BY STEPHANIE STEINBERG
Daily Staff Reporter
Published April 1, 2009
Mars may be one step closer to sustaining life.
Nilton Renno, professor of Atmospheric, Oceanic and Space Sciences and co-investigator of the Phoenix Mars Mission, along with a group of University of Michigan scientists have recently discovered the presence of liquid salt water on Mars — a new discovery given that water was heretofore only believed to be on the red planet in the form of ice and water vapor.
The discovery was made from images taken by NASA’s Mars Phoenix Lander — a spacecraft that landed on May 25, 2008.
Liquid water is the essential ingredient for life, and while no organisms have been found on Mars, the evidence of liquid water is a major scientific discovery.
“This is the first time that liquid water has been seen anywhere outside our own planet,” Renno said.
Manish Mehta, a graduate student in the department of Atmospheric, Oceanic and Space Sciences, worked with Renno on the mission. Mehta performed experiments to determine the amount of soil Phoenix was going to lift from Mars’ surface upon landing.
From his investigation, Mehta found Phoenix would remove Mars’ topsoil and expose a deeper layer of the planet’s surface. This would melt any ice on the topsoil, causing the mixture of soil and melted ice to splash around the lander.
Renno said after Phoenix landed the team started taking images from under the lander to figure out if the spacecraft removed the soil like Mehta had suggested.
And it did.
“It was a huge surprise,” Renno said. “That was one of the great moments of the mission to find out the ice was completely exposed under the lander.”
After analyzing images from the lander, the researchers noticed one of the lander’s legs contained moving particles.
Renno said the particles “looked very strange” when he first saw the image.
“It looked like something had splashed there,” he said. “We started taking images as soon as we could to monitor what was going on. And then to my surprise, after three images, I noticed that some of those particles were growing.”
The researchers then took more images, which showed some of the particles were not only growing, but moving as well. Renno said this was surprising because particles only move if they are in a liquid state.
Because scientists previously believed water only existed on Mars in the form of ice or water vapor, Renno was doubtful the particles were moving in liquid.
He said he thought liquid water could not exist on Mars because the planet’s cold temperatures would cause the liquid to freeze.
After monitoring the lander a few more days, Renno hypothesized that salt in Mars’ soil prohibited some areas of the planet’s surface from freezing, allowing water to exist in a liquid state.
When Phoenix returned to Earth Nov. 10, 2008, researchers analyzed the soil collected from the lander.
What they discovered proved Renno’s hypothesis correct.
“We found out that the soil had lots of perchlorate — that are very powerful anti-freeze (salts),” Renno said. “We found out we could have liquid saline water at a temperature even lower than we had described.”
The perchlorate salts found in Mars’ soil freeze in temperatures of -90 to -105 degrees Fahrenheit. The average temperature where Phoenix landed was -75 degrees Fahrenheit, proving the salts kept the water from freezing.
This discovery has led some scientists to believe liquid water may exist in other areas on Mars’ surface and has spurred NASA to further investigate the presence of water on the planet.
Despite the breakthrough discovery, some researchers are hesitant to say that the saltwater found on Mars directly indicates the possibility of life there.
Jasper Kok, graduate student in the department of Atmospheric, Oceanic and Space Sciences, contributed to the discovery by calculating the size and growth rate of the particles on Phoenix’s leg.
He said he does not believe the finding proves life can exist on Mars even though “liquid water is tied to life.”
“(Mars) has such a high salt content that the implications for life might make it difficult,” he said.