                        Astronomy Picture of the Day

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

                               2021 November 14

                    How to Identify that Light in the Sky
       Illustration Credit & Copyright: HK (The League of Lost Causes)

   Explanation: What is that light in the sky? Perhaps one of humanity's
   more common questions, an answer may result from a few quick
   observations. For example -- is it moving or blinking? If so, and if
   you live near a city, the answer is typically an airplane, since planes
   are so numerous and so few stars and satellites are bright enough to be
   seen over the din of artificial city lights. If not, and if you live
   far from a city, that bright light is likely a planet such as Venus or
   Mars -- the former of which is constrained to appear near the horizon
   just before dawn or after dusk. Sometimes the low apparent motion of a
   distant airplane near the horizon makes it hard to tell from a bright
   planet, but even this can usually be discerned by the plane's motion
   over a few minutes. Still unsure? The featured chart gives a
   sometimes-humorous but mostly-accurate assessment. Dedicated sky
   enthusiasts will likely note -- and are encouraged to provide -- polite
   corrections.

       Chart translations: Spanish, Italian, Polish, Kannada, Latvian,
                           Norwegian, and Turkish
                  Tomorrow's picture: volcanic light pillar
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                      A service of: ASD at NASA / GSFC
                             & Michigan Tech. U.

