                        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.

                              2025 September 15

                     Earth During a Powerful Solar Storm
       Video Credit: NASA's SVS, SWRC, CCMC, SWMF; T. Bridgeman et al.

   Explanation: Can our Sun become dangerous? Yes, sometimes. Every few
   years our Sun ejects a scary-large bubble of hot gas into the Solar
   System. Every hundred years or so, when the timing, location, and
   magnetic field connections are just right, such a Coronal Mass Ejection
   (CME) will hit the Earth. When this happens, the Earth not only
   experiences dramatic auroras, but its magnetic field gets quickly
   pushed back and compressed, which causes electric grids to surge. Some
   of these surges could be dangerous, affecting satellites and knocking
   out power grids -- which can take months to fix. Just such a storm --
   called the Carrington Event -- occurred in 1859 and caused telegraph
   wires to spark. A similar CME passed near the Earth in 2012, and the
   featured animated video shows a computer model of what might have
   happened if it had been a direct hit. In this model, the Earth's
   magnetopause becomes so compressed that it went inside the orbit of
   geosynchronous communication satellites.

                    Tomorrow's picture: stellar cathedral
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

