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Baby Stars Brewing in the Wi
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| Title |
Baby Stars Brewing in the Witch Head Nebula |
| Description |
Eight hundred light-years away in the Orion constellation, a gigantic murky cloud called the "Witch Head Nebula" is teeming with dust-obscured newborn stars waiting to be uncovered. In this image, the super sensitive infrared eyes of NASA's Spitzer Space Telescope reveals 12 new baby stars in a small portion of the cloud commonly referred to as the Witch Head's "pointy chin." Observations are currently underway to search for infant stars in the rest of the cloud. The image is a four-color composite where blue represents 3.6 microns, green depicts 4.5 microns, yellow is 5.8 microns, and red is 8.0 microns. |
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Baby Stars in the Witch Head
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| Title |
Baby Stars in the Witch Head Nebula |
| Description |
Eight hundred light-years away in the Orion constellation, a gigantic murky cloud called the "Witch Head" nebula is brewing baby stars. The stellar infants are revealed as pink dots in this image from NASA's Spitzer Space Telescope. Wisps of green in the cloud are carbon-rich molecules called polycyclic aromatic hydrocarbons, which are found on barbecue grills and in automobile exhaust on Earth. This image was obtained as part of the Spitzer Space Telescope Research Program for Teachers and Students, involving high school teachers and their students from across the United States. The infrared image is a three-color composite, in which light with a wavelength of 4.5 microns is blue, 8.0-micron light is green, and 24-micron light is red. |
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Eta and Keyhole in the Carin
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| Title |
Eta and Keyhole in the Carina Nebula |
| Explanation |
South is toward the top in this colorful close-up [ http://www.southern-astro.com.au/gallery.php?PhotoID=13 ] view of the Great Carina Nebula [ http://www.seds.org/Messier/xtra/ngc/n3372.html ] (NGC 3372), famous star-forming region of the southern sky. Covering an area surrounding the dusty Keyhole Nebula [ http://heritage.stsci.edu/2000/06/index.html ] (NGC 3324) near picture center, the image spans about 40 light-years within the larger Carina Nebula [ http://etacar.umn.edu/etainfo/images/index.html#wide ] at an estimated distance of 7,500 light-years. Like the more northerly Orion Nebula, the bright Carina Nebula [ http://www.noao.edu/image_gallery/html/im0667.html ] is easily visible to the naked-eye. But the dramatic colors in this telescopic picture are mapped colors [ http://hubblesite.org/sci.d.tech/ behind_the_pictures/meaning_of_color/eagle.shtml ], based on three exposures through narrow filters each intended to record the light emitted by specific atoms in the gaseous nebula. Sulfur is shown in blue, hydrogen in green and oxygen in red hues. The Carina Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap051015.html ] is home to young, extremely massive stars, including the still enigmatic [ http://arxiv.org/abs/astro-ph/0603168 ] variable Eta Carinae [ http://www.seds.org/messier/xtra/ngc/etacar.html ], a star with well over 100 times the mass of the Sun. Highlighted by diffraction [ http://antwrp.gsfc.nasa.gov/apod/ap010415.html ] spikes, Eta is just above [ http://etacar.umn.edu/etainfo/basic/ ] and right (east) of the Keyhole. |
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NGC 1999: Reflection Nebula
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| Title |
NGC 1999: Reflection Nebula in Orion |
| Explanation |
A dusty bright nebula [ http://home.wxs.nl/~geldo006/brigneb.html ] contrasts dramatically with a dusty dark nebula in this Hubble Space Telescope image [ http://oposite.stsci.edu/pubinfo/pr/2000/10/index.html ] recorded shortly after December's orbital servicing mission [ http://hubble.gsfc.nasa.gov/ ]. The nebula [ http://oposite.stsci.edu/pubinfo/pr/2000/10/faq.html ], cataloged as NGC [ http://antwrp.gsfc.nasa.gov/apod/ap990429.html ] 1999, is a reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ], which shines by reflecting light from a nearby star. Unlike emission nebulae [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], whose reddish glow [ http://antwrp.gsfc.nasa.gov/apod/ap980828.html ] comes from excited atoms of gas, reflection nebulae have a bluish cast [ http://www.physics.muni.cz/~ondra/mix/mix.html ] as their interstellar dust grains [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] preferentially reflect blue starlight. While perhaps the most famous reflection nebulae surround the bright young stars of the Pleiades [ http://antwrp.gsfc.nasa.gov/apod/ap000227.html ] star cluster, NGC 1999's stellar illumination is provided by the embedded variable star V380 [ http://donald.phast.umass.edu/research/comap/V380sm.html ] Orionis, seen here just left of center. Extending right of center, the ominous [ http://antwrp.gsfc.nasa.gov/apod/ap990226.html ] dark nebula [ http://antwrp.gsfc.nasa.gov/apod/dark_nebulae.html ] is actually a condensation of cold molecular gas and dust so thick and dense that it blocks light. From our perspective it lies in front of the bright nebula, silhouetted against the ghostly nebular glow. New stars [ http://dsnra.jpl.nasa.gov/origins/nyt.html ] will likely form within the dark cloud, called a Bok globule [ http://antwrp.gsfc.nasa.gov/apod/ap961229.html ], as self-gravity continues to compress its dense gas and dust. Reflection nebula NGC 1999 [ http://heritage.stsci.edu/public/ 2000mar2/ngc1999table.html ] lies about 1500 light-years away in the constellation Orion [ http://www.seds.org/messier/more/oricloud.html ], just south of Orion's well known emission nebula, M42 [ http://antwrp.gsfc.nasa.gov/apod/ap990522.html ]. |
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Barnard's Loop around the Ho
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| Title |
Barnard's Loop around the Horsehead Nebula |
| Explanation |
Why is the Horsehead Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap030713.html ] surrounded by a bubble? Although glowing like an emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], the origin of the bubble [ http://antwrp.gsfc.nasa.gov/apod/ap050420.html ], known as Barnard's Loop [ http://weblore.com/richard/barnard's_loop.htm ], is currently unknown. Progenitor hypotheses include the wind [ http://www-spof.gsfc.nasa.gov/Education/wsolwind.html ]s from bright Orion stars and the supernovas [ http://heasarc.gsfc.nasa.gov/docs/snr.html ] of stars long gone. Barnard's Loop [ http://www.seds.org/messier/xtra/ngc/b-loop.html ] is too faint to be identified with the unaided eye. The nebula [ http://en.wikipedia.org/wiki/Barnard%27s_Loop ] was discovered only in 1895 by E. E. Barnard [ http://astro.uchicago.edu/yerkes/virtualmuseum/Barnardfull.html ] on long duration film exposures. The above image was taken in a single specific color [ http://en.wikipedia.org/wiki/Hydrogen_alpha ] emitted by hydrogen [ http://periodic.lanl.gov/elements/1.html ] to bring out detail. To the left of the Horsehead Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap040115.html ], visible as the small dark indentation near the image top, is the photogenic Flame Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap990713.html ]. |
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Reflection Nebula M78
| Title |
Reflection Nebula M78 |
| Explanation |
An eerie blue glow and ominous columns of dark dust highlight M78, a bright reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] in the constellation of Orion [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Orion.html ]. The dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] not only absorbs light, but also reflects the light of several bright blue stars that formed recently [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1975ApJ...196..489S ] in the nebula. The same type of scattering that colors the daytime sky [ http://math.ucr.edu/home/baez/physics/blue_sky.html ] further enhances the blue color. M78 [ http://www.seds.org/messier/m/m078.html ] is about five light-years [ http://www.glyphweb.com/esky/concepts/lightyear.html ] across and visible through a small telescope. M78 appears above [ http://www.sdss.org/gallery/gal_data.html ] only as it was 1600 years ago, however, because that is how long it takes light to go from there [ http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1975ApJ...195L..23B ] to here. M78 [ http://www.airdigital.com/M78.html ] belongs to the larger Orion Molecular Cloud Complex [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ] that contains the Great Nebula in Orion [ http://antwrp.gsfc.nasa.gov/apod/ap980127.html ] and the Horsehead Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap990519.html ]. |
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Horse Head Shaped Reflection
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| Title |
Horse Head Shaped Reflection Nebula IC 4592 |
| Explanation |
