                  APOD: 2017 October 20 - A Beautiful Trifid

                         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.

                                2017 October 20
                                      [2]
                              A Beautiful Trifid
 Image Credit & Copyright [3] : Chamaeleon Team [4]  - Franz Hofmann, Wolfgang
                                    Paech

Explanation: The beautiful Trifid Nebula [5]  is a cosmic study in contrasts.
Also known as M20, it lies about 5,000 light-years [6]  away toward the nebula
rich [7] constellation Sagittarius. A star forming region in the plane of our
galaxy, the Trifid does illustrate three different types of astronomical
nebulae; red emission nebulae [8]  dominated by light from hydrogen atoms,
blue reflection nebulae [9]  produced by dust reflecting starlight, and dark
nebulae [10]  where dense dust clouds appear in silhouette. But the red
emission region roughly separated into three parts by obscuring dust lanes is
what lends the Trifid its popular [11]  name. Pillars and jets sculpted by
newborn stars, below and left of the emission nebula's center, appear in
famous Hubble Space Telescope close-up images [12]  of the region. The Trifid
Nebula is about 40 light-years across. Just too faint to be seen by the
unaided eye, it almost covers the area of the Moon [13] in planet Earth's sky.

          Tomorrow's picture: the light, the dark and the dusty [14]

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    Authors & editors: Robert Nemiroff [26] (MTU [27] ) & Jerry Bonnell [28]
                                  (UMCP [29] )
          NASA Official:  Phillip Newman Specific rights apply [30] .
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                           & Michigan Tech. U. [35]
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Site notes:
  [1] archivepix.html
  [2] image/1710/m020_rooisand_cdk_3500x2500.jpg
  [3] lib/about_apod.html#srapply
  [4] http://www.chamaeleon-observatory-onjala.de/index-e.htm
  [5] http://www.messier.seds.org/m/m020.html
  [6] http://www.atlasoftheuniverse.com/5000lys.html
  [7] ap130712.html
  [8] ap080424.html
  [9] ap090521.html
  [10] ap090522.html
  [11] http://en.wikipedia.org/wiki/Trifid
  [12] http://hubblesite.org/image/915/news_release/1999-42
  [13] image/1710/m020_rooisand_cdk_1024_withMoon.jpg
  [14] ap171021.html
  [15] ap171019.html
  [16] archivepix.html
  [17] lib/apsubmit2015.html
  [18] lib/aptree.html
  [19] http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [20] calendar/allyears.html
  [21] /apod.rss
  [22] lib/edlinks.html
  [23] lib/about_apod.html
  [24] http://asterisk.apod.com/discuss_apod.php?date=171020
  [25] ap171021.html
  [26] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [27] http://www.phy.mtu.edu/
  [28] http://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  [29] http://www.astro.umd.edu/
  [30] lib/about_apod.html#srapply
  [31] http://www.nasa.gov/about/highlights/HP_Privacy.html
  [32] http://astrophysics.gsfc.nasa.gov/
  [33] http://www.nasa.gov/
  [34] http://www.nasa.gov/centers/goddard/
  [35] http://www.mtu.edu/
