_______________________________________________________________
Please vote for the TWO best Astronomy Pictures of the Day (image and text) of November 6-12, 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
Massive star IRS 4 is beginning to spread its wings. Born only about 100,000 years ago, material streaming out from this newborn star has formed the nebula dubbed Sharpless 2-106 Nebula (S106), pictured above. A large disk of
dust and gas orbiting Infrared Source 4 (IRS 4), visible in dark red near the image center, gives the nebula an
hourglass or
butterfly shape.
S106 gas near IRS 4 acts as an
emission nebula as it emits light after being
ionized, while
dust far from
IRS 4 reflects light from the central star and so acts as a
reflection nebula. Detailed inspection of
images like the above image has revealed hundreds of low-mass
brown dwarf stars lurking in
the nebula's gas. S106 spans about 2
light-years and lies about 2000 light-years away toward the
constellation of the Swan (
Cygnus).
Click to play embedded YouTube video.
Image Credit: abrigatti, YouTubeWhat's happening above those clouds? In the past few years,
videos have appeared on the web detailing an unusual but little known phenomenon: rapid light changes over clouds. Upon inspection and contemplation, a
leading hypothesis for its cause has now emerged. In sum,
this hypothesis holds that a lightning discharge in a thundercloud can temporarily change the
electric field above the cloud where charged ice crystals were reflecting sunlight. The new electric field quickly re-orients the
geometric crystals to a new orientation that
reflects sunlight differently. In other words, a
lightning discharge can cause a
sundog to jump. Soon, the old electric field may be restored, causing the
ice crystals to return to their original orientation. To help this curious phenomenon become better studied, sky enthusiasts with similar
jumping or
dancing sundog videos are encouraged to share them.
Asteroid 2005 YU55 passed by the Earth yesterday, posing no danger. The space rock,
estimated to be about 400 meters across, coasted by just inside the orbit of Earth's Moon. Although the passing of smaller rocks near the Earth is
not very unusual -- in fact small rocks from space strike Earth daily -- a rock this large hasn't passed this close since 1976. Were
YU55 to have struck land, it might have caused a
magnitude seven
earthquake and left a city-sized
crater. A perhaps larger danger would have occurred were
YU55 to have struck the ocean and raised a large
tsunami. The above
radar image was taken two days ago by the
Deep Space Network radio telescope in
Goldstone,
California,
USA.
YU55 was discovered only in 2005, indicating that other
potentially hazardous asteroids might lurk in
our Solar System currently undetected. Objects like YU55 are hard to detect because they are so faint and
move so fast. However, humanity's ability to scan the sky to detect, catalog, and analyze such objects has
increased notably in recent years.
In 185 AD,
Chinese astronomers recorded the appearance of a new star in the Nanmen asterism - a part of the sky identified with Alpha and Beta Centauri on modern star charts. The new star was visible for months and is thought to be the earliest
recorded supernova. This
multiwavelength composite image from orbiting telescopes of the 21st century, XMM-Newton and Chandra in X-rays, and Spitzer and WISE in infrared,
show supernova remnant RCW 86, understood to be the remnant of that
stellar explosion. The
false-color view shows interstellar gas heated by the expanding supernova shock wave at X-ray energies (blue and green) and interstellar dust radiating at cooler temperatures in infrared light (yellow and red). An abundance of the element iron and lack of a neutron star or pulsar in the remnant suggest that the original supernova was Type Ia.
Type Ia supernovae are thermonuclear explosions that
destroy a white dwarf star as it accretes material from a companion in a binary star system. Shock velocities
measured in the X-ray emitting shell and infrared dust temperatures indicate that the remnant is expanding extremely rapidly into a remarkable low density bubble created before the explosion by the white dwarf system. Near the plane of our
Milky Way Galaxy, RCW 86 is about 8,200 light-years away and has an estimated radius of 50 light-years.
