Astronomy Picture of the Day
Posted By admin On March 29, 2011 @ 10:49 pm In Photo Essays | Comments Disabled
[1]
NGC 5584: Expanding the Universe
Credit: NASA [2], ESA [3], A. Riess [4] (STScI/JHU), L. Macri [4] (Texas A & M Univ.) et al. [5], Hubble Heritage [6] (STScI [7]/AURA [8])
Explanation: Big, beautiful NGC 5548 [9] is more that 50,000 light-years across and lies 72 million light-years away toward the constellation Virgo. The winding spiral arms of this gorgeous island universe [10] are loaded with luminous young star clusters and dark dust lanes. Still, for earthbound astronomers NGC 5548 is not just another pretty face-on spiral galaxy. Home to some 250 Cepheid variable stars [11] and a recent Type Ia supernova [12] explosion, key objects for astronomical distance determinations [13], NGC 5548 is one of 8 galaxies used in a new study that includes additional Hubble Space Telescope observations to improve the measurement of Hubble’s Constant [14] – the expansion rate of the Universe. The results [5] of the study lend weight to the theory that dark energy really is responsible [15] for accelerating the expansion of the Universe, restricting models that try to explain the observed acceleration without the mysterious dark energy. In this sharp Hubble image [16] of NGC 5548, many of the small reddish smudges are distant background galaxies.
Visit the NASA/JPL website to view more Astronomy Pictures of the Day [17]
Article printed from Recorder Online: http://www.berthoudrecorder.com
URL to article: http://www.berthoudrecorder.com/2011/03/29/astronomy-picture-of-the-day-45/
URLs in this post:
[1] Image: http://www.berthoudrecorder.com/wp-content/uploads/2011/03/ngc5584_hstr1.jpg
[2] NASA: http://www.nasa.gov/
[3] ESA: http://www.spacetelescope.org/
[4] A. Riess: http://heritage.stsci.edu/2011/08/bio/bio_primary.html
[5] et al.: http://arxiv.org/abs/1103.2976
[6] Hubble Heritage: http://heritage.stsci.edu/
[7] STScI: http://www.stsci.edu/
[8] AURA: http://www.aura-astronomy.org/
[9] Big, beautiful NGC 5548: http://heritage.stsci.edu/2011/08/caption.html
[10] island universe: http://nedwww.ipac.caltech.edu/level5/March02/Gordon/Gordon2.html
[11] 250 Cepheid variable stars: http://heritage.stsci.edu/2011/08/supplemental.html
[12] Type Ia supernova: http://en.wikipedia.org/wiki/Type_Ia_supernova
[13] astronomical distance determinations: http://csep10.phys.utk.edu/astr162/lect/cosmology/cosmicd.html
[14] Hubble’s Constant: http://apod.nasa.gov/debate/debate96.html
[15] dark energy really is responsible: http://hubblesite.org/newscenter/archive/releases/2011/08/full/
[16] this sharp Hubble image: http://hubblesite.org/newscenter/archive/releases/2011/08/fastfacts/
[17] Astronomy Pictures of the Day: http://antwrp.gsfc.nasa.gov/apod/
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