod.nasa.gov/apod/ap060323.html]cosmic timescale[/url] can ultimately result in a merger into a single galaxy of stars. From our perspective, the bright cores of the Arp 273 galaxies are separated by only a little over 100,000 light-years. The release of this [url=http://hubblesite.org/newscenter/archive/releases/2011/11/]stunning vista celebrates[/url] the 21st anniversary of the Hubble Space Telescope in orbit.
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[c][url=http://apod.nasa.gov/apod/ap110516.html][size=150][b]Time Lapse Clouds and Sky Over the Canary Islands (2011 May 16)[/b][/size][/url][/c]
[float=left][vimeo6]http://vimeo.com/23205323[/vimeo6][c][size=80]Credit & Copyright: Daniel López, IAC; Music: Matti Paalanen, Angel's Tear (Aeon 2)[/size][/c][hr][/hr][/float]If you could sit back and watch clouds and the sky move all night and day, what might you see? One answer from the island of [url=http://en.wikipedia.org/wiki/Tenerife]Tenerife[/url], captured over the [url=http://www.elcielodecanarias.com/]course[/url] of the year, includes sequences that are not only breathtaking but instructive. Visible in the [url=http://vimeo.com/23205323]above time-lapse movie[/url] include clouds that seem to flow like water, a setting sun that shows numerous [url=http://apod.nasa.gov/apod/ap110104.html]green flash[/url]es, the Milky Way Galaxy rising behind towering plants, a colorful double [url=http://apod.nasa.gov/apod/ap100504.html]fogbow[/url], [url=http://apod.nasa.gov/apod/ap090203.html]lenticular clouds[/url] that appear stationary near their mountain peaks, and colorful [url=http://www.atoptics.co.uk/droplets/cormoon.htm]moon coronas[/url]. The [url=http://vimeo.com/23205323]above video[/url] was shot solely from the [url=http://en.wikipedia.org/wiki/Teide_National_Park]Teide National Park[/url] on [url=http://www.youtube.com/watch?v=tRprZWKI98w]Tenerife[/url] in the [url=http://en.wikipedia.org/wiki/Canary_Islands]Canary Islands[/url] of [url=http://www.ilike2learn.com/ilike2learn/Western%20Europe.html]Spain[/url], off the north west coast of [url=http://www.worldatlas.com/webimage/countrys/af.htm]Africa[/url]. The video also features an unusual type of plant in several scenes -- [url=http://asterisk.apod.com/discuss_apod.php?date=110516]can you identify it?[/url]
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[c][url=http://apod.nasa.gov/apod/ap110618.html][size=150][b]Lightning Eclipse from the Planet of the Goats (2011 June 18)[/b][/size][/url][/c]
[float=left][img6="Image Credit & Copyright: Chris Kotsiopoulos (GreekSky)"]http://apod.nasa.gov/apod/image/1106/20110615TLEKotsiopoulos900.jpg[/img6][hr][/hr][/float] Thunderstorms almost spoiled this view of the spectacular June 15 total lunar eclipse. Instead, storm clouds parted for 10 minutes during the [url=http://apod.nasa.gov/apod/ap110617.html]total eclipse phase[/url] and [url=http://apod.nasa.gov/apod/ap100720.html]lightning bolts[/url] contributed to this dramatic skyview. Captured with a 30 second exposure, the scene also inspired what the editor considers may be the best title yet for a picture during the 16 year [url=http://apod.nasa.gov/apod/ap100616.html]history[/url] of Astronomy Picture of the Day. (Title credit to Chris K.) Of course, the lightning reference clearly makes sense, and the [url=http://apod.nasa.gov/apod/ap060909.html]shadow play[/url] of the dark lunar eclipse was [url=http://asterisk.apod.com/viewtopic.php?f=29&t=23957]widely viewed[/url] across planet Earth in Europe, Africa, Asia, and Australia. [url=http://www.greeksky.gr/files/photos/moon/20110615Eclipse.htm]The picture itself, however. was shot[/url] from the Greek Ikaria island at Pezi. That area is known as "the planet of the goats" because of the rough terrain and strange looking rocks.
