by owlice » Sun Aug 07, 2011 2:58 pm
_______________________________________________________________
Please vote for the TWO best Astronomy Pictures of the Day (image and text) of July 31-August 6, 2011.
(Repeated APODs are not included in the poll.)
All titles are clickable and link to the original APOD page.
We ask for your help in choosing an APOW as this helps Jerry and Robert create "
year in APOD images" review lectures, create APOM and
APOY polls that can be used to create a free PDF calendar at year's end, and provides feedback on which images and APODs were relatively well received. You can select two top images for the week.
We are very interested in why you selected the APODs you voted for, and enthusiastically welcome your telling us why by responding to this thread.
Thank you!
_______________________________________________________________
<- Previous week's poll
What's that strange bright streak? It is the
last image ever of a
space shuttle from orbit. A week and a half ago, after decoupling from the
International Space Station, the
Space Shuttle Atlantis fired its rockets for the last time, lost its orbital speed, and plummeted back to Earth. Within the next hour, however, the sophisticated space machine dropped its landing gear and did what used to be unprecedented --
landed like an airplane on a runway. Although the future of human space flight from the
USA will enter a temporary lull, many robotic spacecraft continue to explore our Solar System and peer into our universe, including
Cassini,
Chandra,
Chang'e 2,
Dawn,
Fermi,
Hubble,
Kepler,
LRO,
Mars Express,
Messenger,
MRO,
New Horizons,
Opportunity,
Planck,
Rosetta,
SDO,
SOHO,
Spitzer,
STEREO,
Swift,
Venus-Express, and
WISE.
Why is the northern half of asteroid Vesta more heavily cratered than the south? No one is yet sure. This unexpected mystery has come to light only in the past few weeks since the robotic
Dawn mission became the first
spacecraft to orbit the second largest object in the
asteroid belt between Mars and Jupiter. The northern half of
Vesta, seen on the upper left of the
above image, appears to show some of the densest cratering in the Solar System, while the southern half is unexpectedly smooth. Also unknown is the origin of grooves that circle the asteroid nears its equator, particularly visible on
this Vesta rotation movie, and the nature of
dark streaks that delineate some of Vesta's craters, for example the crater just above the
the image center. As
Dawn spirals in toward
Vesta over the coming months, some answers may emerge, as well as higher resolution and color images. Studying 500-km diameter
Vesta is yielding clues about its history and the early years of our Solar System.
This popular group is famous as the
Leo Triplet - a gathering of three magnificent galaxies in one field of view.
Crowd pleasers when imaged with even modest telescopes, these galaxies can be introduced individually as NGC 3628 (left),
M66 (bottom right), and M65 (top right). All three are large
spiral galaxies. They tend to look dissimilar because their
galactic disks are tilted at different angles to our line of sight.
NGC 3628 is seen
edge-on, with obscuring dust lanes cutting across the plane of the galaxy, while the disks
of M66 and
M65 are both inclined enough to show off their spiral structure.
Gravitational interactions between galaxies in the group have also left
telltale signs, including the
warped and inflated disk of NGC 3628 and the drawn out spiral arms of
M66. This
gorgeous deep view of the region was taken by the new
VLT Survey Telescope (VST) and spans about one degree (two full moons) on the sky. The field covers over 500 thousand
light-years at the trio's estimated distance of 30 million light-years.
These clouds of interstellar dust and gas have blossomed 1,300 light-years away in the fertile star fields of the
constellation Cepheus. Sometimes called the Iris Nebula and dutifully cataloged as
NGC 7023, this is not the only nebula in the sky to evoke the imagery
of flowers. Surrounding it, obscuring clouds of dust and cold molecular gas are also present and can suggest other
convoluted and
fantastic shapes. Within the Iris, the dusty nebular material surrounds a hot, young star. The dominant color of the brighter reflection nebula is blue,
characteristic of dust grains reflecting starlight. Central filaments of the cosmic dust glow with a faint reddish photoluminesence as some dust grains
effectively convert the star's invisible
ultraviolet radiation to visible red light. Infrared
observations indicate that this nebula may contain complex carbon molecules known as
PAHs. At the estimated distance of the Iris Nebula
this remarkable wide field view is over 30 light-years across.
