Detail View: NASA Astronomy Picture of the Day Collection: 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 ]
Credit and Copyright: 
FORS1 [ http://www.eso.org/instruments/fors1/fors.html ], 8.2-meter VLT [ http://www.eso.org/projects/vlt/ ], ESO [ http://www.eso.org/ ]
keyword: 
dark matter
facet_where: 
Goddard Space Flight Center (GSFC)
facet_what: 
Crux
original url: 
http://antwrp.gsfc.nasa.gov/apod/ap980930.html
UID: 
SPD-APOD-ap980930