Galaxies and Nebulae
{thumb} Milky Way -- 2003.10.12
The disk of our Milky Way Galaxy is home to hot nebulae, cold dust, and billions of stars. Most of the mass of the galaxy remains in a form currently unknown.[=] Credits: APOD archive, 2003.09.28. Copyright: John P. Gleason, Celestial Images.
{thumb} Milky Way Center IR -- 2002.11.12
Much of the center of our galaxy is blocked from our view in visible light by intervening dust and gas. Here three otherwise invisible mid-infrared bands appear as blue, green, and red, revealing the thermal emission from dust clouds heated by starlight.[=] Credits: APOD archive, 2002.10.25. Midcourse Space Experiment satellite, IPAC, NASA.
{thumb} Galactic Center -- 2006.01.15
The Spitzer Space Telescope's infrared cameras reveal the stars of the crowded galactic center region. Older, cool stars appear bluish. Reddish glowing dust clouds are associated with young, hot stars in stellar nurseries.[=] Credits: APOD, 2006.01.13. Suzan Stolovy (SSC/Caltech) et al., JPL-Caltech, NASA.
{thumb} Andromeda -- 2002.11.12
Our galaxy is thought to look much like Andromeda (also called M31), the nearest major galaxy, about 2 million ly distant. Its diffuse light comes from the hundreds of billions of stars it includes.[=] Credits: APOD archive, 2002.10.21. Copyright, Robert Gendler.
{thumb} NGC2683 -- 2005.03.01
NGC 2683 is a spiral galaxy comparable to our own Milky Way, here seen nearly edge-on.[=] Credits: APOD archive, 2004.11.17. Copyright: Doug Matthews and Adam Block, NOAO, AURA, NSF.
{thumb} NGC2207 IC2163 -- 2005.12.25
Strong gravitational forces from NGC 2207 (left) have distorted the shape of IC 2163 (right), flinging out stars and gas into long streamers that extend outward 100,000 ly. Eventually the two galaxies will become one.[=] Credits: Hubble Space Telescope, hubblesite.org.
{thumb} M33 -- 2003.09.24
The small constellation Triangulum in the northern sky harbors this magnificent face-on spiral galaxy, M33. Its diameter is over 50,000 ly, making it third largest in the Local Group of galaxies after the Andromeda Galaxy and our own Milky Way.[=] Credits: APOD archive, 2003.09.24. Copyright, Robert Gendler.
{thumb} Saturn and M44 -- 2006.01.30
M44, popularly known as the Beehive star cluster, will be easy to find while bright Saturn, currently directly opposite the Sun with respect to Earth, shows where to look.[=] Credits: APOD, 2006.01.28. Photo and copyright Jimmy Westlake (Colorado Mountain College).
{thumb} M17 Closeup -- 2003.09.14
Sculpted by stellar winds and radiation, these undulating shapes lie within the stellar nursery M17 or the Omega Nebula some 5,500 ly away in the constellation Sagittarius. The picture spans about 3 ly.[=] Credits: APOD archive, 2003.04.25. NASA, ESA, J. Hester (ASU).
{thumb} NGC1365 -- 2003.09.26
Many spiral galaxies have bars across their centers. The persistence and motion of the bar imply relatively massive spiral arms. The placements of bright young blue stars and dark dust lanes also indicate a strong rotating density wave of star formation.[=] Credits: APOD archive, 2003.04.13. FORS Team, 8.2-meter VLT Antu, ESO.
{thumb} NGC4013 -- 2006.01.02
A perfectly "edge-on" galaxy, NGC 4013. This image shows huge clouds of dust and gas extending along and far above the galaxy's main disk. NGC 4013 is about 55 million ly from Earth in the direction of Ursa Major.[=] Credits: NASA and the Hubble Heritage Team (STScI/AURA). J.C. Howk (Johns Hopkins University) and B.D. Savage (University of Wisconsin-Madison).
