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Andromeda of M31 and Goddard Space Flight Center (GSFC)
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Andromeda in Ultraviolet
In a break from its usual ta
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10/14/09
| Description |
In a break from its usual task of searching for distant cosmic explosions, NASA's Swift satellite acquired the highest-resolution view of a neighboring spiral galaxy ever attained in the ultraviolet. The galaxy, known as M31 in the constellation Andromeda, is the largest and closest spiral galaxy to our own. This mosaic of M31 merges 330 individual images taken by Swift's Ultraviolet/Optical Telescope. The image shows a region 200,000 light-years wide and 100,000 light-years high (100 arcminutes by 50 arcminutes). Image Credit: NASA/Swift/Stefan Immler (GSFC) and Erin Grand (UMCP) |
| Date |
10/14/09 |
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Amazing Andromeda Galaxy
| Title |
Amazing Andromeda Galaxy |
| Description |
The many "personalities" of our great galactic neighbor, the Andromeda galaxy, are exposed in this new composite image from NASA's Galaxy Evolution Explorer and the Spitzer Space Telescope. The wide, ultraviolet eyes of Galaxy Evolution Explorer reveal Andromeda's "fiery" nature -- hotter regions brimming with young and old stars. In contrast, Spitzer's super-sensitive infrared eyes show Andromeda's relatively "cool" side, which includes embryonic stars hidden in their dusty cocoons. Galaxy Evolution Explorer detected young, hot, high-mass stars, which are represented in blue, while populations of relatively older stars are shown as green dots. The bright yellow spot at the galaxy's center depicts a particularly dense population of old stars. Swaths of red in the galaxy's disk indicate areas where Spitzer found cool, dusty regions where stars are forming. These stars are still shrouded by the cosmic clouds of dust and gas that collapsed to form them. Together, Galaxy Evolution Explorer and Spitzer complete the picture of Andromeda's swirling spiral arms. Hints of pinkish purple depict regions where the galaxy's populations of hot, high-mass stars and cooler, dust-enshrouded stars co-exist. Located 2.5 million light-years away, the Andromeda is our largest nearby galactic neighbor. The galaxy's entire disk spans about 260,000 light-years, which means that a light beam would take 260,000 years to travel from one end of the galaxy to the other. By comparison, our Milky Way galaxy's disk is about 100,000 light-years across. This image is a false color composite comprised of data from Galaxy Evolution Explorer's far-ultraviolet detector (blue), near-ultraviolet detector (green), and Spitzer's multiband imaging photometer at 24 microns (red). |
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The Trifid Nebula: Stellar S
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The Trifid Nebula: Stellar Sibling Rivalry |
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Deepest View of Space Yields
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| Title |
Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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| Title |
Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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| Title |
Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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| Title |
Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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| Title |
Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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| Title |
Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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| Title |
Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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| Title |
Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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| Title |
Deepest View of Space Yields Young Stars in Andromeda Halo |
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Deepest View of Space Yields
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Deepest View of Space Yields Young Stars in Andromeda Halo |
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Hubble Finds Mysterious Disk
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Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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Hubble Finds Mysterious Disk
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| Title |
Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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Hubble Finds Mysterious Disk
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| Title |
Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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Hubble Finds Mysterious Disk
