Photo: Riddle of Mars's Mysterious "Spiders," "Fans" Solved



New images from NASA's orbiting HiRise camera have revealed some of the secrets behind Mars's bizarre "spiders" (top) and "dark fans" (bottom).

The spiders are delicate tunnels under the polar ice generated by melting carbon dioxide gas, while the fans are alternating deposits of carbon dioxide "snow" (white) and dust (black) thrown out by the erupting gas, experts say.

Images courtesy NASA/JPL/University of Arizona


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