_______________________________________________________________
Please vote for the TWO best Astronomy Pictures of the Day (image and text) of September 4-10, 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
Click to play embedded YouTube video.
Image Credit: NASA, ESA, & P. Haritgan (Rice U.) Stars remain where they are. Nebulas appear the same. Day after day. Year after year. Given the vast distances in astronomy, even fast moving objects will not appear to change their appearance in a
human lifetime. Typically. A recent spectacular exception to this, however, is the supersonic jet in the star forming Herbig Haro 47.
HH 47 is so close -- and the jets are moving so fast -- that images from the
Hubble Space Telescope from 1994 to 2008 have been combined into a time-lapse movie that actually shows a powerful jet expanding.
Visible above, jets of plasma extending over 10,000 times the Earth-Sun distance shoot out from a
forming star at speeds in excess of 150 kilometers per second. Studying how these
jets evolve gives clues not only to how the star in
HH 47 is forming, but how stars like our Sun formed billions of years ago.
HH 47 is located about 1,500 light years away toward the constellation of Sails of a Ship (
Vela).
To some, the outline of the
open cluster of stars M6 resembles a butterfly.
M6, also known as NGC 6405, spans about 20 light-years and lies about 2,000 light years distant.
M6 can best be seen in a dark sky with binoculars towards the
constellation of
Scorpius, coving about as much of the sky as the
full moon. Like other
open clusters, M6 is composed predominantly of
young blue stars, although the brightest star is nearly orange.
M6 is estimated to be about 100 million years old. Determining the distance to clusters like
M6 helps astronomers calibrate the
distance scale of the universe.
Why does this star have so few heavy elements? Stars born in the
generation of our Sun have an expected abundance of elements heavier than
hydrogen and
helium mixed into their atmospheres. Stars born in the generation before our Sun,
Population II stars, the stars that created most of the heavy elements around us today, are seen to have some, although less, elements heavier than H and He. Furthermore, even the elusive never-seen first stars in the universe, so-called
Population III stars, are predicted to have a large mass and a small but set amount of heavy elements. Yet low-mass Milky Way star
SDSS J102915+172927, among others, appears to have less metals than ever predicted for any stars, including at least 50 times less lithium than came out of the Big Bang. The unusual nature of
this star, initially cataloged by the
Sloan Digital Sky Survey (SDSS) and
pictured above, was
discovered by detailed spectroscopic observations by a large
VLT telescope in
Chile. Many models of star formation indicate that such a
star should not even form. Research is ongoing, however, with one leading hypothesis
holding that fragile primordial
lithium was destroyed in the star's hot core.
This view of the Apollo 17 landing site in the Taurus-Littrow valley was captured last month by the Lunar Reconnaissance Orbiter (LRO), the sharpest ever
recorded from space.
The high resolution image data was taken during a period when LRO's orbit was modified to create a close approach of about 22 kilometers as it passed over some of the Apollo landing sites. That altitude corresponds to only about twice the height of a commercial airline flight over planet Earth. Labeled in this image are Apollo 17 lunar lander
Challenger's descent stage (inset), the
lunar rover (LRV) at its final
parking spot, and the Apollo Lunar Surface Experiments Package (ALSEP)
left to monitor the Moon's environment and interior. Clear, dual lunar rover
tracks and the foot trails left by astronauts
Eugene Cernan and Harrison Schmitt, the last to walk on the lunar surface, are also easily visible at the
Apollo 17 site.
Sweeping through planet Earth's night sky, last weekend
Comet Garradd (
C/2009 P1) visited this lovely star field along the Milky Way in the constellation Vulpecula. Suggestively oriented, the colorful skyscape features stars in the
asterism known as
the Coat Hanger with the comet's tail pointing toward the southeast. Also known as
Al Sufi's Cluster, the
Coat Hanger itself is likely just a chance alignment and not a cluster of related stars. But compact open star cluster NGC 6802 does grace the field of view just right of the Coat Hanger, near the edge of the frame. Below naked eye visibility but approaching 7th magnitude in brightness,
Comet Garradd has been a good
target for binoculars and small telescopes. Still, bright moonlit skies this week will make the comet harder to spot.