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[c][url=http://apod.nasa.gov/apod/ap110715.html][size=150][b]NGC 3314: When Galaxies Overlap (2011 July 15)[/b][/size][/url][/c]
[float=left][img6="Credit: Hubble Legacy Archive, ESA, NASA; Processing - Martin Pugh"]http://apod.nasa.gov/apod/image/1107/NGC3314_HLApugh900c.jpg[/img6][hr][/hr][/float][url=http://hubblesite.org/newscenter/newsdesk/archive/releases/2000/14/]NGC 3314[/url] is actually two large [url=http://apod.nasa.gov/apod/ap110406.html]spiral galaxies[/url] which just happen to almost exactly line up. The foreground spiral is viewed nearly [url=http://apod.nasa.gov/apod/ap080815.html]face-on[/url], its pinwheel shape defined by young bright star clusters. But against the glow of the background galaxy, dark swirling lanes of [url=http://apod.nasa.gov/apod/ap030706.html]interstellar dust[/url] appear to dominate the face-on spiral's structure. The [url=http://apod.nasa.gov/apod/ap990821.html]dust lanes[/url] are surprisingly pervasive, and this remarkable [url=http://www.astr.ua.edu/white/pairs/individual.html]pair[/url] of overlapping galaxies is one of a small number of systems in which absorption of light from beyond a galaxy's own stars can be used to directly [url=http://arxiv.org/abs/astro-ph/0106056]explore its distribution[/url] of dust. [url=http://hubblesite.org/newscenter/newsdesk/archive/releases/2000/14/fastfacts/]NGC 3314 is[/url] about 140 million light-years (background galaxy) and 117 million light-years (foreground galaxy) away in the multi-headed [url=http://www.hawastsoc.org/deepsky/hya/index.html]constellation Hydra[/url]. The background galaxy would span nearly 70,000 light-years at its estimated distance. A synthetic third channel was created to construct this dramatic [url=http://www.martinpughastrophotography.id.au/NGC3314.jpg]new composite[/url] of the overlapping galaxies from two color image data in the Hubble Legacy Archive.
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[c][url=http://apod.nasa.gov/apod/ap110730.html][size=150][b]A Tale of Two Hemispheres (2011 July 30)[/b][/size][/url][/c]
[float=left][img6="Image Credit & Copyright: Tunç Tezel and Stéphane Guisard (TWAN)"]http://apod.nasa.gov/apod/image/1107/DoubleGalactic_tezelguisard600h.jpg[/img6][hr][/hr][/float][url=http://www.eso.org/~sguisard/Pagim/darkest_sky.html]A quest[/url] to find planet Earth's darkest night skies led to this intriguing panorama. In projection, the mosaic view sandwiches the horizons visible in [url=http://www.twanight.org/newTWAN/photos.asp?ID=3003290]all-sky images taken[/url] from the northern hemisphere's Canary Island of La Palma (top) and the south's high Atacama Desert between the two hemispheres of the Milky Way Galaxy. The photographers' choice of locations offered locally dark skies enjoyed by La Palma's [url=http://www.iac.es/eno.php?op1=2&lang=en]Roque de los Muchachos[/url] Observatory and [url=http://apod.nasa.gov/apod/ap061104.html]Paranal Observatory[/url] in Chile. But it also allowed the directions to [url=http://www.atlasoftheuniverse.com/galchart.html]the Milky Way's[/url] north and south galactic poles to be placed near the local zenith. That constrained the faint, diffuse glow of the plane of the [url=http://apod.nasa.gov/apod/ap090613.html]Milky Way[/url] to the mountainous horizons. As a result, an even fainter S-shaped band of light, sunlight [url=http://www.astropix.com/HTML/H_OTHER/ZLITE.HTM]scattered by dust[/url] along the solar system's [url=http://apod.nasa.gov/apod/ap100710.html]ecliptic plane[/url], can be completely traced through both northern and southern hemisphere night skies.
