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Crab Nebula Supernova Remnan
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| Title |
Crab Nebula Supernova Remnant (IRAC-MIPS Image) |
| Description |
The Crab Nebula is the shattered remnant of a massive star that ended its life in a massive supernova explosion. Nearly a thousand years old, the supernova was noted in the constellation of Taurus by Chinese astronomers in the year 1054 AD. This view of the supernova remnant obtained by the Spitzer Space Telescope shows the infrared view of this complex object. The blue region traces the cloud of energetic electrons trapped within the star's magnetic field, emitting so-called "synchrotron" radiation. The yellow-red features follow the well-known filamentary structures that permeate this nebula. Though they are known to contain hot gasses, their exact nature is still a mystery that astronomers are examining. The energetic cloud of electrons are driven by a rapidly rotating neutron star, or pulsar, at its core. The nebula is about 6,500 light-years away from the Earth, and is 5 light-years across. This false-color image presents images from Spitzer's Infrared Array Camera (IRAC) and Multiband Imaging Photometer (MIPS) at 3.6 (blue), 8.0 (green), 24 (red) microns. |
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Crab Nebula Supernova Remnan
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| Title |
Crab Nebula Supernova Remnant (IRAC Image) |
| Description |
The Crab Nebula is the shattered remnant of a massive star that ended its life in a massive supernova explosion. Nearly a thousand years old, the supernova was noted in the constellation of Taurus by Chinese astronomers in the year 1054 AD. This view of the supernova remnant obtained by the Spitzer Space Telescope shows the infrared view of this complex object. The blue-white region traces the cloud of energetic electrons trapped within the star's magnetic field, emitting so-called "synchrotron" radiation. The red features follow the well-known filamentary structures that permeate this nebula. Though they are known to contain hot gasses, their exact nature is still a mystery that astronomers are examining. The energetic cloud of electrons are driven by a rapidly rotating neutron star, or pulsar, at its core. The nebula is about 6,500 light-years away from the Earth, and is 5 light-years across. This false-color image presents images from Spitzer's Infrared Array Camera (IRAC) at 3.6 (blue), 4.5 (green), and 8.0 (red) microns. |
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Black Widow Nebula Hiding in
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| Title |
Black Widow Nebula Hiding in the Dust |
| Description |
In the constellation Circinus, where previous visible-light observations by the Digital Sky Survey (left) saw only a faint hourglass-shaped patch of obscuring dust and gas, NASA's Spitzer Space Telescope's dust-piercing eyes see a big "Black Widow Nebula" teeming with clusters of massive young stars (right). In the Spitzer image, the two opposing bubbles are being formed in opposite directions by the powerful outflows from massive groups of forming stars. The baby stars can be seen as specks of yellow where the two bubbles overlap. When individual stars form from molecular clouds of gas and dust they produce intense radiation and very strong particle winds. Both the radiation and the stellar winds blow the dust outward from the star creating a cavity or, bubble. In the case of the Black Widow Nebula, astronomers suspect that a large cloud of gas and dust condensed to create multiple clusters of massive star formation. The combined winds from these groups of large stars probably blew out bubbles into the direction of least resistance, forming a double bubble. The infrared image was captured by the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) Legacy project. The Spitzer picture is a four-channel false-color composite, showing emission from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0 microns (red). |
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Black Widow Nebula Hiding in
…
| Title |
Black Widow Nebula Hiding in the Dust |
| Description |
In the constellation Circinus, where previous visible-light observations by the Digital Sky Survey (left) saw only a faint hourglass-shaped patch of obscuring dust and gas, NASA's Spitzer Space Telescope's dust-piercing eyes see a big "Black Widow Nebula" teeming with clusters of massive young stars (right). In the Spitzer image, the two opposing bubbles are being formed in opposite directions by the powerful outflows from massive groups of forming stars. The baby stars can be seen as specks of yellow where the two bubbles overlap. When individual stars form from molecular clouds of gas and dust they produce intense radiation and very strong particle winds. Both the radiation and the stellar winds blow the dust outward from the star creating a cavity or, bubble. In the case of the Black Widow Nebula, astronomers suspect that a large cloud of gas and dust condensed to create multiple clusters of massive star formation. The combined winds from these groups of large stars probably blew out bubbles into the direction of least resistance, forming a double bubble. The infrared image was captured by the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) Legacy project. The Spitzer picture is a four-channel false-color composite, showing emission from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0 microns (red). |
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Black Widow Nebula Hiding in
…
| Title |
Black Widow Nebula Hiding in the Dust |
| Description |
In the constellation Circinus, where previous visible-light observations by the Digital Sky Survey (left) saw only a faint hourglass-shaped patch of obscuring dust and gas, NASA's Spitzer Space Telescope's dust-piercing eyes see a big "Black Widow Nebula" teeming with clusters of massive young stars (right). In the Spitzer image, the two opposing bubbles are being formed in opposite directions by the powerful outflows from massive groups of forming stars. The baby stars can be seen as specks of yellow where the two bubbles overlap. When individual stars form from molecular clouds of gas and dust they produce intense radiation and very strong particle winds. Both the radiation and the stellar winds blow the dust outward from the star creating a cavity or, bubble. In the case of the Black Widow Nebula, astronomers suspect that a large cloud of gas and dust condensed to create multiple clusters of massive star formation. The combined winds from these groups of large stars probably blew out bubbles into the direction of least resistance, forming a double bubble. The infrared image was captured by the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) Legacy project. The Spitzer picture is a four-channel false-color composite, showing emission from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0 microns (red). |
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Comets Kick up Dust in Helix
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| Title |
Comets Kick up Dust in Helix Nebula |
| Description |
This infrared image from NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye. The nebula, located about 700 light-years away in the constellation Aquarius, belongs to a class of objects called planetary nebulae. Discovered in the 18th century, these colorful beauties were named for their resemblance to gas-giant planets like Jupiter. Planetary nebulae are the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years. In Spitzer's infrared view of the Helix nebula, the eye looks more like that of a green monster's. Infrared light from the outer gaseous layers is represented in blues and greens. The white dwarf is visible as a tiny white dot in the center of the picture. The red color in the middle of the eye denotes the final layers of gas blown out when the star died. The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star. Before the star died, its comets and possibly planets would have orbited the star in an orderly fashion. But when the star blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, resulting in an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded. So far, the Helix nebula is one of only a few dead-star systems in which evidence for comet survivors has been found. This image is made up of data from Spitzer's infrared array camera and multiband imaging photometer. Blue shows infrared light of 3.6 to 4.5 microns, green shows infrared light of 5.8 to 8 microns, and red shows infrared light of 24 microns. |
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Comets Kick up Dust in Helix
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| Title |
Comets Kick up Dust in Helix Nebula |
| Description |
This infrared image from NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye. The nebula, located about 700 light-years away in the constellation Aquarius, belongs to a class of objects called planetary nebulae. Discovered in the 18th century, these colorful beauties were named for their resemblance to gas-giant planets like Jupiter. Planetary nebulae are the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years. In Spitzer's infrared view of the Helix nebula, the eye looks more like that of a green monster's. Infrared light from the outer gaseous layers is represented in blues and greens. The white dwarf is visible as a tiny white dot in the center of the picture. The red color in the middle of the eye denotes the final layers of gas blown out when the star died. The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star. Before the star died, its comets and possibly planets would have orbited the star in an orderly fashion. But when the star blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, resulting in an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded. So far, the Helix nebula is one of only a few dead-star systems in which evidence for comet survivors has been found. This image is made up of data from Spitzer's infrared array camera and multiband imaging photometer. Blue shows infrared light of 3.6 to 4.5 microns, green shows infrared light of 5.8 to 8 microns, and red shows infrared light of 24 microns. |