Big, bright, and beautiful,
spiral galaxy M83 lies a mere twelve million light-years away, near the southeastern tip of the very long constellation
Hydra. This
cosmic close-up, a mosaic based on data from the Hubble Legacy Archive, traces dark dust and young, blue star clusters along prominent spiral arms that lend M83 its nickname, The Southern Pinwheel. Typically found near the edges of the thick dust lanes, a wealth of reddish
star forming regions also suggest another popular moniker for M83,
The Thousand-Ruby Galaxy. Dominated by light from older stars, the bright yellowish core of M83 lies at the upper right. The core is also bright
at x-ray energies that reveal a high concentration of neutron stars and black holes left from an intense burst of star formation. In fact, M83 is a member of a group of galaxies that includes active galaxy
Centaurus A. The close-up field of view spans over 25,000 light-years at the estimated distance
of M83.
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.
<- 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 November 6-12, 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=25796][color=#4040FF][b]<- Previous week's poll[/b][/color][/url][/size]
[hr][/hr]
[c][url=http://apod.nasa.gov/apod/ap111107.html][size=150][b]Star Forming Region S106 (2011 Nov 07)[/b][/size][/url][/c]
[float=left][img6="Image Credit: GRANTECAN and IAC"]http://apod.nasa.gov/apod/image/1111/s106_canarias_900.jpg[/img6][hr][/hr][/float]Massive star IRS 4 is beginning to spread its wings. Born only about 100,000 years ago, material streaming out from this newborn star has formed the nebula dubbed Sharpless 2-106 Nebula (S106), pictured above. A large disk of [url=http://apod.nasa.gov/apod/ap030706.html]dust[/url] and gas orbiting Infrared Source 4 (IRS 4), visible in dark red near the image center, gives the nebula an [url=http://apod.nasa.gov/apod/ap000604.html]hourglass[/url] or [url=http://apod.nasa.gov/apod/ap090910.html]butterfly[/url] shape. [url=http://www.mpia-hd.mpg.de/IRCAM/OPRIME/Gallery/ASTRO/S106.html]S106[/url] gas near IRS 4 acts as an [url=http://apod.nasa.gov/apod/emission_nebulae.html]emission nebula[/url] as it emits light after being [url=http://csep10.phys.utk.edu/astr162/lect/light/ionization.html]ionized[/url], while [url=http://ned.ipac.caltech.edu/level5/Mathis/Mathis1.html]dust[/url] far from [url=http://adsabs.harvard.edu/abs/2009AJ....137.3149S]IRS 4[/url] reflects light from the central star and so acts as a [url=http://apod.nasa.gov/apod/reflection_nebulae.html]reflection nebula[/url]. Detailed inspection of [url=http://www.naoj.org/Pressrelease/2001/02/13/index.html]images like the above[/url] image has revealed hundreds of low-mass [url=http://en.wikipedia.org/wiki/Brown_dwarf]brown dwarf stars[/url] lurking in [url=http://adsabs.harvard.edu/abs/1998AJ....116.1868B]the nebula's[/url] gas. S106 spans about 2 [url=http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html]light-years[/url] and lies about 2000 light-years away toward the [url=http://en.wikipedia.org/wiki/Constellation]constellation[/url] of the Swan ([url=http://www.astro.wisc.edu/~dolan/constellations/constellations/Cygnus.html]Cygnus[/url]).
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[c][url=http://apod.nasa.gov/apod/ap111108.html][size=150][b]Jumping Sundogs Over Thunderclouds (2011 Nov 08)[/b][/size][/url][/c]
[float=left][youtube6]http://www.youtube.com/watch?v=E4sY98zsBH0[/youtube6]
[size=85]Image Credit: abrigatti, YouTube[/size][/float]What's happening above those clouds? In the past few years, [url=http://amasci.com/amateur/sundog.html]videos have appeared[/url] on the web detailing an unusual but little known phenomenon: rapid light changes over clouds. Upon inspection and contemplation, a [url=http://forgetomori.com/2011/science/leaping-streams-of-light-a-new-natural-phenomenon/]leading hypothesis[/url] for its cause has now emerged. In sum, [url=http://blogs.discovermagazine.com/badastronomy/2011/10/25/amazing-video-of-a-bizarre-twisting-dancing-cloud/]this hypothesis[/url] holds that a lightning discharge in a thundercloud can temporarily change the [url=http://www.its.caltech.edu/~phys1/java/phys1/EField/EField.html]electric field[/url] above the cloud where charged ice crystals were reflecting sunlight. The new electric field quickly re-orients the [url=http://www.atoptics.co.uk/halo/crystals.htm]geometric crystals[/url] to a new orientation that [url=http://apod.nasa.gov/apod/ap110818.html]reflects sunlight[/url] differently. In other words, a [url=http://apod.nasa.gov/apod/ap100720.html]lightning discharge[/url] can cause a [url=http://apod.nasa.gov/apod/ap990823.html]sundog[/url] to jump. Soon, the old electric field may be restored, causing the [url=http://commons.wikimedia.org/wiki/File:Snow_crystals.jpg]ice crystals[/url] to return to their original orientation. To help this curious phenomenon become better studied, sky enthusiasts with similar [url=http://www.youtube.com/watch?v=Hly0vuXPG-M]jumping[/url] or [url=http://www.youtube.com/watch?v=ZDWTjkHb9nY]dancing[/url] sundog videos are encouraged to share them.