Do you see the horse's head? What you are seeing is not the famous Horsehead nebula [ http://antwrp.gsfc.nasa.gov/apod/ap051130.html ] toward Orion but rather a fainter nebula that only takes on a familiar form with deeper imaging. The main part of the above imaged [ http://www.robgendlerastropics.com/IC4592JM.html ] molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap060409.html ] complex is a reflection nebula [ http://en.wikipedia.org/wiki/Reflection_nebula ] cataloged as IC 4592 [ http://aisig.sdaa.org/astroblogDetail.asp?imgID=1035&UserID=66 ]. Reflection nebulas are actually made up of very fine dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] that normally appears dark but can look quite blue when reflecting the light of energetic nearby stars. In this case, the source of much of the reflected light is a star at the eye of the horse. That star is part of Nu Scorpii [ http://en.wikipedia.org/wiki/Nu_Scorpii ], one of the brighter star systems toward the constellation of Scorpius [ http://www.astro.uiuc.edu/~kaler/sow/sco-t.html ]. A second reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] dubbed IC 4601 is visible surrounding two stars on the far right. |
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NGC 1499: The California Neb
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| Title |
NGC 1499: The California Nebula |
| Explanation |
What's California doing in space? Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud [ http://www.anzwers.org/free/universe/nebulae/ ngc1499.html ] by chance echoes the outline of California [ http://en.wikipedia.org/wiki/California ] on the west coast of the United States [ https://www.cia.gov/cia/publications/factbook/geos/us.html ]. Our own Sun also lies within the Milky Way's Orion Arm [ http://www.anzwers.org/free/universe/5000lys.html ], only about 1,500 light-years from the California Nebula [ http://en.wikipedia.org/wiki/California_Nebula ]. Also known as NGC 1499 [ http://www.seds.org/~spider/spider/ Misc/n1499.html ], the classic emission nebula is around 100 light-year [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ]s long. It glows with the red light characteristic of hydrogen atoms recombining with long lost [ http://antwrp.gsfc.nasa.gov/apod/lib/lament.html ] electrons, stripped away (ionized [ http://csep10.phys.utk.edu/ astr162/lect/light/ionization.html ]) by energetic starlight. In this case, the star most likely providing the energetic starlight is the bright, hot, bluish Xi Persei, just right of the nebula and above picture center. Fittingly, this composite [ http://www.astro.caltech.edu/~wsk/ngc1499.html ] picture was made with images from a telescope in California - the 48-inch (1.2-meter) Samuel Oschin Telescope [ http://www.astro.caltech.edu/~wsk/sot.html ] - taken as a part of the second National Geographic Palomar [ http://antwrp.gsfc.nasa.gov/apod/ap030807.html ] Observatory Sky Survey [ http://www.astro.caltech.edu/~wws/poss2.html ]. |
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Orion's Horsehead Nebula
| Title |
Orion's Horsehead Nebula |
| Explanation |
The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the black indentation to the red emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] seen just to the right of center of the above photograph. The bright star near the center is located in the belt of the familiar constellation of Orion. The horse-head [ http://antwrp.gsfc.nasa.gov/apod/ap990519.html ] feature is dark because it is really an opaque dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] cloud which lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will alter its appearance. The emission nebula [ http://www.seds.org/billa/twn/types.html ]'s red color is caused by electrons [ http://www.aip.org/history/electron/ ] recombining with protons [ http://www.neutron.anl.gov/proton.htm ] to form hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ] atoms. Also visible in the picture are blue reflection nebulae [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ], which preferentially reflect the blue light [ http://antwrp.gsfc.nasa.gov/apod/ap000227.html ] from nearby stars. |
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M42: Wisps of the Orion Nebu
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| Title |
M42: Wisps of the Orion Nebula |
| Explanation |
The Great Nebula in Orion [ http://www.seds.org/billa/twn/n1976x.html ], an immense, nearby starbirth region [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ], is probably the most famous of all astronomical nebulas [ http://www.seds.org/billa/twn/ ]. Here, glowing gas [ http://fusedweb.pppl.gov/CPEP/Chart_Pages/5.Plasmas/Nebula/Emission.html ] surrounds hot young stars at the edge of an immense [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ] interstellar molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap030202.html ] only 1500 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away. In the above deep image [ http://christensenastroimages.com/nebula/m42_2005.htm ], faint wisps and sheets of dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] and gas are particularly evident. The Great Nebula in Orion [ http://www.seds.org/messier/m/m042.html ] can be found with the unaided eye just below and to the left of the easily identifiable [ http://antwrp.gsfc.nasa.gov/apod/ap021225.html ] belt of three stars in the popular constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] Orion [ http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=60 ]. In addition to housing a bright open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars known as the Trapezium [ http://antwrp.gsfc.nasa.gov/apod/ap971118.html ], the Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap061120.html http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?Orion+Nebula ] contains many stellar nurseries [ http://archive.ncsa.uiuc.edu/Cyberia/Bima/StarForm.html ]. These nurseries contain hydrogen [ http://periodic.lanl.gov/elements/1.html ] gas, hot young stars, proplyds [ http://antwrp.gsfc.nasa.gov/apod/ap961017.html ], and stellar jets [ http://antwrp.gsfc.nasa.gov/apod/ap991129.html ] spewing material at high speeds. Also known as M42 [ http://antwrp.gsfc.nasa.gov/apod/ap020213.html ], the Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap980421.html ] spans about 40 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] and is located in the same spiral arm [ http://www.anzwers.org/free/universe/5000lys.html ] of our Galaxy [ http://adc.gsfc.nasa.gov/mw/mmw_images.html ] as the Sun [ http://www.nineplanets.org/sol.html ]. |
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IC 2118: The Witch Head Nebu
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| Title |
IC 2118: The Witch Head Nebula |
| Explanation |
Double, double toil and trouble, Fire burn, and cauldron bubble -- maybe Macbeth [ http://the-tech.mit.edu/Shakespeare/macbeth/ ] should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] is associated with the bright star Rigel [ http://www.astro.uiuc.edu/~kaler/sow/rigel.html ] in the constellation Orion [ http://www.astro.uiuc.edu/~kaler/sow/orion-p.html ]. More formally known as IC 2118 [ http://www.astrocruise.com/ic2118.htm ], the Witch Head Nebula glows primarily by light reflected from bright star Rigel [ http://adsabs.harvard.edu/cgi-bin/ nph-bib_query?bibcode=1997MNRAS.290..521I ], located just off the upper right edge of the full image. Fine dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] in the nebula reflects the light. The blue color is caused not only by Rigel [ http://en.wikipedia.org/wiki/Rigel ]'s blue color but because the dust grains reflect blue light [ http://leo.astronomy.cz/mix/mix.html ] more efficiently than red. The same physical process [ http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html ] causes Earth's daytime sky to appear blue [ http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html ], although the scatterers in Earth's atmosphere [ http://liftoff.msfc.nasa.gov/academy/space/atmosphere.html ] are molecules of nitrogen [ http://periodic.lanl.gov/elements/7.html ] and oxygen [ http://periodic.lanl.gov/elements/8.html ]. The nebula lies about 1000 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away. |
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NGC 2174: Emission Nebula in
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| Title |
NGC 2174: Emission Nebula in Orion |
| Explanation |
A lesser known sight in the nebula-rich [ http://antwrp.gsfc.nasa.gov/apod/ap061015.html ] constellation Orion, NGC 2174 [ http://www.astropix.com/HTML/B_WINTER/NGC2174.HTM ] can be found with binoculars near the head of the celestial hunter [ http://www.windows.ucar.edu/tour/link=/the_universe/ Constellations/orion.html&edu=high ]. About 6,400 light-years distant, the glowing cosmic cloud surrounds loose clusters of young stars. Covering an area larger than the full Moon on the sky, this stunning narrow band image [ http://www.photonhunter.com/nebulae/NGC2174.html ] adopts a typical color mapping of the atomic emission from NGC 2174. The false-color mapping [ http://hubblesite.org/gallery/behind_the_pictures/ meaning_of_color/eagle.shtml ] shows otherwise red hydrogen emission in green hues and emphasizes sulfur emission in red and oxygen in blue. Placing your cursor on the image will reveal an alternative image of the nebula made through broad band filters [ http://hubblesite.org/gallery/behind_the_pictures/ meaning_of_color/filters.shtml ]. The broad band image combines filters in a closer analogy [ http://hubblesite.org/gallery/behind_the_pictures/ meaning_of_color/rgb.shtml ] to human vision, dominated by the red glow [ http://antwrp.gsfc.nasa.gov/apod/ap060324.html ] of hydrogen. |
