Over spring break, 18 Cornell students traveled to Mars -- well, almost. For planetary scientists, Arizona is the next best thing.

Meteor Crater in northern Arizona certainly looks like it could be on the surface of another planet. The same impact processes that created this 550-foot-deep hole in the desert have been occurring on every other planet since the formation of the solar system. Meteor Crater is, essentially, a giant natural laboratory, 4,000 feet across, for planetary science.

That's why Jim Bell, Cornell associate professor of astronomy, thought it was so important to take his Planetary Surface Processes class there; it was, in fact, the first time the astronomy department has ever led such a field excursion, and it is part of the department's vision to reform its planetary science program, Bell said.

He led both graduate and undergraduate students from astronomy, geology, engineering and other fields on a tour of northern Arizona, March 17-24, where they studied the same geologic features seen on Mars, the moon and other parts of the solar system. Local geology experts from the U.S. Geological Survey (USGS) and Arizona State University accompanied students to the Grand Canyon, Meteor Crater and various volcanoes.

"Before this course, there was no way to give planetary science students experience with the 'real world' of geology," Bell said. "We can now give students specific field experience with the types of processes and features they are encountering in data from the Mars Exploration Rovers and other spacecraft." That's a subject that Bell understands intimately: He is the leader of the Pancam color camera team for NASA's Mars Rover mission.

Standing at the edge of the Grand Canyon, USGS geologist Ivo Lucchitta lectured to the class about the erosion processes that carved it, the same processes that have sculpted landscapes on Mars. At Red Mountain, students hiked into the exposed side of a cinder cone, where Bell challenged them to interpret how it formed and how it might differ on other planets.

For many students the highlight was Lava River Cave, where they crawled 1.5 miles through an underground lava tube (similar to lava tubes seen on the moon), studying its walls to learn how the lava flowed and cooled.

"What an amazing trip," said Briony Horgan, graduate student in astronomy. "Some students spend their entire grad school careers studying rocks on other planets without ever touching a rock themselves. It's important to get out into the field and actually understand what's going on."

Funding for this year's trip was provided by the geology department, the College of Arts and Sciences (Office of the Vice Provost for Undergraduate Education) and by a donation from Ed Hewitt '54, B.M.E. '55, a longtime supporter of science education at Cornell and a retired nuclear engineer who once designed reactors for submarines and power plants.

Graduate student Melissa Rice is a writer intern at the Cornell Chronicle.