Fix your digital camera to a tripod, start a long series of exposures, and you too can record star trails. The concentric arcs traced by the stars as planet Earth
rotates on its axis often produce
dreamlike scenes in otherwise
familiar situations.
Fall asleep, though, and the results might surprise you. Setting up on a summer night, photographer Mike Rosinski began his exposures, initially planning to capture about 45-55 minutes worth of star trails from his yard in Hartland, Michigan, USA. But he dozed, only to awaken some 3 hours later to find his camera had continued to run until the battery died. Composing the resulting images, the graceful concentric star trails were expected, along with light from a late rising Moon glinting on windows. Still, as he slept on the warm night a blizzard of yellow streaks flooded the scene, not left
by fairies but
fireflies.
Recorded on August 2,
this telescopic composite image catches
Comet Garradd (C/2009 P1) in the same field of view as globular
star cluster M15. The celestial scene would have been a rewarding one for influential 18th century comet hunter Charles Messier. While Messier scanned French skies for comets, he carefully cataloged positions of things which might be fuzzy and comet-like in appearance but did not move against the background stars and so were definitely not comets. M15 (lower right), the 15th entry in his famous
not-a-comet catalog, is now understood to be a cluster of over 100,000 stars some 35,000 light-years distant. The comet, discovered in August 2009 by astronomer G. J. Garradd (Siding Spring Observatory, Australia) is currently
sweeping across the constellation Pegasus, some 13
light-minutes from Earth. Shinning faintly around 9th magnitude,
comet Garradd will brighten in the coming months,
predicted to be just below naked eye visibility near its peak in February 2012.
<- Previous week's poll
[size=200][color=#FF0000]_______________________________________________________________[/color][/size]
Please vote for the TWO best Astronomy Pictures of the Day (image and text) of July 31-August 6, 2011.
(Repeated APODs are not included in the poll.)
All titles are clickable and link to the original APOD page.
We ask for your help in choosing an APOW as this helps Jerry and Robert create "[url=http://www.youtube.com/watch?v=NAQXYYbBa1s]year in APOD images[/url]" review lectures, create APOM and [url=http://asterisk.apod.com/viewtopic.php?f=29&t=22695&p=141942#p141942]APOY polls[/url] that can be used to create a free PDF calendar at year's end, and provides feedback on which images and APODs were relatively well received. You can select two top images for the week.
We are very interested in why you selected the APODs you voted for, and enthusiastically welcome your telling us why by responding to this thread.
Thank you!
[size=200][color=#FF0000]_______________________________________________________________[/color][/size]
[size=110][url=http://asterisk.apod.com/viewtopic.php?f=29&t=24637][color=#4040FF][b]<- Previous week's poll[/b][/color][/url][/size]
[c][url=http://apod.nasa.gov/apod/ap110801.html][size=150][b]Shuttle Reentry Streak from Orbit (2011 August 1)[/b][/size][/url][/c]
[float=left][img3="[size=85]Image Credit: ISS Expedition 28 Crew, STS-135 Mission, NASA[/size]"]http://apod.nasa.gov/apod/image/1108/atlantisfalloff_nasa_900.jpg[/img3][/float]What's that strange bright streak? It is the [url=http://spaceflight.nasa.gov/gallery/images/station/crew-28/html/iss028e018221.html]last image[/url] ever of a [url=http://apod.nasa.gov/apod/ap110620.html]space shuttle[/url] from orbit. A week and a half ago, after decoupling from the [url=http://apod.nasa.gov/apod/ap110309.html]International Space Station[/url], the [url=http://www.youtube.com/watch?v=qPne2ffaG9Q]Space Shuttle