                         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 October 28
                                      [2]
              Ultraviolet Earth from an Observatory on the Moon
 Image Credit: G. Carruthers [3] (NRL [4] ) et al., Far UV Camera [5] , Apollo
                              16 [6] , NASA [7]

Explanation: Which planet is this? Earth [8] . The featured [9]  false color
picture [10]  shows how the Earth shines in ultraviolet [11] (UV) light. The
image is historic because it was taken from the surface of the Moon [12] by
humanity's first lunar observatory [13] . (Another is operating now [14] .)
Although very little UV light [15] is transmitted through the Earth's
atmosphere, what sunlight does make it through might cause a sunburn [16] .
The part of the Earth facing the Sun [17] reflects much UV light, but perhaps
more interesting is the side facing away from the Sun. Here bands of UV
emission [18]  are the result of auroras [19]  and are caused by charged
particles [20]  expelled by the Sun. Other planets showing auroras in the UV
include Mars [21] , Saturn [22] , Jupiter [23] , and Uranus [24] .

                      Tomorrow's picture: shelled galaxy

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    Authors & editors: Robert Nemiroff [36] (MTU [37] ) & Jerry Bonnell [38]
                                  (UMCP [39] )
          NASA Official:  Phillip Newman Specific rights apply [40] .
              NASA Web Privacy Policy and Important Notices [41]
              A service of: ASD [42]  at NASA [43]  / GSFC [44]
                           & Michigan Tech. U. [45]
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Site notes:
  [1] archivepix.html
  [2] image/1810/EarthUV_Apollo16_1719.jpg
  [3] https://en.wikipedia.org/wiki/George_Robert_Carruthers
  [4] https://www.nrl.navy.mil/
  [5]
https://www.nasa.gov/image-feature/
looking-back-dr-george-carruthers-and-apollo-16-far-ultraviolet-
cameraspectrograph
  [6] https://www.nasa.gov/mission_pages/apollo/missions/apollo16.html
  [7] https://www.nasa.gov/
  [8] https://solarsystem.nasa.gov/planets/earth/overview/
  [9]
https://spaceflight.nasa.gov/gallery/images/apollo/apollo16/hires/s72-40821.jpg
  [10]
https://commons.wikimedia.org/wiki/
File:Earth_in_ultraviolet_from_the_Moon_(S72-40821).jpg
  [11] https://science.nasa.gov/ems/10_ultravioletwaves
  [12]
https://www.forbes.com/sites/startswithabang/2018/10/25/
why-dont-we-put-a-space-telescope-on-the-moon/
  [13]
https://www.nasa.gov/image-feature/
looking-back-dr-george-carruthers-and-apollo-16-far-ultraviolet-
cameraspectrograph
  [14]
http://english.nao.cas.cn/Research2015/rp2015/201701/t20170120_173602.html
  [15] https://en.wikipedia.org/wiki/Ultraviolet
  [16] https://en.wikipedia.org/wiki/Sunburn
  [17] https://solarsystem.nasa.gov/solar-system/sun/overview/
  [18] http://solar-center.stanford.edu/about/uvlight.html
  [19] ap171210.html
  [20] http://www-spof.gsfc.nasa.gov/Education/Intro.html
  [21] ap171006.html
  [22] ap180903.html
  [23] ap160711.html
  [24]
https://www.nasa.gov/image-feature/goddard/2017/hubble-spots-auroras-on-uranus
  [25] ap181027.html
  [26] archivepix.html
  [27] lib/apsubmit2015.html
  [28] lib/aptree.html
  [29] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [30] calendar/allyears.html
  [31] /apod.rss
  [32] lib/edlinks.html
  [33] lib/about_apod.html
  [34] http://asterisk.apod.com/discuss_apod.php?date=181028
  [35] ap181029.html
  [36] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [37] http://www.phy.mtu.edu/
  [38] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  [39] http://www.astro.umd.edu/
  [40] lib/about_apod.html#srapply
  [41] https://www.nasa.gov/about/highlights/HP_Privacy.html
  [42] https://astrophysics.gsfc.nasa.gov/
  [43] https://www.nasa.gov/
  [44] https://www.nasa.gov/centers/goddard/
  [45] http://www.mtu.edu/