{thumb} NGC4697 -- 2002.11.13
The bright, point-like sources in this Chandra Observatory x-ray image lie within NGC 4697, a galaxy 40 million ly away towards Virgo. Neutron stars and black holes are the endpoints in the lives of massive stars, so NGC 4697 must have had many bright, massive stars in the past.[=] Credits: APOD archive, 2002.06.17. C. Sarazin (UVa), et al., CXC, NASA.
{thumb} NGC6946 -- 2002.11.13
NGC 6946 seen face-on. 10 milion ly away, the big spiral galaxy's colors show a striking change from the yellowish light of old stars in the center to young blue star clusters and reddish star-forming regions. NGC 6946 is also bright in IR light and rich in gas and dust, indicating a high rate of star birth and death.[=] Credits: APOD archive, 2002.10.04. Copyright Robert Gendler.
{thumb} Sombrero -- 2003.10.12
50 million ly away, the Sombrero Galaxy features an unusually large and extended central bulge, containing billions of stars. The very center is thought to house a large black hole.[=] Credits: APOD archive, 2003.10.08. Hubble Heritage Team (AURA/STScI /NASA).
{thumb} Starburst M94 -- 2002.11.21
Spiral galaxy M94 has a ring of newly formed stars surrounding its nucleus, giving it a strong interior glow. M94 is about 30,000 ly across and about 15 million ly away.[=] Credits: APOD archive, 2002.01.21. Hillary Mathis & N.A.Sharp (NOAO), AURA, NSF.
{thumb} Orion 1 -- 2003.02.09
This photo was recorded in a five-minute exposure on high-speed color film and a 35mm camera mounted on a small telescope. Cool red giant Betelgeuse takes on a yellowish tint as the brightest star at the upper left. Hot blue stars dominate Orion. The fuzzy, reddish middle "star" of the sword is the Great Nebula of Orion.[=] Credits: APOD archive, 2003.02.07. Copyright: Matthew Spinelli.
{thumb} Orion 2 -- 2003.09.21
This distinctively detailed image of the Orion Nebula was constructed using data from the 2 Micron All Sky Survey or 2MASS. Observations in three infrared bands were translated to blue, green, and red colors to produce this composite image.[=] Credits: APOD archive, 2002.04.20. Copyright: 2MASS Collaboration, U. Mass., IPAC Mosaic by E. Kopan.
{thumb} Orion Dust Clouds -- 2003.02.09
In the vast Orion Molecular Cloud complex, two of the most prominent reflection nebulas -- dust clouds lit by the reflecting light of bright embedded stars -- are M78, on the upper right, and NGC 2071, on the lower left.[=] Credits: APOD archive, 2003.01.21. Copyright: Daniel Verschatse (Antilhue Obs.)
{thumb} LMC Gas -- 2006.01.23
This mosaic of over 1,500 images of the Large Magellanic Cloud in specific colors of light shows what a busy and violent place the inside of the LMC really is.[=] Credits: APOD archive, 2006.01.23. C. Smith, S. Points, the MCELS Team and NOAO/AURA/NSF.
{thumb} Supernova 1994D -- 2002.11.13
Supernova 1994D, visible as the bright spot on the lower left, is not of interest for how similar to other supernovae it is. If all Type 1a supernovae have the same intrinsic brightness, then the dimmer a supernova appears, the farther away it must be.[=] Credits: APOD archive, 2002.03.12. High-Z Supernova Search Team, HST, NASA.
{thumb} Bow Shock -- 2006.01.02
In 1995 Hubble caught this view of the shockwave caused by the collision of particles streaming away from the young star LL Ori with slow-moving gas evaporating from the center of the Orion Nebula.[=] Credits: NASA and the Hubble Heritage Team (STScI/AURA). C.R. O'Dell (Vanderbilt University).
{thumb} Pleiades -- 2002.12.01
Visible without binoculars and known as the Seven Sisters or M45, the Pleiades is one of the brightest, closest open clusters. It contains over 3000 stars. It's about 400 ly away and only 13 ly across. The photo shows blue reflection nebulae surrounding the bright cluster stars.[=] Credits: APOD archive, 2002.12.01. Copyright: David Malin (AAO), ROE, UKS Telescope.