This dramatic
time-lapse photo traces a 20 minute long, late evening rollback of the lighted
Mobile Service Tower at Cape Canaveral Air Force Station Launch Complex 17. Twin spacecraft are snug inside the 13 story tall Delta 2 rocket
poised for launch. The duo will journey to the Moon on NASA's
Gravity Recovery and Interior Laboratory mission, GRAIL, using precision formation flying to
map the Moon's gravity field. The scene was captured prior to the first launch attempt, canceled due to upper level winds, on September 8. Further launch opportunities for GRAIL begin this morning, September 10. The GRAIL launch is the last one planned from
Complex 17 on Cape Canaveral's oldest still active pad, in use since 1957.
<- 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 September 4-10, 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=25142][color=#4040FF][b]<- Previous week's poll[/b][/color][/url][/size]
[c][url=http://apod.nasa.gov/apod/ap110905.html][size=150][b]HH 47: A Young Star Jet Expands (2011 September 05)[/b][/size][/url][/c]
[float=left][youtube6]http://www.youtube.com/watch?v=bFB0vgjIHiI[/youtube6]
[size=85]Image Credit: NASA, ESA, & P. Haritgan (Rice U.) [/size][/float]Stars remain where they are. Nebulas appear the same. Day after day. Year after year. Given the vast distances in astronomy, even fast moving objects will not appear to change their appearance in a [url=https://www.cia.gov/library/publications/the-world-factbook/rankorder/2102rank.html]human lifetime[/url]. Typically. A recent spectacular exception to this, however, is the supersonic jet in the star forming Herbig Haro 47. [url=http://www.universetoday.com/88557/hubble-movies-star-supersonic-jets/]HH 47[/url] is so close -- and the jets are moving so fast -- that images from the [url=http://apod.nasa.gov/apod/ap090525.html]Hubble Space Telescope[/url] from 1994 to 2008 have been combined into a time-lapse movie that actually shows a powerful jet expanding. [url=http://www.youtube.com/watch?v=bFB0vgjIHiI]Visible above[/url], jets of plasma extending over 10,000 times the Earth-Sun distance shoot out from a [url=http://imgsrc.hubblesite.org/hu/db/images/hs-2011-20-j-compass_large_web.jpg]forming star[/url] at speeds in excess of 150 kilometers per second. Studying how these [url=http://www.youtube.com/watch?v=zXPrIiLIAh8]jets evolve[/url] gives clues not only to how the star in [url=http://hubblesite.org/newscenter/archive/releases/2011/20/video/b/]HH 47[/url] is forming, but how stars like our Sun formed billions of years ago. [url=http://apod.nasa.gov/apod/ap951012.html]HH 47[/url] is located about 1,500 light years away toward the constellation of Sails of a Ship ([url=http://en.wikipedia.org/wiki/Vela_(constellation)]Vela[/url]).
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[c][url=http://apod.nasa.gov/apod/ap110906.html][size=150][b]M6: The Butterfly Cluster (2011 September 06)[/b][/size][/url][/c]
[float=left][img6="[size=85]Image Credit & Copyright: Sergio Eguivar Buenos Aires Skies[/size]"]http://apod.nasa.gov/apod/image/1109/m6_eguivar_900.jpg[/img6][/float]To some, the outline of the [url=http://asterisk.apod.com/viewtopic.php?f=24&t=18009]open cluster[/url] of stars M6 resembles a butterfly. [url=http://www.seds.org/messier/m/m006.html]M6[/url], also known as NGC 6405, spans about 20 light-years and lies about 2,000 light years distant. [url=http://www.baskies.com.ar/PHOTOS/M6%20LHaRGB.htm]M6[/url] can best be seen in a dark sky with binoculars towards the [url=http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html]constellation[/url] of [url=http://astro.gmu.edu/classes/a113/constellations/SCO1.HTM]Scorpius[/url], coving about as much of the sky as the [url=http://apod.nasa.gov/apod/ap980107.html]full moon[/url]. Like other [url=http://en.wikipedia.org/wiki/Open_cluster]open clusters[/url], M6 is composed predominantly of [url=http://apod.nasa.gov/apod/ap091014.html]young blue stars[/url], although the brightest star is nearly orange. [url=http://adsabs.harvard.edu/abs/1977ApJ...218..105W]M6[/url] is estimated to be about 100 million years old. Determining the distance to clusters like [url=http://en.wikipedia.org/wiki/Messier_6]M6[/url] helps astronomers calibrate the [url=http://apod.nasa.gov/diamond_jubilee/debate_1920.html]distance scale[/url] of the universe.