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The Tarantula Nebula
| Title |
The Tarantula Nebula |
| Description |
NASA's new Spitzer Space Telescope has captured in stunning detail the spidery filaments and newborn stars of the Tarantula Nebula, a rich star-forming region also known as 30 Doradus. In this animation the infrared structures seen by this new observatory are compared with a visible light image from the ground-based European Southern Observatory (ESO) to highlight the power of Spitzer to see what other telescopes cannot. Starting with the ESO visible-light image, the spider-like filaments that inspired this nebula's name fill the view. The pinkish color in this image originates from the gas, mostly hydrogen heated to high temperatures by the many brilliant young stars. Dark swaths cutting through this region suggest the sooty, dense dust clouds that fuel star formation. Zooming into one dust lane at the upper right side of the nebula, the transition to the infrared view reveals a streamer of bright red emission from a visually dark cloud. Here, and throughout the nebula, these red filaments reveal the presence of molecular material thought to be rich in hydrocarbons, a Spitzer finding highlighting a previously unseen aspect of this nebula. Green indicate the hottest regions of gas, coming from the same hydrogen gas that produces the visible light. Moving down and around the heart of the Tarantula, the lower cavity of the nebula moves into view. Dense pillars of gas line the edge of this opening, looking almost like teeth around a mouth. In visible light the outer surfaces of these pillars glow brilliantly while the infrared view reveals a more complex structure. The green outer surfaces trace the surrounding hot gas while red filaments expose the dense, buried cloud cores, almost like a dentist's X-ray probing hidden roots within the teeth. Finally, pulling back to see the entire nebula, the striking differences and similarities between the visible and infrared images are clear. By expanding our view beyond the limits of visible light we can see otherwise invisible dust clouds and hidden stars that greatly enhance our understanding of the Tarantula Nebula. |
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Eagle Nebula Flaunts Its Inf
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| Title |
Eagle Nebula Flaunts Its Infrared Feathers |
| Description |
This set of images from NASA's Spitzer Space Telescope shows the Eagle nebula in different hues of infrared light. Each view tells a different tale. The left picture shows lots of stars and dusty structures with clarity. Dusty molecules found on Earth called polycyclic aromatic hydrocarbons produce most of the red, gas is green and stars are blue. The middle view is packed with drama, because it tells astronomers that a star in this region violently erupted, or went supernova, heating surrounding dust (orange). This view also reveals that the hot dust is shell shaped, another indication that a star exploded. The final picture highlights the contrast between the hot, supernova-heated dust (green) and the cooler dust making up the region's dusty star-forming clouds and towers (red, blue and purple). The left image is a composite of infrared light with the following wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange), and 8 microns (red). The right image includes longer infrared wavelengths, and is a composite of light of 4.5 to 8.0 microns (blue), 24 microns (green), and 70 microns (red). The middle image is made up solely of 24-micron light. |
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The Tarantula Nebula
| Title |
The Tarantula Nebula |
| Description |
NASA's new Spitzer Space Telescope, formerly known as the Space Infrared Telescope Facility, has captured in stunning detail the spidery filaments and newborn stars of the Tarantula Nebula, a rich star-forming region also known as 30 Doradus. This cloud of glowing dust and gas is located in the Large Magellanic Cloud, the nearest galaxy to our own Milky Way, and is visible primarily from the Southern Hemisphere. This image of an interstellar cauldron provides a snapshot of the complex physical processes and chemistry that govern the birth -- and death -- of stars. At the heart of the nebula is a compact cluster of stars, known as R136, which contains very massive and young stars. The brightest of these blue supergiant stars are up to 100 times more massive than the Sun, and are at least 100,000 times more luminous. These stars will live fast and die young, at least by astronomical standards, exhausting their nuclear fuel in a few million years. The Spitzer Space Telescope image was obtained with an infrared array camera that is sensitive to invisible infrared light at wavelengths that are about ten times longer than visible light. In this four-color composite, emission at 3.6 microns is depicted in blue, 4.5 microns in green, 5.8 microns in orange, and 8.0 microns in red. The image covers a region that is three-quarters the size of the full moon. The Spitzer observations penetrate the dust clouds throughout the Tarantula to reveal previously hidden sites of star formation. Within the luminescent nebula, many holes are also apparent. These voids are produced by highly energetic winds originating from the massive stars in the central star cluster. The structures at the edges of these voids are particularly interesting. Dense pillars of gas and dust, sculpted by the stellar radiation, denote the birthplace of future generations of stars. The Spitzer image provides information about the composition of the material at the edges of the voids. The surface layers closest to the massive stars are subject to the most intense stellar radiation. Here, the atoms are stripped of their electrons, and the green color of these regions is indicative of the radiation from this highly excited, or 'ionized,' material. The ubiquitous red filaments seen throughout the image reveal the presence of molecular material thought to be rich in hydrocarbons. The Tarantula Nebula is the nearest example of a 'starburst' phenomenon, in which intense episodes of star formation occur on massive scales. Most starbursts, however, are associated with dusty and distant galaxies. Spitzer infrared observations of the Tarantula provide astronomers with an unprecedented view of the lifecycle of massive stars and their vital role in regulating the birth of future stellar and planetary systems. |
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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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M20: The Trifid Nebula
| Title |
M20: The Trifid Nebula |
| Explanation |
Unspeakable beauty and unimaginable bedlam can be found together in the Trifid Nebula [ http://www.seds.org/messier/m/m020.html ]. Also known as M20, this photogenic nebula [ http://www.noao.edu/image_gallery/html/im0587.html ] is visible with good binoculars towards the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Sagittarius [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Sagittarius.html ]. The energetic processes of star formation [ http://antwrp.gsfc.nasa.gov/apod/ap990502.html ] create not only the colors but the chaos. The red-glowing gas [ http://antwrp.gsfc.nasa.gov/apod/ap980828.html ] results from high-energy starlight striking interstellar hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ] gas. The dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] filaments [ http://antwrp.gsfc.nasa.gov/apod/ap990607.html ] that lace M20 [ http://antwrp.gsfc.nasa.gov/apod/ap970828.html ] were created in the atmospheres of cool giant stars [ http://www.astro.keele.ac.uk/workx/starlife/StarpageS_26M.html ] and in the debris [ http://antwrp.gsfc.nasa.gov/apod/ap990803.html ] from supernovae [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html ] explosions. Which bright young stars light up the blue reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] is still being investigated [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1986AJ.....92.1125L ]. The light from M20 [ http://www.aao.gov.au/local/www/dfm/aat069.html ] we see today left perhaps 3000 years ago, although the exact distance remains unknown. Light takes about 50 years to cross M20 [ http://www.seds.org/billa/twn/n6514x.html ]. |
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The Carina Nebula in Infrare
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| Title |
The Carina Nebula in Infrared |
| Explanation |
About three million years ago, the stars in the Keyhole Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap990523.html ] began to form. The above picture [ http://www.ipac.caltech.edu/2mass/gallery/powarc.html ] of the Keyhole Nebula [ http://www.seds.org/nineplanets/twn/n3324x.html ], also known as the Carina Nebula or NGC 3372, shows in infrared light [ http://www.ipac.caltech.edu/Outreach/Edu/infrared.html ] many facets of this dramatic stellar nursery [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ] which lies only 9,000 light-years away. Fine dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] reflects starlight while being heated and emitting light of its own. Open clusters [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] Trumpler 14 and Trumpler [ http://www.treasure-troves.com/bios/Trumpler.html ] 16 are visible in the lower left and upper right of the nebula. The bright star near Trumpler 14 [ http://www.aao.gov.au/images/captions/aat037.html ] is called Eta Carinae [ http://www.seds.org/billa/twn/n3372x.html ] and is one of the most unusual [ http://www.bris.ac.uk/Depts/Chemistry/MOTM/silly/sillymols.htm ] stars known. A candidate for a supernova [ http://msgc.engin.umich.edu/cgi-bin/tour.cgi?link=/the_universe/supernova.html ] in the next few thousand years, Eta Carinae [ http://antwrp.gsfc.nasa.gov/apod/ap980816.html ] faded from being one of the brightest stars in the sky during the 1800s. Despite intensive study [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000ApJ...530L.107D ], astronomers remain unsure whether Eta Carinae [ http://heasarc.gsfc.nasa.gov/docs/objects/heapow/archive/stars/etacar_pspc_19990525.html ] is part of a binary star [ http://antwrp.gsfc.nasa.gov/apod/ap970219.html ] system. |
