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 August 17
                                      [2]
                    Perseid Fireball and Persistent Train
                Image Credit & Copyright [3] : Petr Horalek [4]

Explanation: Before local midnight on August 12 [5] , this brilliant Perseid
meteor flashed above the Poloniny Dark Sky Park, Slovakia, planet Earth.
Streaking beside [6]  the summer Milky Way, its initial color is likely due to
the shower meteor's characteristically high speed. Moving at about 60
kilometers per second, Perseid meteors can excite green emission from oxygen
atoms while passing through the thin atmosphere at high altitudes [7] . Also
characteristic of bright meteors, this Perseid left a lingering visible trail
known as a persistent train [8] , wafting in the upper atmosphere. Its
development is followed in the inset frames, exposures separated by one minute
and shown at the scale of the original image. Compared to the brief flash of
the meteor, the wraith-like trail really is persistent. After an hour faint
remnants of this one could still be traced, expanding to over 80 degrees on
the sky.

                       Tomorrow's picture: Seeing Titan

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Site notes:
  [1] archivepix.html
  [2] image/1808/2018_08_12_Bolid_Perseus_1600px.jpg
  [3] lib/about_apod.html#srapply
  [4] http://www.astronom.cz/horalek/?page_id=20
  [5] http://www.astronom.cz/horalek/?p=4182
  [6] https://blogs.nasa.gov/Watch_the_Skies/tag/al...
  [7] ap140810.html
  [8] ap151116.html
  [9] ap180816.html
  [10] archivepix.html
  [11] lib/apsubmit2015.html
  [12] lib/aptree.html
  [13] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apo...
  [14] calendar/allyears.html
  [15] /apod.rss
  [16] lib/edlinks.html
  [17] lib/about_apod.html
  [18] http://asterisk.apod.com/discuss_apod.php?dat...
  [19] ap180818.html
  [20] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [21] http://www.phy.mtu.edu/
  [22] https://antwrp.gsfc.nasa.gov/htmltest/jbonnel...
  [23] http://www.astro.umd.edu/
  [24] lib/about_apod.html#srapply
  [25] https://www.nasa.gov/about/highlights/HP_Priv...
  [26] https://astrophysics.gsfc.nasa.gov/
  [27] https://www.nasa.gov/
  [28] https://www.nasa.gov/centers/goddard/
  [29] http://www.mtu.edu/

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