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[hr][/hr]
[c][url=http://apod.nasa.gov/apod/ap111109.html][size=150][b]Asteroid 2005 YU55 Passes the Earth (2011 Nov 09)[/b][/size][/url][/c]
[float=left][img6="Image Credit: Deep Space Network, JPL, NASA"]http://apod.nasa.gov/apod/image/1111/yu55_dsn_900.jpg[/img6][hr][/hr][/float]Asteroid 2005 YU55 passed by the Earth yesterday, posing no danger. The space rock, [url=http://www.jpl.nasa.gov/news/news.cfm?release=2011-343]estimated[/url] to be about 400 meters across, coasted by just inside the orbit of Earth's Moon. Although the passing of smaller rocks near the Earth is [url=http://apod.nasa.gov/apod/ap110306.html]not very unusual[/url] -- in fact small rocks from space strike Earth daily -- a rock this large hasn't passed this close since 1976. Were [url=http://en.wikipedia.org/wiki/YU55]YU55[/url] to have struck land, it might have caused a [url=http://www.geo.mtu.edu/UPSeis/magnitude.html]magnitude[/url] seven [url=http://www.youtube.com/watch?v=XqTNfNQjrug]earthquake[/url] and left a city-sized [url=http://apod.nasa.gov/apod/ap090517.html]crater[/url]. A perhaps larger danger would have occurred were [url=http://www.nasa.gov/mission_pages/asteroids/multimedia/yu55-20111107.html]YU55[/url] to have struck the ocean and raised a large [url=http://en.wikipedia.org/wiki/Tsunami]tsunami[/url]. The above [url=http://photojournal.jpl.nasa.gov/catalog/PIA15019]radar image[/url] was taken two days ago by the [url=http://deepspace.jpl.nasa.gov/dsn/]Deep Space Network[/url] radio telescope in [url=http://deepspace.jpl.nasa.gov/dsn/features/goldstonetours.html]Goldstone[/url], [url=http://en.wikipedia.org/wiki/California]California[/url], [url=http://en.wikipedia.org/wiki/United_States]USA[/url]. [url=http://en.wikipedia.org/wiki/YU55]YU55[/url] was discovered only in 2005, indicating that other [url=http://neo.jpl.nasa.gov/]potentially hazardous asteroids[/url] might lurk in [url=http://space.jpl.nasa.gov/]our Solar System[/url] currently undetected. Objects like YU55 are hard to detect because they are so faint and [url=http://apod.nasa.gov/apod/ap060328.html]move[/url] so fast. However, humanity's ability to scan the sky to detect, catalog, and analyze such objects has [url=http://spacewatch.lpl.arizona.edu/]increased notably[/url] in recent years.
