                        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 December 1
   A starfield is shown around a comet. The green coma of the comet is on
     the lower left. A meandering blue-tinted tail goes off to the upper
   right. A slight anti-tail is seen from the coma toward the lower left.
          Please see the explanation for more detailed information.

                  3I ATLAS: Tails of an Interstellar Comet
          Image Credit & Copyright: Victor Sabet & Julien De Winter

   Explanation: How typical is our Solar System? Studying 3I/ATLAS, a
   comet just passing through, is providing clues. Confirmed previous
   interstellar visitors include an asteroid, a comet, a meteor, and a gas
   wind dominated by hydrogen and helium. Comet 3I/ATLAS appears
   relatively normal when compared to Solar System comets, therefore
   providing more evidence that our Solar System is a somewhat typical
   star system. For example, Comet 3I/ATLAS has a broadly similar chemical
   composition and ejected dust. The featured image was captured last week
   from Texas and shows a green coma, a wandering blue-tinted ion tail
   likely deflected by our Sun's wind, and a slight anti-tail, all typical
   cometary attributes. The comet, visible with a telescope, passed its
   closest to the Sun in late October and will pass its closest to the
   Earth in mid-December, after which it will return to interstellar space
   and never return.

                 Explore the Universe: Random APOD Generator
                      Tomorrow's picture: active galaxy
     __________________________________________________________________

       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.

