William Atkins
Friday, 19 December 2008 23:06
Science -
Space
Page 2 of 3
Generally, it is thought by scientists that the presence of carbonates in rock is direct evidence for the presence of liquid water (either on Earth or any place else in the Universe).
NASA states,
“Carbonate rocks are created when water and carbon dioxide interact with calcium, iron or magnesium in volcanic rocks. Carbon dioxide from the atmosphere becomes trapped within the rocks. If all of the carbon dioxide locked in Earth's carbonates were released, our atmosphere would be thicker than that of Venus."
It adds,
"Some researchers believe that a thick, carbon dioxide-rich atmosphere kept ancient Mars warm and kept water liquid on its surface long enough to have carved the valley systems observed today.”
Thus, their presence on Mars counters many scientists’ viewpoints that Mars primarily had an acidic environment in his past. With the presence of carbonates on Mars, scientists are now modifying their stance, instead saying that such a discovery indicates the possibility of many different environments in Mars’ distant past.
Scientists contend that with many different environments comes the larger chance that Mars once supported life.
Scientist Scott Murchie (from Johns Hopkins University Applied Physics Laboratory), who is the principal investigator for the CRISM instrument, stated,
"We're excited to have finally found carbonate minerals because they provide more detail about conditions during specific periods of Mars' history,"
The paper containing the conclusions of this study appears in the December 19, 2008 issue of Science magazine. The title of the article is “
Orbital Identification of Carbonate-Bearing Rocks on Mars.”
Its authors are: Bethany L. Ehlmann, John F. Mustard, Scott L. Murchie, Francois Poulet, Janice L. Bishop, Adrian J. Brown, Wendy M. Calvin, Roger N. Clark, David J. Des Marais, Ralph E. Milliken, Leah H. Roach, Ted L. Roush, Gregg A. Swayze, and James J. Wray.
Page three contains excerpts from the scientists' paper.