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[hr][/hr]
[c][url=http://apod.nasa.gov/apod/ap111110.html][size=150][b]RCW 86: Historical Supernova Remnant (2011 Nov 10)[/b][/size][/url][/c]
[float=left][img6="Credit: X-ray: XMM-Newton, Chandra / IR: WISE, Spitzer"]http://apod.nasa.gov/apod/image/1111/rcw86_IRXraycomposite960.jpg[/img6][hr][/hr][/float] In 185 AD, [url=http://en.wikipedia.org/wiki/Chinese_astronomy]Chinese astronomers[/url] recorded the appearance of a new star in the Nanmen asterism - a part of the sky identified with Alpha and Beta Centauri on modern star charts. The new star was visible for months and is thought to be the earliest [url=http://arxiv.org/abs/astro-ph/0301603]recorded supernova[/url]. This [url=http://coolcosmos.ipac.caltech.edu/cosmic_classroom/multiwavelength_astronomy/multiwavelength_astronomy/]multiwavelength[/url] composite image from orbiting telescopes of the 21st century, XMM-Newton and Chandra in X-rays, and Spitzer and WISE in infrared, [url=http://www.spitzer.caltech.edu/news/1324-ssc2011-09-NASA-Telescopes-Help-Solve-Ancient-Supernova-Mystery]show supernova remnant RCW 86[/url], understood to be the remnant of that [url=http://apod.nasa.gov/apod/ap060728.html]stellar explosion[/url]. The [url=http://www.spitzer.caltech.edu/images/4777-nhsc2011-09b-All-Eyes-on-Oldest-Recorded-Supernova]false-color view[/url] shows interstellar gas heated by the expanding supernova shock wave at X-ray energies (blue and green) and interstellar dust radiating at cooler temperatures in infrared light (yellow and red). An abundance of the element iron and lack of a neutron star or pulsar in the remnant suggest that the original supernova was Type Ia. [url=http://en.wikipedia.org/wiki/Type_Ia_supernova]Type Ia supernovae[/url] are thermonuclear explosions that [url=http://apod.nasa.gov/apod/ap110430.html]destroy[/url] a white dwarf star as it accretes material from a companion in a binary star system. Shock velocities [url=http://arxiv.org/abs/1108.1207]measured in[/url] the X-ray emitting shell and infrared dust temperatures indicate that the remnant is expanding extremely rapidly into a remarkable low density bubble created before the explosion by the white dwarf system. Near the plane of our [url=http://apod.nasa.gov/apod/ap110520.html]Milky Way[/url] Galaxy, RCW 86 is about 8,200 light-years away and has an estimated radius of 50 light-years.
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[c][url=http://apod.nasa.gov/apod/ap111111.html][size=150][b]In the Arms of M83 (2011 Nov 11)[/b][/size][/url][/c]
[float=left][img6="Credit: Hubble Legacy Archive, ESA, NASA; Processing and additional imaging - Robert Gendler"]http://apod.nasa.gov/apod/image/1111/M83_HSTgendler600h.jpg[/img6][hr][/hr][/float]Big, bright, and beautiful, [url=http://www.seds.org/messier/m/m083.html]spiral galaxy M83[/url] lies a mere twelve million light-years away, near the southeastern tip of the very long constellation [url=http://www.hawastsoc.org/deepsky/hya/index.html]Hydra[/url]. This [url=http://www.robgendlerastropics.com/M83-HST-Gendler.html]cosmic close-up, a mosaic[/url] based on data from the Hubble Legacy Archive, traces dark dust and young, blue star clusters along prominent spiral arms that lend M83 its nickname, The Southern Pinwheel. Typically found near the edges of the thick dust lanes, a wealth of reddish [url=http://apod.nasa.gov/apod/ap061123.html]star forming regions[/url] also suggest another popular moniker for M83, [url=http://www.eso.org/public/news/eso0825/]The Thousand-Ruby Galaxy[/url]. Dominated by light from older stars, the bright yellowish core of M83 lies at the upper right. The core is also bright [url=http://apod.nasa.gov/apod/ap030206.html]at x-ray energies[/url] that reveal a high concentration of neutron stars and black holes left from an intense burst of star formation. In fact, M83 is a member of a group of galaxies that includes active galaxy [url=http://apod.nasa.gov/apod/ap080110.html]Centaurus A[/url]. The close-up field of view spans over 25,000 light-years at the estimated distance [url=http://hubblesite.org/newscenter/archive/releases/2009/29/]of M83[/url].
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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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[size=110][url=http://asterisk.apod.com/viewtopic.php?f=29&t=25796][color=#4040FF][b]<- Previous week's poll[/b][/color][/url][/size]