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| Title |
Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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Hubble Finds Mysterious Disk
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| Title |
Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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Hubble Finds Mysterious Disk
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| Title |
Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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Hubble Finds Mysterious Disk
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| Title |
Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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Hubble Finds Mysterious Disk
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| Title |
Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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Hubble Finds Mysterious Disk
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| Title |
Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
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The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
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The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
|
The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
|
The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
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X For Andromeda
| Title |
X For Andromeda |
| Explanation |
A big beautiful spiral galaxy 2 million light-years away, Andromeda (M31) [ http://antwrp.gsfc.nasa.gov/apod/ap991114.html ] has long been touted as an analog to the Milky Way, a distant mirror of our own galaxy. The popular 1960s British sci-fi series, A For Andromeda [ http://www.cs.monash.edu.au/~lloyd/tildeImages/Film/ Andromeda/index.html ], even postulated that it was home to another technological civilization that communicated [ http://www.bigear.org/vol1no2/sagan.htm ] with us. Using the newly unleashed observing power of the orbiting Chandra [ http://antwrp.gsfc.nasa.gov/apod/ap990727.html ] X-ray telescope, astronomers have now imaged [ http://chandra.harvard.edu/press/00_releases/press_011400m31.html ] the center of our near-twin island universe [ ftp://crux.astr.ua.edu/web/goodies/data_resources/galaxies.text ], finding evidence for an object so bizarre it would have impressed many 60s science fiction [ http://www.magicdragon.com/UltimateSF/timeline1970.html ] writers (and readers). Like the Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap000120.html ], Andromeda's galactic center appears to harbor an X-ray source characteristic of a black hole [ http://chandra.harvard.edu/xray_sources/black_holes.html ] of a million or more solar masses. Seen above, the false-color X-ray picture [ http://chandra.harvard.edu/photo/cycle1/0007/index.html ] shows a number of X-ray sources, likely X-ray binary stars [ http://heasarc.gsfc.nasa.gov/docs/binary.html ], within Andromeda's central region as yellowish dots. The blue source located right at the galaxy's center is coincident with the position of the suspected massive black hole. While the X-rays [ http://chandra.harvard.edu/xray_astro/xrays.html ] are produced as material falls into the black hole and heats up, estimates from the X-ray data show Andromeda's central source to be surprisingly cool - only a million degrees or so compared to the tens of millions of degrees indicated for Andromeda's X-ray binaries [ http://antwrp.gsfc.nasa.gov/apod/ap991219.html ]. |
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The Comet and the Galaxy
| Title |
The Comet and the Galaxy |
| Explanation |
The Moon almost ruined this photograph. During late March and early April 1997, Comet Hale-Bopp [ http://www.jpl.nasa.gov/comet/ ] passed nearly in front of the Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap040718.html ]. Here the Great Comet of 1997 [ http://cometography.com/lcomets/1995o1.html ] and the Great Galaxy in Andromeda [ http://www.seds.org/messier/m/m031.html ] were photographed together [ http://antwrp.gsfc.nasa.gov/apod/ap970401.html ] on 1997 March 24th. The problem was the brightness of the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap970924.html ]. The Moon [ http://www.seds.org/nineplanets/nineplanets/luna.html ] was full that night and so bright that long exposures meant to capture the tails of Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970416.html ] and the disk of M31 [ http://antwrp.gsfc.nasa.gov/apod/ap961011.html ] would capture instead only moonlight reflected off the Earth's atmosphere. By the time the Moon would set, this opportunity would be gone. That's why this picture was taken during a total lunar eclipse [ http://antwrp.gsfc.nasa.gov/apod/ap960926.html ]. |
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M33: Spiral Galaxy in Triang
