                         Astronomy Picture of the Day

                         Astronomy Picture of the Day

    Discover the cosmos! [1] Each day a different image or photograph of our
 fascinating universe is featured, along with a brief explanation written by a
                           professional astronomer.

                               2018 December 17
                                      [2]
                          M31: The Andromeda Galaxy
                 Image Credit & Copyright: Robert Gendler [3]

Explanation: What is the nearest major galaxy [4]  to our own Milky Way Galaxy
[5] ? Andromeda. In fact, our Galaxy is thought to look much like Andromeda
[6] . Together these two galaxies dominate the Local Group [7]  of galaxies.
The diffuse light from Andromeda [8] is caused by the hundreds of billions of
star [9] s that compose it. The several distinct stars that surround Andromeda
[10] 's image are actually stars in our Galaxy [11] that are well in front of
the background object. Andromeda [12]  is frequently referred to as M31 since
it is the 31st object [13]  on Messier [14] 's list of diffuse sky objects.
M31 [15]  is so distant it takes about two million years for light to reach us
from there. Although visible without aid [16] , the featured image [17]  of
M31 is a digital mosaic of 20 frames taken with a small telescope. Much about
M31 remains unknown [18] , including exactly how long it will before it
collides with our home galaxy [19] .

            Jump around the Universe: Random APOD Generator [20]
                      Tomorrow's picture: bubble trouble?

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    Authors & editors: Robert Nemiroff [32] (MTU [33] ) & Jerry Bonnell [34]
                                  (UMCP [35] )
          NASA Official:  Phillip Newman Specific rights apply [36] .
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              A service of: ASD [38]  at NASA [39]  / GSFC [40]
                           & Michigan Tech. U. [41]
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Site notes:
  [1] archivepix.html
  [2] image/1812/m31_gendler_2700.jpg
  [3] http://www.robgendlerastropics.com/
  [4] https://science.nasa.gov/astrophysics/focus-areas/what-are-galaxies
  [5] http://map.gsfc.nasa.gov/universe/rel_milkyway.html
  [6] https://en.wikipedia.org/wiki/Andromeda_Galaxy
  [7] http://www.atlasoftheuniverse.com/localgr.html
  [8] ap180108.html
  [9] http://en.wikipedia.org/wiki/Star
  [10] ap010917.html
  [11] https://solarsystem.nasa.gov/resources/285/the-milky-way-galaxy/
  [12] http://www.noao.edu/image_gallery/html/im0424.html
  [13] ap960626.html
  [14] http://messier.seds.org/xtra/history/biograph.html
  [15] ap020412.html
  [16] ap150817.html
  [17] http://www.robgendlerastropics.com/M31Page.html
  [18] https://youtu.be/U_ZHsk0-eF0?t=1587
  [19] ap120604.html
  [20] http://apod.nasa.gov/apod/random_apod.html
  [21] ap181216.html
  [22] archivepix.html
  [23] lib/apsubmit2015.html
  [24] lib/aptree.html
  [25] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [26] calendar/allyears.html
  [27] /apod.rss
  [28] lib/edlinks.html
  [29] lib/about_apod.html
  [30] http://asterisk.apod.com/discuss_apod.php?date=181217
  [31] ap181218.html
  [32] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [33] http://www.phy.mtu.edu/
  [34] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  [35] http://www.astro.umd.edu/
  [36] lib/about_apod.html#srapply
  [37] https://www.nasa.gov/about/highlights/HP_Privacy.html
  [38] https://astrophysics.gsfc.nasa.gov/
  [39] https://www.nasa.gov/
  [40] https://www.nasa.gov/centers/goddard/
  [41] http://www.mtu.edu/