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The Crab Nebula in Blue and
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| Title |
The Crab Nebula in Blue and White |
| Explanation |
The Crab Nebula is a complex shell of expanding gas. The Crab Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap991122.html ] formed from a star that was seen to explode in a supernova [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html ] about 1000 years ago. This two color composite image [ http://www.noao.edu/image_gallery/html/im0466.html ] taken with the WIYN 3.5-meter telescope [ http://www.noao.edu/wiyn/wiynis.html ] shows in great detail filamentary structure of the glowing hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ] gas. Also known as M [ http://www.seds.org/messier/xtra/history/CMessier.html ]1, the center is home to a dense neutron star [ http://www.astro.umd.edu/~miller/nstar.html ], a star as massive as our Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ] but only the size of a city [ http://antwrp.gsfc.nasa.gov/apod/ap970408.html ]. The neutron star [ http://antwrp.gsfc.nasa.gov/apod/neutron_stars.html ] is a pulsar [ http://lheawww.gsfc.nasa.gov/users/padi/Pulse/crab.html ] that spins thirty times a second and spits out energy that powers the nebula. The nebula [ http://nineplanets.org/twn/n1952x.html ] is named from its likeness to a crab [ http://www.clever.net/kerry/creature/helmet.htm ] in an early drawing. The Crab Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap981122.html ] still presents mysteries [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1995ApJ...454L.129F ] today as the total mass of the nebula and pulsar [ http://www.jb.man.ac.uk/~pulsar/Education/Sounds/sounds.html ] appears much less than the mass of the original pre-supernova star [ http://antwrp.gsfc.nasa.gov/apod/ap970812.html ]! |
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Light from the Heart Nebula
| Title |
Light from the Heart Nebula |
| Explanation |
What powers the Heart Nebula? The large emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] dubbed IC 1805 [ http://antwrp.gsfc.nasa.gov/apod/ap040917.html ] looks, in whole, like a human heart [ http://www.pbs.org/wgbh/nova/heart/heartmap.html ]. The nebula glows brightly in red light emitted by its most prominent element: hydrogen [ http://en.wikipedia.org/wiki/Hydrogen ]. The red glow and the larger shape are all created by a small group of stars near the nebula's center [ http://antwrp.gsfc.nasa.gov/apod/ap060922.html ]. A close up spanning about 30 light years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] contains many of these stars is shown above [ http://www.telescopes.cc/ic1805large.htm ] . This open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars contains a few bright stars [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2006A%26A...456.1121D ] nearly 50 times the mass of our Sun, many dim stars only a fraction of the mass of our Sun, and an absent microquasar [ http://antwrp.gsfc.nasa.gov/apod/ap040916.html ] that was expelled millions of years ago. The Heart Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap031022.html ] is located about 7,500 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away toward the constellation [ http://www.mallorcaweb.net/masm/descon1.htm ] of Cassiopeia [ http://www.seds.org/Maps/Stars_en/Fig/cassiopeia.html ]. |
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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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Emerging Planetary Nebula CR
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| Title |
Emerging Planetary Nebula CRL 618 |
| Explanation |
CRL 618 may look to some like an Olympian [ http://www.olympics.com/ ] declaring victory. Only a few hundred years ago, however, CRL 618 [ http://hubble.esa.int/hubble/news/index.cfm?oid=24527 ] appeared as a relatively modest red giant star [ http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971016.html ]. Since then it has run out of core material to fuse [ http://fusedweb.pppl.gov/CPEP/Chart.html ] and so has started to become a planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ]. In its current proto-planetary nebula [ http://www.astro.washington.edu/palen/Research/nsf/intro.html ] phase, CRL 618 [ http://hubble.esa.int/content/news/index.cfm?aid=18&cid=599&oid=12850 ] is evolving quickly, expelling hot gasses in complex jets [ http://antwrp.gsfc.nasa.gov/apod/ap960129.html ] and rings moving outwards faster than 700,000 kilometers per hour. In a few thousand years, the glowing core of the cool red giant [ http://www.historyoftheuniverse.com/starold.html ] will be bare, revealing a hot white dwarf star [ http://antwrp.gsfc.nasa.gov/apod/ap971102.html ]. Much remains unknown about planetary nebulae [ http://antwrp.gsfc.nasa.gov/apod/ap990321.html ] formation, including details of how geometries like this form. Perhaps one day some part of this nebula will be able to declare victory - CRL 618 [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999ESASP.427..285C ] has an extraordinary abundance of carbon-chain molecules [ http://www.ifa.hawaii.edu/~wynnwill/110/16_life.htm ]. |
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NGC 6960: The Witch's Broom
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| Title |
NGC 6960: The Witch's Broom Nebula |
| Explanation |
Ten thousand years ago, before the dawn of recorded human history [ http://news.bbc.co.uk/hi/english/sci/tech/newsid_334000/334517.stm ], a new light must suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was an exploding star [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html ] and record the colorful expanding cloud as the Veil Nebula [ http://nineplanets.org/twn/cygnusx.html ]. Pictured above [ http://robgendler.astrodigitals.com/Nebulas.html ] is the west end of the Veil Nebula [ http://www.astropix.com/HTML/E_SUM_N/VEIL.HTM ] known technically as NGC [ http://www.ngcic.com/dss/dss_images.htm ] 6960 but less formally as the Witch's Broom Nebula. The rampaging gas gains its colors by impacting and exciting existing [ http://antwrp.gsfc.nasa.gov/apod/ap960307.html ] nearby gas. The supernova remnant [ http://antwrp.gsfc.nasa.gov/apod/supernova_remnants.html ] lies about 1400 light-years away towards the constellation of Cygnus [ http://www.multimania.com/cdadfs/constellation/cygne/cygnus.htm ]. This Witch's Broom actually spans over three times the angular size of the full Moon [ http://antwrp.gsfc.nasa.gov/apod/moon.html ]. The bright blue star 52 Cygnus [ http://www.seds.org/Maps/Stars_en/Fig/cygnus.html ] is visible with the unaided eye from a dark location but unrelated to the ancient supernova [ http://www.chapman.edu/oca/benet/intro_sn.htm ]. |
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The Helix Nebula from CFHT
| Title |
The Helix Nebula from CFHT |
| Explanation |
One day our Sun may look like this. The Helix Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap960417.html ] is the closest example of a planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ] created at the end of the life of a Sun-like star. The outer gasses of the star expelled into space [ http://www.seds.org/messier/planetar.html ] appear from our vantage point as if we are looking down a helix [ http://mathworld.wolfram.com/Helix.html ]. The remnant central stellar core, destined to become a white dwarf star [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html ], glows in light so energetic [ http://snoopy.gsfc.nasa.gov/~orfeus2/ultraviolet.html ] it causes the previously expelled gas to fluoresce [ http://www.exploratorium.edu/xref/exhibits/fluorescent_tube.html ]. The Helix Nebula [ http://www-personal.umich.edu/~jstys/nebulae/ngc7293.html ], given a technical designation of NGC 7293 [ http://www.seds.org/messier/xtra/ngc/n7293.html ], lies 450 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away towards the constellation [ http://www.emufarm.org/~cmbell/myth/myth.html ] of Aquarius [ http://www.astronomical.org/constellations/aqr.html ] and spans 1.5 light-years. The above image was taken with the Canada-France-Hawaii Telescope [ http://www.cfht.hawaii.edu/ ] (CFHT) located atop a dormant volcano in Hawaii [ http://www.state.hi.us/ ], USA. A close-up of the inner edge [ http://antwrp.gsfc.nasa.gov/apod/ap970720.html ] of the Helix Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap970901.html ] shows unusual gas knots of unknown origin [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998ApJ...503..792B ]. |
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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 418: The Spirograph Nebul
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| Title |
IC 418: The Spirograph Nebula |
| Explanation |
