Washington: It has long been believed that
Mars' surface is too oxidised for life to survive. But, a new
study has now claimed that the soil on the Red Planet may be
less inhospitable than than previously thought.
Scientists believe that the Martian surface is packed
full of oxidising compounds, which could make it difficult for
complex molecules like organic chemicals -- the building
blocks of life as we know it -- to exist.
But the new study, which analysed data gathered by NASA's
Mars Phoenix Lander, suggested that is actually not the case.
"Although there may be some small amounts of oxidants in
the soil, the bulk material is actually quite benign," said
lead study author Richard Quinn of NASA's Ames Research Center
and the SETI Institute in Mountain View, California.
"It's very similar to moderate soils that we find on
Earth," Quinn was quoted as saying.
NASA's USD 420 million Phoenix lander, which touched down
near the Martian north pole in late May 2008, had done a
number of observations and interesting soil measurements using
its onboard wet chemistry laboratory (WCL). One of those was
the Mars dirt's acidity, or pH, level.
Quinn and his team studied the Phoenix data, focusing on
measurements of Martian soils' oxidation-reduction potential.
Oxidation refers to the stripping away of electrons. It's
a destructive process that can tear up complex molecules like
DNA, which is why people need antioxidants as diet.
Scientists had reason to think that Martian soil might be
highly oxidising, Quinn said. In the mid-1970s, NASA's Viking
landers mixed some organic compounds into Martian dirt, and
the chemicals appeared to decompose.
But the new results, reported in the journal Geophysical
Research Letters, paint a rosier picture of Red Planet soil as
far as habitability is concerned.
"When you look at the composite of all the material in
there, and you measure the overall reactivity of that soil in
solution, it's comparable to what you would find in
terrestrial soils, Earth soils," Quinn said. "So it's not an
extreme environment in that regard."
The results don't prove that Martian life exists or ever
However, they and other finding -- including evidence
from the High Resolution Imaging Science Experiment (HiRISE)
camera aboard NASA's Mars Reconnaissance Orbiter that liquid
water may have flowed just beneath the Martian surface in the
last year or so -- are making scientists more and more
hopeful, Quinn said.
"The evidence from the HiRISE team that there may be
seasonal water flow at some locations, combined with this
measurement that shows that when the soil is wetted it's
actually not harsh conditions -- it's very positive in terms
of the potential for life to get a foothold," he said.
First Published: Wednesday, August 24, 2011, 16:42