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M100: A Grand Design
| Title |
M100: A Grand Design |
| Explanation |
Majestic [ http://www.lhl.lib.mo.us/pubserv/hos/stars/welcome.htm ] on a truly cosmic scale, M100 [ http://bozo.lpl.arizona.edu/messier/m/m100.html ] is appropriately known as a Grand Design spiral [ http://antwrp.gsfc.nasa.gov/apod/ap961030.html ] galaxy. A large galaxy of over 100 billion or so stars with well defined spiral arms [ http://antwrp.gsfc.nasa.gov/apod/ap960409.html ], it is similar to our own Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap970315.html ]. One of the brightest members of the Virgo Cluster of galaxies [ http://bozo.lpl.arizona.edu/messier/more/virgo.html ] , M100 (alias NGC 4321) is 56 million light-years distant in the spring constellation of Coma Berenices [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Coma_Berenices.html ]. This Hubble Space Telescope image [ http://oposite.stsci.edu/pubinfo/PR/94/01.html ] of the central region of M100 was made in 1993 with the Wide Field and Planetary Camera 2. It reveals the bright blue star clusters [ http://antwrp.gsfc.nasa.gov/apod/ap980329.html ] and intricate winding dust lanes [ http://antwrp.gsfc.nasa.gov/apod/ap980116.html ] which are hallmarks of this class of galaxies [ http://hermes.astro.washington.edu:80/scied/astro/hubble/hubble.html ]. Studies of stars in M100 [ http://antwrp.gsfc.nasa.gov/apod/ap960110.html ] have recently played an important role in determining the size and age [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/ debate_1996.html ] of the Universe. |
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M100: A Grand Design
| Title |
M100: A Grand Design |
| Explanation |
Majestic [ http://www.lhl.lib.mo.us/pubserv/hos/stars/welcome.htm ] on a truly cosmic scale, M100 [ http://bozo.lpl.arizona.edu/messier/m/m100.html ] is appropriately known as a Grand Design spiral galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap961030.html ]. A large galaxy of over 100 billion or so stars with well defined spiral arms [ http://antwrp.gsfc.nasa.gov/apod/ap960409.html ], it is similar to our own Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap970315.html ]. One of the brightest members of the Virgo Cluster of galaxies [ http://bozo.lpl.arizona.edu/messier/more/virgo.html ] , M100 (alias NGC 4321) is 56 million light-years distant in the spring constellation of Coma Berenices [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Coma_Berenices.html ]. This Hubble Space Telescope image [ http://oposite.stsci.edu/pubinfo/PR/94/01.html ] of the central region of M100 was made in 1993 with the Wide Field and Planetary Camera 2. It reveals the bright blue star clusters [ http://antwrp.gsfc.nasa.gov/apod/ap980329.html ] and intricate winding dust lanes [ http://antwrp.gsfc.nasa.gov/apod/ap980116.html ] which are hallmarks of this class of galaxies [ http://hermes.astro.washington.edu:80/scied/astro/hubble/hubble.html ]. Studies of stars in M100 [ http://antwrp.gsfc.nasa.gov/apod/ap960110.html ] have recently played an important role in determining the size and age of the Universe. |
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Spiral Galaxy NGC 1232
| Title |
Spiral Galaxy NGC 1232 |
| Explanation |
Galaxies [ ftp://crux.astr.ua.edu/web/goodies/data_resources/galaxies.text ] are fascinating not only for what is visible, but for what is invisible. Grand spiral [ http://antwrp.gsfc.nasa.gov/apod/ap980606.html ] galaxy NGC 1232 [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997AAS...191.8203B&db_key=AST&high=34f6e1de7f27181 ], recently captured [ http://www.eso.org/outreach/press-rel/pr-1998/pr-14-98.html ] in detail by the new Very Large Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap960901.html ], is a good example. The visible is dominated by millions of bright stars [ http://antwrp.gsfc.nasa.gov/apod/ap971018.html ] and dark dust [ http://antwrp.gsfc.nasa.gov/apod/ap961119.html ], caught up in a gravitational swirl of spiral arms rotating about the center. Open clusters [ http://antwrp.gsfc.nasa.gov/apod/ap980329.html ] containing bright blue stars can be seen sprinkled along these spiral arms, while dark lanes [ http://antwrp.gsfc.nasa.gov/apod/ap980116.html ] of dense interstellar dust [ http://antwrp.gsfc.nasa.gov/apod/ap980121.html ] can be seen sprinkled between them. Less visible, but detectable, are billions of dim normal stars and vast tracts of interstellar gas [ http://antwrp.gsfc.nasa.gov/apod/ap980301.html ], together wielding such high mass that they dominate the dynamics of the inner galaxy [ http://hermes.astro.washington.edu:80/scied/astro/hubble/hubble.html ]. Invisible are even greater amounts of matter in a form we don't yet know - pervasive dark matter [ http://xrtpub.harvard.edu/Xray/dark_matter.html ] needed to explain the motions [ http://www.astro.queensu.ca/~dursi/dm-tutorial/dm2.html ] of the visible in the outer galaxy. What's out there? [ http://antwrp.gsfc.nasa.gov/debate/debate98.html ] |
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