                        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.

                              2024 December 29
   A frozen lake is shown that appears quite blue. Many oval light-colored
   bubbles are frozen into the ice, many times in columns. Please see the
                 explanation for more detailed information.

                    Methane Bubbles Frozen in Lake Baikal
                 Image Credit & Copyright: Kristina Makeeva

   Explanation: What are these bubbles frozen into Lake Baikal? Methane.
   Lake Baikal, a UNESCO World Heritage Site in Russia, is the world's
   largest (by volume), oldest, and deepest lake, containing over 20% of
   the world's fresh water. The lake is also a vast storehouse of methane,
   a greenhouse gas that, if released, could potentially increase the
   amount of infrared light absorbed by Earth's atmosphere, and so
   increase the average temperature of the entire planet. Fortunately, the
   amount of methane currently bubbling out is not climatologically
   important. It is not clear what would happen, though, were temperatures
   to significantly increase in the region, or if the water level in Lake
   Baikal were to drop. Pictured, bubbles of rising methane froze during
   winter into the exceptionally clear ice covering the lake.

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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                             & Michigan Tech. U.