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| Title |
M33: Spiral Galaxy in Triangulum |
| Explanation |
The small, northern constellation Triangulum [ http://www.hawastsoc.org/deepsky/tri/index.html ] harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy [ http://www.seds.org/messier/m/m033.html ]. M33 is over 50,000 light-years in diameter, third largest in the Local Group [ http://atlasoftheuniverse.com/localgr.html ] of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap021021.html ] and astronomers [ http://arxiv.org/abs/astro-ph?papernum=0506609 ] in these two galaxies would likely have spectacular views of each other's grand spiral star systems. As for the view from planet Earth, this detailed, wide field image [ http://www.tvdavisastropics.com/astroimages-1_00001f.htm ] nicely shows off M33's blue star clusters and pinkish star [ http://www.astropix.com/HTML/SHOW_DIG/031.HTM ] forming regions which trace the galaxy's loosely wound spiral arms. In fact, the cavernous NGC 604 [ http://antwrp.gsfc.nasa.gov/apod/ap021102.html ] is the brightest star forming region, seen here at about the 1 o'clock position from the galaxy center. Like M31, M33's population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick [ http://cfa-www.harvard.edu/~kstanek/DIRECT/ ] for establishing [ http://adsabs.harvard.edu/cgi-bin/ bib_query?1926ApJ....63..236H ] the distance scale [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/ debate96.html ] of the Universe. |
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Andromeda Island Universe
| Title |
Andromeda Island Universe |
| Explanation |
How far can you see? The most distant object easily visible to the unaided eye is M31 [ http://www.seds.org/messier/xtra/history/m-m31_42.html ], the great Andromeda Galaxy [ http://www.seds.org/messier/m/m031.html ] some two million light-years away. Without a telescope, even this immense spiral galaxy appears as an unremarkable, faint, nebulous cloud in the constellation Andromeda [ http://www.astronomical.org/constellations/and.html ]. But a bright yellow nucleus, dark winding dustlanes, gorgeous blue spiral arms and star clusters are recorded in this stunning telescopic digital [ http://www.geocities.com/CapeCanaveral/Hall/6432/ homepage.html ] mosaic of the nearby island universe. While even casual skygazers [ http://badastronomy.com/bitesize/galaxies.html ] are now inspired by the knowledge that there are many [ http://antwrp.gsfc.nasa.gov/apod/ap000709.html ] distant galaxies like M31, astronomers seriously debated [ http://adsbit.harvard.edu/cgi-bin/ nph-iarticle_query?1995PASP%2E%2E107%2E1133T ] this fundamental concept only 80 years ago. Were these "spiral nebulae" simply outlying components of our own Milky Way Galaxy or were they instead "island universes" -- distant systems of stars comparable to the Milky Way itself? This question was central to the famous Shapley-Curtis [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/ debate20.html ] debate [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/debate.html ] of 1920, which was later resolved by observations [ http://antwrp.gsfc.nasa.gov/apod/ap960406.html ] of M31 in favor of Andromeda, island universe [ http://www.astr.ua.edu/goodies/data_resources/galaxies.text ]. |
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M31: The Andromeda Galaxy
| Title |
M31: The Andromeda Galaxy |
| Explanation |
Andromeda is the nearest major galaxy [ http://www.seds.org/messier/galaxy.html] to our own Milky Way Galaxy [ http://cassfos02.ucsd.edu/public/tutorial/MW.html ]. Our Galaxy is thought to look much like Andromeda [ http://antwrp.gsfc.nasa.gov/apod/ap020518.html ]. Together these two galaxies dominate the Local Group [ http://www.seds.org/messier/more/local.html ] of galaxies. The diffuse light from Andromeda [ http://www.seds.org/messier/m/m031.html ] is caused by the hundreds of billions of stars [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#star ] that compose it. The several distinct stars that surround Andromeda [ http://antwrp.gsfc.nasa.gov/apod/ap010917.html ]'s image are actually stars in our Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap000518.html ] that are well in front of the background object. Andromeda [ http://www.noao.edu/image_gallery/html/im0424.html ] is frequently referred to as M31 since it is the 31st object [ http://antwrp.gsfc.nasa.gov/apod/ap960626.html ] on Messier [ http://www.seds.org/messier/xtra/history/biograph.html ]'s list of diffuse sky objects. M31 [ http://antwrp.gsfc.nasa.gov/apod/ap020412.html ] is so distant it takes about two million years for light to reach us from there. Although visible without aid, the above image [ http://www.robgendlerastropics.com/M31Page.html ] of M31 is a digital mosaic of 20 frames taken with a small telescope. Much about M31 remains unknown [ http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1995ApJ...444..157A ], including how the center acquired two nuclei [ http://antwrp.gsfc.nasa.gov/apod/ap961011.html ]. |