Atlantis[/url] fired its rockets for the last time, lost its orbital speed, and plummeted back to Earth. Within the next hour, however, the sophisticated space machine dropped its landing gear and did what used to be unprecedented -- [url=http://www.youtube.com/watch?v=HLDG5sNMX2M]landed[/url] like an airplane on a runway. Although the future of human space flight from the [url=https://www.cia.gov/library/publications/the-world-factbook/geos/us.html]USA[/url] will enter a temporary lull, many robotic spacecraft continue to explore our Solar System and peer into our universe, including [url=http://apod.nasa.gov/apod/ap100215.html]Cassini[/url], [url=http://apod.nasa.gov/apod/ap110305.html]Chandra[/url], [url=http://en.wikipedia.org/wiki/Chang%27e_2]Chang'e 2[/url], [url=http://apod.nasa.gov/apod/ap110719.html]Dawn[/url], [url=http://apod.nasa.gov/apod/ap101110.html]Fermi[/url], [url=http://apod.nasa.gov/apod/ap110424.html]Hubble[/url], [url=http://apod.nasa.gov/apod/ap110329.html]Kepler[/url], [url=http://apod.nasa.gov/apod/ap110706.html]LRO[/url], [url=http://apod.nasa.gov/apod/ap110124.html]Mars Express[/url], [url=http://apod.nasa.gov/apod/ap110331.html]Messenger[/url], [url=http://apod.nasa.gov/apod/ap100119.html]MRO[/url], [url=http://apod.nasa.gov/apod/ap080108.html]New Horizons[/url], [url=http://apod.nasa.gov/apod/ap110129.html]Opportunity[/url], [url=http://apod.nasa.gov/apod/ap100322.html]Planck[/url], [url=http://apod.nasa.gov/apod/ap091123.html]Rosetta[/url], [url=http://apod.nasa.gov/apod/ap110610.html]SDO[/url], [url=http://apod.nasa.gov/apod/ap090531.html]SOHO[/url], [url=http://apod.nasa.gov/apod/ap100410.html]Spitzer[/url], [url=http://apod.nasa.gov/apod/ap110207.html]STEREO[/url], [url=http://apod.nasa.gov/apod/ap090917.html]Swift[/url], [url=http://apod.nasa.gov/apod/ap100928.html]Venus-Express[/url], and [url=http://apod.nasa.gov/apod/ap100601.html]WISE[/url].
[clear][/clear]
[c][url=http://apod.nasa.gov/apod/ap110802.html][size=150][b]Asteroid Vesta Full Frame (2011 August 2)[/b][/size][/url][/c]
[float=left][img3="[size=85]Image Credit: NASA, JPL-Caltech, UCLA, MPS, DLR, IDA[/size]"]http://apod.nasa.gov/apod/image/1108/vesta2_dawn_900.jpg[/img3][/float]Why is the northern half of asteroid Vesta more heavily cratered than the south? No one is yet sure. This unexpected mystery has come to light only in the past few weeks since the robotic [url=http://dawn.jpl.nasa.gov/mission/]Dawn mission[/url] became the first [url=http://en.wikipedia.org/wiki/Dawn_%28spacecraft%29]spacecraft[/url] to orbit the second largest object in the [url=http://en.wikipedia.org/wiki/Asteroid_belt]asteroid belt[/url] between Mars and Jupiter. The northern half of [url=http://apod.nasa.gov/apod/ap110719.html]Vesta[/url], seen on the upper left of the [url=http://www.nasa.gov/mission_pages/dawn/multimedia/pia14317.html]above image[/url], appears to show some of the densest cratering in the Solar System, while the southern half is unexpectedly smooth. Also unknown is the origin of grooves that circle the asteroid nears its equator, particularly visible on [url=http://www.youtube.com/watch?v=FaUaoy33gHE]this Vesta rotation movie[/url], and the nature of [url=http://apod.nasa.gov/apod/ap040614.html]dark streaks[/url] that delineate some of Vesta's craters, for example the crater just above the [url=http://photojournal.jpl.nasa.gov/catalog/PIA14317]the image[/url] center. As [url=http://apod.nasa.gov/apod/ap070929.html]Dawn[/url] spirals in toward [url=http://en.wikipedia.org/wiki/4_Vesta]Vesta[/url] over the coming months, some answers may emerge, as well as higher resolution and color images. Studying 500-km diameter [url=http://planetary.org/blog/article/00003126/]Vesta[/url] is yielding clues about its history and the early years of our Solar System.