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[c][url=http://apod.nasa.gov/apod/ap110907.html][size=150][b]SDSS J102915+172927: A Star That Should Not Exist (2011 September 07)[/b][/size][/url][/c]
[float=left][img6="[size=85]Image Credit: ESO, DSS2[/size]"]http://apod.nasa.gov/apod/image/1109/j102915_vlt_900.jpg[/img6][/float]Why does this star have so few heavy elements? Stars born in the [url=http://www.daviddarling.info/encyclopedia/P/PopI.html]generation of our Sun[/url] have an expected abundance of elements heavier than [url=http://periodic.lanl.gov/1.shtml]hydrogen[/url] and [url=http://periodic.lanl.gov/2.shtml]helium[/url] mixed into their atmospheres. Stars born in the generation before our Sun, [url=http://en.wikipedia.org/wiki/Population_II_stars#Population_II_stars]Population II stars[/url], the stars that created most of the heavy elements around us today, are seen to have some, although less, elements heavier than H and He. Furthermore, even the elusive never-seen first stars in the universe, so-called [url=http://apod.nasa.gov/apod/ap030610.html]Population III[/url] stars, are predicted to have a large mass and a small but set amount of heavy elements. Yet low-mass Milky Way star [url=http://www.eso.org/public/news/eso1132/]SDSS J102915+172927[/url], among others, appears to have less metals than ever predicted for any stars, including at least 50 times less lithium than came out of the Big Bang. The unusual nature of [url=http://www.youtube.com/watch?v=VHKi8R6aqm4]this star[/url], initially cataloged by the [url=http://apod.nasa.gov/apod/ap980617.html]Sloan Digital Sky Survey[/url] (SDSS) and [url=http://www.eso.org/public/images/eso1132b/]pictured above[/url], was [url=http://www.eso.org/public/archives/releases/sciencepapers/eso1132/eso1132.pdf]discovered[/url] by detailed spectroscopic observations by a large [url=http://apod.nasa.gov/apod/ap110601.html]VLT telescope[/url] in [url=http://en.wikipedia.org/wiki/Chile]Chile[/url]. Many models of star formation indicate that such a [url=http://www.eso.org/public/videos/eso1132a/]star[/url] should not even form. Research is ongoing, however, with one leading hypothesis [url=http://www.metafilter.com/107125/Star-in-Leo-shouldnt-exist]holding[/url] that fragile primordial [url=http://en.wikipedia.org/wiki/Lithium]lithium[/url] was destroyed in the star's hot core.
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[c][url=http://apod.nasa.gov/apod/ap110908.html][size=150][b]Apollo 17 Site: A Sharper View (2011 September 08)[/b][/size][/url][/c]
[float=left][img6="[size=85]Credit: NASA / GSFC / Arizona State Univ. / Lunar Reconnaissance Orbiter[/size]"]http://apod.nasa.gov/apod/image/1109/apollo17area1_lro900.jpg[/img6][/float][url=http://www.nasa.gov/mission_pages/LRO/news/apollo-sites.html]This view of the Apollo 17[/url] landing site in the Taurus-Littrow valley was captured last month by the Lunar Reconnaissance Orbiter (LRO), the sharpest ever [url=http://apod.nasa.gov/apod/ap020628.html]recorded from space[/url]. [url=http://lroc.sese.asu.edu/news/?archives/454-Skimming-the-Moon.html]The high resolution image[/url] data was taken during a period when LRO's orbit was modified to create a close approach of about 22 kilometers as it passed over some of the Apollo landing sites. That altitude corresponds to only about twice the height of a commercial airline flight over planet Earth. Labeled in this image are Apollo 17 lunar lander [url=http://apod.nasa.gov/apod/ap060107.html]Challenger's[/url] descent stage (inset), the [url=http://apod.nasa.gov/apod/ap040605.html]lunar rover[/url] (LRV) at its final [url=http://apod.nasa.gov/apod/ap080706.html]parking spot[/url], and the Apollo Lunar Surface Experiments Package (ALSEP) [url=http://www.lpi.usra.edu/expmoon/Apollo17/A17_science.html]left to monitor[/url] the Moon's environment and interior. Clear, dual lunar rover [url=http://apod.nasa.gov/apod/ap040417.html]tracks[/url] and the foot trails left by astronauts [url=http://apod.nasa.gov/apod/ap051217.html]Eugene Cernan and Harrison Schmitt[/url], the last to walk on the lunar surface, are also easily visible at the [url=http://www.lpi.usra.edu/expmoon/Apollo17/A17_lsite.html]Apollo 17 site[/url].
