5 July 1998

Solar System's Hottest Surfaces Discovered On Jupiter's Moon

Hundreds of millions of miles from the Sun, volcanoes on Jupiter's moon Io sizzle at the highest recorded surface temperatures of any planetary body in the solar system. Such is the finding of scientists from the University of Arizona, Brown University and five other institutions, reported in the cover story of the July 3 issue of Science.

The report provides an important clue to understanding the geophysical processes within Io, which may be similar to the early stages in the evolution of Earth, Venus and other planetary bodies.

"The very hot lavas erupting on Io are hotter than anything that has erupted on earth for billions of years," says lead author Alfred McEwen, director of the Planetary Image Research Lab at the University of Arizona. "They are the highest surface temperatures in the solar system other than the Sun itself."

At least twelve different vents on Io spew lava at temperatures greater than 2200 degrees Fahrenheit. One volcanic vent may be as hot as 3100 degrees Fahrenheit - about three times hotter than the hottest sunlit surface of Mercury, the closest planet to the Sun. The surface temperatures on Io, which is 1245 million miles from the Sun, stay well below freezing (minus 243 degrees Fahrenheit) except for the volcanic hot spots.

Image � Science