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Dwarf Elliptical Galaxy NGC
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| Title |
Dwarf Elliptical Galaxy NGC 205 in the Local Group |
| Explanation |
Our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] is not alone. It is part of a gathering of about 25 galaxies known as the Local Group [ http://www.seds.org/messier/more/local.html ]. Members include the Great Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap991114.html ] (M31), M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ], M33 [ http://antwrp.gsfc.nasa.gov/apod/ap980721.html ], the Large Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap000222.html ], the Small Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap000430.html ], Dwingeloo 1 [ http://antwrp.gsfc.nasa.gov/apod/ap000109.html ], several small irregular galaxies [ http://www.seds.org/messier/irre.html ], and many dwarf elliptical [ http://nedwww.ipac.caltech.edu/level5/Ferguson/frames.html ] and dwarf spheroidal galaxies [ http://www.astro.uu.se/~ns/review.html ]. Pictured [ http://www.cfht.hawaii.edu/Science/Astros/Imageofweek/ciw061299.html ] on the lower left is one of the many dwarf ellipticals [ http://www.astro.psu.edu/users/pdurrell/dE.html ]: NGC 205 [ http://www.seds.org/messier/m/m110.html ]. Like M32 [ http://www.seds.org/messier/m/m032.html ], NGC 205 [ http://nedwww.ipac.caltech.edu/level5/Hodge/Hodge5_5.html ] is a companion to the large M31, and can sometimes be seen to the south of M31 [ http://www.seds.org/messier/m/m031.html ]'s center in photographs. The above image [ http://www.cfht.hawaii.edu/Science/Astros/Imageofweek/ciw061299.html ] shows NGC 205 to be unusual [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998ApJ...499..209W ] for an elliptical galaxy [ http://antwrp.gsfc.nasa.gov/apod/elliptical_galaxies.html ] in that it contains at least two dust clouds [ http://antwrp.gsfc.nasa.gov/apod/ap990919.html ] (at 1 and 4 o'clock - they are visible but hard to spot) and signs of recent star formation [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ]. This galaxy is sometimes known as M110, although it was actually not part of Messier [ http://antwrp.gsfc.nasa.gov/apod/ap960626.html ]'s original catalog [ http://antwrp.gsfc.nasa.gov/apod/messier.html ]. |
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Moon Over Andromeda
| Title |
Moon Over Andromeda |
| Explanation |
The Great Spiral Galaxy in Andromeda [ http://antwrp.gsfc.nasa.gov/apod/ap051222.html ] (aka M31), a mere 2.5 million light-years distant [ http://arxiv.org/abs/astro-ph/0511045 ], is the closest large spiral to our own Milky Way. Andromeda is visible to the unaided eye as a small, faint, fuzzy patch, but because its surface brightness is so low, casual skygazers [ http://www.physics.ucla.edu/~huffman/m31.html ] can't appreciate the galaxy's impressive extent in planet Earth's sky. This entertaining composite image compares the angular size [ http://chandra.harvard.edu/photo/scale.html ] of the nearby galaxy to a brighter, more familiar celestial sight. In it, a deep exposure of Andromeda [ http://www.caelumobservatory.com/gallery/m31abtp.shtml ], tracing beautiful blue star clusters in spiral arms far beyond the bright yellow core, is combined with a typical view of a nearly full Moon. Shown at the same angular scale, the Moon covers about 1/2 degree on the sky, while the galaxy is clearly [ http://www.regulusastro.com/regulus/papers/ m31/ ] several times that size. The deep Andromeda exposure also includes two bright satellite galaxies, M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ] and M110 [ http://antwrp.gsfc.nasa.gov/apod/ap060908.html ] (bottom). |
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Infrared Andromeda
| Title |
Infrared Andromeda |
| Explanation |
This wide, detailed Spitzer Space Telescope view [ http://www.spitzer.caltech.edu/Media/releases/ssc2006-14/ index.shtml ] features infrared light from dust (red) and old stars (blue) in Andromeda, a massive spiral galaxy a mere 2.5 million light-years away. In fact, with over twice the diameter of our own [ http://antwrp.gsfc.nasa.gov/apod/ap050825.html ] Milky Way, Andromeda is [ http://www.seds.org/Messier/m/m031.html ] the largest nearby [ http://www.seds.org/Messier/more/ local.html ] galaxy. Andromeda's population of bright young stars define its sweeping spiral arms in visible light images [ http://antwrp.gsfc.nasa.gov/apod/ap051222.html ], but here the infrared view clearly follows the lumpy dust lanes heated by the young stars as they wind even closer to the galaxy's core [ http://antwrp.gsfc.nasa.gov/apod/ap041227.html ]. Constructed to explore [ http://nedwww.ipac.caltech.edu/level5/ANDROMEDA_Atlas/ Hodge_contents.html ] Andromeda's infrared brightness [ http://coolcosmos.ipac.caltech.edu// ] and stellar populations, the full mosaic image is composed of about 3,000 individual frames. Two smaller companion galaxies, NGC 205 [ http://antwrp.gsfc.nasa.gov/apod/ap001023.html ] (below) and M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ] (above) are also included in the combined fields. The data confirm that Andromeda (aka M31) houses around 1 trillion [ http://kokogiak.com/megapenny/thirteen.asp ] stars, compared to [ http://astronomy.swin.edu.au/~gmackie/billions.html ] 4 hundred billion [ http://kokogiak.com/megapenny/nine.asp ] for the Milky Way. |