[clear][/clear]
[c][url=http://apod.nasa.gov/apod/ap110803.html][size=150][b]The Leo Triplet Galaxies from VST (2011 August 3)[/b][/size][/url][/c]
[float=left][img3="[size=85]Image Credit: ESO, INAF-VST, OmegaCAM;
Acknowledgement: OmegaCen, Astro-WISE, Kapteyn I.[/size]"]http://apod.nasa.gov/apod/image/1108/leotriplet_vst_900.jpg[/img3][/float]This popular group is famous as the [url=http://en.wikipedia.org/wiki/Leo_Triplet]Leo Triplet[/url] - a gathering of three magnificent galaxies in one field of view. [url=http://data.whicdn.com/images/4888787/tumblr_l7w5s18RbI1qctvlmo1_400_large.jpg]Crowd pleasers[/url] when imaged with even modest telescopes, these galaxies can be introduced individually as NGC 3628 (left), [url=http://www.youtube.com/watch?v=IFcUNHJb_ic]M66[/url] (bottom right), and M65 (top right). All three are large [url=http://cassfos02.ucsd.edu/public/tutorial/Galaxies.html]spiral galaxies[/url]. They tend to look dissimilar because their [url=http://asterisk.apod.com/viewtopic.php?f=24&t=18005]galactic[/url] disks are tilted at different angles to our line of sight. [url=http://apod.nasa.gov/apod/ap050408.html]NGC 3628[/url] is seen [url=http://apod.nasa.gov/apod/ap010510.html]edge-on[/url], with obscuring dust lanes cutting across the plane of the galaxy, while the disks [url=http://apod.nasa.gov/apod/ap101113.html]of M66[/url] and [url=http://apod.nasa.gov/apod/ap070601.html]M65 are[/url] both inclined enough to show off their spiral structure. [url=http://www.youtube.com/watch?v=xNBQTpdOFMk]Gravitational interactions[/url] between galaxies in the group have also left [url=http://apod.nasa.gov/apod/ap070727.html]telltale[/url] signs, including the [url=http://apod.nasa.gov/apod/ap030607.html]warped[/url] and inflated disk of NGC 3628 and the drawn out spiral arms of [url=http://apod.nasa.gov/apod/ap100413.html]M66[/url]. This [url=http://www.eso.org/public/images/eso1126a/]gorgeous deep view[/url] of the region was taken by the new [url=http://en.wikipedia.org/wiki/VLT_Survey_Telescope]VLT Survey Telescope[/url] (VST) and spans about one degree (two full moons) on the sky. The field covers over 500 thousand [url=http://chandra.harvard.edu/photo/cosmic_distance.html]light-years[/url] at the trio's estimated distance of 30 million light-years.
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[c][url=http://apod.nasa.gov/apod/ap110804.html][size=150][b]A Dusty Iris Nebula (2011 August 4)[/b][/size][/url][/c]
[float=left][img3="[size=85]Image Credit & Copyright: Máximo Ruiz[/size]"]http://apod.nasa.gov/apod/image/1108/NGC7023_ruiz900.jpg[/img3][/float]These clouds of interstellar dust and gas have blossomed 1,300 light-years away in the fertile star fields of the [url=http://www.astropix.com/HTML/E_SUM_N/CEPHEUSO.HTM]constellation Cepheus[/url]. Sometimes called the Iris Nebula and dutifully cataloged as [url=http://www.universetoday.com/17597/ngc-7023-iris-from-the-dust-by-kent-wood/]NGC 7023[/url], this is not the only nebula in the sky to evoke the imagery [url=http://apod.nasa.gov/apod/ap080214.html]of flowers[/url]. Surrounding it, obscuring clouds of dust and cold molecular gas are also present and can suggest other [url=http://apod.nasa.gov/apod/ap071018.html]convoluted[/url] and [url=http://apod.nasa.gov/apod/ap081031.html]fantastic[/url] shapes. Within the Iris, the dusty nebular material surrounds a hot, young star. The dominant color of the brighter reflection nebula is blue, [url=http://leo.astronomy.cz/mix/mix.html]characteristic of dust[/url] grains reflecting starlight. Central filaments of the cosmic dust glow with a faint reddish photoluminesence as some dust grains [url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1989ApJ...347L..25W&db_key=AST&high=3bc4bede8e21358]effectively convert[/url] the star's invisible [url=http://imagers.gsfc.nasa.gov/ems/uv.html]ultraviolet[/url] radiation to visible red light. Infrared [url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2000A%26A...354L..17M&db_key=AST&nosetcookie=1]observations[/url] indicate that this nebula may contain complex carbon molecules known as [url=http://legacy.spitzer.caltech.edu/features/articles/20050627.shtml]PAHs[/url]. At the estimated distance of the Iris Nebula [url=http://www.astromodelismo.es/Web%20Astronomia/Web%20enlazables/%20Fotos%20propias/Nebulosas/Datos%20cientificos/Datos%20NGC%207023/index.htm]this remarkable wide field view[/url] is over 30 light-years across.