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The Orion Nebula in Hydrogen
| Title |
The Orion Nebula in Hydrogen |
| Explanation |
The Great Nebula in Orion [ http://nineplanets.org/twn/n1976x.html ] can be found just below and to the left of the easily identifiable belt of three stars in the popular constellation Orion [ http://www.seds.org/Maps/Stars_en/Fig/orion.html ]. This fuzzy patch, visible to the unaided eye [ http://antwrp.gsfc.nasa.gov/apod/ap970825.html ], contains one of the closest stellar nurseries [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ], lying at a distance of about 1500 light years [ http://www.howstuffworks.com/question94.htm ]. The above picture [ http://robgendler.astrodigitals.com/Nebulas.html ] highlights red light emitted by the nebula's hydrogen [ http://school.discovery.com/homeworkhelp/worldbook/atozscience/h/268980.html ] gas. Dark dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] filaments punctuate regions of this glowing hydrogen gas and reflect light from the nebula's brightest stars [ http://antwrp.gsfc.nasa.gov/apod/ap971118.html ]. Recent observations of the Orion Nebula [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?m42 ] by the Hubble Space Telescope [ http://www.stsci.edu/hst/ ] have located solar-system sized regions [ http://antwrp.gsfc.nasa.gov/apod/ap990228.html ] that are thought to be planet-forming circumstellar disks. |
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Flame Nebula Close-Up
| Title |
Flame Nebula Close-Up |
| Explanation |
Of course, the Flame Nebula is not on fire. Also known as NGC 2024 [ http://www.astropix.com/HTML/B_WINTER/NGC2024.HTM ], the nebula's suggestive reddish color is due to the glow of hydrogen [ http://antwrp.gsfc.nasa.gov/apod/lib/lament.html ] atoms at the edge of the giant Orion [ http://antwrp.gsfc.nasa.gov/apod/ap070125.html ] molecular cloud complex some 1,500 light-years away. The hydrogen atoms have been ionized [ http://csep10.phys.utk.edu/astr162/lect/light/ ionization.html ], or stripped of their electrons, and glow as the atoms and electrons recombine. But what ionizes the hydrogen [ http://casswww.ucsd.edu/public/tutorial/ISM.html ] atoms? In this close-up view [ http://www.robgendlerastropics.com/FlameNM.html ], a dark lane of absorbing interstellar dust stands out in silhouette against the hydrogen glow [ http://vis.sdsc.edu/research/hayden2.html ] and actually hides the true source of the Flame Nebula's energy from optical telescopes. Behind the dark lane lies a cluster of hot, young stars, seen at infrared wavelengths [ http://www.astro.caltech.edu/palomar/flame.html ] through the obscuring dust. A young, massive star in that cluster is the likely source [ http://arxiv.org/abs/astro-ph/0303029 ] of energetic ultraviolet radiation that ionizes the hydrogen gas in the Flame Nebula. |
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The Dark Horsehead Nebula
| Title |
The Dark Horsehead Nebula |
| Explanation |
While drifting through the cosmos this magnificent interstellar dust cloud, sculpted by stellar winds and radiation, has chanced to assume a recognizable shape. Fittingly named The Horsehead Nebula [ http://www.seds.org/billa/twn/b33x.html ] it is embedded in the immense complex of star forming gas and dust [ http://antwrp.gsfc.nasa.gov/apod/ap000924.html ] surrounding the Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap990522.html ] some 1,500 light-years distant. The dark nebula [ http://antwrp.gsfc.nasa.gov/apod/dark_nebulae.html ] is cataloged as Barnard [ http://astro.uchicago.edu/yerkes/ virtualmuseum/Barnard.html ] 33 and is visible only because its obscuring dust is silhouetted against the bright emission nebulae [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] which lie behind it. In fact, the prominent horse head portion [ http://antwrp.gsfc.nasa.gov/apod/ap980806.html ] of the nebula is really just part of a larger cloud of dust which can be seen extending off the bottom of the picture. A potentially rewarding but difficult object to view with a small instrument, this gorgeous color image [ http://www.ghg.net/akelly/ ] is a composite of exposures made with a digital camera and astronomical BVR filters [ http://herbie.ucolick.org/techdocs/ filters/phot_filt_curves.html ] using a 1-meter diameter telescope. |
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The Orion Nebula from VLT
| Title |
The Orion Nebula from VLT |
| Explanation |
The Great Nebula in Orion is a colorful place. Visible to the unaided eye, it appears as a small fuzzy patch [ http://antwrp.gsfc.nasa.gov/apod/ap970825.html ] in the constellation of Orion [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Orion.html ]. But this image [ http://www.eso.org/outreach/press-rel/pr-2001/phot-03-01.html ], a representative-color composite of 81 near-infrared light [ http://www.ipac.caltech.edu/Outreach/Edu/infrared.html ] images taken with VLT's ISAAC [ http://www.eso.org/instruments/isaac/ ], shows the Orion Nebula [ http://www-astronomy.mps.ohio-state.edu/~ryden/ast162_3/notes14.html ] to be a busy neighborhood of young stars, hot gas, and dark dust. The power behind much of the Orion Nebula [ http://www.seds.org/billa/twn/n1976x.html ] (M42) is the Trapezium [ http://antwrp.gsfc.nasa.gov/apod/ap971118.html ] - four of the brightest stars in the nebula. The eerie blue glow surrounding the bright stars pictured here is their own starlight reflected [ http://antwrp.gsfc.nasa.gov/apod/ap990829.html ] by nearby dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ]. Dark brown dust filaments [ http://antwrp.gsfc.nasa.gov/apod/ap980318.html ] cover much of the region [ http://antwrp.gsfc.nasa.gov/apod/ap980612.html ]. The whole Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ] cloud complex, which includes [ http://antwrp.gsfc.nasa.gov/apod/ap990103.html ] the Horsehead Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000827.html ], will slowly disperse over the next 100,000 years. |
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The Witch Head Nebula
| Title |
The Witch Head Nebula |
| Explanation |
Double, double toil and trouble, Fire burn, and cauldron bubble -- maybe Macbeth [ http://tech-two.mit.edu/Shakespeare/macbeth/index.html ] should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] is associated with the bright star Rigel [ http://www.astro.uiuc.edu/~kaler/sow/rigel.html ] in the constellation Orion [ http://www.astro.uiuc.edu/~kaler/sow/orion-p.html ]. More formally known as IC 2118 [ http://www.astrocruise.com/ic2118.htm ], the Witch Head Nebula glows primarily by light reflected from Rigel [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997MNRAS.290..521I ], located just outside the top right corner of the above image [ http://home.earthlink.net/~gstevens914/pwitch.htm ]. Fine dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] in the nebula reflects the light. The blue color is caused not only by Rigel's blue color but because the dust grains reflect blue light [ http://www.physics.muni.cz/~ondra/mix/mix.html ] more efficiently than red. The same physical process [ http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html ] causes Earth's daytime sky to appear blue [ http://math.ucr.edu/home/baez/physics/blue_sky.html ], although the scatterers in Earth's atmosphere [ http://liftoff.msfc.nasa.gov/academy/space/atmosphere.html ] are molecules of nitrogen [ http://pearl1.lanl.gov/periodic/elements/7.html ] and oxygen [ http://pearl1.lanl.gov/periodic/elements/8.html ]. The nebula lies about 1000 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away. |
|
LDN 1622: Dark Nebula in Ori
…
| Title |
LDN 1622: Dark Nebula in Orion |
| Explanation |
The silhouette of an intriguing dark nebula [ http://en.wikipedia.org/wiki/Dark_nebula ] inhabits this cosmic scene, based on images from the Palomar Observatory Sky Survey [ http://www.astro.caltech.edu/~wws/poss2.html ]. Lynds' Dark Nebula (LDN [ http://heasarc.gsfc.nasa.gov/W3Browse/ nebula-catalog/ldn.html ]) 1622 appears against a faint background of glowing hydrogen gas only easily seen in long telescopic exposures of the region. LDN 1622 lies near the plane of our Milky Way Galaxy, close on the sky [ http://antwrp.gsfc.nasa.gov/apod/ap030404.html ] to Barnard's Loop [ http://www.seds.org/messier/xtra/ngc/b-loop.html ] - a large cloud surrounding the rich complex of emission nebulae [ http://antwrp.gsfc.nasa.gov/apod/ap070125.html ] found in the Belt and Sword of Orion [ http://www.gb.nrao.edu/~rmaddale/Education/OrionTourCenter/ optical.html ]. But the obscuring dust of LDN 1622 is thought to be much closer than Orion's more famous nebulae, perhaps only 500 light-years away. At that distance, this 1 degree wide field of view would span less than 10 light-years. |
|
The Horsehead Nebula
| Title |