What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula [ http://heritage.stsci.edu/public/2000sept7/ic418table.html ] for its resemblance to drawings from a cyclical drawing tool [ http://www.wordsmith.org/~anu/java/spirograph.html ], planetary nebula [ http://www.noao.edu/jacoby/pn_gallery.html ] IC 418 shows patterns [ http://mathworld.wolfram.com/Spirograph.html ] that are not well understood. Perhaps they are related to chaotic winds [ http://www-spof.gsfc.nasa.gov/Education/wsolwind.html ] from the variable central star, which changes brightness unpredictably [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997A%26A...320..125H ] in just a few hours. By contrast, evidence indicates that only a few million years ago, IC 418 [ http://www.skyhound.com/sh/archive/jan/IC_418.html ] was probably a well-understood star similar to our Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ]. Only a few thousand years ago, IC 418 was probably a common red giant [ http://www.historyoftheuniverse.com/starold.html ] star. Since running out of nuclear fuel [ http://csep10.phys.utk.edu/astr162/lect/energy/ppchain.html ], though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white-dwarf star [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html ], visible in the image [ http://heritage.stsci.edu/public/2000sept7/displayic418.html ] center. The light from the central core excites surrounding atoms [ http://www.pbs.org/wgbh/aso/tryit/atom/ ] in the nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ] causing them to glow. IC 418 lies about 2000 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away and spans 0.3 light-years across. This recently released false-color image [ http://heritage.stsci.edu/public/2000sept7/ic418table.html ] taken from the Hubble Space Telescope [ http://www.stsci.edu/hst/ ] reveals the unusual details. |
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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 6960: The Witch's Broom
…
| Title |
NGC 6960: The Witch's Broom Nebula |
| Explanation |
Ten thousand years ago, before the dawn of recorded human history [ http://news.bbc.co.uk/hi/english/sci/tech/newsid_334000/334517.stm ], a new light must suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was an exploding star [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html ] and record the colorful expanding cloud as the Veil Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap010928.html ]. Pictured above [ http://www.noao.edu/image_gallery/html/im0852.html ] is the west end of the Veil Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap030204.html ] known technically as NGC [ http://en.wikipedia.org/wiki/New_General_Catalog ] 6960 but less formally as the Witch [ http://antwrp.gsfc.nasa.gov/apod/ap061211.html ]'s Broom [ http://www.broomshop.com/history/ ] Nebula. The rampaging gas gains its colors by impacting and exciting existing [ http://www.seds.org/billa/twn/cygnusx.html ] nearby gas. The supernova remnant [ http://antwrp.gsfc.nasa.gov/apod/supernova_remnants.html ] lies about 1400 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away towards the constellation of Cygnus [ http://www.multimania.com/cdadfs/constellation/cygne/cygnus.htm ]. This Witch's Broom actually spans over three times the angular size [ http://imagine.gsfc.nasa.gov/YBA/HTCas-size/more-ang_size.html ] of the full Moon [ http://antwrp.gsfc.nasa.gov/apod/ap030810.html ]. The bright star 52 Cygnus [ http://www.seds.org/Maps/Stars_en/Fig/cygnus.html ] is visible with the unaided eye from a dark location but unrelated to the ancient supernova [ http://en.wikipedia.org/wiki/Supernova ]. |
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The Eagle Nebula in Infrared
| Title |
The Eagle Nebula in Infrared |
| Explanation |
In visible light, the whole thing looks like an eagle [ http://video.google.com/videoplay?docid=-4639730101975502715&q=eagle&hl=en ]. The region was captured recently in unprecedented detail in infrared light [ http://imagers.gsfc.nasa.gov/ems/infrared.html ] by the robotic orbiting Spitzer Space Telescope [ http://en.wikipedia.org/wiki/Spitzer_space_telescope ] (SSC). Shown above [ http://www.spitzer.caltech.edu/Media/releases/ssc2007-01/ssc2007-01a.shtml ], the infrared image allows observers to peer through normally opaque dust [ http://antwrp.gsfc.nasa.gov/apod/ap060409.html ] and so better capture the full complexity of the Eagle Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap060226.html ] star forming region. In particular, the three famous pillars [ http://antwrp.gsfc.nasa.gov/apod/ap050424.html ] near the image center are seen bathed in dust likely warmed by a supernova [ http://en.wikipedia.org/wiki/Supernova ] explosion. The warm dust is digitally assigned the false color of red. Also visible, near the bottom of the image, is ten light-year long pillar sometimes dubbed the Fairy [ http://antwrp.gsfc.nasa.gov/apod/ap050425.html ] of Eagle Nebula. The greater Eagle emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], tagged M16, lies about 6500 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away, spans about 20 light-years, and is visible with binoculars [ http://www.birdwatching.com/optics/binoculars1.html#How Binoculars Work ] toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Serpens [ http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=76 ]. |
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M8: In the Center of the Lag
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| Title |
M8: In the Center of the Lagoon Nebula |
| Explanation |
In the center of the Lagoon Nebula [ http://www.seds.org/messier/m/m008.html ] one finds glowing gas [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], star clusters, and dense knots of gas and dust [ http://antwrp.gsfc.nasa.gov/apod/ap961229.html ] just now forming stars. The young open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars, designated NGC 6523, can be seen in the center of the above image [ http://www.janis.or.jp/users/kitahara/e-m8-95.jpg.html ]. These stars emit energetic light [ http://snoopy.gsfc.nasa.gov/~orfeus2/ultraviolet.html ] that ionizes [ http://csep10.phys.utk.edu/astr162/lect/light/ionization.html ] the surrounding hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ] gas. As this gas reacquires electrons [ http://www.aip.org/history/electron/ ], it emits red light [ http://csep10.phys.utk.edu/astr162/lect/light/absorption.html ]. The Lagoon Nebula [ http://www.seds.org/billa/twn/n6523x.html ] lies about 5000 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away and spans about 100 light-years across. The nebula [ http://antwrp.gsfc.nasa.gov/apod/ap980707.html ] occupies an area on the sky larger than a full moon [ http://antwrp.gsfc.nasa.gov/apod/ap991108.html ], and can be seen even without binoculars from a dark location towards the constellation [ http://www.allthesky.com/constellations/const.html ] of Sagittarius [ http://www.astronomical.org/constellations/sgr.html ]. |
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The Rosette Nebula
| Title |
The Rosette Nebula |
| Explanation |
Would the Rosette Nebula [ http://www.seds.org/messier/xtra/ngc/n2244.html ] by any other name [ http://www.bartleby.com/100/138.28.22.html ]"look" as sweet [ ftp://ibiblio.org/pub/docs/books/gutenberg/etext00/0ws1610.txt ]? The bland New General Catalog [ http://www.ngcic.org/history.htm ] designation of NGC 2237 [ http://nineplanets.org/twn/n2237x.html ] doesn't appear to diminish the appearance of the this [ http://www.robgendlerastropics.com/RosettemegamosaicNM.html ] flowery emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ]. Inside the nebula lies an open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of bright young stars designated NGC 2244 [ http://antwrp.gsfc.nasa.gov/apod/ap000822.html ]. These stars formed about four million years ago [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ApJ...414..664K ] from the nebular material and their stellar winds [ http://www.bartol.udel.edu/~owocki/apsposter/sld001.htm ] are clearing a hole in the nebula's center, insulated by a layer of dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] and hot gas. Ultraviolet light [ http://liftoff.msfc.nasa.gov/academy/universe/ultraviolet.html ] from the hot cluster stars causes the surrounding nebula to glow. The Rosette Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000111.html ] spans about 100 light-years [ http://domeofthesky.com/clicks/lightyear.html ] across, lies about 5000 light-years away [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000A%26A...358..553H ], and can be seen with a small telescope towards the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Monoceros [ http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=55 ]. |
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Stars, Dust and Nebula in NG
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| Title |
Stars, Dust and Nebula in NGC 2170 |
| Explanation |
When stars form, pandemonium reigns. A textbook [ http://zebu.uoregon.edu/text.html ] case is the star forming region NGC 2170 [ http://antwrp.gsfc.nasa.gov/apod/ap060805.html ]. Visible above [ http://www.rc-astro.com/photo/id1178.html ] are red glowing emission nebulas [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] of hydrogen [ http://periodic.lanl.gov/elements/1.html ], blue reflection nebulas [ http://en.wikipedia.org/wiki/Reflection_nebula ] of dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ], dark absorption nebulas [ http://www.glyphweb.com/esky/concepts/absorptionnebula.html ] of dust, and the stars that formed from them. The first massive stars formed from the dense gas will emit energetic light [ http://imagers.gsfc.nasa.gov/ems/uv.html ] and winds [ http://www.peripatus.gen.nz/Astronomy/SteWin.html ] that erode, fragment, and sculpt [ http://antwrp.gsfc.nasa.gov/apod/ap050425.html ] their birthplace. And then they explode [ http://heasarc.gsfc.nasa.gov/docs/snr.html ]. The resulting morass [ http://antwrp.gsfc.nasa.gov/apod/ap020424.html ] is often as beautiful as it is complex. After tens of millions of years, the dust boils away, the gas gets swept away, and all that is left is a naked open cluster [ http://antwrp.gsfc.nasa.gov/apod/ap040222.html ] of stars. |
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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. |
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Planetary Nebula Mz3: The An
