                        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.

                                 2024 May 13
    A distant Sun is seen over water and between foreground trees. On the
   lower part of the Sun is the gigantic active region AR 3664 visible by
       its dark sunspots. Please see the explanation for more detailed
                                information.

                          AR 3664 on a Setting Sun
                   Image Credit & Copyright: Marco Meniero

   Explanation: It was larger than the Earth. It was so big you could
   actually see it on the Sun's surface without magnification. It
   contained powerful and tangled magnetic fields as well as numerous dark
   sunspots. Labelled AR 3664, it developed into one of the most energetic
   areas seen on the Sun in recent years, unleashing a series of
   explosions that led to a surge of energetic particles striking the
   Earth, which created beautiful auroras. And might continue. Although
   active regions on the Sun like AR 3664 can be quite dangerous, this
   region's Coronal Mass Ejections have not done, as yet, much damage to
   Earth-orbiting satellites or Earth-surface electrical grids. Pictured,
   the enormous active region was captured on the setting Sun a few days
   ago from Civitavecchia, Rome, Italy. The composite image includes a
   very short exposure taken of just the Sun's surface, but mimics what
   was actually visible. Finally, AR 3664 is now rotating away from the
   Earth, although the region may survive long enough to come around
   again.

             Gallery: Earth Aurora from Solar Active Region 6443
                     Tomorrow's picture: What is 42 - 5?
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                           NASA Science Activation
                             & Michigan Tech. U.

