                         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.

                                2019 February 3
                                      [2]
                       An Airglow Fan from Lake to Sky
  Image Credit & Copyright: Dave Lane [3] ; Rollover Annotation:  Judy Schmidt
                                      [4]

Explanation: Why would the sky look like a giant fan? Airglow [5] . The
featured intermittent green glow [6] appeared to rise from a lake through the
arch of our Milky Way Galaxy [7] , as captured during 2015 next to Bryce
Canyon [8]  in Utah [9] , USA. The unusual pattern was created by [10]
atmospheric gravity waves [11] , ripples of alternating air pressure that can
grow with height as the air thins, in this case about 90 kilometers up [12] .
Unlike auroras [13]  powered by collisions with energetic charged particles
and seen at high latitudes, airglow is due to chemiluminescence [14] , the
production of light [15]  in a chemical reaction. More typically seen near the
horizon, airglow [16]  keeps the night sky from ever being completely dark.

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                    Tomorrow's picture: stellar superbubble

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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/1601/AirglowFan_Lane_2400.jpg
  [3] mailto: david dot lane07 at gmail dot com
  [4] http://geckzilla.com/
  [5] http://www.atoptics.co.uk/highsky/airglow1.htm
  [6] https://www.youtube.com/watch?v=te_H0Uo6YEA
  [7] http://www.atlasoftheuniverse.com/galaxy.html
  [8] https://www.youtube.com/watch?v=R1B-umhdy0g
  [9] https://en.wikipedia.org/wiki/Utah
  [10] https://www.atoptics.co.uk/highsky/hgrav.htm
  [11] http://www.nasa.gov/multimedia/imagegallery/image_feature_484.html
  [12] http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=79817
  [13] ap140714.html
  [14] http://www.atoptics.co.uk/highsky/airglow2.htm
  [15] ap130619.html
  [16] http://en.wikipedia.org/wiki/Airglow
  [17] https://www.instagram.com/astronomypicturesdaily/
  [18] https://www.facebook.com/AstronomyPictureOfTheDay
  [19] https://www.reddit.com/r/apod
  [20] http://twitter.com/apod/
  [21] ap190202.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=190203
  [31] ap190204.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/