The Horsehead Nebula |
| Explanation |
One of the most identifiable nebulae in the sky, the Horsehead Nebula [ http://www.seds.org/billa/twn/b33x.html ] in Orion [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Orion.html ], is part of a large, dark, molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010923.html ]. Also known as Barnard [ http://en.wikipedia.org/wiki/Edward_Emerson_Barnard ] 33, the unusual shape was first discovered [ http://www.seds.org/messier/xtra/ngc/b33.html ] on a photographic plate [ http://www.astro.virginia.edu/~afs5z/photography.html ] in the late 1800s. The red glow originates from hydrogen [ http://periodic.lanl.gov/elements/1.html ] gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis [ http://www.dibonsmith.com/ori_s.htm ]. The darkness of the Horsehead [ http://antwrp.gsfc.nasa.gov/apod/ap061015.html ] is caused mostly by thick dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ], although the lower part of the Horsehead [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?horsehead ]'s neck casts a shadow to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field [ http://www-spof.gsfc.nasa.gov/Education/whmfield.html ]. Bright spots in the Horsehead Nebula [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1987AJ.....93.1514Z ]'s base are young stars just in the process of forming [ http://antwrp.gsfc.nasa.gov/apod/ap070218.html ]. Light takes about 1500 years to reach us from the Horsehead Nebula [ http://heritage.stsci.edu/public/2001may/table.html ]. The above image [ http://www.noao.edu/image_gallery/html/im0057.html ] was taken with the 0.9-meter telescope [ http://www.noao.edu/0.9m/index.html ] at Kitt Peak National Observatory [ http://www.noao.edu/kpno/kpno.html ]. |
|
Tentacles of the Tarantula N
…
| Title |
Tentacles of the Tarantula Nebula |
| Explanation |
The largest, most violent star forming region known in the whole Local Group of galaxies [ http://en.wikipedia.org/wiki/Local_Group ] lies in our neighboring galaxy the Large Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap060510.html ] (LMC). Were the Tarantula Nebula at the distance of the Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap060119.html ] -- a local star forming region -- it would take up fully half the sky. Also called 30 Doradus [ http://en.wikipedia.org/wiki/30_Doradus ], the red and pink gas indicates a massive emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], although supernova remnants [ http://antwrp.gsfc.nasa.gov/apod/ap051202.html ] and dark nebula [ http://antwrp.gsfc.nasa.gov/apod/ap060409.html ] also exist there. The bright knot of stars left of center is called R136 [ http://antwrp.gsfc.nasa.gov/apod/ap051211.html ] and contains many of the most massive, hottest, and brightest stars known. The above image [ http://www.eso.org/public/outreach/press-rel/pr-2006/phot-50-06.html ] taken with the European Southern Observatory [ http://www.eso.org/public/about-eso/index.html ]'s (ESO's) Wide Field Imager [ http://www.ls.eso.org/lasilla/sciops/2p2/E2p2M/WFI/ ] is one of the most detailed ever [ http://www.eso.org/public/outreach/press-rel/pr-2006/pr-50-06.html ] of this vast star forming region. ESO has made it possible to fly around and into this detailed image by clicking here [ http://www.eso.org/public/outreach/press-rel/pr-2006/images/phot-50a-06-w0.html ]. |
|
NGC 1977: Blue Reflection Ne
…
| Title |
NGC 1977: Blue Reflection Nebula in Orion |
| Explanation |
The Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap980127.html ] is visible to the unaided eye as a fuzzy patch near the famous belt of three stars [ http://antwrp.gsfc.nasa.gov/apod/ap970820.html ] in the |
|
The Great Carina Nebula
| Title |
The Great Carina Nebula |
| Explanation |
A jewel of the southern sky [ http://antwrp.gsfc.nasa.gov/apod/ap070222.html ], the Great Carina Nebula [ http://seds.org/messier/xtra/ngc/n3372.html ], aka NGC 3372, spans over 300 light-years, one of our galaxy's [ http://antwrp.gsfc.nasa.gov/apod/ap071020.html ] largest star forming regions. Like the smaller, more northerly Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap070106.html ], the Carina Nebula is easily visible to the naked eye, though at a distance of 7,500 light-years it is some 5 times farther away. This stunning telescopic view [ http://www.robgendlerastropics.com/EtacarinaeSG.html ] reveals remarkable details of the region's glowing filaments of interstellar gas and dark cosmic dust clouds. The Carina Nebula is home to young, extremely massive stars, including the still enigmatic variable Eta Carinae [ http://etacar.umn.edu/etainfo/images/index.html#wide ], a star with well over 100 times the mass of the Sun. Eta Carinae [ http://www.astro.uiuc.edu/~kaler/sow/etacar.html ] is the bright star left of the central dark notch in this field and just below the dusty Keyhole [ http://antwrp.gsfc.nasa.gov/apod/ap060316.html ] Nebula (NGC 3324). |
|
The Horsehead Nebula
| Title |
The Horsehead Nebula |
| Explanation |
One of the most identifiable nebulae in the sky, the Horsehead Nebula [ http://www.seds.org/billa/twn/b33x.html ] in Orion [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Orion.html ], is part of a large, dark, molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010923.html ]. Also known as Barnard [ http://astro.uchicago.edu/yerkes/virtualmuseum/Barnard.html ] 33, the unusual shape was first discovered [ http://www.seds.org/messier/xtra/ngc/b33.html ] on a photographic plate [ http://www.astro.virginia.edu/~afs5z/photography.html ] in the late 1800s. The red glow originates from hydrogen [ http://chemlab.pc.maricopa.edu/periodic/h.html ] gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis [ http://www.dibonsmith.com/ori_s.htm ]. The darkness of the Horsehead [ http://antwrp.gsfc.nasa.gov/apod/ap010224.html ] is caused mostly by thick dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ], although the lower part of the Horsehead [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?horsehead ]'s neck casts a shadow to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field [ http://theory.uwinnipeg.ca/physics/mag/node6.html ]. Bright spots in the Horsehead Nebula [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1987AJ.....93.1514Z ]'s base are young stars just in the process of forming [ http://antwrp.gsfc.nasa.gov/apod/ap011125.html ]. Light takes about 1500 years to reach us from the Horsehead Nebula [ http://heritage.stsci.edu/public/2001may/table.html ]. The above image [ http://www.noao.edu/image_gallery/html/im0057.html ] was taken with the 0.9-meter telescope [ http://www.noao.edu/0.9m/manual.html ] at Kitt Peak National Observatory [ http://www.noao.edu/kpno/kpno.html ]. |
|
The Great Nebula in Orion
| Title |
The Great Nebula in Orion |
| Explanation |
The Great Nebula in Orion, M42, can be found on the night sky just below and to the left of the easily identifiable belt of three stars in the popular constellation Orion. This nebula is one of the closest stellar nurseries - where young stars are being formed even now. Clumps of gas (mostly hydrogen and helium) and dust in the nebula are squeezed together by their own gravity until they collapse and form stars. Some stars we can see here partially obscured by the nebula, are only about 100,000 years old - just babies compared to the 5 billion (5,000,000,000) years of our Sun. For more information see NASA, Hubble Space Telescope Scientific Institute press release. [ http://www.stsci.edu/ftp/stsci/epa/gif/OrionFull.txt ] |
|
Reflection Nebula M78
| Title |
Reflection Nebula M78 |
| Explanation |
An eerie blue glow and ominous columns of dark dust highlight M78 [ http://www.seds.org/messier/m/m078.html ], one of the brightest reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] on the sky. M78 is visible with a small telescope toward the constellation of Orion [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Orion.html ]. The dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] not only absorbs light, but also reflects the light of several bright blue stars that formed recently [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1975ApJ...196..489S ] in the nebula. The same type of scattering that colors the daytime sky [ http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html ] further enhances the blue color. M78 [ http://www.seds.org/messier/more/m078_m2.html ] is about five light-years [ http://www.glyphweb.com/esky/concepts/lightyear.html ] across. M78 appears above [ http://www.aao.gov.au/images/captions/aatccd017.html ] only as it was 1600 years ago, however, because that is how long it takes light to go from there [ http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1975ApJ...195L..23B ] to here. M78 [ http://www.airdigital.com/M78.html ] belongs to the larger Orion Molecular Cloud Complex [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ] that contains the Great Nebula in Orion [ http://antwrp.gsfc.nasa.gov/apod/ap980127.html ] and the Horsehead Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap011216.html ]. |
|
The Great Nebula in Orion
| Title |
The Great Nebula in Orion |
| Explanation |