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[c][url=http://apod.nasa.gov/apod/ap110829.html][size=150][b]Hickson 44 in Leo (2011 Aug 29)[/b][/size][/url][/c]
[float=left][img6="Image Credit & Copyright: Stephen Leshin"]http://apod.nasa.gov/apod/image/1108/Hickson44_leshin1200.jpg[/img6][hr][/hr][/float]Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact [url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1989ApJS...70..687H&db_key=AST&high=39d9fcfee518892]groups of galaxies[/url], now appropriately called [url=http://www.deep-sky.co.uk/observing/galaxies/hickson.htm]Hickson Compact Groups[/url]. The four prominent galaxies seen in this intriguing [url=http://sleshin.startlogic.com/stargazergallery/main.php?g2_itemId=547&g2_imageViewsIndex=0]telescopic skyscape[/url] are one such group, Hickson 44, about 100 million light-years distant toward the constellation Leo. The two spiral galaxies in the center of the image are edge-on NGC 3190 with its distinctive, warped dust lanes, and S-shaped NGC 3187. Along with the bright elliptical, NGC 3193 at the right, they are also known as Arp 316. The spiral in the upper left corner is NGC 3185, the 4th member of the Hickson group. Like other galaxies in Hickson groups, these show signs of distortion and [url=http://apod.nasa.gov/apod/ap061024.html]enhanced star formation[/url], evidence of a gravitational tug of war that will eventually result in [url=http://burro.cwru.edu/JavaLab/GalCrashWeb/backgrnd.html]galaxy mergers[/url] on a cosmic timescale. The merger process is now understood to be a normal part of the evolution of galaxies, including [url=http://www.galaxydynamics.org/tflops.html]our own Milky Way[/url]. For scale, [url=http://apod.nasa.gov/apod/ap100503.html]NGC 3190[/url] is about 75,000 light-years across at the estimated distance of Hickson 44.
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[c][url=http://apod.nasa.gov/apod/ap110915.html][size=150][b]NGC 3521: Galaxy in a Bubble (2011 Sept 15)[/b][/size][/url][/c]
[float=left][img6="Image Credit & Copyright: R Jay Gabany (Blackbird Obs.), Collaboration: David Martinez-Delgado (MPIA, IAC), et al."]http://apod.nasa.gov/apod/image/1109/ngc3521_gabany901.jpg[/img6][hr][/hr][/float]Gorgeous spiral galaxy [url=http://apod.nasa.gov/apod/ap110113.html]NGC 3521 is[/url] a mere 35 million light-years away, toward the [url=http://www.universetoday.com/21173/leo/]constellation Leo[/url]. Relatively bright in planet Earth's sky, NGC 3521 is easily visible in small telescopes but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like [url=http://apod.nasa.gov/apod/ap110803.html]M66 and M65[/url]. It's hard to overlook in [url=http://www.cosmotography.com/images/small_ngc3521.html]this colorful cosmic portrait[/url], though. Spanning some 50,000 light-years the galaxy sports [url=http://adsabs.harvard.edu/abs/1982MNRAS.201.1021E]characteristic[/url] patchy, irregular spiral arms laced with dust, pink star forming regions, and clusters of young, blue stars. Remarkably, this deep image also finds NGC 3521 embedded in gigantic bubble-like shells. The shells are likely tidal debris, streams of stars torn from satellite galaxies that have [url=http://www.cosmotography.com/images/galaxy_formation_and_evolution.html]undergone mergers[/url] with NGC 3521 in the distant past.