{thumb} IC1396B -- 2005.12.19
Clouds of glowing hydrogen gas mingle with dark dust lanes in this close-up of IC 1396, an active star-forming region some 2,000 ly away in the constellation Cepheus. The image spans about 20 ly.[=] Credits: APOD archive, 2005.09.30. Nick Wright (University College London), IPHAS Collaboration.
{thumb} Witchs Broom Nebula -- 2006.01.02
This supernova remnant lies about 1400 ly away towards the constellation Cygnus. The bright star 52 Cygnus is visible with the unaided eye from a dark location but is unrelated to the ancient supernova.[=] Credits: APOD archive, 2004.03.02. Copyright: T. A. Rector (U. Alaska), NOAO, AURA, NSF.
{thumb} Flamingstar Nebula -- 2006.02.28
The bright star AE Aurigae, visible toward the image left, is so hot it is blue.[=] Credits: APOD archive, 2006.02.28. Copyright Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT, 2006.
{thumb} Thor Helmet -- 2006.02.03
The helmet-shaped structure with wing-like appendages, NGC 2359, is known as Thor's Helmet and is about 30 ly across.[=] Credits: APOD, 2006.02.02. Photo and copyright Don Goldman, 2006.
{thumb} Boomerang Nebula -- 2003.02.25
The Boomerang Nebula lies about 5,000 ly away towards the constellation Centaurus. The symmetric cloud may have been created by a high-speed wind of gas and dust blowing from an aging central star. Rapid expansion has cooled molecules in the nebular gas to about one degree absolute -- making it the coldest region observed in the distant Universe.[=] Credits: APOD archive, 2003.02.20. Copyright: R. Sahai and J. Trauger (JPL), NASA/ESA.
{thumb} Bubble Nebula -- 2003.02.09
In this wide-angle view, the Bubble nebula, about 10 ly in diameter, lies at the center of a larger complex of shocked glowing gas about 11,000 ly distant in Cassiopeia.[=] Credits: APOD archive, 2003.01.17. Copyright: Brian Lula.
{thumb} Cassiopeia A Chandra -- 2002.11.13
The complex shell of a star seen to explode 300 years ago is helping astronomers to understand how that star exploded. This Chandra Observatory image of supernova remnant Cassiopeia A (Cas A, 10 ly across and 10000 ly distant) shows unprecedented detail in three x-ray colors.[=] Credits: APOD archive, 2002.08.24. John Hughes et al. (Rutgers), NASA/ CXC/ SAO.
{thumb} Cats Eye Nebula -- 2004.09.18
Three thousand ly from Earth, the Cat's Eye (NGC 6543) represents a final, brief but glorious phase in the life of a sun-like star.[=] Credits: APOD archive, 2004.09.10. Copyright: NASA, ESA, HEIC, Hubble Heritage Team (STScI/(AURA).
{thumb} Cats Paw Nebula -- 2003.09.25
5500 ly distant, Cat's Paw is an emission nebula whose red color originates from an abundance of ionized hydrogen atoms. It's also known as the Bear Claw Nebula or NGC6334.[=] Credits: APOD archive, 2003.07.17. Copyright: Bernd Flach-Wilken & Volker Wendel (Spiegelteam).
{thumb} Cocoon Nebula -- 2002.11.11
IC 5146, the strikingly beautiful Cocoon Nebula is about 4000 ly toward the constellation Cygnus. Inside the nebula is a newly developing open cluster of stars.[=] Credits: APOD archive, 2002.10.14. Copyright, Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT.
{thumb} Cone Nebula -- 2003.09.17
Cones, pillars, and flowing shapes abound in stellar nurseries where clouds of gas and dust are buffeted by energetic winds from newborn stars. The Cone Nebula, within the star-forming region NGC 2264, is about 7 ly long; its blunted head is about 2.5 ly across.[=] Credits: APOD archive, 2002.05.03. ACS Science & Engineering Team, NASA.