Few astronomical sights excite the imagination like the nearby stellar nursery known as the Orion Nebula [ http://www.seds.org/billa/twn/n1976x.html ]. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010923.html ] only 1500 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away. The Great Nebula in Orion [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?Orion+Nebula ] can be found with the unaided eye just below and to the left of the easily identifiable belt of three stars [ http://www.spacekids.com/skywatch/eyes_skies_000124.html ] in the popular constellation Orion [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Orion.html ]. The above image [ http://www.robgendlerastropics.com/M42DM.html ] has been contrast balanced [ http://www.robgendlerastropics.com/LRGB.html ] to bring out Orion's detail in spectacular fashion. Visible simultaneously are the bright stars of the Trapezium [ http://antwrp.gsfc.nasa.gov/apod/ap971118.html ] in Orion's heart [ http://antwrp.gsfc.nasa.gov/apod/ap000830.html ], the sweeping lanes of dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] that cross the center, the pervasive red glowing hydrogen gas [ http://antwrp.gsfc.nasa.gov/apod/ap020129.html ], and the blue tinted dust [ http://antwrp.gsfc.nasa.gov/apod/ap010227.html ] that reflects the light of newborn stars. The whole Orion Nebula cloud complex [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ], which includes the Horsehead Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap011216.html ], will slowly disperse over the next 100,000 years. |
|
Orion's Horsehead Nebula
| Title |
Orion's Horsehead Nebula |
| Explanation |
The black indentation to the red emission nebula [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#emis_neb ] seen just to the right of center of the above photograph is one of the most famous features in any nebulae on the sky. Because of its shape, it is known as the Horsehead Nebula [ http://seds.lpl.arizona.edu/billa/twn/b33x.html ]. The bright star near the center is located in the belt of the familiar constellation of Orion. The horse head feature is dark because it is really a dense dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] cloud which lies in front of the bright nebula and blocks the light. Like clouds in our sky, this cosmic cloud has chanced to assume a recognizable shape. After thousands of years, the internal motions of the cloud will alter its appearance. The emission nebula [ http://zebu.uoregon.edu/textbook/ism.html ]'s red color is caused by electrons recombining with protons to form hydrogen [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#hydrogen ] atoms. Also visible in the picture are blue reflection nebulae [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#refl_neb ]. This type of nebula contains dust which preferentially reflects the blue light of nearby stars. |
|
Orion Nebula: The 2MASS View
| Title |
Orion Nebula: The 2MASS View |
| Explanation |
Few astronomical sights excite the imagination like the nearby stellar nursery [ http://antwrp.gsfc.nasa.gov/apod/ap980411.html ] known as the Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap970511.html ]. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1,500 light-years away. This distinctively detailed image [ http://www.ipac.caltech.edu/2mass/gallery/images_hii.html ] of the Orion Nebula was constructed using data from the 2 Micron All Sky Survey [ http://pegasus.phast.umass.edu/GradProg/2mass.html ] or 2MASS. Using telescopes in the [ http://pegasus.phast.umass.edu/2mass/pub/telescope.html ] Northern and Southern Hemispheres of planet Earth, the 2MASS project [ http://www.ipac.caltech.edu/2mass/overview/about2mass.html ] has mapped the entire sky in infrared light [ http://www.ipac.caltech.edu/Outreach/Edu/univ_index.html ]. The wavelength of infrared light [ http://www.ipac.caltech.edu/Outreach/Edu/ ] is longer than visible light but more easily penetrates obscuring dust clouds. 2MASS cameras were sensitve to near infrared wavelengths around 2 microns or about 0.00008 inches. Visible light has a wavelength of about 0.00002 inches. Survey observations [ http://www.astro.virginia.edu/~mfs4n/milky/ ] in three infrared bands were translated to blue, green, and red colors to produce this composite image. |
|
M42: Orion Nebula Mosaic
| Title |
M42: Orion Nebula Mosaic |
| Explanation |
The Great Nebula in Orion [ http://www.stsci.edu/pubinfo/gif/OrionMos.txt ] is one of the most interesting of all astronomical nebulae known. Here fifteen pictures [ http://www.stsci.edu/pubinfo/PR/95/45.html ] from the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap950810.html ] have been merged to show the great expanse and diverse nature of the nebula. In addition to housing a bright open cluster [ http://antwrp.gsfc.nasa.gov/apod/ap951101.html ] of stars known as the Trapezium, the Orion Nebula contains many stellar nurseries [ http://antwrp.gsfc.nasa.gov/apod/ap951106.html ]. These nurseries contain hydrogen [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#hydrogen ] gas, hot young stars [ http://antwrp.gsfc.nasa.gov/apod/ap950620.html ], proplyds [ http://antwrp.gsfc.nasa.gov/apod/ap950911.html ], and stellar jets [ http://antwrp.gsfc.nasa.gov/apod/ap951012.html ] spewing material at high speeds. Much of the filamentary structure visible in this image are actually shock waves - fronts where fast moving material encounters slow moving gas. Some shock waves are visible near one of the bright stars in the lower left of the picture. The Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap950703.html ] is located in the same spiral arm of our Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950908.html ] as is our Sun [ http://antwrp.gsfc.nasa.gov/apod/ap951004.html ]. It takes light about 1500 years to reach us from there. |
|
The Keyhole Nebula Near Eta
…
| Title |
The Keyhole Nebula Near Eta Carinae |
| Explanation |
The dark dusty Keyhole Nebula gets its name from its unusual shape. Designated NGC 3324, the Keyhole Nebula [ http://seds.lpl.arizona.edu/billa/twn/n3324x.html ] is a smaller region superposed on the bright Eta Carina Nebula [ http://seds.lpl.arizona.edu/billa/twn/n3372x.html ]. The Eta Carina Nebula is the largest nebula in angular extent on the sky, larger than the famous Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap951121.html ], but its southerly location makes it less familiar to Northern Hemisphere skywatchers. The star Eta Carinae [ http://antwrp.gsfc.nasa.gov/apod/ap960111.html ] itself is extremely variable and has faded in a mere 150 years - formerly one of the brightest in the sky it is now invisible without a telescope. The nebula created [ http://antwrp.gsfc.nasa.gov/apod/ap950712.html ] by the star's 19th century outburst [ http://www.stsci.edu/pubinfo/gif/WFPCEtaCar.txt ] has been photographed by the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap950810.html ]. |
|
Orion's Horsehead Nebula
| Title |
Orion's Horsehead Nebula |
| Explanation |
The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the dark indentation to the red emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] seen above and to the right of center in the above photograph [ http://www.starryscapes.com/nebula/ic434.html ]. The bright star on the left is located in the belt of the familiar constellation of Orion. The horse-head [ http://antwrp.gsfc.nasa.gov/apod/ap011216.html ] feature is dark because it is really an opaque dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] cloud which lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will alter its appearance. The emission nebula [ http://www.seds.org/billa/twn/types.html ]'s red color is caused by electrons [ http://www.aip.org/history/electron/ ] recombining with protons [ http://www.neutron.anl.gov/hyper-physics/proton.html ] to form hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ] atoms. Also visible in the picture are blue reflection nebulae [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ], which preferentially reflect the blue light [ http://antwrp.gsfc.nasa.gov/apod/ap030121.html ] from nearby stars. |
|
M42: Wisps of the Orion Nebu
…
| Title |
M42: Wisps of the Orion Nebula |
| Explanation |
The Great Nebula in Orion [ http://www.seds.org/billa/twn/n1976x.html ], an immense, nearby starbirth region [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ], is probably the most famous of all astronomical nebulas [ http://www.seds.org/billa/twn/ ]. Here, glowing gas [ http://fusedweb.pppl.gov/CPEP/Chart_Pages/5.Plasmas/Nebula/Emission.html ] surrounds hot young stars at the edge of an immense [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ] interstellar molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap030202.html ] only 1500 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away. In the above deep image [ http://www.celestialimage.com/page100.html ], faint wisps and sheets of dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] and gas are particularly evident. The Great Nebula in Orion [ http://www.seds.org/messier/m/m042.html ] can be found with the unaided eye just below and to the left of the easily identifiable [ http://antwrp.gsfc.nasa.gov/apod/ap021225.html ] belt of three stars in the popular constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] Orion [ http://www.astronomical.org/constellations/ori.html ]. In addition to housing a bright open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars known as the Trapezium [ http://antwrp.gsfc.nasa.gov/apod/ap971118.html ], the Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap030225.html http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?Orion+Nebula ] contains many stellar nurseries [ http://archive.ncsa.uiuc.edu/Cyberia/Bima/StarForm.html ]. These nurseries contain hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ] gas, hot young stars, proplyds [ http://antwrp.gsfc.nasa.gov/apod/ap961017.html ], and stellar jets [ http://antwrp.gsfc.nasa.gov/apod/ap991129.html ] spewing material at high speeds. Also known as M42 [ http://antwrp.gsfc.nasa.gov/apod/ap020213.html ], the Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap980421.html ] spans about 40 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] and is located in the same spiral arm [ http://www.anzwers.org/free/universe/5000lys.html ] of our Galaxy [ http://adc.gsfc.nasa.gov/mw/mmw_images.html ] as the Sun [ http://www.nineplanets.org/sol.html ]. |