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Southwest Andromeda
| Title |
Southwest Andromeda |
| Explanation |
This new image composite [ http://www.subaru.naoj.org/Latestnews/200109/M31/index.html ] of the southwest region of M31 [ http://antwrp.gsfc.nasa.gov/apod/ap991114.html ] from the Subaru Telescope [ http://www.subaru.naoj.org/Introduction/outline.html ] shows many stars, nebulae, and star clusters never before resolved. An older population of stars near Andromeda's center [ http://antwrp.gsfc.nasa.gov/apod/ap961011.html ] causes the yellow hue visible on the upper right. Young blue stars stand out in the spiral arms [ http://fuse.pha.jhu.edu/~danforth/spiral/ ] on the lower left. Red emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], blue open clusters [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars, and sweeping lanes of dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] punctuate the swirling giant. Andromeda [ http://www.seds.org/messier/m/m031.html ], at about 2.5 million light years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] distant, and our Milky Way [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] are the largest galaxies [ http://www.seds.org/messier/galaxy.html ] in the Local Group of Galaxies [ http://www.seds.org/messier/more/local.html ]. Understanding M31 [ http://antwrp.gsfc.nasa.gov/apod/ap000908.html ] helps astronomers to understand our own Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap000130.html ], since the two are so similar. |
|
Elements of Nearby Spiral M3
…
| Title |
Elements of Nearby Spiral M33 |
| Explanation |
Spiral galaxy [ http://www.seds.org/messier/spir.html ] M33 is a mid-sized member of our Local Group of Galaxies [ http://www.seds.org/messier/more/local.html ]. M33 [ http://antwrp.gsfc.nasa.gov/apod/ap980721.html ] is also called the Triangulum Galaxy [ http://www.seds.org/messier/m/m033.html ] for the constellation [ http://www.astronomical.org/constellations/tri.html ] in which it resides. About four times smaller (in radius) than our Milky Way Galaxy [ http://www.star.le.ac.uk/edu/mway/ ] and the Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap991114.html ] (M31), it is much larger than the many of the local dwarf spheroidal [ http://antwrp.gsfc.nasa.gov/apod/ap991003.html ] galaxies. M33 [ http://antwrp.gsfc.nasa.gov/apod/ap960708.html ]'s proximity to M31 [ http://antwrp.gsfc.nasa.gov/apod/ap010917.html ] causes it to be thought by some to be a satellite galaxy of this more massive galaxy. M33 [ http://sirtf.caltech.edu/Education/Messier/m33.html ]'s proximity to our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] causes it to appear more than twice the angular size of the Full Moon [ http://antwrp.gsfc.nasa.gov/apod/ap010218.html ], and be visible with a good pair of binoculars. The above high-resolution image [ http://www.lowell.edu/users/massey/lgsurvey.html ] highlights light emitted by hydrogen [ http://periodic.lanl.gov/elements/1.html ] in red and oxygen [ http://periodic.lanl.gov/elements/8.html ] in blue. It was taken to help separate stars from emission nebulae [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], and therefore help study [ http://www.aas.org/publications/baas/v32n4/aas197/743.htm ] how galaxies form stars. |
|
Andromeda Island Universe
| Title |
Andromeda Island Universe |
| Explanation |
The most distant object easily visible to the unaided eye is M31 [ http://www.seds.org/messier/xtra/history/m-m31_42.html ], the great Andromeda Galaxy [ http://www.seds.org/messier/m/m031.html ] some two and a half million light-years away. But without a telescope, even this immense spiral galaxy - spanning over [ http://antwrp.gsfc.nasa.gov/apod/ap061228.html ] 200,000 light years - appears as a faint, nebulous cloud in the constellation Andromeda [ http://www.hawastsoc.org/deepsky/and/index.html ]. In contrast, a bright yellow nucleus, dark winding dust lanes, gorgeous blue spiral arms and star clusters are recorded in this stunning telescopic digital mosaic [ http://astrophoto.com/M31.htm ]. While even casual skygazers [ http://badastronomy.com/bitesize/galaxies.html ] are now inspired by the knowledge that there are many [ http://antwrp.gsfc.nasa.gov/apod/ap070208.html ] distant galaxies like M31, astronomers seriously debated [ http://adsbit.harvard.edu/cgi-bin/ nph-iarticle_query?1995PASP%2E%2E107%2E1133T ] this fundamental concept less than 90 years ago. Were these "spiral nebulae" simply outlying components of our own Milky Way Galaxy or were they instead "island universes" -- distant systems of stars comparable to the Milky Way itself? This question was central to the famous Shapley-Curtis [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/ debate20.html ] debate [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/debate.html ] of 1920, which was later resolved by observations [ http://antwrp.gsfc.nasa.gov/apod/ap960406.html ] of M31 in favor of Andromeda, island universe [ http://www.astr.ua.edu/goodies/data_resources/galaxies.text ]. |
