[meteorite-list] Rover Reveals Mars' Watery Past

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon Sep 11 00:11:39 2006
Message-ID: <200609110411.VAA23443_at_zagami.jpl.nasa.gov>

http://www.sgvtribune.com/news/ci_4304814

Rover reveals Mars' watery past
By Elise Kleeman
San Gabriel Valley Tribune
September 8, 2006

PASADENA - The Mars rover Opportunity has found evidence that water once
covered an even larger expanse of the Red Planet than was first known.

Over the past 2 1/2 years, the intrepid robotic explorer has driven over
more than 5 miles of the planet's surface, uncovering signs of the
presence of water everywhere along the way, said Caltech planetary
scientist John Grotzinger.

"There was definitely a phase in the history of Mars when the planet got
wet," Grotzinger said. "By extrapolation, based on orbital data, we
think that the area extends to something at least the size of Oklahoma."

It's been at least 1 billion years - and possibly as many as 4 billion -
since water was freely flowing on Mars, Grotzinger said. Even when it
did, it was about as acidic as vinegar, said Larry Soderblom, a
geologist with the United States Geological Survey.

"The fact that these were acidic environments lowers the probability
that would be likely," he said.

Opportunity is poised for even more impressive findings in the near
future. Next week, the rover will reach the edge of the Victoria crater,
the largest feature it has yet to explore.

A half-mile wide and 230 feet deep, Victoria crater is nearly the size
of Meteor crater in Arizona, Soderblom said, and exposes many more of
the rock layers that record Mars' geologic history.

For now, Opportunity is stopped for a few martian days to study the much
smaller crater Emma Dean, but is only a day's drive away from Victoria
crater, said Al Herrera, the mission manager at the Jet Propulsion
Laboratory.

"It should be a gorgeous view of steep cliffs," Grotzinger said.

After taking in the view, the rover will begin driving around the
crater's edge.

"We have to go to a large extent halfway around the crater to get a good
sense of where it is safest to go down," Herrera said. "That may take us
a while - several weeks if not months."

The sun will delay Opportunity's trip into Victoria even further. For
two weeks in mid-October, it will be between Mars and the Earth,
blocking communications to the rover.

Once the rover does make the descent, however, the planetary scientists
hope to find more clues about how long water existed on Mars' surface.

After the martian winter passes, Opportunity's twin, Spirit, will also
be continuing its investigation. During its exploration on the other
side of the planet, Spirit has only found signs of groundwater, but
perhaps that could change, Grotzinger said.

"Just before winter came, we discovered an outcrop that's the most
exciting outcrop we've seen yet because it has really well-developed
layers," he said. "Any time you see layers, there is always a chance
that you can find evidence of surface water."
Received on Mon 11 Sep 2006 12:11:16 AM PDT