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| Title |
Planetary Nebula Mz3: The Ant Nebula |
| Explanation |
Why isn't this ant a big sphere? Planetary nebula [ http://www.noao.edu/jacoby/pn_gallery.html ] Mz3 is being cast off by a star similar to our Sun [ http://www.nineplanets.org/sol.html ] that is, surely, round. Why then would the gas that is streaming away create an ant [ http://www.discovery.com/cams/ant/learn.html ]-shaped nebula that is distinctly not round? Clues might include [ http://hubble.esa.int/hubble/news/ index.cfm?oid=25994 ] the high 1000-kilometer per second speed of the expelled gas, the light-year [ http://starchild.gsfc.nasa.gov/docs/StarChild/ questions/question19.html ] long length of the structure, and the magnetism [ http://www.wondermagnet.com/dev/magfaq.html ] of the star visible above [ http://heritage.stsci.edu/public/2001feb/display.html ] at the nebula's center. One possible answer is that Mz3 [ http://heritage.stsci.edu/public/2001feb/table.html ] is hiding a second, dimmer star that orbits close [ http://antwrp.gsfc.nasa.gov/apod/ap991219.html ] in to the bright star. A competing hypothesis holds that the central star's own spin and magnetic field [ http://antwrp.gsfc.nasa.gov/apod/ap980629.html ] are channeling the gas. Since the central star appears to be so similar to our own Sun, astronomers [ http://www.aas.org/%7Eeducation/career.html ] hope that increased understanding of the history of this giant space ant [ http://www.ag.ohio-state.edu/~ohioline/hyg-fact/2000/2064.html ] can provide useful insight into the likely future of our own Sun [ http://antwrp.gsfc.nasa.gov/apod/sun.html ] and Earth [ http://antwrp.gsfc.nasa.gov/apod/earth.html ]. |
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The Rosette Nebula
| Title |
The Rosette Nebula |
| Explanation |
Would the Rosette Nebula [ http://www.seds.org/messier/xtra/ngc/n2244.html ] by any other name [ http://www.bartleby.com/100/138.28.22.html ]"look" as sweet [ ftp://ibiblio.org/pub/docs/books/gutenberg/etext00/0ws1610.txt ]? The bland New General Catalog [ http://www.ngcic.org/ ] designation of NGC 2237 [ http://nineplanets.org/twn/n2237x.html ] doesn't appear to diminish the appearance of the this [ http://robgendler.astrodigitals.com/ROSMOSLRGB.html ] flowery emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ]. Inside the nebula lies an open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of bright young stars designated NGC 2244 [ http://antwrp.gsfc.nasa.gov/apod/ap000822.html ]. These stars formed about four million years ago [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ApJ...414..664K ] from the nebular material and their stellar winds [ http://www.bartol.udel.edu/~owocki/apsposter/sld001.htm ] are clearing a hole in the nebula's center, insulated by a layer of dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] and hot gas. Ultraviolet light [ http://liftoff.msfc.nasa.gov/academy/universe/ultraviolet.html ] from the hot cluster stars causes the surrounding nebula to glow. The Rosette Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000111.html ] spans about 100 light-years [ http://einstein.stcloudstate.edu/Dome/constellns/lightyear.html ] across, lies about 5000 light-years away [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000A%26A...358..553H ], and can be seen with a small telescope towards the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Monoceros [ http://www.astronomical.org/constellations/mon.html ]. |
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MWC 922: The Red Square Nebu
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| Title |
MWC 922: The Red Square Nebula |
| Explanation |
What could cause a nebula to appear square? No one is quite sure. The hot star system known as MWC 922 [ http://www.sciencemag.org/cgi/content/abstract/316/5822/247 ], however, appears to be imbedded in a nebula with just such a shape. The above image [ http://www.physics.usyd.edu.au/~gekko/redsquare.html ] combines infrared [ http://en.wikipedia.org/wiki/Infrared ] exposures from the Hale Telescope [ http://www.astro.caltech.edu/palomar/hale.html ] on Mt. Palomar [ http://www.astro.caltech.edu/palomar/ ] in California [ http://en.wikipedia.org/wiki/California ], and the Keck-2 Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap971227.html ] on Mauna Kea [ http://antwrp.gsfc.nasa.gov/apod/ap050704.html ] in Hawaii [ http://en.wikipedia.org/wiki/Hawaii ]. A leading progenitor hypothesis for the square nebula [ http://antwrp.gsfc.nasa.gov/apod/ap020618.html ] is that the central star or stars somehow expelled cones of gas during a late developmental stage [ http://instruct1.cit.cornell.edu/courses/astro101/java/evolve/evolve.htm ]. For MWC 922 [ http://www.keckobservatory.org/article.php?id=104 ], these cones happen to incorporate nearly right angles [ http://en.wikipedia.org/wiki/Right_angle ] and be visible from the sides. Supporting evidence for the cone [ http://mathworld.wolfram.com/Cone.html ] hypothesis includes radial spokes in the image that might run along the cone walls. Researchers speculate that the cones viewed from another angle would appear similar to the gigantic rings of supernova 1987A [ http://antwrp.gsfc.nasa.gov/apod/ap070107.html ], possibly indicating that a star in MWC 922 might one day itself explode in a similar supernova [ http://heasarc.gsfc.nasa.gov/docs/snr.html ]. |
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In the Center of Reflection
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| Title |
In the Center of Reflection Nebula NGC 1333 |
| Explanation |
The dust is so thick in the center of NGC 1333 that you can hardly see the stars forming. Conversely, the very dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] clouds that hide the stars also reflects their optical light [ http://fuse.pha.jhu.edu/~wpb/spectroscopy/em_spec.html ], giving NGC 1333 [ http://www.robgendlerastropics.com/NGC1333text.html ]'s predominantly blue glow the general designation of a reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ]. A highly detailed image of the nebula, shown above [ http://www.noao.edu/image_gallery/html/im1037.html ], was taken recently by the Mayall 4-meter telescope [ http://www.noao.edu/outreach/kptour/mayall.html ] on Kitt Peak [ http://www.noao.edu/kpno/ ] in Arizona [ http://en.wikipedia.org/wiki/Arizona ], USA [ http://en.wikipedia.org/wiki/United_States ] and released to honor astronomer Stephen Strom [ http://www.noao.edu/outreach/press/pr07/pr0706.html ] on his retirement. Visible near the image top are vast blue regions of dust [ http://antwrp.gsfc.nasa.gov/apod/ap061211.html ] predominantly reflecting the light from bright massive stars [ http://antwrp.gsfc.nasa.gov/apod/ap060109.html ]. Visible in the thick central dust are not only newly formed stars but red jets [ http://antwrp.gsfc.nasa.gov/apod/ap070430.html ] and red-glowing gas energized by the light and winds [ http://www-spof.gsfc.nasa.gov/Education/wsolwind.html ] from recently formed young stars. The NGC 1333 [ http://adsabs.harvard.edu/abs/2002ApJ...580..959N ] nebula contains [ http://antwrp.gsfc.nasa.gov/apod/ap061006.html ] hundreds of newly formed stars that are less than one million years old. Reflection nebula [ http://en.wikipedia.org/wiki/Reflection_nebula ] NGC 1333 lies about 1,000 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away toward the constellation of Perseus [ http://chandra.harvard.edu/photo/constellations/perseus.html ]. |
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The Snowflake Cluster versus
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| Title |
The Snowflake Cluster versus the Cone Nebula |
| Explanation |
Strange shapes and textures can be found in the neighborhood of the Cone Nebula. These patterns result from the tumultuous unrest that accompanies the formation of the open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars known as NGC 2264 [ http://www.seds.org/messier/xtra/ngc/n2264.html ], the Snowflake cluster. To better understand this process, a detailed image of this region was taken in two colors of infrared light [ http://coolcosmos.ipac.caltech.edu//cosmic_classroom/classroom_activities/herschel_bio.html ] by the orbiting Spitzer Space Telescope [ http://en.wikipedia.org/wiki/Spitzer_Space_Telescope ]. Bright stars from the Snowflake [ http://www.its.caltech.edu/~atomic/snowcrystals/photos/photos.htm ] cluster dot the field. These stars soon heat up and destroy the gas and dust mountains [ http://antwrp.gsfc.nasa.gov/apod/ap051111.html ] in which they formed. One such dust mountain [ http://antwrp.gsfc.nasa.gov/apod/ap070224.html ] is the famous Cone Nebula, visible in the above image [ http://sscws1.ipac.caltech.edu/Imagegallery/image.php?image_name=sig05-028 ] on the left, pointing toward a bright star near the center of the field. The entire NGC 2264 [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?2264 ] region is located about 2,500 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away toward the constellation of the Unicorn [ http://en.wikipedia.org/wiki/Unicorn ] (Monoceros [ http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=55 ]). |
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Dust Pillar of the Carina Ne
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| Title |
Dust Pillar of the Carina Nebula |
| Explanation |
