New imagery of Jupiter’s moon Io, including a flyover
animation of one volcanic area and three-dimensional views of
another, shows a world so volcanically hyperactive that nearly
its entire surface is likely to be lava that’s still in various
stages of cooling.

The images are based on observations made by NASA’s Galileo
spacecraft during flights close to Io in 1999 and 2000, and are
available online from NASA’s Jet Propulsion Laboratory, Pasadena,
Calif., at

and from the University of Arizona’s Planetary Image Research
Laboratory, Tucson, at .

Scientists are studying these images and other Galileo data
for a better understanding of how Io’s mountains form, how much
heat Io generates internally and other questions. The extreme
heat of the lava erupting on Io makes that world today a model
for the type of volcanism Earth experienced billions of years

Galileo has been orbiting Jupiter and its moons since
December 1995. More information about the mission is available
at .

JPL, a division of the California Institute of Technology,
Pasadena, manages Galileo for NASA’s Office of Space Science,
Washington, D.C.