                        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 July 5
   A map of the observable universe is illustrated in a wedge with the the
   Earth on the bottom and the universe fanning out above. Please see the
                 explanation for more detailed information.

                      A Map of the Observable Universe
   Image Credit & Copyright: B. Ménard & N. Shtarkman; Data: SDSS, Planck,
                            JHU, Sloan, NASA, ESA

   Explanation: What if you could see out to the edge of the observable
   universe? You would see galaxies, galaxies, galaxies, and then, well,
   quasars, which are the bright centers of distant galaxies. To expand
   understanding of the very largest scales that humanity can see, a map
   of the galaxies and quasars found by the Sloan Digital Sky Survey from
   2000 to 2020 -- out to near the edge of the observable universe -- has
   been composed. Featured here, one wedge from this survey encompasses
   about 200,000 galaxies and quasars out beyond a look-back time of 12
   billion years and cosmological redshift 5. Almost every dot in the
   nearby lower part of the illustration represents a galaxy, with redness
   indicating increasing redshift and distance. Similarly, almost every
   dot on the upper part represents a distant quasar, with blue-shaded
   dots being closer than red. Clearly shown among many discoveries,
   gravity between galaxies has caused the nearby universe to condense and
   become increasingly more filamentary than the distant universe.

                 More Detailed Maps: Related to Today's APOD
                       Tomorrow's picture: open space
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