Inside the head of this interstellar monster is a star that is slowly destroying it. The monster, actually an inanimate pillar of gas [ http://periodic.lanl.gov/elements/1.html ] and dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ], measures over a light year [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] in length. The star, not itself visible through the opaque dust, is bursting out partly by ejecting energetic beams of particles [ http://en.wikipedia.org/wiki/Particle_beam_weapon ]. Similar epic battles are being waged all over the star-forming Carina Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap070425.html ]. The stars will win in the end, destroying their pillars of creation [ http://antwrp.gsfc.nasa.gov/apod/ap070218.html ] over the next 100,000 years, and resulting in a new open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars. The pink dots are newly formed stars that have already been freed from their birth monster. The above image [ http://hubblesite.org/newscenter/archive/releases/2007/16/image/i/ ] is only a small part of a highly detailed panoramic mosaic [ http://hubblesite.org/newscenter/archive/releases/2007/16/image/a/format/zoom/ ] of the Carina Nebula [ http://heritage.stsci.edu/2007/16/supplemental.html ] taken by the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap010806.html ] and released last week. The technical name for the stellar jets are Herbig-Haro objects [ http://en.wikipedia.org/wiki/Herbig-Haro_objects ]. How a star creates Herbig-Haro jet [ http://antwrp.gsfc.nasa.gov/apod/ap060203.html ]s is an ongoing topic of research [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2006MNRAS.369.1167L ], but it likely involves an accretion disk [ http://antwrp.gsfc.nasa.gov/apod/ap991219.html ] swirling around a central star. A second impressive Herbig-Haro jet [ http://antwrp.gsfc.nasa.gov/apod/ap991129.html ] is visible across the bottom of a larger image. |
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IC 4603: Reflection Nebula i
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| Title |
IC 4603: Reflection Nebula in Ophiuchius |
| Explanation |
Why does this starfield photograph resemble an impressionistic painting [ http://www.ibiblio.org/wm/paint/glo/impressionism/ ]? The effect is created not by digital trickery [ http://antwrp.gsfc.nasa.gov/apod/ap030324.html ] but by large amounts of interstellar dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ]. Dust, minute globs rich in carbon [ http://www.nyu.edu/pages/mathmol/modules/carbon/carbon1.html ] and similar in size [ http://www.lakeair.com/particle.html ] to cigarette smoke [ http://amos.indiana.edu/library/scripts/smoke.html ], frequently starts in the outer atmospheres of large, cool, young stars. The dust [ http://nedwww.ipac.caltech.edu/level5/March02/Li/Li_contents.html ] is dispersed as the star dies and grows as things stick to it in the interstellar medium [ http://www-ssg.sr.unh.edu/ism/intro.html ]. Dense dust clouds are opaque [ http://antwrp.gsfc.nasa.gov/apod/ap030202.html ] to visible light [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html ] and can completely hide background stars. For less dense clouds, the capacity of dust to preferentially reflect blue [ http://www.why-is-the-sky-blue.org/why-is-the-sky-blue.html ] starlight becomes important, effectively blooming the stars blue light out and marking the surrounding dust. Nebular gas emissions, typically brightest in red light [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], can combine to form areas seemingly created on an artist's canvas. Photographed above [ http://ryutao.main.jp/english/stl_ant.html ] is roughly four square degrees of the nebula IC 4603 [ http://antwrp.gsfc.nasa.gov/apod/ap060714.html ] near the bright star Antares [ http://en.wikipedia.org/wiki/Antares ] toward the constellation [ http://en.wikipedia.org/wiki/Constellation ] of Ophiuchus [ http://www.seds.org/Maps/Stars_en/Fig/ophiuchus.html ]. |
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Wisps of the Iris Nebula
| Title |
Wisps of the Iris Nebula |
| Explanation |
Like delicate cosmic petals, these clouds of interstellar dust and gas have blossomed 1,300 light-years away in the fertile star fields of the constellation Cepheus [ http://www.astropix.com/HTML/E_SUM_N/CEPHEUSO.HTM ]. Sometimes called the Iris Nebula and dutifully cataloged as NGC [ http://www.seds.org/billa/ngc.html ] 7023, this is not the only nebula in the sky to evoke the imagery of flowers [ http://antwrp.gsfc.nasa.gov/apod/ap010214.html ]. Still, this beautiful digital image [ http://www.tvdavisastropics.com/astroimages-1_00000f.htm ] shows off the Iris [ http://en.wikipedia.org/wiki/Iris_(plant) ] Nebula's range of colors and symmetries in impressive detail. Within the Iris, dust [ http://www.youtube.com/watch?v=zmZJc68zyAA ]y nebular material surrounds a massive, hot, young star in its formative [ http://antwrp.gsfc.nasa.gov/apod/ap040315.html ] years. Central filaments of cosmic dust glow with a reddish photoluminescence [ http://en.wikipedia.org/wiki/Photoluminescence ] as some dust grains effectively convert [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query? bibcode=1989ApJ...347L..25W&db_key=AST&high=3bc4bede8e21358 ] the star's invisible ultraviolet [ http://imagers.gsfc.nasa.gov/ems/uv.html ] radiation to visible red light. Yet the dominant color of the central nebula is blue, characteristic of dust [ http://leo.astronomy.cz/mix/mix.html ] grains reflecting starlight [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ]. Dark, obscuring clouds of dust and cold molecular gas [ http://antwrp.gsfc.nasa.gov/apod/ap041219.html ] are present on the left of the image, and lead the eye to see other convoluted [ http://antwrp.gsfc.nasa.gov/apod/ap010720.html ] and fantastic [ http://antwrp.gsfc.nasa.gov/apod/ap031229.html ] shapes. Infrared observations [ http://cdsads.u-strasbg.fr/cgi-bin/ nph-bib_query?2000A%26A...354L..17M&db_key=AST&nosetcookie=1 ] indicate that this nebula may contain complex carbon molecules known as PAHs [ http://www.chem.ucl.ac.uk/cosmicdust/pah.htm ]. As shown here, the bright blue portion of the Iris Nebula [ http://www.noao.edu/outreach/aop/observers/n7023.html ] is about six light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] across. |
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The Lagoon Nebula in Gas, Du
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| Title |
The Lagoon Nebula in Gas, Dust, and Stars |
| Explanation |
Stars are battling gas and dust in the Lagoon Nebula but the photographers are winning. Also known as M8, this photogenic nebula [ http://astrosurf.com/afernandez/gallery/deepsky/m8/m8_lrgb_asa_70.htm ] is visible [ http://antwrp.gsfc.nasa.gov/apod/ap011229.html ] even without binoculars towards the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Sagittarius [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Sagittarius.html ]. The energetic processes of star formation [ http://antwrp.gsfc.nasa.gov/apod/ap030816.html ] create not only the colors but the chaos [ http://antwrp.gsfc.nasa.gov/apod/ap031228.html ]. The red-glowing gas [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] results from high-energy starlight striking interstellar hydrogen [ http://en.wikipedia.org/wiki/Hydrogen ] gas. The dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] filaments [ http://antwrp.gsfc.nasa.gov/apod/ap010928.html ] that lace M8 [ http://www.seds.org/messier/m/m008.html ] were created in the atmospheres of cool giant stars [ http://www.astro.keele.ac.uk/workx/starlife/StarpageS_26M.html ] and in the debris [ http://antwrp.gsfc.nasa.gov/apod/ap990803.html ] from supernovae [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html ] explosions. The light from M8 [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?m8 ] we see today left about 5,000 years ago [ http://en.wikipedia.org/wiki/3rd_millennium_BC ]. Light takes about 50 years to cross this section of M8 [ http://www.seds.org/billa/twn/n6523.html ]. |
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Pulsar Wind in the Vela Nebu
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| Title |
Pulsar Wind in the Vela Nebula |
| Explanation |
The Vela pulsar was born [ http://antwrp.gsfc.nasa.gov/apod/ap980425.html ] 10,000 years ago at the center of a supernova -- an exploding star [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/ supernovae.html ]. In this Chandra Observatory x-ray image [ http://chandra.harvard.edu/photo/cycle1/velawv/ index.html ], the pulsar still produces a glowing nebula at the heart of the expanding cloud of stellar debris. The pulsar [ http://www.jb.man.ac.uk/~pulsar/Education/Sounds/ sounds.html ] itself is a neutron star [ http://heasarc.gsfc.nasa.gov/docs/objects/binaries/ neutron_star_structure.html ], formed as the stellar core was compacted [ http://observe.ivv.nasa.gov/nasa/space/stellardeath/ stellardeath_3a.html ] to nuclear densities. With a strong magnetic field, approximately the mass of the Sun, and a diameter of about 20 kilometers, the Vela pulsar rotates 11 times "a second". The sharp Chandra image aids astronomers [ http://xxx.lanl.gov/abs/astro-ph/0105128 ] in understanding such extreme systems as efficient high-voltage generators [ http://chandra.harvard.edu/chronicle/0201/vela.html ] which drive structured winds [ http://antwrp.gsfc.nasa.gov/apod/ap000609.html ] of electrically charged particles. An x-ray bright nebula is created as the pulsar winds slam into the surrounding material. This view spans about 6 light-years across the central region of the much larger Vela supernova remnant [ http://antwrp.gsfc.nasa.gov/apod/ap960612.html ]. |
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The Trifid Nebula in Stars a
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| Title |
The Trifid Nebula in Stars and Dust |
| Explanation |
