Six days from now, on October 16, a unique expedition begins. A team of scientists led by Dr. Nathalie Cabrol and her husband Dr. Edmond Grin take off for Chile to scale Lincancabur, a 5,916 meter (19, 473.5 feet) tall volcano. By comparison, Mt. Whitney, the tallest peak in the Sierra Nevada range is 4,418 meters tall (14,496 feet), almost a mile lower, and Mt. McKinley in Alaska, the tallest peak in North America is only slightly taller than Lincancabur at 6,194 meters (20,320 feet). All of these are topped by another South American volcano, Aconcaqua at 6,960 meters (22,910 feet) in Argentina, the tallest in the Western hemisphere. Any way you look at it, Lincancabur is a long hike up.

The Licancabur volcano located at the boundary of Chile and Bolivia hosts the highest and one of the least explored lakes on Earth. Lincancabur is still warm, and the lake sits in the caldera at its peak. At times, this lake is liquid, at times iced over. As I described in my previous column, Search for Life at the Top of the World, Cabrol, Grin and their crew plan to explore this lake. They are seeking to understand the life that exists there while dreaming of seeking life on Mars. Planetary geologists explore places and conditions on Earth to study life in extreme conditions. They seek sites analogous to Mars. In the case on Lincancabur, the lake environment combines low-oxygen, low atmospheric pressure, and high-UV radiation. Sediments are formed in volcanic material. It is ice-covered most of the year but the bottom water temperature remains above freezing. These conditions make Licancabur a unique analog to ancient Martian lakes. Despite the extreme environment, living organisms are thriving in the lake.

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So can you imagine hiking to the top of a dormant but not dead volcano, hauling along all the necessary equipment, and then diving into the world's highest lake? This is a true true test of the outdoor explorer and planetary geologist. Or, better yet for the less adventurous, you can join the expedition virtually from your classroom or your armchair at the Extreme Environments web site: http://www.extremeenvironment.com

And, you can bring along your children's class on this extreme field trip. Cabrol, Grin and the science support team have joined with Brian Grigsby of the Schrader Planetarium in Redding, California, to create an online virtual field experience. Grigsby is the onsite educator for the expedition, and will be in contact with schools and the public via the internet. He will be linked from the mountains via a computer hooked up to a satellite phone. As the expedition progresses, daily reports and photographs will be posted to the web site. Teachers and students can post individual questions to Grigsby and the team, and answers will be posted back from the field expedition on the Extreme Environment web site for all to read.

What sorts of questions might be asked? As a child, I noticed that it took longer to boil eggs for breakfast while at altitude in the mountains. As you climb higher, water boils at a lower temperature, and it takes longer to cook your food. So, my first question for Grigsby might be "What is the temperature of boiling water on top of Lincancabur?" Or, I might ask about how long they plan to stay at different altitudes on the way up to adjust to the lower amount of oxygen available to breath. Teachers and students can also learn more about these questions with classroom lessons posted at the Extreme Environments web site. Just follow the link to "Teacher Resources."

Adventurers, young and old, are invited to join the virtual expedition to Lincancabur. October 16 through November 8. The expedition is funded by NASA Ames Research Center for science, and by a NASA IDEAS program grant from the Office of Space Sciences for the virtual field trip led by Grigsby in cooperation with the SETI Institute.