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The natural world. Looking pretty for 3.5b years.

Io's Active Geology

Io's Active Geology

Author: Hugh Bollinger/Wednesday, May 2, 2018/Categories: natural history, video, space science, environment, adventure

                                    Composite Image Jupiter’s Moon Io, 1997 (credit: Galileo mission)

Jupiter's volcanic moon Io continues providing information on extreme geology. When the Galileo spacecraft arrived at Jupiter in 1995, it wasn't known if volcanoes existed on the moon. During the robot's first flyby of Io, active eruptions were photographed. The Galileo mission ended in 2003 but so much data was gathered about the giant planet and its moons (Io, Europa, Ganymede, and Callisto) that analysis of the information is still in progress. During its flybys, Galileo discovered that Io has hundreds of active volcanoes, mountain ranges the float on continental size land masses, and a surface that is reformed by the lava geysers every million years or so. When New Horizons flew by Jupiter 2007 it used the planet for a course correction to reach the outer planets and took a series of Io photographs as well. The spacecraft captured the same volcano Galileo that had observed and it was still erupting.

  Io Eruption Video Captured by New Horizons, 2007 (credit: NASA/Johns Hopkins University)

Still reviewing all the Galileo data, an exciting new finding was presented last year at a geophysical conference where a type of vulcanism, similar to Italy's Stromboli volcano, was discovered on Io. Using infrared data from Galileo's spectrometer, investigators were able to determine Io's heat radiance. The 'heat signatures' were similar to what has been seen during eruptions on Stromboli where hot lava blasts lava particles high in the air and they cool fast. Such temperature measurements will help determine the composition of Io's lava and rock types. Stromboli is also one of the most active volcanoes on Earth with its own persistent eruptions.

The surface of Io isn't the only geologic feature to constantly fluctuate on the moon. Land-based telescope and spectographic data has revealed Io's sulfur dioxide (SO2) atmosphere completely collapses as snow at -270F when the moon is eclipsed by Jupiter with no warming by the Sun. The atmosphere reforms when the moon returns to full sunlight.

It would be exciting if some future mission to Jupiter might be able to orbit Io for closer measurements. The chances of the spacecraft surviving the extreme environmental conditions that close to Jupiter are low.



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