Unspeakable beauty and unimaginable bedlam can be found together in the Trifid Nebula [ http://www.seds.org/messier/m/m020.html ]. Also known as M20, this photogenic nebula [ http://www.cosmotography.com/images/lrg_m20.html ] is visible [ http://antwrp.gsfc.nasa.gov/apod/ap011229.html ] with good binoculars towards the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Sagittarius [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Sagittarius.html ]. The energetic processes of star formation [ http://antwrp.gsfc.nasa.gov/apod/ap030816.html ] create not only the colors but the chaos [ http://en.wikipedia.org/wiki/Chaos_%28physics%29 ]. The red-glowing gas [ http://antwrp.gsfc.nasa.gov/apod/ap980828.html ] results from high-energy starlight striking interstellar hydrogen [ http://periodic.lanl.gov/elements/1.html ] gas. The dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] filaments [ http://antwrp.gsfc.nasa.gov/apod/ap010928.html ] that lace M20 [ http://antwrp.gsfc.nasa.gov/apod/ap970828.html ] were created in the atmospheres of cool giant stars [ http://www.astro.keele.ac.uk/workx/starlife/StarpageS_26M.html ] and in the debris [ http://antwrp.gsfc.nasa.gov/apod/ap990803.html ] from supernovae [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html ] explosions. Which bright young stars light up the blue reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] is still being investigated [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1986AJ.....92.1125L ]. The light from M20 [ http://www.noao.edu/image_gallery/html/im0587.html ] we see today left perhaps 3000 years ago, although the exact distance remains unknown. Light takes about 50 years to cross M20 [ http://www.seds.org/billa/twn/n6514x.html ]. |
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The Red Spider Planetary Neb
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| Title |
The Red Spider Planetary Nebula |
| Explanation |
Oh what a tangled web [ http://www.bartleby.com/100/338.25.html ] a planetary nebula [ http://www.seds.org/messier/planetar.html ] can weave. The Red Spider Planetary Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap980106.html ] shows the complex structure that can result when a normal star [ http://antwrp.gsfc.nasa.gov/apod/ap000815.html ] ejects its outer gases and becomes a white dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap000910.html ] star. Officially tagged NGC [ http://www.encyclopedia.com/printablenew/33395.html ] 6537 [ http://www.astro.washington.edu/balick/WFPC2/n6537.caption.html ], this two-lobed symmetric planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ] houses one of the hottest white dwarfs [ http://antwrp.gsfc.nasa.gov/apod/ap000730.html ] ever observed, probably as part of binary star [ http://astrosun.tn.cornell.edu/courses/astro201/binstar.htm ] system. Internal winds [ http://www-spof.gsfc.nasa.gov/Education/wsolwind.html ] emanating from the central stars, visible in the center, have been measured in excess of 1000 kilometers per second. These winds [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ] expand the nebula, flow along the nebula's walls, and cause waves of hot gas [ http://pearl1.lanl.gov/periodic/elements/1.html ] and dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] to collide. Atoms [ http://education.jlab.org/atomtour/ ] caught in these colliding shocks radiate light shown in the above representative-color picture [ http://www.spacetelescope.org/pressroom/embargo/heic0109_embargo.html ]. The Red Spider Nebula [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000A%26A...362L..17P ] lies toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Sagittarius [ http://www.astronomical.org/constellations/sgr.html ]. It's distance is not well known but estimated by some [ http://cdsads.u-strasbg.fr/cgi-bin/bib_query?1986A&A...157..191G ] to be about 4000 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ]. |
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M57: The Ring Nebula
| Title |
M57: The Ring Nebula |
| Explanation |
Except for the rings of Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap000212.html ], the Ring Nebula [ http://seds.lpl.arizona.edu/messier/m/m057.html ] (M57) is probably the most famous celestial band. This planetary nebula's [ http://www.astro.washington.edu/balick/WFPC2/ ] simple, graceful appearance is thought to be due to perspective -- our view from planet Earth [ http://antwrp.gsfc.nasa.gov/apod/earth.html ] looking straight into what is actually a barrel-shaped cloud [ http://www.seds.org/billa/twn/n6720x.html ] of gas shrugged off by a dying central star. Astronomers of the Hubble Heritage Project [ http://heritage.stsci.edu/ ] produced this strikingly sharp image [ http://heritage.stsci.edu/public/jan6/ringbond.html ] from Hubble Space Telescope [ http://www.stsci.edu/hst/ ] observations using natural appearing colors to indicate the temperature of the stellar gas shroud. Hot blue gas near the energizing central star gives way to progressively cooler green and yellow gas at greater distances [ http://antwrp.gsfc.nasa.gov/apod/ap990922.html ] with the coolest red gas along the outer boundary. Dark, elongated structures [ http://antwrp.gsfc.nasa.gov/apod/ap970720.html ] can also be seen near the nebula's edge. The Ring Nebula [ http://seds.lpl.arizona.edu/messier/more/m057_jac.html ] is about one light-year [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] across and 2,000 light-years away in the northern constellation Lyra [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Lyra.html ]. |
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The Lagoon Nebula in Three C
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| Title |
The Lagoon Nebula in Three Colors |
| Explanation |
The bright Lagoon Nebula [ http://www.seds.org/messier/m/m008.html ] is home to a diverse array of astronomical objects. Particularly interesting sources include a bright open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars and several energetic star-forming regions [ http://antwrp.gsfc.nasa.gov/apod/stellar_nursuries.html ]. When viewed by eye, cluster light [ http://antwrp.gsfc.nasa.gov/apod/ap980707.html ] is dominated by an overall red glow that is caused by luminous hydrogen gas [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], while the dark filaments are caused by absorption by dense lanes [ http://antwrp.gsfc.nasa.gov/apod/ap980116.html ] of dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ]. The above picture [ http://antwrp.gsfc.nasa.gov/apod/ap010820.html http://lilen.fcaglp.unlp.edu.ar/ ], from the Curtis-Schmidt Telescope [ http://www.noao.edu/image_gallery/html/im0131.html ], however, shows the nebula's emission in three exact colors specifically emitted by hydrogen [ http://www.eren.doe.gov/hydrogen/ ], oxygen [ http://pearl1.lanl.gov/periodic/elements/8.html ], and sulfur [ http://pearl1.lanl.gov/periodic/elements/16.html ]. The Lagoon Nebula [ http://www.seds.org/billa/twn/n6523x.html ], also known as M [ http://www.seds.org/messier/xtra/history/CMessier.html ]8 and NGC [ http://www.ngcic.org/mission.htm ] 6523, lies about 5000 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away. The Lagoon Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap010103.html ] can be located with binoculars in the constellation of Sagittarius [ http://www.astronomical.org/constellations/sgr.html ] spanning a region over three times the diameter of a full Moon [ http://antwrp.gsfc.nasa.gov/apod/ap010218.html ]. |
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The Making of the Rotten Egg
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| Title |
The Making of the Rotten Egg Nebula |
| Explanation |
Fast expanding gas clouds mark the end for a central star in the Rotten Egg Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap991101.html ]. The once-normal star has run out of nuclear fuel [ http://observe.ivv.nasa.gov/nasa/exhibits/stars/star_5.html ], causing the central regions to contract into a white dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap000910.html ]. Some of the liberated energy causes the outer envelope of the star to expand. In this case, the result is a photogenic proto- planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ]. As the million-kilometer per hour gas rams into the surrounding interstellar gas [ http://antwrp.gsfc.nasa.gov/apod/ap000412.html ], a supersonic [ http://antwrp.gsfc.nasa.gov/apod/ap010221.html ] shock front [ http://www.pbs.org/wgbh/nova/barrier/boom/concept3.html ] forms where ionized [ http://csep10.phys.utk.edu/astr162/lect/light/ionization.html ] hydrogen [ http://www.chemicalelements.com/elements/h.html ] and nitrogen [ http://www.webelements.com/webelements/elements/text/N/key.html ] glow blue. The complex shock front [ http://antwrp.gsfc.nasa.gov/apod/ap001128.html ] had been hypothesized previously [ http://hubble.esa.int/hubble/news/newsrelease.cfm?oid=28169 ] but never so clearly imaged. Thick gas and dust [ http://antwrp.gsfc.nasa.gov/apod/ap010813.html ] hide the dying central star. The Rotten Egg Nebula [ http://oposite.stsci.edu/pubinfo/pr/1999/39/ ], also known as the Calabash Nebula [ http://sci.esa.int/content/searchimage/searchresult.cfm?aid=1&cid=14&ooid=28184 ] and OH231.8+4.2, will likely develop into a full bipolar planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/ap001217.html ] over the next 1000 years. The nebula, pictured above [ http://hubble.esa.int/hubble/gallery/new_searchresult.cfm?ooid=28164&imgid=12318 ], is about 1.4 light-years in extent and located about 5000 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Puppis [ http://www.astronomical.org/constellations/pup.html ]. |
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The Cocoon Nebula from CFHT
| Title |
The Cocoon Nebula from CFHT |
| Explanation |
