                        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.

                              2023 September 6

                 HESS Telescopes Explore the High-Energy Sky
   Credit & Copyright: Video Credit & Copyright: Jeff Dai (TWAN), H.E.S.S.
                               Collaboration;
         Music: Ibaotu catalog number 1044988 (Used with permission)

   Explanation: They may look like modern mechanical dinosaurs, but they
   are enormous swiveling eyes that watch the sky. The High Energy
   Stereoscopic System (H.E.S.S.) Observatory is composed of four 12-meter
   reflecting-mirror telescopes surrounding a larger telescope housing a
   28-meter mirror. They are designed to detect strange flickers of blue
   light -- Cherenkov radiation --emitted when charged particles move
   slightly faster than the speed of light in air. This light is emitted
   when a gamma ray from a distant source strikes a molecule in Earth's
   atmosphere and starts a charged-particle shower. H.E.S.S. is sensitive
   to some of the highest energy photons (TeV) crossing the universe.
   Operating since 2003 in Namibia, H.E.S.S. has searched for dark matter
   and has discovered over 50 sources emitting high energy radiation
   including supernova remnants and the centers of galaxies that contain
   supermassive black holes. Pictured in June, H.E.S.S. telescopes swivel
   and stare in time-lapse sequences shot in front of our Milky Way Galaxy
   and the Magellanic Clouds -- as the occasional Earth-orbiting satellite
   zips by.

                  Surf the Universe: Random APOD Generator
                    Tomorrow's picture: large star cloud
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