AstronomyPicture of the Day—20181220

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.

2018December 18

MethaneBubbles Frozen in Lake Baikal

ImageCredit & Copyright: Kristina Makeeva

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