What creates the colors of the Cocoon Nebula? The Cocoon Nebula [ http://www.noao.edu/outreach/aop/observers/ic5146.html ], cataloged as IC [ http://en.wikipedia.org/wiki/Index_Catalog ] 5146, is a strikingly beautiful nebula located about 4,000 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of the Swan (Cygnus [ http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=31 ]). Inside the Cocoon [ http://video.google.com/videoplay?docid=44640880585792574 ] Nebula is a newly developing open cluster [ http://www.seds.org/messier/open.html ] of stars. Like other stellar nurseries [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ], the Cocoon Nebula holds, at the same time, a bright red emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], blue reflection nebulas [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ], and dark absorption nebulas [ http://antwrp.gsfc.nasa.gov/apod/dark_nebulae.html ]. Given different mixtures, these three processes create a host of colors in this image [ http://www.cfht.hawaii.edu/HawaiianStarlight/AIOM/English/ CFHT-Coelum-AIOM-Apr2007.html ] taken recently by the Canada-France-Hawaii Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap000905.html ] (CFHT) in Hawaii [ http://en.wikipedia.org/wiki/Hawaii ], USA. Speculation based on recent measurements [ http://adsabs.harvard.edu/cgi-bin/ nph-bib_query?bibcode=2002AJ....123..304H ] holds that the massive star towards the left of the picture [ http://www.cfht.hawaii.edu/HawaiianStarlight/AIOM/English/ CFHT-Coelum-AIOM-Apr2007.html ] opened a hole in an existing molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010923.html ] through which much of the glowing material flows. The same star, which formed about 100,000 years ago, now provides the energy source for much of the emitted and reflected light [ http://antwrp.gsfc.nasa.gov/apod/ap061211.html ] from this nebula. |
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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. |
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The Snake Nebula from CFHT
| Title |
The Snake Nebula from CFHT |
| Explanation |
What slithers overhead? The dark winding lanes visible in part of the constellation [ http://www.adlerplanetarium.org/history/exhibits/constellations/timeline.html ] of Ophiuchus [ http://www.seds.org/Maps/Stars_en/Fig/ophiuchus.html ] belong to the Snake Nebula [ http://www.darkskyimages.com/snake.htm ]. Also known as Barnard [ http://astro.uchicago.edu/yerkes/virtualmuseum/Barnard.html ] 72, the Snake Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap970824.html ] is a series of dark absorption clouds [ http://antwrp.gsfc.nasa.gov/apod/dark_nebulae.html ] made up of molecular gas [ http://antwrp.gsfc.nasa.gov/apod/ap970430.html ] and interstellar dust. Interstellar dust grains [ http://antwrp.gsfc.nasa.gov/apod/ap010813.html ] - composed predominantly of carbon [ http://pearl1.lanl.gov/periodic/elements/6.html ] - absorb visible starlight and reradiate much of it in the infrared [ http://www.gemini.edu/public/infrared.html ]. This absorption causes stars behind the clouds [ http://www.anzwers.org/free/universe/darknebs.html ] to be obscured from view, hence the appearance of starless voids [ http://antwrp.gsfc.nasa.gov/apod/ap010923.html ] on the sky. Molecular clouds [ http://origins.jpl.nasa.gov/poster/bigbang3.html ] like the Snake Nebula [ http://www.rawbw.com/~shekhar/b72.html ] are places where new stars [ http://antwrp.gsfc.nasa.gov/apod/ap011125.html ] are likely to form. The Snake Nebula [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1977ApJ...213..654R ], pictured above [ http://www.cfht.hawaii.edu/HawaiianStarlight/AIOM/English/CFHT-Coelum-AIOM-Apr2002.html ], lies about 650 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away and spans the angular width of a full moon [ http://antwrp.gsfc.nasa.gov/apod/ap010218.html ]. |
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The Trifid Nebula from AAO
| Title |
The Trifid Nebula from AAO |
| Explanation |
Unspeakable beauty and unimaginable bedlam can be found together in the Trifid Nebula [ http://www.seds.org/messier/m/m020.html ]. Also known as M20, this photogenic nebula [ http://www.aao.gov.au/images/captions/aat012.html ] is visible [ http://antwrp.gsfc.nasa.gov/apod/ap011229.html ] with good binoculars towards the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Sagittarius [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Sagittarius.html ]. The energetic processes of star formation [ http://antwrp.gsfc.nasa.gov/apod/ap020108.html ] create not only the colors but the chaos [ http://antwrp.gsfc.nasa.gov/apod/ap011230.html ]. The red-glowing gas [ http://antwrp.gsfc.nasa.gov/apod/ap980828.html ] results from high-energy starlight striking interstellar hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ] gas. The dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] filaments [ http://antwrp.gsfc.nasa.gov/apod/ap010928.html ] that lace M20 [ http://antwrp.gsfc.nasa.gov/apod/ap970828.html ] were created in the atmospheres of cool giant stars [ http://www.astro.keele.ac.uk/workx/starlife/StarpageS_26M.html ] and in the debris [ http://antwrp.gsfc.nasa.gov/apod/ap990803.html ] from supernovae [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html ] explosions. Which bright young stars light up the blue reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] is still being investigated [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1986AJ.....92.1125L ]. The light from M20 [ http://www.noao.edu/image_gallery/html/im0587.html ] we see today left perhaps 3000 years ago, although the exact distance remains unknown. Light takes about 50 years to cross M20 [ http://www.seds.org/billa/twn/n6514x.html ]. |
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East of the Lagoon Nebula
| Title |
East of the Lagoon Nebula |
| Explanation |
To the east of the Lagoon Nebula [ http://www.astropix.com/HTML/D_SUM_S/M8.HTM ] is a star field rich in diversity. On the lower left are clouds rich in dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] that hide background stars [ http://antwrp.gsfc.nasa.gov/apod/ap010923.html ] and young star systems [ http://antwrp.gsfc.nasa.gov/apod/ap010604.html ] still forming. Dark clouds [ http://antwrp.gsfc.nasa.gov/apod/ap020409.html ] include LDN 227 [ http://homepage.interaccess.com/~purcellm/lcas/Articles/darkne.htm ] on the left and IC 1275 on the right, with a bright star near its tip. On the upper right are clouds rich in hot glowing gas [ http://antwrp.gsfc.nasa.gov/apod/ap010103.html ], including part of the emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] NGC 6559 [ http://www.astropix.com/HTML/D_SUM_S/NGC6559.HTM ]. On the right, between the two regions, is a nebula reflecting [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] light from a group of massive blue stars [ http://antwrp.gsfc.nasa.gov/apod/ap970128.html ]. The NGC 6559 complex pictured above spans about 3 light years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] and likely has a common history with the Lagoon Nebula [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?Lagoon ]. The complex [ http://www.seds.org/messier/m/m008.html ] lies about 5000 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Sagittarius [ http://www.astronomical.org/constellations/sgr.html ]. |
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The Fox Fur Nebula
| Title |
The Fox Fur Nebula |
| Explanation |
The nebula surrounding bright star S Mon is filled with dark dust and glowing gas. The strange shapes [ http://antwrp.gsfc.nasa.gov/apod/ap020108.html ] originate from fine interstellar dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] reacting in complex ways with the energetic light and hot gas being expelled by the young stars. The region just below S Mon [ http://antwrp.gsfc.nasa.gov/apod/ap010424.html ], the bright star in the above picture [ http://www.aao.gov.au/images/captions/aat014b.html ], is nicknamed the Fox Fur Nebula for its color and texture. The blue glow directly surrounding S Mon results from reflection [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ], where neighboring dust reflects light from the bright star. The more diffuse red glow results from emission [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], where starlight ionizes hydrogen [ http://antwrp.gsfc.nasa.gov/apod/ap010113.html ] gas. Pink areas are lit by a combination of the two processes. S Mon is part of a young open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars named NGC 2264 [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2002AAS...200.7002L ], located about 2500 light years [ http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980211a.html ] away toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Monoceros [ http://www.hawastsoc.org/deepsky/mon/index.html ], just north [ http://www.aao.gov.au/images/captions/aat014.html ] of the Cone Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap020503.html ]. |
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In the Center of the Trifid
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| Title |
In the Center of the Trifid Nebula |
| Explanation |
Clouds of glowing gas mingle with lanes of dark dust in the Trifid Nebula [ http://www.seds.org/messier/m/m020.html ], a star forming region toward the constellation [ http://www.att.virtualclassroom.org/vc99/vc_04/cons_stars/cons/hist_cons.html ] of Sagittarius [ http://www.astronomical.org/constellations/sgr.html ]. In the center, the three huge dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] lanes that give the Trifid [ http://antwrp.gsfc.nasa.gov/apod/ap020424.html ] its name all come together. Mountains [ http://antwrp.gsfc.nasa.gov/apod/ap011230.html ] of opaque dust appear on the lower left, while filaments of dust are visible threaded throughout the nebula. A single massive star [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001ApJ...562..446R ] visible near the center causes much of the Trifid's glow [ http://antwrp.gsfc.nasa.gov/apod/ap980828.html ]. The Trifid, also known as M20 [ http://www.astrocruise.com/m20.htm ], is only about 300,000 years old, making it among the youngest emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] known. The nebula lies about 5000 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away and part pictured above spans about 20 light years. The above false-color digitally enhanced image [ http://www.gemini.edu/media/images_2002-10.html ] was taken with the Gemini North telescope [ http://antwrp.gsfc.nasa.gov/apod/ap990629.html ] earlier this month. |
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