                        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.

                                2026 June 28
   The Sun is pictured in yellow with surface structure. In the middle of
      the frame are many circuitous dark spots. The edge of the Sun is
    visible at the top of the image. Please see the explanation for more
                            detailed information.

                        AR 4478: Giant Sunspot Group
                Image Credit & Copyright: Alfredo Vidal Pérez

   Explanation: Right now, one of the largest sunspot groups in recent
   history is crossing the Sun. Active Region 4478 is not only big -- it's
   violent, showing tangled magnetic fields capable of throwing off huge
   clouds of particles into the Solar System. Some of these CMEs might
   impact the Earth. At the extreme, these solar storms could cause some
   Earth-orbiting satellites to malfunction, the Earth's atmosphere to
   slightly distort, and electrical power grids to surge. When impacting
   Earth's upper atmosphere, these particles can produce beautiful
   auroras. Pictured here, AR 4478 and its dark sunspots were captured in
   visible light a few days ago from Barcelona, Spain. Almost as large as
   AR 3664 was in 2024, the AR 4478 sunspot group is so big that it is
   visible just with glasses specially designed to view solar eclipses.
   This week, skygazing enthusiasts all over the globe will not only be
   tracking AR 4478 during the day -- but keenly watching night skies for
   its corresponding bright auroras.

    Sky Surprise: What picture did APOD feature on your birthday? (after
                                    1995)
                   Tomorrow's picture: supergalactic wind
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
                  NASA Web Privacy, Accessibility, Notices;
                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

