                        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 March 7

                          Planetary Nebula Abell 7
            Image Credit: Image Credit & Copyright: Vikas Chander

   Explanation: Very faint planetary nebula Abell 7 is about 1,800
   light-years distant. It lies just south of Orion in planet Earth's
   skies toward the constellation Lepus, The Hare. Surrounded by Milky Way
   stars and near the line-of-sight to distant background galaxies its
   generally simple spherical shape, about 8 light-years in diameter, is
   revealed in this deep telescopic image. Within the cosmic cloud are
   beautiful and complex structures though, enhanced by the use of long
   exposures and narrowband filters that capture emission from hydrogen,
   sulfur, and oxygen atoms. Otherwise Abell 7 would be much too faint to
   be appreciated by eye. A planetary nebula represents a very brief final
   phase in stellar evolution that our own Sun will experience 5 billion
   years hence, as the nebula's central, once sun-like star shrugs off its
   outer layers. Abell 7 itself is estimated to be 20,000 years old. But
   its central star, seen here as a fading white dwarf, is some 10 billion
   years old.

                      Tomorrow's picture: light-weekend
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