Io's Deadly feature ( Extra )

Before the astronomers visited Jupiter, if you had described Io you'll probably think of volcanoes. Jupiter's strange moon is literally bursting with volcanoes. Dozens of active vents pepper the landscape with volcanic rings the size of California. The volcanoes themselves are the hottest spots in the solar system, with temperatures exceeding 1800 Kelvin (1527 Celsius) about 1/3 the temperature of the surface of the Sun! The flaming hot plumes which rise as much as 500 kilometers into space are so large they can be seen from Earth by the Hubble Space Telescope.

These high-rising, seem to be made up of, not hot lava, but frozen sulfur dioxide. For a world dominated by active volcanoes, it's curious that Io is also very, very cold. The ground just around the volcanic vents is literally sizzling, but most of Io's surface is 150 degrees or more below 0 Celsius which is astonishing.