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[c][url=http://apod.nasa.gov/apod/ap110924.html][size=150][b]Mangaia's Milky Way (2011 Sept 24)[/b][/size][/url][/c]
[float=left][img6="Image Credit & Copyright: Tunç Tezel (TWAN)"]http://apod.nasa.gov/apod/image/1109/MangaiaMW_tezel900.jpg[/img6][hr][/hr][/float]From Sagittarius to Carina, the Milky Way Galaxy shines in this dark night sky above planet Earth's lush island paradise of Mangaia. Familiar to denizens of the southern hemisphere, the gorgeous skyscape includes the bulging galactic center at the upper left and bright stars Alpha and Beta Centauri just right of center. About 10 kilometers wide, volcanic Mangaia is the southernmost of the Cook Islands. Geologists estimate that at 18 million years old it is the oldest island in the Pacific Ocean. Of course, the Milky Way is somewhat older, with the galaxy's oldest stars estimated to be over 13 billion years old. [i](Editor's note: This image holds the distinction of being selected as winner in the Royal Observatory, Greenwich, Astronomy Photographer of the Year competition in the Earth and Space category.)[/i]
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[c][url=http://apod.nasa.gov/apod/ap111011.html][size=150][b]NGC 7635: The Bubble Nebula (2011 Oct 11)[/b][/size][/url][/c]
[float=left][img6="Image Credit & Copyright: Larry Van Vleet"]http://apod.nasa.gov/apod/image/1110/bubble_vanvleet_900.jpg[/img6][hr][/hr][/float]It's the bubble versus the cloud. NGC 7635, the [url=http://apod.nasa.gov/apod/ap091030.html]Bubble Nebula[/url], is being pushed out by the [url=http://apod.nasa.gov/apod/ap000318.html]stellar wind[/url] of massive central star [url=http://adsabs.harvard.edu/abs/2002AJ....124.3305M]BD+602522[/url]. Next door, though, lives a giant [url=http://apod.nasa.gov/apod/ap090623.html]molecular cloud[/url], visible to the right. At this place in space, an [url=http://en.wikipedia.org/wiki/Irresistible_force_paradox]irresistible force[/url] meets an [url=http://1.bp.blogspot.com/-s8wPzTQVHwk/TZ23dhVwPTI/AAAAAAAAARY/1SsZ9s_A_J4/s1600/big+pumpkin.jpg]immovable object[/url] in an interesting way. The [url=http://heritage.stsci.edu/1998/31/index.html]cloud[/url] is able to contain the expansion of the bubble gas, but gets blasted by the hot radiation from the [url=http://www.exploratorium.edu/ronh/bubbles/bubbles.html]bubble[/url]'s central star. The [url=http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html]radiation[/url] heats up dense regions of the [url=http://en.wikipedia.org/wiki/Molecular_cloud]molecular cloud[/url] causing it to glow. The [url=http://apod.nasa.gov/apod/ap030617.html]Bubble Nebula[/url], [url=http://apod.nasa.gov/apod/]pictured above[/url] in scientifically mapped colors to bring up contrast, is about 10 [url=http://chandra.harvard.edu/photo/cosmic_distance.html]light-years[/url] across and part of a much [url=http://apod.nasa.gov/apod/ap100909.html]larger complex[/url] of stars and shells. The [url=http://apod.nasa.gov/apod/ap000118.html]Bubble Nebula[/url] can be seen with a small telescope towards the [url=http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html]constellation[/url] of the Queen of [url=http://en.wikipedia.org/wiki/Ethiopia_(mythology)]Aethiopia[/url] ([url=http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=18]Cassiopeia[/url]).
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[c][url=http://apod.nasa.gov/apod/ap111026.html][size=150][b]In, Through, and Beyond Saturn's Rings (2011 Oct 26)[/b][/size][/url][/c]
[float=left][img6="Image Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA"]http://apod.nasa.gov/apod/image/1110/fourmoons_cassini_900.jpg[/img6][hr][/hr][/float]A fourth moon is visible on the [url=http://photojournal.jpl.nasa.gov/catalog/PIA14579]above image[/url] if you look hard enough. First -- and furthest in the background -- is [url=http://apod.nasa.gov/apod/ap110401.html]Titan[/url], the largest moon of Saturn and one of the larger moons in the Solar System. The dark feature across the top of this perpetually cloudy world is the [url=http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3689]north polar hood[/url]. The next most obvious moon is bright [url=http://en.wikipedia.org/wiki/Dione_%28moon%29]Dione[/url], visible in the foreground, complete with craters and long [url=http://apod.nasa.gov/apod/ap060905.html]ice cliffs[/url]. Jutting in from the left are several of Saturn's [url=http://apod.nasa.gov/apod/ap050525.html]expansive rings[/url], including Saturn's A ring featuring the dark [url=http://en.wikipedia.org/wiki/Encke_Division#Encke_Gap]Encke Gap[/url]. On the far right, just outside the rings, is [url=http://en.wikipedia.org/wiki/Pandora_%28moon%29]Pandora[/url], a moon only 80-kilometers across that [url=http://www.youtube.com/watch?v=fdUlpeUFfxI]helps shepherd[/url] Saturn's F ring. The fourth moon? If you look closely in the Encke Gap you'll find a speck that is actually [url=http://en.wikipedia.org/wiki/Pan_%28moon%29]Pan[/url]. Although one of Saturn's smallest moons at 35-kilometers across, Pan is massive enough to help keep the [url=http://planetary.org/explore/topics/saturn/pan.html]Encke gap[/url] relatively free of ring particles.
