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
                    written by a professional astronomer.

                              2019 November 14

                          Mercury and the Quiet Sun
                   Image Credit & Copyright: John Chumack

   Explanation: On November 11, 2019 the Sun was mostly quiet,
   experiencing a minimum in its 11 year cycle of activity. In fact, the
   only spot visible was actually planet Mercury, making a leisurely 5 1/2
   hour transit in front of the calm solar disk. About 1/200th the
   apparent diameter of the Sun, the silhouette of the solar system's
   inner most planet is near center in this sharp, full Sun snapshot.
   Taken with a hydrogen alpha filter and safe solar telescope, the image
   also captures prominences around the solar limb, the glowing plasma
   trapped in arcing magnetic fields. Of course, only inner planets
   Mercury and Venus can transit the Sun to appear in silhouette when
   viewed from planet Earth. Following its transit in 2016, this was
   Mercury's 4th of 14 transits across the solar disk in the 21st century.
   The next transit of Mercury will be on November 13, 2032.

                Tomorrow's picture: star streams and galaxies
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                             & Michigan Tech. U.

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