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[c][url=http://apod.nasa.gov/apod/ap110805.html][size=150][b]A Summer Night's Dream (2011 August 5)[/b][/size][/url][/c]
[float=left][img3="[size=85]Image Credit & Copyright: Mike Rosinski[/size]"]http://apod.nasa.gov/apod/image/1108/FirefliesStartrails_rosinski900.jpg[/img3][/float] [url=http://www.astropix.com/HTML/I_ASTROP/TRIPOD/TRIPOD2.HTM]Fix your digital camera[/url] to a tripod, start a long series of exposures, and you too can record star trails. The concentric arcs traced by the stars as planet Earth [url=http://apod.nasa.gov/apod/ap070519.html]rotates[/url] on its axis often produce [url=http://apod.nasa.gov/apod/ap101029.html]dreamlike[/url] scenes in otherwise [url=http://apod.nasa.gov/apod/ap100618.html]familiar[/url] situations. [url=http://photography-on-the.net/forum/showthread.php?p=12799553#post12799553]Fall asleep, though[/url], and the results might surprise you. Setting up on a summer night, photographer Mike Rosinski began his exposures, initially planning to capture about 45-55 minutes worth of star trails from his yard in Hartland, Michigan, USA. But he dozed, only to awaken some 3 hours later to find his camera had continued to run until the battery died. Composing the resulting images, the graceful concentric star trails were expected, along with light from a late rising Moon glinting on windows. Still, as he slept on the warm night a blizzard of yellow streaks flooded the scene, not left [url=http://shakespeare.mit.edu/midsummer/full.html]by fairies[/url] but [url=http://www.firefly.org/firefly-pictures.html#boy]fireflies[/url].
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[c][url=http://apod.nasa.gov/apod/ap110806.html][size=150][b]Comet Garradd and Messier 15 (2011 August 6)[/b][/size][/url][/c]
[float=left][img3="[size=85]Image Credit & Copyright: Gregg Ruppel[/size]"]http://apod.nasa.gov/apod/image/1108/GarraddM15_ruppel080211_900.jpg[/img3][/float]Recorded on August 2, [url=http://www.ruppel.darkhorizons.org/c2009%20P1%20Garradd.htm]this telescopic composite[/url] image catches [url=http://cometography.com/lcomets/2009p1.html]Comet Garradd (C/2009 P1)[/url] in the same field of view as globular [url=http://apod.nasa.gov/apod/ap110503.html]star cluster M15[/url]. The celestial scene would have been a rewarding one for influential 18th century comet hunter Charles Messier. While Messier scanned French skies for comets, he carefully cataloged positions of things which might be fuzzy and comet-like in appearance but did not move against the background stars and so were definitely not comets. M15 (lower right), the 15th entry in his famous [url=http://seds.org/messier/xtra/history/m-cat.html]not-a-comet catalog[/url], is now understood to be a cluster of over 100,000 stars some 35,000 light-years distant. The comet, discovered in August 2009 by astronomer G. J. Garradd (Siding Spring Observatory, Australia) is currently [url=http://astrobob.areavoices.com/2011/08/03/comets-pack-more-bang-for-the-buck/]sweeping across[/url] the constellation Pegasus, some 13 [url=http://www.haydenplanetarium.org/universe/duguide/app_light_travel_time_dista.php]light-minutes[/url] from Earth. Shinning faintly around 9th magnitude, [url=http://asterisk.apod.com/viewtopic.php?f=29&t=24696]comet Garradd[/url] will brighten in the coming months, [url=http://www.aerith.net/comet/catalog/2009P1/2009P1.html]predicted to be[/url] just below naked eye visibility near its peak in February 2012.
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[size=110][url=http://asterisk.apod.com/viewtopic.php?f=29&t=24637][color=#4040FF][b]<- Previous week's poll[/b][/color][/url][/size]