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 July 15

                  The Space Station Crosses a Spotless Sun
                 Image Credit & Copyright: Rainee Colacurcio

   Explanation: That's no sunspot. It's the International Space Station
   (ISS) caught passing in front of the Sun. Sunspots, individually, have
   a dark central umbra, a lighter surrounding penumbra, and no solar
   panels. By contrast, the ISS is a complex and multi-spired mechanism,
   one of the largest and most sophisticated machines ever created by
   humanity. Also, sunspots occur on the Sun, whereas the ISS orbits the
   Earth. Transiting the Sun is not very unusual for the ISS, which orbits
   the Earth about every 90 minutes, but getting one's timing and
   equipment just right for a great image is rare. Strangely, besides that
   fake spot, in this recent two-image composite, the Sun lacked any real
   sunspots. The featured picture combines two images -- one capturing the
   space station transiting the Sun -- and another taken consecutively
   capturing details of the Sun's surface. Sunspots have been rare on the
   Sun since the dawn of the current Solar Minimum, a period of low solar
   activity. For reasons not yet fully understood, the number of sunspots
   occurring during both the previous and current solar minima have been
   unusually low.

                       Tomorrow's picture: moon launch
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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