                        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 January 20
   A comet is seen near the top of the image. The comet has several tails
    visible, some being white but others having different colors. Please
             see the explanation for more detailed information.

                         Comet ATLAS Rounds the Sun
     Image Credit: NASA, SOHO Spacecraft, LASCO C3; Processing: Rolando
                                  Ligustri

   Explanation: Why does Comet ATLAS have such colorful tails? Last week
   Comet C/2024 G3 (ATLAS) passed its closest to the Sun -- well inside
   the orbit of Mercury -- and brightened dramatically. Unfortunately, the
   comet was then so angularly near the Sun that it was very hard for
   humans to see. But NASA's SOHO spacecraft saw it. Pictured is a SOHO
   (LASCO C3) image of Comet ATLAS that is a composite of several
   different color filters. Of the several tails visible, the central
   white tails are likely made of dust and just reflecting back sunlight.
   The red, blue, and green tails are likely ion tails with their colors
   dominated by light emitted by specific gases that were ejected from the
   comet and energized by the Sun. Currently, Comet ATLAS is showing long
   tails in southern skies but fading as it moves out of the inner Solar
   System.

                      Growing Gallery: Comet ATLAS (G3)
                       Tomorrow's picture: long tails
     __________________________________________________________________

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