|
M20: The Trifid Nebula
| Title |
M20: The Trifid Nebula |
| Explanation |
The vivid blue and violet colors present in the Trifid Nebula result from the abundance of young stars there. The light from young massive stars is quite blue and has the ability to remove electrons from surrounding gas. When these electrons re-combine with the gas, radiation rich in blue and violet light is emitted. Some of the nebula's light also results from the reflection of star light off of extremely small carbon specks known as 'dust'. This object is known to astronomers as M20 - the twentieth object on Charles Messier's [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#messier ] list of diffuse sky objects. This image was taken with a 6-inch refracting telescope. For more information on M20 see The Electronic Universe Project's write-up. [ http://zebu.uoregon.edu/messier/m20.txt ] Many images of Messier objects can be found in The Electronic Universe Project's The Galaxy Gallery: Messier Objects. [ http://zebu.uoregon.edu/messier.html ] Tomorrow's picture: M31: The Andromeda Galaxy |
|
M31: The Andromeda Galaxy
| Title |
M31: The Andromeda Galaxy |
| Explanation |
Andromeda is the nearest major galaxy to our own Milky Way Galaxy. Our Galaxy is thought to look much like Andromeda. Together these two galaxies dominate the Local Group of galaxies. The diffuse light from Andromeda is caused by the hundreds of billions of stars that compose it. The several distinct stars that surround Andromeda's image are actually stars in our Galaxy that are well in front of the background object. Andromeda is frequently referred to as M31 since it is the 31st object on Messier's [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#messier ] list of diffuse sky objects. M31 is so distant it takes about 2 million years for light to reach us from there. For more information on M31 see The Electronic Universe Project's write-up. [ http://zebu.uoregon.edu/messier/m31.txt ] Many images of Messier objects can be found in The Electronic Universe Project's The Galaxy Gallery: Messier Objects. [ http://zebu.uoregon.edu/messier.html ] Tomorrow's picture: M1: The Crab Nebula |
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Ikeya-Zhang: Comet Over Colo
…
| Title |
Ikeya-Zhang: Comet Over Colorado |
| Explanation |
Comet Ikeya-Zhang [ http://cometography.com/lcomets/2002c1.html ] ("ee-KAY-uh JONG") has become a most photogenic comet [ http://science.nasa.gov/spaceweather/comets/ gallery_iz.html ]. This lovely early evening view of the comet [ http://www.comet-track.com/iz/iz.html ] in Rocky Mountain skies [ http://antwrp.gsfc.nasa.gov/apod/ap970421.html ] looks northwest over ridges and low clouds. The time exposure was recorded on March 31st from an 8,000 foot elevation near Yampa, Colorado, USA. Sporting [ http://antwrp.gsfc.nasa.gov/apod/ap970320.html ] a sweeping yellowish dust tail [ http://www.ifa.hawaii.edu/faculty/jewitt/tail.html ] and blue ion tail [ http://antwrp.gsfc.nasa.gov/apod/ap020318.html ] eight to ten degrees long, Ikeya-Zhang is nestled near the horizon in the northern constellation of Andromeda [ http://www.seds.org/Maps/Stars_en/Fig/andromeda.html ]. To the comet's left is the bright star Mirach [ http://www.astro.wisc.edu/~dolan/constellations/ hr/0337.html ] or Beta Andromedae while the stretched celestial fuzzball to the comet's right is M31 or the Andromeda galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap000908.html ], the nearest bright spiral galaxy to our own Milky Way. As the days pass, Comet Ikeya-Zhang's apparent motion [ http://encke.jpl.nasa.gov/images/02C1/ c2002c1chart.jpg ] through the sky is towards the right in this image. Tonight, comet-watchers [ http://encke.jpl.nasa.gov/ ] blessed with clear skies should find Ikeya-Zhang posing perfectly [ http://spaceweather.com/images2002/04apr02/ skymap_north.gif ] for binoculars and cameras just above M31, less than two degrees from the center of the bright galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap990314.html ]. |
|
A Galaxy is not a Comet
| Title |
A Galaxy is not a Comet |
| Explanation |
