Illustration credit: Robert McCall
Peter Smith feels pretty certain we’ll be finding life on Mars within the next decade.
Smith, the University of Arizona professor who led NASA’s Phoenix Mars Mission, made his predictions to a spellbound audience during a lecture at the University of Delaware earlier this month, and he discussed his ideas by phone on Thursday. He carries a “sense of optimism” about finding life on Mars, he said, because of the tantalizing clues Phoenix sent to Earth.
“Finding life on Mars would be one of the great discoveries of all time,” he said. “We’re not that far away. The next mission could be the one.”
Phoenix launched in August of 2007 and spent five months in one spot, controlled by Smith and his Tucson-based crew who directed it to dig and analyze soil samples from an area about the size of a couch.
Mars’ closest corollary on Earth is the Dry Valleys of Antarctica, Smith said. Although no life was discovered on Mars by Phoenix, tiny organisms inhabit the soils of Antarctica’s Dry Valleys, including a predatory nematode about a sixteenth of an inch long.
“Phoenix got me excited because it’s really the next step beyond the Dry Valleys of Antarctica. In the coldest places in the Dry Valleys … nobody thought anything would live there.”
Last week, scientists announced the discovery of a biological community living in dark, oxygen-deprived briny pool beneath a glacier near Dry Valleys.
“The idea is on Mars, it’s probably much too cold right now, but in the recent past, the climate has been different,” he said. “It might have been closer to the Dry Valleys during those times. We’re looking at a situation where this may be a periodically habitable zone.”
Some of the Phoenix team members believe liquid water was photographed on the lander’s legs, but Smith isn’t one of them. Still, he admits that Phoenix sent back hints of life that have him on the edge of his seat.
“Martian soil is really sticky and clumpy,” Smith said, noting that the probe would get a scoop of soil to pour into its ovens for chemistry experiments, but it would take four days of shaking to get the soil through the screens.
“Many times it takes liquid water to make the soils clumpy like that,” he said, adding the clumpiness could be a result of electrostatic forces.
Phoenix found calcium carbonate in the Martian soil, which typically requires liquid water in its formation process. It saw clouds and falling snow.
Another experiment, the HiRise camera aboard the Mars Reconnaissance Orbiter, spotted near-surface ice as far as 40 degrees latitude, “whereas we thought it was cutting off around 60 degrees,” he said.
And Smith pointed out the recent discovery of methane on Mars. “Where in the heck does methane come from?” he mused. “On Earth, it’s linked with biological functions.”
Besides active volcanoes — which are not known to exist on Mars — another terrestrial source of methane is a mineralization process that happens at tectonic plate boundaries. But he said that doesn’t match what we know about Martian geology either.
On the other hand, “If you had fractures in the soil, and the fractures went down to a wet environment, you could have a biological community down there,” Smith said.
The Phoenix mission was a collaboration of numerous agencies and academic institutions besides the University of Arizona, including NASA’s Jet Propulsion Laboratory in Pasadena, California, Lockheed Martin Space Systems in Denver and scientific institutes in Canada, Denmark, Finland, Germany, and Switzerland.
The mission outlasted its expected time limits by several months, but went into a possibly permanent “Sleeping Beauty” mode when Martian winter hit. It won’t awaken until October if it awakens at all.
Smith said the next mission, the Mars Science Laboratory, will include a large rover the size of a MINI-Cooper, with big tires, that would last at least five years and land near an area of high interest, such as the edge of a canyon.
“I think the next decade is a very active time for searching for signatures on Mars,” he said, “and my personal belief is we’ll find them.”
Sources: Eurekalert and an interview with Peter Smith