Thirsty? Hot? Take a Trip to Mars
Scientists find plenty of water on the cold, cold clime of Mars in the form of a huge sea of ice. Does that mean life really exists there?
WASHINGTON -- A huge sea of ice lies just under the surface of Mars, ready to be tapped by future explorers as a source of fuel and maybe even drinking water, scientists report.
It might also harbor life, and certainly explains where some of the water went when Mars went from being a warm and wet place to the cold, dry desert it is now, the researchers report in this week's issue of the journal Science.
"It turns out it is really quite a bit more ice than I think most people ever really expected," William Boynton of the University of Arizona, who led one of the studies being published this week, said in a telephone interview.
"What we are seeing is there is a layer of ice just a little beneath the surface. It is maybe a meter (three feet) beneath the surface."
He said the quantity seen compares to the amount of water in Lake Michigan, one of the Great Lakes between Canada and the United States.
Scientists studying Mars have been looking for water for a number of reasons. For one, life as we know it requires water, and anyone who wants to spend any time on the planet would need water to drink and to use as a source of hydrogen for fuel.
"The amount of water present on Mars is sufficiently large that it can support future human exploration activities," said Bill Feldman of the Department of Energy's Los Alamos National Laboratory, who helped direct the research.
"We see it is ... a big, huge whopping jumble of soil and ice," NASA's Jim Garvin said. "It's a lot of stuff and it was found in a way that was not totally expected and it bodes well for Mars offering us more goodies as we go into the ground."
Scientists are also fascinated by what the finding means for understanding the weather and geology of Mars.
Mars seems to have once had water on the surface -- lots of it. There are deep canyons, one deeper and wider than anything on Earth, and places that look like dried-up lakes or seabeds.
The surface is now dry and dusty and the ice that covers the poles is frozen carbon dioxide. With average surface temperatures of -63 degrees F (-53 C), and a thin atmosphere, there is little hope of finding water at the surface.
But NASA has used a range of instruments to see if water is there and if so, if it is easy to get at.
Evidence has been seen in photographs of seeping water, and the orbiting Odyssey spacecraft was directed to look for chemical evidence of water, which should be recognizable because of its high hydrogen content.
Hydrogen quickly combines with other elements, so if it is found on a cold planet, it is very likely to have teamed up with oxygen to form water.
Odyssey looked at the ways gamma and neutron rays interacted with particles on the planet and indeed found strong evidence of hydrogen just under the surface.
The regions examined extend from the south pole of Mars to about 45 degrees latitude. "It's kind of equivalent to the latitude of Paris," Boynton said.
"It's very close to the surface and so the astronauts could get at it easily," he added. "Some people were talking about getting some complicated devices that would extract water from soil if there was only 1 to 2 percent water, and you'd have to heat it to high temperatures to get it out."
But this water is so plentiful it would only have to be heated to 33 degrees F (just above 0 degrees C) to be usable.
Garvin said astronauts would not drink it -- at least not right away. "If Martian microbes are sitting there waiting to bloom, the last thing we would want is a war of the worlds waiting to blow up in our bellies," he said.
Scientists from across the United States joined up with Russian and French teams to analyze Odyssey's data. It will take much more work to confirm that the substance found on Mars really is frozen water. But the experts seem convinced.
"The subsurface ice detected by the Odyssey instruments represents only the tip of an iceberg frozen under ground," Jim Bell of Cornell University, wrote in a commentary in Science.
Spacecraft sent to Mars in the 1970s probably missed the ice by just a few inches, Boyton said.
"The interesting thing is, it looks like the Viking 2 lander actually landed in a region that we think probably had the same ice beneath it," he said.
"If they could have dug down a meter deep instead of 10 to 20 cm they could have found this ice. Isn't that interesting? They were probably right on top of it all the time and never had the slightest idea it was there."