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[c][url=http://apod.nasa.gov/apod/ap111112.html][size=150][b]Sunspot Castle (2011 Nov 12)[/b][/size][/url][/c]
[float=left][img6="Image Credit & Copyright: Jens Hackmann"]http://apod.nasa.gov/apod/image/1111/SunspotCastle_hackmann900.jpg[/img6][hr][/hr][/float]Each day can have a beautiful ending as the [url=http://apod.nasa.gov/apod/ap090924.html]Sun sets[/url] below the western horizon. This week, the setting Sun added naked-eye sunspots to its finale, as enormous active regions [url=http://apod.nasa.gov/apod/ap991021.html]rotated[/url] across the dimmed, reddened solar disc. Near the Sun's center in this closing telephoto view from November 7th are sunspots in [url=http://www.youtube.com/watch?v=Nnwqkm6rL4M]Active Region 1339[/url]. Responsible for a powerful [url=http://www.nasa.gov/mission_pages/sunearth/news/News110411-x1.9-cme.html]X-class flare on November 3rd[/url], Active Region 1339 is larger than Jupiter. In the foreground, the ruined tower of a medieval castle stands in [url=http://www.kopfgeist.com/sonne_mond/sonne/sonnenuntergang_neuhaus02.htm]dramatic silhouette[/url]. Located in Igersheim, Germany and traditionally known as [url=http://de.wikipedia.org/wiki/Burg_Neuhaus_%28Igersheim%29]castle Neuhaus[/url], it might be [url=http://apod.nasa.gov/apod/ap050218.html]named[/url] Sunspot Castle for this well-composed scene.
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[c][url=http://apod.nasa.gov/apod/ap111221.html][size=150][b]A Horseshoe Einstein Ring from Hubble (2011 Dec 21)[/b][/size][/url][/c]
[float=left][img6="Image Credit: ESA/Hubble & NASA"]http://apod.nasa.gov/apod/image/1112/lensshoe_hubble_900.jpg[/img6][hr][/hr][/float]What's large and blue and can wrap itself around an entire galaxy? A [url=http://en.wikipedia.org/wiki/Gravitational_lensing]gravitational lens[/url] mirage. [url=http://www.spacetelescope.org/images/potw1151a/]Pictured above[/url], the gravity of a luminous red galaxy ([url=http://adsabs.harvard.edu/abs/2001AJ....122.2267E]LRG[/url]) has [url=http://apod.nasa.gov/apod/ap040807.html]gravitationally distorted[/url] the light from a much more distant blue galaxy. More typically, such light bending results in [url=http://apod.nasa.gov/apod/ap020908.html]two discernible images[/url] of the distant galaxy, but here the [url=http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html]lens alignment[/url] is so precise that the background galaxy is distorted into a horseshoe -- a nearly complete ring. Since such a [url=http://www.youtube.com/watch?v=2-My9CChyBw]lensing effect[/url] was generally predicted in some detail by [url=http://en.wikipedia.org/wiki/Einstein]Albert Einstein[/url] over [url=http://adsabs.harvard.edu/abs/1936Sci....84..506E]70 years ago[/url], rings [url=http://apod.nasa.gov/apod/ap080728.html]like this[/url] are now known as [url=http://apod.nasa.gov/apod/ap980330.html]Einstein Rings[/url]. Although LRG 3-757 was discovered in 2007 in data from the [url=http://www.sdss.org/]Sloan Digital Sky Survey[/url] (SDSS), the image shown above is a follow-up observation taken with the [url=http://www.stsci.edu/hst/HST_overview/]Hubble Space Telescope[/url]'s [url=http://www.stsci.edu/hst/wfc3]Wide Field Camera 3[/url]. Strong gravitational lenses like LRG 3-757 are more than oddities -- their multiple properties allow astronomers to determine the mass and [url=http://en.wikipedia.org/wiki/Dark_matter]dark matter[/url] content of the foreground galaxy lenses.
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[url=http://asterisk.apod.com/viewtopic.php?f=29&t=22695][b]<< APOY 2010[/b][/url]