A lone mountain on the dwarf planet Ceres could be an extinct volcano. Only this volcano, dubbed Ahuna Mons, didn’t spew molten rock, but instead likely “breathed” ice and mud, a so-called cryovolcano. "Ahuna Mons is evidence of an unusual type of volcanism, involving salty water and mud, at work on Ceres," said Ottaviano Ruesch of NASA's Goddard Space...