                        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 November 6

                              21st Century M101
             Image Credit: NASA, ESA, CXC, JPL - Caltech, STScI

   Explanation: One of the last entries in Charles Messier's famous
   catalog, big, beautiful spiral galaxy M101 is definitely not one of the
   least. About 170,000 light-years across, this galaxy is enormous,
   almost twice the size of our own Milky Way Galaxy. M101 was also one of
   the original spiral nebulae observed with Lord Rosse's large 19th
   century telescope, the Leviathan of Parsonstown. In contrast, this
   multiwavelength view of the large island universe is a composite of
   images recorded by space-based telescopes in the 21st century. Color
   coded from X-rays to infrared wavelengths (high to low energies), the
   image data was taken from the Chandra X-ray Observatory (purple), the
   Galaxy Evolution Explorer (blue), Hubble Space Telescope(yellow), and
   the Spitzer Space Telescope(red). While the X-ray data trace the
   location of multimillion degree gas around M101's exploded stars and
   neutron star and black hole binary star systems, the lower energy data
   follow the stars and dust that define M101's grand spiral arms. Also
   known as the Pinwheel Galaxy, M101 lies within the boundaries of the
   northern constellation Ursa Major, about 25 million light-years away.

                  Tomorrow's picture: The Titan's daughters
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                             & Michigan Tech. U.

