                        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 18
    A dark brown cloud that appears similar to a shark is seen against a
    background filled with stars and less prominent blue-shaded nebulas.
          Please see the explanation for more detailed information.

                         LDN 1235: The Shark Nebula
                  Image Credit & Copyright: Timothy Martin

   Explanation: There is no sea on Earth large enough to contain the Shark
   nebula. This predator apparition poses us no danger as it is composed
   only of interstellar gas and dust. Dark dust like that featured here is
   somewhat like cigarette smoke and created in the cool atmospheres of
   giant stars. After expelling gas and gravitationally recondensing,
   massive stars may carve intricate structures into their birth cloud
   using their high energy light and fast stellar winds as sculpting
   tools. The heat they generate evaporates the murky molecular cloud as
   well as causing ambient hydrogen gas to disperse and glow red. During
   disintegration, we humans can enjoy imagining these great clouds as
   common icons, like we do for water clouds on Earth. Including smaller
   dust nebulae such as Van den Bergh 149 & 150, the Shark nebula,
   sometimes cataloged as LDN 1235, spans about 15 light years and lies
   about 650 light years away toward the constellation of the King of
   Aethiopia (Cepheus).

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