Researchers find evidence of water on the red planet

Researchers working on the Phoenix Mars Mission say they've found evidence that liquid water exists on the red planet, though some mission scientists remain skeptical of the conclusion.
If true, the theory would significantly expand scientific understanding of Mars and strengthen the possibility of the existence of life on the planet.
While the Phoenix mission scientifically proved that Mars contains ice, researchers continue to debate whether the planet has conditions that could support liquid water.
Central to the theory, which will be presented in a research paper at a national conference later this month, are a series of photographs taken by Phoenix and research on the role salts can play in freezing water.
A number of photographs of one of the lander's legs show what appears to be several small globs of material moving toward one another and eventually merging.
The photos suggest that liquid water was moving along the lander's leg and pooling, said Nilton Renno, a member of the Phoenix Mars Mission team and lead author on the research paper.
"The most convincing evidence are two of these large droplets, which become darker and partially disappear," said Renno, a professor with the University of Michigan. "That would only happen if it were a liquid."
The water was able to stay in liquid form because of high concentrations of salt, which lowered the water's freezing point significantly, Renno said.
By lowering the freezing point - in a process similar to adding anti-freeze to a vehicle's coolant system - the water was able to remain liquid at temperatures that dipped to an average of about 176 degrees below zero Fahrenheit (80 degrees below zero Celsius).
Renno said the paper, which is co-authored by nearly two dozen other researchers, has received warm reviews from independent scientists, with the greatest skepticism coming from fellow Phoenix team members.
Peter Smith, the University of Arizona scientist who led the mission and co-authored the paper, said the appearance of the globs on the legs is strange but he stopped short of endorsing Renno's theory.
Smith said the images may show remnants of fuel used by the lander's thrusters when it touched down on Mars over Memorial Day weekend.
"They do things that are kind of odd, but I don't know what they might be," he said. "But there is a chance that it is true."
Renno said that he doesn't believe extra fuel was present, as experiments conducted by Phoenix and in labs on Earth didn't find evidence of the material.
Another member of the Phoenix team, Michael Hecht, is concerned that the photographs of the lander's leg don't provide enough detail. There also are potential problems with some of the modeling done for the paper, he said.
Instead of the objects being liquid water, it's likely that they are frost, Hecht said.
However Hecht, a physicist at NASA's Jet Propulsion Laboratory, said he wasn't discounting the theory entirely and that the disagreements are a part of the scientific process.
Renno said he welcomed the discussion but added that he is confident in his theory because work in the laboratory confirmed that liquid water could exist at the temperatures seen on Mars.
Despite their differences, both Renno and Hecht agreed that the research has brought increased scientific attention to the possibility that salt-rich liquid water could exist on Mars.
"We have really injected new life into that line of argument - we have found the smoking gun," Hecht said. "I think everyone has to go back and re-examine all the arguments put forward up to this point."
E-mail Aaron Mackey at amackey(at)azstarnet.com

(Distributed by Scripps Howard News Service, www.scrippsnews.com.)
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