{thumb} Eagle Nebula -- 2006.01.02
From afar, it looks like an Eagle. In the center an open cluster of stars is being formed. The Eagle emission nebula (M16), lies about 6500 light years away, spans about 20 light-years, and is visible with binoculars toward the constellation Serpens.[=] Credits: APOD archive, 2002.06.11. Copyright: T. A. Rector and B. A. Wolpa.
{thumb} Eskimo Nebula -- 2005.12.29
The Eskimo Nebula's complex gas clouds are not fully understood. The inner filaments are being ejected by strong wind of particles from the central star. The outer disk contains unusual light-year long orange filaments.[=] Credits: APOD archive, 2002.04.07. Andrew Fruchter (STScI) et al., WFPC2, HST, NASA.
{thumb} Gum Nebula -- 2003.04.21
The Gum Nebula is the closest supernova remnant. Spanning 40 degrees across the sky, the front edge of the vast, faint nebula is 450 ly from us, its farther edge 1500 ly away.[=] Credits: APOD archive, 2003.04.20. Copyright: John Gleason (Celestial Images).
{thumb} Horsehead Nebula -- 2003.02.09
The bright star is in the constellation Orion. The Horesehead Nebula is an opaque dust cloud lying in front of the bright red emission nebula.[=] Credits: APOD archive, 2003.01.29. Copyright, Loke Kun Tan.
{thumb} Iris Nebula -- 2005.12.31
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.[=] Credits: APOD archive, 2005.12.29. Copyright: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT.
{thumb} Little Ghost Nebula -- 2002.11.13
William Herschel discovered NGC 6369, the Little Ghost Nebula, in the 18th century. The white dwarf star near the center powers the expanding nebula's glow. Ionized oxygen, hydrogen, and nitrogen atoms are colored blue, green, and red, respectively.[=] Credits: APOD archive, 2002.11.08. Hubble Heritage Team, NASA.
{thumb} NGC1970s -- 2003.10.12
Reflection nebulae NGC 1972, 1975 and 1977 in Orion, lying just north of the Orion Nebula in the sword of the eponymous constellation.[=] Credits: APOD archive, 2003.10.02. Copyright: Dean Jacobsen.
{thumb} Trifid Nebula -- 2002.11.16
Also known as M20, its red glow comes from high-energy starlight striking interstellar hydrogen gas. The dark dust filaments were created in the atmospheres of cool giant stars and in the debris from supernovae. M20 is about 3000 ly away and about 50 ly across.[=] Credits: APOD archive, 2002.04.24. Copyright Anglo-Australian Observatory, photo by David Malin.
{thumb} Stellar Nursery -- 2002.11.13
NGC 604 contains over 200 newly formed hot, massive stars. This cloud of interstellar gas, 1500 ly across, is 3 million ly away in spiral galaxy M33. The newborn stars irradiate the gas with energetic UV light, producing a characteristic nebular glow.[=] Credits: APOD archive, 2002.11.02. H. Yang (UIUC), HST, NASA.
{thumb} Eta Carinae IR -- 2002.11.12
Eta Carinae, a massive star about 7500 ly distant with a history of flaring and fading, is near the center of this false-color infrared image. Astronomers think the star may explode as a supernova in the next million years or so. It may even become a hypernova and the potential source of a gamma-ray burst.[=] Credits: APOD archive, 2002.10.10. Photo by the Midcourse Space Experiment satellite.
{thumb} Sky Map -- 2003.02.12
A new high-resolution map of microwave light emitted only 380,000 years after the Big Bang indicates that the universe is 13.7 billion years old, composed of 73% dark energy, 23% cold dark matter, and only 4% atoms, is currently expanding at the rate of 71 km/sec/Mpc, underwent episodes of rapid expansion called inflation, and will expand forever.[=] Credits: APOD archive, 2003.02.12. WMAP Science Team, NASA.