By
Jeremy Duda
Arizona Daily Wildcat
Galileo spacecraft snaps photos of peculiar volcanoes
The University of Arizona's Lunar and Planetary Laboratories have finished processing new images of Io, a moon of Jupiter.
The images obtained by NASA's Galileo spacecraft were sent back to Earth in the fall. They revealed constant volcanic activity and scores of mountains - the highest measuring about 17 kilometers - caused by that activity.
"The mountains have been puzzling. Why are these tall mountains on Io?" said Alfred McEwen, a UA planetary sciences associate professor.
McEwen is the head of the group from the Lunar and Planetary Laboratories that has been analyzing and processing the images sent back by Galileo for four years. These images have provided information about temperature, landscape and eruption rates for volcanoes on Io.
Galileo has been in orbit around Jupiter since 1995. Since then it has completed 28 revolutions of Jupiter, including four encounters with Io. Each revolution of the planet supplies about 170 photos, said Michael Belton, head of the Galileo Solid State Imaging Team.
The team is responsible for deciding what the satellite photographs. The 25 members of the team often debate on which features of Jupiter - including its moons - merit photographs.
"My role as the leader of the team is to decide what gets done based on these arguments," Belton said.
His company, Belton Space Exploration Initiatives, is under a contract with NASA to oversee missions like the Galileo expedition.
The images sent back from Galileo give a good impression of what Earth's surface was like about four billion years ago, McEwen said. The constant volcanic activity on Io is similar to prehistoric Earth, before the surface cooled.
"We haven't seen such eruptions on Earth, so we're getting to see them in real time," McEwen said.
The Lunar and Planetary Laboratories crew has gained new insight about the nearly 300 active volcanoes on Io, including the eruption rate for the longest active lava flow known in the solar system, and the surface temperature on Io, which ranges from nearly 2,800 degrees Fahrenheit to 280 degrees below zero. Plumes of smoke and ash from these volcanoes reach heights up to 100 kilometers.
Galileo is scheduled to crash onto the surface of Jupiter in early 2003, by which time it will have made three more passes of Io, McEwen said.