|
In the Center of the Lagoon
…
| Title |
In the Center of the Lagoon Nebula |
| Explanation |
The center of the Lagoon Nebula is busy with the awesome spectacle of star formation [ http://antwrp.gsfc.nasa.gov/apod/ap011125.html ]. Visible in the lower left, at least two long funnel-shaped clouds, each roughly half a light-year [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] long, have been formed by extreme stellar winds [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ] and intense energetic starlight. The tremendously bright nearby star, Hershel 36 [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1995ApJ...445L.153S ], lights the area. Vast walls of dust [ http://antwrp.gsfc.nasa.gov/apod/ap010813.html ] hide and redden [ http://www.physics.gmu.edu/classinfo/astr103/CourseNotes/Ppt/Lec04_pt7_interstellarMedium_noPics/sld015.htm ] other hot young stars. As energy from these stars pours into the cool dust [ http://antwrp.gsfc.nasa.gov/apod/ap010914.html ] and gas, large temperature differences in adjoining regions can be created generating shearing winds [ http://www.chaseday.com/clyde-tornado.htm ] which may cause the funnels. This picture, spanning about 5 light years, was taken in 1995 by the orbiting Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap030304.html ap010806.html ]. The Lagoon Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap021006.html ], also known as M8 [ http://www.seds.org/messier/m/m008.html ], lies about 5000 light years [ http://einstein.stcloudstate.edu/Dome/constellns/lightyear.html ] distant toward the constellation [ http://www.emufarm.org/~cmbell/myth/myth.html ] of Sagittarius [ http://www.astronomical.org/constellations/sgr.html ]. |
|
Explanation: Are planets com
…
| Title |
Explanation: Are planets common in our galaxy? Strong evidence that the answer is "yes" was provided in this 1994 image [ http://www.stsci.edu/pubinfo/PR/94/24.html ] made by the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap950810.html ] . A close-up of the Orion Nebulae [ http://antwrp.gsfc.nasa.gov/apod/ap951121.html ], it reveals what seem to be disks of dust and gas surrounding newly formed stars. These fuzzy blobs, called "proplyds [ http://www.stsci.edu/pubinfo/gif/OrionProplyds.txt ]", appear to be infant solar systems in the process of formation [ http://antwrp.gsfc.nasa.gov/apod/ap960119.html ]. Of the five stars in this field which spans about 0.14 light years, four appear to have associated proplyds - three bright ones and one dark one seen in silhouette against the bright nebula. A more complete survey of 110 stars in the region found 56 with proplyds. If extra-solar planetary systems are common place, are there extra-terrestrial civilizations out there as well? [ http://www.seti-inst.edu/ ] |
|
Tomorrow's picture: Orion's
…
| Title |
Tomorrow's picture: Orion's Horsehead Nebula |
|
The Colorful Horsehead Nebul
…
| Title |
The Colorful Horsehead Nebula |
| Explanation |
While drifting through the cosmos, a magnificent interstellar dust cloud became sculpted by stellar winds and radiation to assume a recognizable shape. Fittingly named the Horsehead Nebula [ http://www.seds.org/messier/xtra/ngc/b33.html ], it is embedded in the vast and complex Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ]. The dark molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010923.html ], roughly 1,500 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] distant, is cataloged as Barnard 33 [ http://www.seds.org/billa/twn/b33x.html ] and is visible only because its obscuring dust is silhouetted against the bright emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] IC 434. The bright blue reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] NGC 2023 is visible on the lower left. The prominent horse head [ http://antwrp.gsfc.nasa.gov/apod/ap030713.html ] portion of the nebula is really just part of a larger cloud [ http://antwrp.gsfc.nasa.gov/apod/ap030129.html ] of dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] which can be seen extending toward the bottom of the picture. A potentially rewarding but difficult object to view with a small telescope, this gorgeous representative-color image [ http://www.cfht.hawaii.edu/HawaiianStarlight/AIOM/English/CFHT-Coelum-AIOM.html ] was taken by the large 3.6-m Canada-France-Hawaii Telescope [ http://www.cfht.hawaii.edu/CFHT/ ] in Hawaii [ http://www.state.hi.us/ ], USA [ http://www.cia.gov/cia/publications/factbook/geos/us.html ]. |
|
The Witch Head Nebula
| Title |
The Witch Head Nebula |
| Explanation |
Double, double toil and trouble, Fire burn, and cauldron bubble -- maybe Macbeth [ http://the-tech.mit.edu/Shakespeare/macbeth/ ] should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] is associated with the bright star Rigel [ http://www.astro.uiuc.edu/~kaler/sow/rigel.html ] in the constellation Orion [ http://www.astro.uiuc.edu/~kaler/sow/orion-p.html ]. More formally known as IC 2118 [ http://www.astrocruise.com/ic2118.htm ], the Witch Head Nebula glows primarily by light reflected from Rigel [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997MNRAS.290..521I ], located just outside the top right corner of the above image [ http://www.ricksastro.com/Gallery/htm/10D_witch.htm ]. Fine dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] in the nebula reflects the light. The blue color is caused not only by Rigel [ http://einstein.stcloudstate.edu/Dome/constellns/rigel.html ]'s blue color but because the dust grains reflect blue light [ http://leo.astronomy.cz/mix/mix.html ] more efficiently than red. The same physical process [ http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html ] causes Earth's daytime sky to appear blue [ http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html ], although the scatterers in Earth's atmosphere [ http://liftoff.msfc.nasa.gov/academy/space/atmosphere.html ] are molecules of nitrogen [ http://pearl1.lanl.gov/periodic/elements/7.html ] and oxygen [ http://pearl1.lanl.gov/periodic/elements/8.html ]. The nebula lies about 1000 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away. |
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McNeil's Nebula
| Title |
McNeil's Nebula |
| Explanation |
It was a clear, cold western Kentucky night [ http://www.wkaa.net/ article.php?articleid=32&cat=NW&ret=index.php ] on January 23rd as seasoned amateur astronomer Jay McNeil tried out his recently acquired 3-inch refracting telescope by imaging the area [ http://wkaa.net/gallery/mcneil/m78Lrgb ] around a familiar object, the M78 reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/ap030121.html ] in Orion. Days later while processing the images, he noted a substantial but totally unfamiliar nebulosity in the region! With a little help from his friends, his amazing discovery [ http://cfa-www.harvard.edu/iauc/08200/08284.html ] is now recognized as a newly visible reflection nebula surrounding a newborn star -- McNeil's Nebula [ http://spacsun.rice.edu/~has/ Articles.html#McNeils%20Nebula ]. Pictured here at the center of this close-up [ http://www.noao.edu/outreach/aop/observers/mcneil.html ], McNeil's Nebula with its illuminating young star [ http://antwrp.gsfc.nasa.gov/apod/ap970619.html ] at the tip, do not appear in images of the area before September 2003. The emergence of McNeil's Nebula [ http://www.rc-astro.com/nebulae/mcneil_anim.htm ] is a rare event to witness and astronomers are eagerly following its development, but Orion will soon lie too close to the Sun in the sky, interrupting further observations for several months. The Orion nebula complex [ http://www.seds.org/messier/more/oricloud.html ] itself is around 1,500 light-years away. At that distance, the above image spans less than 10 light-years. "Update (Feb. 19)": While McNeil's Nebula was not seen on previous images, some dating back to 1951, it is reportedly apparent in an image of the region recorded in the mid-1960s and available on the SEDs [ http://www.seds.org/messier/more/ m078_mcneil.html ] web site. This would indicate that the intriguing reflection nebula and illuminating star are variable, rather than "newly" emerging. |
