                        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.

                                2026 March 11
    A cometary globule extends in front of a field of stars, showing what
    seems like an open mouth towards a distant galaxy in the background.
          Please see the explanation for more detailed information.

                      CG 4: The Globule and the Galaxy
                  Image Credit & Copyright: William Vrbasso
             Text: Cecilia Chirenti (NASA GSFC, UMCP, CRESST II)

   Explanation: Is this a cosmic monster ready to devour an unsuspecting
   galaxy? Thankfully, that is not the case. The red “monster” shown in
   the featured image is Cometary Globule CG 4, 1,300 light-years away in
   the Constellation Puppis. CG 4 is a molecular cloud, where hydrogen
   becomes cold enough to form molecules that can be brought together by
   gravity to create stars. The shape of CG 4 resembles that of a comet,
   but its head is 1.5 light-year in diameter and its tail is 8
   light-years long; for comparison, the distance from the Earth to the
   sun is only 8 light-minutes. Astronomers believe that the tail of a
   cometary globule could have been shaped by a nearby supernova explosion
   or by irradiation from hot, massive stars. Indeed, CG 4 and other
   nearby globules point away from the Vela Supernova Remnant, at the
   center of the Gum Nebula. The edge-on spiral galaxy, ESO 257-19, is
   more than a hundred million light-years beyond CG 4, and is completely
   safe from the “monster”.

                         Tomorrow's picture: Uranus
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
                  NASA Web Privacy, Accessibility, Notices;
                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

