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Mars May be Emerging From an Ice Age



 
 
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Old December 18th 03, 12:01 AM
Ron Baalke
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Default Mars May be Emerging From an Ice Age


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Donald Savage (202) 358-1547
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Guy Webster (818) 354-6278
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Mark Nickel (401) 863-2476
Brown University, Providence, R.I.

RELEASE: 2003-169 December 17, 2003

Mars May be Emerging From an Ice Age

NASA's Mars Global Surveyor and Mars Odyssey missions have provided
evidence of a recent ice age on Mars. In contrast to Earth's ice ages,
a martian ice age waxes when the poles warm up and water vapor is
transported toward lower latitudes. Martian ice ages wane when the
poles cool and lock water into polar icecaps.

The "pacemakers" of ice ages on Mars appear to be much more extreme
than the comparable drivers of climate change on Earth. Variations in
the planet's orbit and tilt produce remarkable changes in the
distribution of water ice from polar regions down to latitudes
equivalent to Houston or Egypt. Researchers, using NASA spacecraft
data and analogies to Earth's Antarctic Dry Valleys, report their
findings in the Thursday, Dec. 18 edition of the journal Nature.

"Of all the solar system planets, Mars has the climate most like that
of Earth. Both are sensitive to small changes in orbital parameters,"
said planetary scientist Dr. James Head of Brown University,
Providence, R.I., lead author of the study. "Now we're seeing that
Mars, like Earth, is in a period between ice ages."

Discoveries on Mars, since 1999, of relatively recent water-carved
gullies, glacier-like flows, regional buried ice and possible snow
packs created excitement among scientists who study Earth and other
planets. Information from the Mars Global Surveyor and Odyssey
missions provided more evidence of an icy recent past.

Head and his co-authors from Brown (Drs. John Mustard and Ralph
Milliken), Boston University (Dr. David Marchant) and Kharkov National
University, Ukraine (Dr. Mikhail Kreslavsky) examined global patterns
of landscape shapes and near-surface water ice mapped by the orbiters.
They concluded that a covering of water ice mixed with dust mantled
the surface of Mars to latitudes as low as 30 degrees, and is now
degrading and retreating. By observing the small number of impact
craters in those features and by backtracking the known patterns of
changes in Mars' orbit and tilt, they estimated the most recent ice
age occurred just 400,000 to 2.1 million years ago, very recent in
geological terms. "These results show that Mars is not a dead planet,
but it undergoes climate changes that are even more pronounced than on
Earth," Head said.

Marchant, a glacial geologist who has spent 17 field seasons in the
Mars-like Antarctic Dry Valleys, said, "These extreme changes on Mars
provide perspective for interpreting what we see on Earth. Landforms
on Mars that appear to be related to climate changes help us calibrate
and understand similar landforms on Earth. Furthermore, the range of
microenvironments in the Antarctic Dry Valleys helps us read the Mars
record."

Mustard said, "The extreme climate changes on Mars are providing us
with predictions we can test with upcoming Mars missions, such as
Europe's Mars Express and NASA's Mars Exploration Rovers. Among the
climate changes that occurred during these extremes is warming of the
poles and partial melting of water at high altitudes. This clearly
broadens the environments in which life might occur on Mars."

According to the researchers, during a martian ice age, polar warming
drives water vapor from polar ice into the atmosphere. The water comes
back to ground at lower latitudes as deposits of frost or snow mixed
generously with dust. This ice-rich mantle, a few meters or yards
thick, smoothes the contours of the land. It locally develops a bumpy
texture at human scales, resembling the surface of a basketball and
also seen in some Antarctic icy terrains. When ice at the top of the
mantling layer sublimes back into the atmosphere, it leaves behind
dust, which forms an insulating layer over remaining ice. On Earth, by
contrast, ice ages are periods of polar cooling. The buildup of ice
sheets draws water from liquid-water oceans, which Mars lacks.

"This exciting new research really shows the mettle of NASA's
'follow-the-water' strategy for studying Mars," said Dr. Jim Garvin,
NASA's lead scientist for Mars exploration. "We hope to continue
pursuing this strategy in January, if the Mars Exploration Rovers land
successfully. Later, the 2005 Mars Reconnaissance Orbiter and 2007
Phoenix near-polar lander will be able to directly follow up on these
astounding findings by Professor Head and his team."

Global Surveyor has been orbiting Mars since 1997, Odyssey since 2001.
NASA's Jet Propulsion Laboratory, a division of the California
Institute of Technology, Pasadena, manages both missions for the NASA
Office of Space Science, Washington, D.C. Information about NASA's
Mars missions is available on the Internet at:

http://mars.jpl.nasa.gov

  #2  
Old December 18th 03, 07:23 PM
I R A Darth Aggie
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Default Mars May be Emerging From an Ice Age

Alternatively, we're causing global warming on Mars, too...

James
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Consulting Minister for Consultants, DNRC
I can please only one person per day. Today is not your day. Tomorrow
isn't looking good, either.
I am BOFH. Resistance is futile. Your network will be assimilated.
 




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