This gorgeous galaxy and comet portrait [ http://science.nasa.gov/spaceweather/comets/ gallery_iz.html ] was recorded on April 5th in the skies over the Oriental Pyrenees near Figueres, Spain [ http://www.odci.gov/cia/publications/factbook/geos/ sp.html ]. From a site above 1,100 meters, astrophotographer [ http://www.skylook.net/nav/indexe.htm ] Juan Carlos Casado used a guided time exposure, fast film, and a telephoto lens to capture the predicted conjunction of the bright Comet Ikeya-Zhang [ http://antwrp.gsfc.nasa.gov/apod/ap020404.html ] (right) and the Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap000908.html ] (left). This stunning celestial scene would also have been a rewarding one for the influential 18th century comet hunter Charles Messier [ http://www.seds.org/messier/xtra/history/ biograph.html ]. While Messier scanned French skies for comets, he carefully cataloged positions of things which were fuzzy and comet-like in appearance but did not move against the background stars and so were definitely not comets. The Andromeda Galaxy [ http://nedwww.ipac.caltech.edu/level5/ANDROMEDA_Atlas/ frames.html ], also known as M31, is the 31st object in his famous not-a-comet catalog [ http://seds.lpl.arizona.edu/messier/xtra/history/ m-cat.html ]. Not-a-comet object number 110 [ http://www.seds.org/messier/m/ m110.html ], a late addition to Messier's catalog, is one of Andromeda's small satellite galaxies, and can be seen here just below M31. Our modern [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/ debate20.html ] understanding [ http://www.astr.ua.edu/goodies/data_resources/ galaxies.text ] holds that the Andromeda galaxy is a large spiral galaxy some 2 million light-years distant [ http://www.anzwers.org/free/universe/localgr.html ]. The photogenic Comet Ikeya-Zhang [ http://www.stardate.org/nightsky/comet_IZ.html ], now a lovely sight in early morning skies [ http://www.spaceweather.com/images2002/08apr02/ skymap_north.gif ], is about 80 million kilometers (4 light-minutes) from planet Earth. |
|
Andromeda Island Universe
| Title |
Andromeda Island Universe |
| Explanation |
How far can you see? The most distant object easily visible to the unaided eye is M31 [ http://www.seds.org/messier/xtra/history/m-m31_42.html ], the great Andromeda Galaxy [ http://www.seds.org/messier/m/m031.html ] some two million light-years away. Without a telescope, even this immense spiral galaxy appears as an unremarkable, faint, nebulous cloud in the constellation Andromeda [ http://www.astronomical.org/constellations/and.html ]. But a bright yellow nucleus, dark winding dust lanes, gorgeous blue spiral arms and star clusters are recorded in this stunning telescopic digital [ http://www.robgendlerastropics.com/index.html ] mosaic of the nearby island universe. While even casual skygazers [ http://badastronomy.com/bitesize/galaxies.html ] are now inspired by the knowledge that there are many [ http://antwrp.gsfc.nasa.gov/apod/ap000709.html ] distant galaxies like M31, astronomers seriously debated [ http://adsbit.harvard.edu/cgi-bin/ nph-iarticle_query?1995PASP%2E%2E107%2E1133T ] this fundamental concept only 80 years ago. Were these "spiral nebulae" simply outlying components of our own Milky Way Galaxy or were they instead "island universes" -- distant systems of stars comparable to the Milky Way itself? This question was central to the famous Shapley-Curtis [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/ debate20.html ] debate [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/debate.html ] of 1920, which was later resolved by observations [ http://antwrp.gsfc.nasa.gov/apod/ap960406.html ] of M31 in favor of Andromeda, island universe [ http://www.astr.ua.edu/goodies/data_resources/galaxies.text ]. |
|
Local Group Galaxy NGC 205
| Title |
Local Group Galaxy NGC 205 |
| Explanation |
The Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950908.html ] is not alone. It is part of a gathering of about 25 galaxies known as the Local Group [ http://www.csc.fi/jpr/galaxy/lbang.html ]. Members include the Great Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950724.html ] (M31), M32 [ http://antwrp.gsfc.nasa.gov/apod/ap960106.html ], M33 [ http://seds.lpl.arizona.edu/messier/m/m033.html ], the Large Magellanic Clouds [ http://antwrp.gsfc.nasa.gov/apod/ap950918.html ], the Small Magellanic Clouds [ http://antwrp.gsfc.nasa.gov/apod/ap950919.html ], Dwingeloo 1 [ http://antwrp.gsfc.nasa.gov/apod/ap951017.html ], several small irregular galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap950728.html ], and many dwarf elliptical galaxies [ http://www.physics.mcmaster.ca/Grads/PRD2.html ]. Pictured is one of the many dwarf ellipticals: NGC 205. Like M32, NGC 205 is a companion to the large M31, and can sometimes be seen to the south of M31 [ http://seds.lpl.arizona.edu/messier/m/m031.html ]'s center in photographs. The above image [ http://crux.astr.ua.edu/gifimages/m110r.html ] shows this galaxy to be unusual for an elliptical galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950913.html ] in that it contains at least two dust clouds [ http://antwrp.gsfc.nasa.gov/apod/ap951107.html ] (at 7 and 11 o'clock - they are visible but hard to spot) and signs of recent star formation. This galaxy is sometimes known as M110, although it was actually not part of Messier [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#messier ]'s original catalog. |
