
Landforms indicate 'recent' warm weather on Mars
SCIENCE AND TECHNOLOGY FACILITIES COUNCIL NEWS RELEASE Posted: June 29, 2009

New research led by a UK scientist indicates that Mars had significantly warmer weather in its recent past than previously thought.
The research, funded by the UK's Science and Technology
Facilities Council (STFC) and published in Earth and Planetary Science
Letters, is good news in our quest for life on Mars, as the shorter
the time period since the last warm weather on the planet, the better
the chance that any organisms that may have lived in warmer times are
still alive under the planet's surface.
Dr. Matthew Balme, from The Open University, made the new discovery by
studying detailed images of equatorial landforms that formed by
melting of ice-rich soils. His work indicates that the Martian surface
experienced "freeze thaw" cycles as recently as 2 million years ago,
and that Mars has not been locked in permafrost conditions for
billions of years as had been previously thought.
The high resolution images, which show a variety of interesting
landforms, were taken with NASA's HiRISE (High Resolution Imaging
science Experiment) which is onboard the Mars Reconnaissance Orbiter
(MRO) mission.
Dr. Matthew Balme said, "The features of this terrain were previously
interpreted to be the result of volcanic processes. The amazingly
detailed images from HiRISE show that the features are instead caused
by the expansion and contraction of ice, and by thawing of ice-rich
ground. This all suggests a very different climate to what we see
today."
All of the landforms observed are in an outflow channel, thought to
have been active as recently as 2 million to 8 million years ago.
Since the landforms exist within, and cut across, the pre-existing
features of the channel, this suggests that they too were created
within this timeframe.
The pictures show polygonally patterned surfaces, branched channels,
blocky debris and mound/cone structures. All of these features are
similar to landforms on Earth typical of areas where permafrost
terrain is melting.
Dr. Balme said, "These observations demonstrate not only that there
was ice near the Martian equator in the last few million years, but
also that the ice melted to form liquid water and then refroze. And
this probably happened for many cycles. Given that liquid water seems
to be essential for life, these kinds of environments could be a great
place to look for evidence of past life on Mars."
Professor Keith Mason, CEO of the Science and Technology Facilities
Council (STFC), said, "This new research has revealed more about Mars
and provided fascinating evidence of geological process similar to
Earth. The history of our neighboring planet, and the question of
whether it has ever sustained life, has long fascinated man.
Understanding current processes on the surface of Mars and the past
and present role of climate improves our knowledge of the planet's
history and thus the chances of one day detecting evidence for past or
present life. UK scientists are involved in a number of different Mars
studies, which are helping to paint a full picture of this mysterious
planet."
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