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The Orion Nebula from CFHT
| Title |
The Orion Nebula from CFHT |
| Explanation |
Few astronomical sights excite the imagination like the nearby stellar nursery known as the Orion Nebula [ http://www.seds.org/billa/twn/n1976x.html ]. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010923.html ] only 1500 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away. The Great Nebula in Orion [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?Orion+Nebula ] can be found with the unaided eye just below and to the left of the easily identifiable belt of three stars [ http://www.spacekids.com/skywatch/eyes_skies_000124.html ] in the popular constellation Orion [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Orion.html ]. The above image [ http://www.cfht.hawaii.edu/HawaiianStarlight/AIOM/English/CFHT-Coelum-AIOM-Mar2004.html ] from the 3.6-meter Canada-France-Hawaii Telescope [ http://www.cfht.hawaii.edu/HawaiianStarlight/English/CFHT-Story.html ] atop a dormant volcano in Hawaii [ http://antwrp.gsfc.nasa.gov/apod/ap031203.html ] brings out Orion's detail [ http://antwrp.gsfc.nasa.gov/apod/ap020213.html ] in spectacular fashion. Buried in the complex nebulosity are the bright stars of the Trapezium [ http://antwrp.gsfc.nasa.gov/apod/ap030302.html ] in Orion's heart [ http://antwrp.gsfc.nasa.gov/apod/ap000830.html ], the sweeping lanes of dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] that cross the center, the pervasive red glowing hydrogen gas [ http://antwrp.gsfc.nasa.gov/apod/ap020129.html ], and the blue tinted dust [ http://antwrp.gsfc.nasa.gov/apod/ap031229.html ] that reflects the light of newborn stars. The whole Orion Nebula cloud complex [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ], which includes the Horsehead Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap030713.html ], will slowly disperse over the next 100,000 years. |
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The Great Nebula in Orion
| Title |
The Great Nebula in Orion |
| Explanation |
The Great Nebula in Orion [ http://www.seds.org/billa/twn/n1976x.html ] can be found just below and to the left of the easily identifiable belt of three stars [ http://www.adler.uchicago.edu/ISE/ORION4.HTM ] in the popular constellation Orion [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Orion.html ]. This fuzzy patch contains one of the closest stellar nurseries, lying at a distance of about 1500 light years. In the above picture, the red region on the left consists of nebulae designated M42 and M43 and contains the bright Trapezium [ http://seds.lpl.arizona.edu/messier/more/m042_more.html ] open cluster [ http://antwrp.gsfc.nasa.gov/apod/ap971118.html ]. The blue region on the right is a nebula primarily reflecting [ http://antwrp.gsfc.nasa.gov/apod/index/ReflectionNebulae.html ] the light from internal bright stars. Recent observations of the Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ] by the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap970306.html ] have located solar-system sized star-forming regions [ http://antwrp.gsfc.nasa.gov/apod/ap961017.html ]. |
|
NGC 1977: Blue Reflection Ne
…
| Title |
NGC 1977: Blue Reflection Nebula in Orion |
| Explanation |
The Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap980127.html ] is visible to the unaided eye as a fuzzy patch near the famous belt of three stars [ http://antwrp.gsfc.nasa.gov/apod/ap951114.html ] in the constellation [ http://galileo.gmu.edu/constellation/constellation.html ] Orion [ http://antwrp.gsfc.nasa.gov/apod/ap970523.html ]. The above picture captures a part of the Orion Nebula [ http://seds.lpl.arizona.edu/billa/twn/n1976x.html ] that primarily reflects light from bright Orion stars. This reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/index/ReflectionNebulae.html ] appears blue because the blue light from the neighboring stars scatters more efficiently from nebula gas than does red light. The dark lanes are composed of mostly interstellar dust [ http://antwrp.gsfc.nasa.gov/apod/ap980116.html ] - fine needle-shaped carbon grains. |
|
The Witch Head Nebula
| Title |
The Witch Head Nebula |
| Explanation |
Double, double toil and trouble, Fire burn, and cauldron bubble ... Maybe Macbeth [ http://the-tech.mit.edu/Shakespeare/Tragedy/macbeth/macbeth.html ] should have consulted [ http://the-tech.mit.edu/Shakespeare/Tragedy/macbeth/macbeth.4.1.html ] the Witch Head Nebula [ http://www.astroimages.com/ic2118.htm ]. This suggestively shaped reflection nebula [ http://antwrp.gsfc.nasa.gov/cgi-bin/cossc/apod_search?reflection+nebula ] is associated with the bright star Rigel [ http://www.astro.wisc.edu/~dolan/constellations/hr/1713.html ] in the constellation Orion [ http://antwrp.gsfc.nasa.gov/apod/ap970825.html ]. More formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from Rigel. Rigel is located about one photo-width off the image to the right. Fine dust [ http://antwrp.gsfc.nasa.gov/apod/ap980104.html ] in the nebula reflects the light. The blue color is caused not only by Rigel's blue color but because the dust grains reflect blue light [ http://www.sci.muni.cz/~ondra/mix/mix.html ] more efficiently than red. The same physical process causes Earth's daytime sky to appear blue [ http://math.ucr.edu/home/baez/physics/blue_sky.html ], although the scatterers here are molecules of nitrogen [ http://cst.lanl.gov/CST/imagemap/periodic/7.html ] and oxygen [ http://cst.lanl.gov/CST/imagemap/periodic/8.html ]. The nebula lies about 1000 light-years away. |
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Orion Nebula in Oxygen, Hydr
…
| Title |
Orion Nebula in Oxygen, Hydrogen, and Sulfur |
| Explanation |
The Great Nebula in Orion [ http://www.seds.org/messier/m/m042.html ], an immense [ http://antwrp.gsfc.nasa.gov/apod/ap971201.html ], nearby starbirth region, is arguably the most famous of all astronomical nebulae. The Orion Nebula [ http://www.seds.org/billa/twn/n1976x.html ], also known as M42, is shown above [ http://www.eso.org/outreach/press-rel/pr-2004/phot-20-04.html ] through ultraviolet [ http://imagers.gsfc.nasa.gov/ems/uv.html ] and blue filters augmented with three exact colors specifically emitted by hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ], oxygen [ http://pearl1.lanl.gov/periodic/elements/8.html ], and sulfur [ http://pearl1.lanl.gov/periodic/elements/16.html ]. In addition to housing a bright open cluster of stars known as the Trapezium [ http://antwrp.gsfc.nasa.gov/apod/ap030302.html ], the Orion Nebula [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?Orion+Nebula ] contains many stellar nurseries [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ]. These nurseries contain glowing gas, hot young stars, proplyds [ http://antwrp.gsfc.nasa.gov/apod/ap961017.html ], and stellar jets [ http://antwrp.gsfc.nasa.gov/apod/ap030127.html ] spewing material at high speeds. Many of the filamentary structures visible in this image [ http://www.eso.org/outreach/press-rel/pr-2004/phot-20-04.html ] are actually shock waves [ http://antwrp.gsfc.nasa.gov/apod/ap031115.html ] - fronts where fast moving material encounters slow moving gas. The Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap980421.html ] spans about 40 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] and is located about 1500 light years away in the same spiral arm [ http://www.anzwers.org/free/universe/5000lys.html ] of our Galaxy [ http://adc.gsfc.nasa.gov/mw/mmw_images.html ] as the Sun [ http://www.nineplanets.org/sol.html ]. |
|
The Great Nebula in Orion
| Title |
The Great Nebula in Orion |
| Explanation |
The Great Nebula in Orion is a colorful place. Visible to the unaided eye, it appears as a small fuzzy patch [ http://antwrp.gsfc.nasa.gov/apod/ap030207.html ] in the constellation of Orion [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Orion.html ]. Long exposure, digitally sharpened images like this, however, show the Orion Nebula [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?orion+nebula ] to be a busy neighborhood of young stars, hot gas, and dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ]. The power behind much of the Orion Nebula [ http://nineplanets.org/twn/n1976x.html ] (M42) is the Trapezium [ http://antwrp.gsfc.nasa.gov/apod/ap030302.html ] - four of the brightest stars in the nebula. Many of the filamentary structures [ http://antwrp.gsfc.nasa.gov/apod/ap030225.html ] visible are actually shock wave [ http://antwrp.gsfc.nasa.gov/apod/ap031115.html ]s - fronts where fast moving material encounters slow moving gas. The Orion Nebula spans about 40 light years and is located [ http://antwrp.gsfc.nasa.gov/apod/ap020530.html ] about 1500 light years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away in the same spiral arm [ http://www.astronomycafe.net/qadir/q2233.html ] of our Galaxy [ http://www.damtp.cam.ac.uk/user/gr/public/gal_milky.html ] as the Sun [ http://www.nineplanets.org/sol.html ]. |
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Orion Nebula: The 2MASS View
| Title |
Orion Nebula: The 2MASS View |
| Explanation |