|
Dwarf Elliptical Galaxy M32
| Title |
Dwarf Elliptical Galaxy M32 |
| Explanation |
Being the largest galaxy around can sometimes make you popular. Pictured is M31's companion galaxy M32 [ http://crux.astr.ua.edu/gifimages/m32.html ]. M31 [ http://antwrp.gsfc.nasa.gov/apod/ap950724.html ], the Andromeda galaxy, is the largest galaxy in our Local Group [ http://www.csc.fi/jpr/galaxy/lbang.html ] of galaxies - even our tremendous Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950908.html ] is smaller. Little M32 is visible in most pictures of M31 - it is the small circular spot north of M31's center. M32 is a dwarf elliptical galaxy [ http://www.physics.mcmaster.ca/Grads/PRD2.html ]. Elliptical galaxies [ http://sousun1.phys.soton.ac.uk/PH308/galaxies/ellipticals.html ] have little or no measurable gas [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#hydrogen ] or dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] - they are composed completely of stars [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#star ] and typically appear more red than spiral galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap951218.html ]. Elliptical galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap950913.html ] do not have disks - they generally have oblong shapes and therefore show elliptical profiles on the sky. |
|
Island Universe, Cosmic Sand
| Title |
Island Universe, Cosmic Sand |
| Explanation |
On August 13, while counting Perseid meteors [ http://comets.amsmeteors.org/meteors/showers/ perseids.html ] under dark [ http://www.darksky.org/ida/darksky/ index.html ], early morning Arizona skies, Rick Scott set out to photograph [ http://members.cox.net/rmscott/ gallery_space_sky02.html ] their fleeting but fiery trails. The equipment he used included a telephoto lens and fast color film. After 21 pictures he'd caught only two meteors, but luckily this was one of them. Tracking the sky, his ten minute long exposure shows a field of many stars in our own Milky Way galaxy [ http://www.seds.org/messier/ more/mw.html ], most too faint to be seen by the unaided eye. Flashing [ http://antwrp.gsfc.nasa.gov/apod/ap990219.html ] from lower left to upper right, the bright meteor would have been an easy eyeful though, as friction with Earth's atmosphere vaporized [ http://antwrp.gsfc.nasa.gov/apod/ap020816.html ] the hurtling grain of cosmic sand [ http://antwrp.gsfc.nasa.gov/apod/ap001117.html ], a piece of dust from Comet Swift-Tuttle [ http://comets.amsmeteors.org/comets/pcomets/ 109p.html ]. Just above and left of center, well beyond the stars of the Milky Way, lies the island universe [ http://antwrp.gsfc.nasa.gov/apod/ap020518.html ] known as M31 or the Andromeda galaxy. The visible meteor trail begins about 100 kilometers above Earth's surface, one of the closest celestial objects seen in the sky. In contrast, Andromeda [ http://www.seds.org/messier/m/ m031.html ], about 2 million light-years away, is the most distant object easily visible to the naked-eye. |
|
Nearby Spiral M33
| Title |
Nearby Spiral M33 |
| Explanation |
Spiral galaxy [ http://www.seds.org/messier/spir.html ] M33 is a mid-sized member of our Local Group of Galaxies [ http://www.seds.org/messier/more/local.html ]. M33 [ http://antwrp.gsfc.nasa.gov/apod/ap980721.html ] is also called the Triangulum Galaxy [ http://www.seds.org/messier/m/m033.html ] for the constellation [ http://www.astronomical.org/constellations/tri.html ] in which it resides. About four times smaller (in radius) than our Milky Way Galaxy [ http://www.star.le.ac.uk/edu/mway/ ] and the Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap021021.html ] (M31), it is much larger than the many of the local dwarf spheroidal [ http://antwrp.gsfc.nasa.gov/apod/ap991003.html ] galaxies. M33 [ http://antwrp.gsfc.nasa.gov/apod/ap960708.html ]'s proximity to M31 [ http://antwrp.gsfc.nasa.gov/apod/ap010917.html ] causes it to be thought by some to be a satellite galaxy of this more massive galaxy. M33 [ http://sirtf.caltech.edu/Education/Messier/m33.html ]'s proximity to our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] causes it to appear more than twice the angular size of the Full Moon [ http://antwrp.gsfc.nasa.gov/apod/ap010218.html ], and be visible with a good pair of binoculars. The above high-resolution image [ http://www.noao.edu/image_gallery/html/im0775.html ] from the 0.90-m telescope [ http://www.noao.edu/0.9m/manual.html ] at Kitt Peak National Observatory [ http://www.noao.edu/kpno/ ] is a four-color composite. |
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