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Astronomy Picture of the Day

Posted By Editor On October 30, 2011 @ 7:27 am In Photo Essays | Comments Disabled

Similar in size and grand design to our home Galaxy (although without the central bar), spiral galaxy NGC 3370 lies about 100 million light-years away toward the constellation of the Lion (Leo). 
Spiral Galaxy NGC 3370 from Hubble 
Image Credit: NASA [2]ESA [3]Hubble Heritage [4] (STScI [5]/AURA [6]); Acknowledgement: A. Reiss [7] et al. [8] (JHU [9])

Explanation: Is this what our own Milky Way Galaxy looks like from far away? Similar in size and grand design to our home Galaxy [10] (although without the central bar), spiral galaxy NGC 3370 [11] lies about 100 million light-years [12] away toward the constellation of the Lion (Leo [13]). Recorded above [14] in exquisite detail by the Hubble Space Telescope [15]‘s Advanced Camera for Surveys [16], the big, beautiful face-on spiral is not only photogenic, but has proven sharp [17] enough to study individual stars known as Cepheids [18]. These pulsating stars [19] have been used to accurately determine NGC 3370’s distance.NGC 3370 [20] was chosen for this study because in 1994 the spiral galaxy [21] was also home to a well studied stellar explosion — a Type Ia supernova [22]. Combining the known distance to this standard candle [23]supernova, based on the Cepheid measurements, with observations of supernovas [24] at even greater distances, has helped to reveal the size and expansion rate [25] of the entire Universe itself.

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URLs in this post:

[1] Image: http://www.berthoudrecorder.com/wp-content/uploads/2011/10/ngc3370_hst_6031.jpg

[2] NASA: http://www.nasa.gov/

[3] ESA: http://www.spacetelescope.org/

[4] Hubble Heritage: http://heritage.stsci.edu/

[5] STScI: http://www.stsci.edu/

[6] AURA: http://www.aura-astronomy.org/

[7] A. Reiss: http://heritage.stsci.edu/2003/24/bio/bio_primary.html

[8] et al.: http://heritage.stsci.edu/2003/24/fast_facts.html

[9] JHU: http://physics-astronomy.jhu.edu/

[10] home Galaxy: http://apod.nasa.gov/apod/ap080606.html

[11] NGC 3370: http://en.wikipedia.org/wiki/NGC_3370

[12] light-years: http://chandra.harvard.edu/photo/cosmic_distance.html

[13] Leo: http://www.ianridpath.com/startales/leo.htm

[14] above: http://hubblesite.org/newscenter/archive/releases/2003/24/image/a/

[15] Hubble Space Telescope: http://www.nasa.gov/mission_pages/hubble/story/the_story.html

[16] Advanced Camera for Surveys: http://acs.pha.jhu.edu/

[17] sharp: http://hubblesite.org/newscenter/archive/releases/2003/24/video/a/

[18] Cepheids: http://apod.nasa.gov/apod/ap960110.html

[19] pulsating stars: http://en.wikipedia.org/wiki/Cepheid_variable

[20] NGC 3370: http://heritage.stsci.edu/gallery/pzgallery/0324m.shtml

[21] spiral galaxy: http://cas.sdss.org/dr6/en/proj/basic/galaxies/spirals.asp

[22] Type Ia supernova: http://www.pbs.org/wgbh/nova/universe/supernova1a_nf_01.html

[23] standard candle: http://www.starstryder.com/2007/10/03/type-1a-supernoave-a-non-standard-candle/

[24] supernovas: http://www.youtube.com/watch?v=0J8srN24pSQ

[25] expansion rate: http://cfa-www.harvard.edu/~huchra/hubble/

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