Few astronomical sights excite the imagination like the nearby stellar nursery [ http://antwrp.gsfc.nasa.gov/apod/ap980411.html ] known as the Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap970511.html ]. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1,500 light-years away. This distinctively detailed image [ http://spider.ipac.caltech.edu/staff/vandyk/2mass/orion/ ] of the Orion Nebula was constructed using data from the 2 Micron All Sky Survey [ http://pegasus.phast.umass.edu/GradProg/2mass.html ] or 2MASS. Now underway with telescopes in the [ http://pegasus.phast.umass.edu/2mass/pub/telescope.html ] Northern and Southern Hemispheres of planet Earth, the 2MASS project will [ http://www.ipac.caltech.edu/2mass/2mass_overview.html ] map the entire sky in infrared light [ http://www.ipac.caltech.edu/Outreach/Edu/univ_index.html ]. The wavelength of infrared light [ http://www.ipac.caltech.edu/Outreach/Edu/ ] is longer than visible light but more easily penetrates obscuring dust clouds. 2MASS cameras are sensitve to near infrared wavelengths around 2 microns or about 0.00008 inches. Visible light has a wavelength of about 0.00002 inches. Survey observations [ http://spider.ipac.caltech.edu/staff/vandyk/2mass/imagegal.html ] in three infrared bands were translated to blue, green, and red colors to produce this composite image. |
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Comet, Meteor, Nebula, Star
| Title |
Comet, Meteor, Nebula, Star |
| Explanation |
Several wonders of the late-year northern sky appeared together for a few fleeting moments on December 13. On the bottom left, just above the hill, is blue Sirius [ http://www.exoplaneten.de/sirius/english.html ], the brightest star in the sky. Above Sirius [ http://antwrp.gsfc.nasa.gov/apod/ap000611.html ] and slightly to the right of the belt of Orion [ http://www.gb.nrao.edu/~rmaddale/Education/OrionTourCenter/belt.html ] is the red Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap020213.html ], one of the most famous nebulas on the sky. Below and to the right of the Orion Nebula [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?Orion+Nebula ] streaks a yellow meteor, although moving in the wrong direction to be from the Geminids meteor shower [ http://antwrp.gsfc.nasa.gov/apod/ap981229.html ] that peaked the night. Finally, above and to the right of the meteor is Comet Machholz [ http://antwrp.gsfc.nasa.gov/apod/ap041213.html ], whose coma [ http://www.windows.ucar.edu/tour/link=/comets/coma.html ] appears here relatively green. Since the time since this image was taken over a Californian hill, the Geminid [ http://science.nasa.gov/headlines/y2004/06dec_geminids.htm ] meteor has long since evaporated. Comet Machholz [ http://cometography.com/lcomets/2004Q2.html ] has brightened and moved to the north. Sirius, however, will remain in the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Canis Major [ http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=14 ] indefinitely. |
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NGC 1499: California Nebula
| Title |
NGC 1499: California Nebula |
| Explanation |
Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud [ http://www.anzwers.org/free/universe/nebulae/ ngc1499.html ] by chance echoes the outline of California on the west coast of the United States. Our own Sun also lies within the Milky Way's Orion Arm [ http://www.anzwers.org/free/universe/5000lys.html ], only about 1,500 light-years from the California Nebula. Also known as NGC 1499 [ http://www.seds.org/~spider/spider/ Misc/n1499.html ], the classic emission nebula is around 100 light-years long. It glows with the red light characteristic of hydrogen atoms recombining with long lost [ http://antwrp.gsfc.nasa.gov/apod/lib/lament.html ] electrons, stripped away (ionized [ http://csep10.phys.utk.edu/ astr162/lect/light/ionization.html ]) by energetic starlight. In this case, the star most likely providing the energetic starlight is the bright, hot, bluish Xi Persei, just right of the nebula and above picture center. Fittingly, this composite [ http://www.astro.caltech.edu/~wsk/ngc1499.html ] picture was made with images from a telescope in California - the 48-inch (1.2-meter) Samuel Oschin Telescope [ http://www.astro.caltech.edu/~wsk/sot.html ] - taken as a part of the second National Geographic Palomar [ http://antwrp.gsfc.nasa.gov/apod/ap030807.html ] Observatory Sky Survey [ http://www.astro.caltech.edu/~wws/poss2.html ]. |
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Orion's Horsehead Nebula
| Title |
Orion's Horsehead Nebula |
| Explanation |
The Horsehead Nebula [ http://www.seds.org/billa/twn/b33x.html ] is one of the most famous nebulae on the sky. It is visible as the dark indentation to the red emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] seen above and to the right of center in the above photograph [ http://www.noao.edu/outreach/aop/observers/horsewide.html ]. The bright star on the left is located in the belt of the familiar constellation of Orion. The horse-head [ http://antwrp.gsfc.nasa.gov/apod/ap030713.html ] feature is dark because it is really an opaque dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] cloud which lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape [ http://www.brucevanpatter.com/cloudshapes.html ] by chance. After many thousands of years, the internal motions of the cloud will alter its appearance. The emission nebula [ http://www.seds.org/billa/twn/types.html ]'s red color is caused by electrons [ http://www.aip.org/history/electron/ ] recombining with protons [ http://www.neutron.anl.gov/hyper-physics/proton.html ] to form hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ] atoms. Also visible in the picture are blue reflection nebulae [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ], which preferentially reflect the blue light [ http://antwrp.gsfc.nasa.gov/apod/ap030121.html ] from nearby stars. |
|
Orion's Horsehead Nebula
| Title |
Orion's Horsehead Nebula |
| Explanation |
The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the black indentation to the red emission nebula [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#emis_neb ] seen just to the right of center of the above photograph. The bright star near the center is located in the belt of the familiar constellation of Orion. The horse-head feature is dark because it is really an opaque dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] cloud which lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will alter its appearance. The emission nebula [ http://zebu.uoregon.edu/textbook/ism.html ]'s red color is caused by electrons recombining with protons to form hydrogen [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#hydrogen ] atoms. Also visible in the picture are blue reflection nebulae [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#refl_neb ], which preferentially reflect the blue light [ http://antwrp.gsfc.nasa.gov/apod/ap971018.html ] from nearby stars. |
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The Orion Nebula from Subaru
| Title |
The Orion Nebula from Subaru |
| Explanation |
The Orion Nebula [ http://www.seds.org/billa/twn/n1976x.html ] (M42) shows a host of treasures when viewed in infrared [ http://www.ipac.caltech.edu/Outreach/Edu/discovery.html ] light. Some stars in the Trapezium [ http://antwrp.gsfc.nasa.gov/apod/ap971118.html ], an open cluster [ http://antwrp.gsfc.nasa.gov/apod/ap970128.html ] of stars at the center, are only visible in infrared light. The orange feature above center is called the Kleinman-Low Nebula [ http://www-astronomy.mps.ohio-state.edu/~ryden/ast162_3/notes14.html ], and appears greatly affected by newly forming central star IRc2. The blue emission in this representative color photograph is caused by hot gas ionized by the Trapezium [ http://seds.lpl.arizona.edu/messier/more/m042_more.html ] stars. This is one of the first photographs [ http://www.subaru.naoj.org/outreach/press_releases/990128/ ] ever taken through Japan's new Subaru Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap990201.html ]. |
|
|
![Explanation: Are planets common in our galaxy? Strong evidence that the answer is "yes" was provided in this 1994 image [ http://www.stsci.edu/pubinfo/PR/94/24.html ] made by the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap950810.html ] . A close-up of the Orion Nebulae [ http://antwrp.gsfc.nasa.gov/apod/ap951121.html ], it reveals what seem to be disks of dust and gas surrounding newly formed stars. These fuzzy blobs, called "proplyds [ http://www.stsci.edu/pubinfo/gif/OrionProplyds.txt ]", appear to be infant solar systems in the process of formation [ http://antwrp.gsfc.nasa.gov/apod/ap960119.html ]. Of the five stars in this field which spans about 0.14 light years, four appear to have associated proplyds - three bright ones and one dark one seen in silhouette against the bright nebula. A more complete survey of 110 stars in the region found 56 with proplyds. If extra-solar planetary systems are common place, are there extra-terrestrial civilizations out there as well? [ http://www.seti-inst.edu/ ]](http://mm04.nasaimages.org/MediaManager/srvr?mediafile=/Size1/NVA2-4-NA/8084/proplyds_hst.jpg&userid=1&username=admin&resolution=1&servertype=JVA&cid=4&iid=NVA2&vcid=NA&usergroup=NASA_Astronomy_Picture_of_the_Day_Collecti-4-Admin&profileid=16)
