Thursday, February 18, 2010

Cottonwood Students Learn About Mars

By John Larson

SOCORRO – Students of Cottonwood Valley Charter School learned that there was evidence of underground water in large aquifers on the planet Mars. Scientist Bill Feldman gave the talk to the Charter school’s fourth through eighth graders Friday, Feb. 5, at the County Annex meeting room.
Using close-up photographs of the planet’s surface, Feldman said, “evidence shows that Mars once had large oceans. The question we have to ask is, where did all that water go?”
“There must have been liquid water at one time because certain features on Mars shows mass wasting,” he said. “A lot of soil that is missing.”
Feldman, Senior Scientist at the Planetary Science Institute in Tucson, has had a long and distinguished career in the scientific community. Formerly with Los Alamos National Laboratory, Feldman was the principal investigator of the neutron spectrometer on the 2001 Mars Odyssey mission.
At PSI, Feldman and his team use satellite images of geographical features on Earth to interpret what is seen on the surface of the red planet.
“Look at the color of big rivers running on the Earth. The water is brown,” he said. “Running water can hold a certain amount of soil in it.

“On Mars you have these huge canyons. They are cut deep, cut wide. All that soil has gone somewhere,” Feldman said. “And how much water was needed to carry that huge amount?”
He said current thought is that under the surface is a global aquifer.
“We have only been able to dig down a half foot, which is nothing, really. We need to go down a couple of hundred feet,” he said.
Another indication is the makeup of Mars’ polar ice cap.
“What we can sense from the outside is only a fraction of what's below the surface of the ice on the poles,” he said. “It only accounts for five percent of what we think we see on Mars at any one time.”
Scientists are also continuing to look at deep craters for evidence of water ice.
“We have to land in these deep places, and then see if we can look in detail at the sides of these craters to see if there’s water coming from them,” Feldman said.
The problem to solve, he said, was how to ascertain the presence of water, and then how to measure it. There is evidence that any aquifers may start about 750 feet below the surface.
“People come up with a lot of ideas. There’s a lot of creative thinking,” Feldman said. “One was to have a balloon close to a canyon wall that rises in the day and falls at night. There would be cameras mounted under it that could take close up pictures of the canyon walls where there was evidence of water streaks.”
Another was to get to bottom of glaciers with heaters on, say, the polar ice cap, and have it melt its way to the bottom,” he said.
After the talk, students were able to get an up close look at the neutron measuring instruments Feldman helped to design; one was attached to the LCROSS project that slammed into the Moon, and another that’s currently on its way to study the surface of Mercury.

Pictured: Students from Cottonwood Valley Charter School examine instruments used to measure the amount of water on the Moon and Mercury. Bill Feldman of the Planetary Science Institute gave a presentation to fourth through eighth graders, sponsored by Karen Gram’s Fifth Grade Science Program.

Photo byh John Larson
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