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[c][url=http://apod.nasa.gov/apod/ap110909.html][size=150][b]Comet Garradd and the Coat Hanger (2011 September 09)[/b][/size][/url][/c]
[float=left][img6="[size=85]Image Credit & Copyright: Rogelio Bernal Andreo[/size]"]http://apod.nasa.gov/apod/image/1109/mcr_2011-09-03_C2009_P1_Garradd900.jpg[/img6][/float]Sweeping through planet Earth's night sky, last weekend [url=http://www.skyandtelescope.com/observing/highlights/128836743.html]Comet Garradd[/url] ([url=http://www.aerith.net/comet/catalog/2009P1/2009P1.html]C/2009 P1)[/url] visited this lovely star field along the Milky Way in the constellation Vulpecula. Suggestively oriented, the colorful skyscape features stars in the [url=http://www.deep-sky.co.uk/asterisms.htm]asterism[/url] known as [url=http://apod.nasa.gov/apod/ap081223.html]the Coat Hanger[/url] with the comet's tail pointing toward the southeast. Also known as [url=http://seds.org/messier/xtra/Bios/alsufi.html]Al Sufi's[/url] Cluster, the [url=http://seds.org/messier/xtra/ngc/brocchi.html]Coat Hanger[/url] itself is likely just a chance alignment and not a cluster of related stars. But compact open star cluster NGC 6802 does grace the field of view just right of the Coat Hanger, near the edge of the frame. Below naked eye visibility but approaching 7th magnitude in brightness, [url=http://apod.nasa.gov/apod/ap110806.html]Comet Garradd[/url] has been a good [url=http://asterisk.apod.com/viewtopic.php?f=29&t=24696]target for[/url] binoculars and small telescopes. Still, bright moonlit skies this week will make the comet harder to spot.
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[c][url=http://apod.nasa.gov/apod/ap110910.html][size=150][b]Rollback from GRAIL's Rocket (2011 September 10)[/b][/size][/url][/c]
[float=left][img6="[size=85]Image Credit & Copyright: Ben Cooper (Launch Photography)[/size]"]http://apod.nasa.gov/apod/image/1109/Delta2_GRAIL_MST_rollback900.jpg[/img6][/float]This dramatic [url=http://www.launchphotography.com/GRAIL_MST_rollback.html]time-lapse photo traces[/url] a 20 minute long, late evening rollback of the lighted [url=http://www.launchphotography.com/GRAIL_MST_rollback_2.html]Mobile Service Tower[/url] at Cape Canaveral Air Force Station Launch Complex 17. Twin spacecraft are snug inside the 13 story tall Delta 2 rocket [url=http://www.nasaspaceflight.com/2011/09/live-ula-deltaii-launch-grail-spacecraft-to-moon/]poised for launch[/url]. The duo will journey to the Moon on NASA's [url=http://www.nasa.gov/mission_pages/grail/main/index.html]Gravity Recovery and Interior Laboratory[/url] mission, GRAIL, using precision formation flying to [url=http://solarsystem.nasa.gov/grail/home.cfm]map the Moon's gravity field[/url]. The scene was captured prior to the first launch attempt, canceled due to upper level winds, on September 8. Further launch opportunities for GRAIL begin this morning, September 10. The GRAIL launch is the last one planned from [url=http://www.afspacemuseum.org/CCAFS/CX17/index.htm]Complex 17[/url] on Cape Canaveral's oldest still active pad, in use since 1957.
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[size=110][url=http://asterisk.apod.com/viewtopic.php?f=29&t=25142][color=#4040FF][b]<- Previous week's poll[/b][/color][/url][/size]