An experiment designed by the Arkansas-Oklahoma
Center for Space and Planetary Sciences, now in place on the polar
plateau of Antarctica, may help interpret the recent history of Mars.

The experiment, built by professors Derek Sears and Paul Benoit,
University of Arkansas, and Stephen McKeever, Oklahoma State University,
is designed to measure the ability of ice to stop high-energy “cosmic
rays,” or protons traveling at high speeds. Cosmic rays occur in outer
space, and penetrate the atmospheres of Earth and Mars. Rocks and soil
stop cosmic rays as the protons crash into the atoms in the solids,
releasing energy and storing some of that energy within the soil and
rocks as luminescence. Researchers can measure this luminescence and
determine the age of the object in question.

Up until now there has been little interest in gathering luminescence
data for ice — researchers usually use the technique to date pots
and campfires in archaeology or to determine radiation exposure in
laboratories. However, as scientists have learned more about the polar
ice caps on Mars, their interest in dating ice has blossomed.

Antarctica provides an ideal environment for the luminescence experiment
due to the presence of old, dense ice far from rock outcrops that could
produce radiation. Antarctic ice, which flows at a slow rate, makes an
Earth-based “lab” site that most closely resembles the polar ice caps
found on Mars.

The experiment is part of a larger effort to produce a spacecraft
instrument, called ODIN, to study the polar ice caps of Mars. The
instrument used in Antarctica will date how long ice deposits have
been stable by measuring the amount of radiation exposure they have
experienced.

“The Antarctic case is really just a test case for Mars — if we can
work successfully with Antarctic ice, Mars shouldn’t prove any more
difficult,” Benoit said.

The experiment was placed 1.5 meters into the ice near the Meteorite
Hills on Dec.10, 2001, by a field party lead by Ralph Harvey from the
Antarctic Search for Meteorites (ANSMET), sponsored by the National
Science Foundation, and will return home with the expedition in early
February.

IMAGE CAPTION:

[http://pigtrail.uark.edu/news/2002/JAN02/chabot.jpg (103KB)]
Dr. Nancy Chabot of Case Western Researve University with the Arkansas-
Oklahoma Center for Space and Planetary Sciences radiation dosimetry
experiment near the Darwin Glacier, Antarctica.