It takes a lot of stress, and a little chaos, to create some of the tallest mountains in our solar system. That is the theory proposed by earth and planetary scientists at Washington University in St. Louis studying mountain formation and volcanic activity on Io, one of Jupiter's many moons. The researchers analyzed images taken by the Galileo and Voyager spacecraft and found that Io's enigmatic mountains may be the combined result of heating, melting, and tilting of giant blocks of crust. Images taken with different lighting and from different positions by NASA's Galileo spacecraft provide information about the three-dimensional structure of a large mountain named Tohil Mons on Io.
North is to the top of the image.
The Sun was almost directly behind the spacecraft, so shadows are negligible. The other image is a topographic representation of what Tohil Mons looks like when seen from the northeast. The topography has been vertically exaggerated. The origin of Io's prodigious mountains has intrigued planetary scientists for over 20 years. Io's surface is dotted with active volcanoes spewing plumes of sulfurous gas and emitting vast streams of scorching lava.