From Earth to Mars: Structure of CO2 Crystals Helps
Interplanetary StudiesBy Hank Becker
Discoveries by Agricultural
Research Service scientists may affect future Mars missions to study the
Red Planet's polar ice caps.
P. Wergin and botanist Eric F. Erbe at ARS'
Laboratory in Beltsville, Md., developed the first technique for viewing
and photographing carbon dioxide crystals using a scanning electron microscope
or SEM. SEM images are formed by electrons that pass through a magnetic field.
The field serves as a "lens." The images can be displayed on a cathode ray tube
similar to a TV screen and recorded.
Frozen CO2 makes up most of the Martian polar ice caps. Earth and
Mars are the only two planets in our solar system with polar ice caps that
expand and contract in response to changing seasons. These facts have made the
Beltsville scientists' research of great interest to their colleagues "next
door" in nearby Greenbelt, Md., at Goddard
Space Flight Center of the National
Aeronautics and Space Administration.
ARS and NASA scientists are cooperating to adapt SEM technology to
studies of the Martian surface. Goddard collaborators include climatologist
James L. Foster, physicist Al T. C. Chang and hydrologist Dorothy K. Hall at
NASA's Laboratory of Hydrospheric Processes, and geologist J. Barton of General
NASA scientists say SEM technology, together with modeling studies
and experiments using microwave radiometers, may enable them to assess for the
first time the thickness of the seasonal Martian ice caps. On Mars, as on
Earth, ice plays an important role in large-scale climate processes.
ARS is the research arm of the U.S.
Department of Agriculture. A story about the SEM project appears in the
October issue of ARS' Agricultural Research magazine. The story also is
Scientific contact: William P. Wergin, ARS Nematology
Laboratory, Beltsville Agricultural Research Center, Beltsville, Md., (301)
504-9027, fax (301) 504-8923, firstname.lastname@example.org.