We may not know yet whether life exists on Mars, but we do know that the Red Planet is alive.
At a NASA news conference this afternoon, a team of scientists led by Michael Mumma of the Goddard Space Flight Center announced the discovery of plumes of methane emanating from the surface of Mars during the planet's late spring and early summer. Methane is a key component of natural gas, and much of the Earth's supply of the chemical comes from organisms that release it as they digest nutrients. But the five scientists were cautious to avoid claiming the methane spouts as evidence of life, saying that geologic activity could also put pressure on the methane and blast it through cracks in the surface. Either way, Mumma said, the plumes show that Mars is not merely a dead planet that once may have hosted life or liquid water. "We are entering a new era," he said. "Now we're looking at an active Mars."
The team first began this research in 1999, and its biggest methane find came in 2003 using the Keck Observatory in Hawaii. The scientists identified multiple plumes, one of which spewed 19,000 metric tons of methane, according to Geronimo Villanueva. They analyzed the spectral data for years, and yesterday finally published their findings in the journal Science.
Though the exact origins of the methane still aren't clear, the plumes hold promising signs for those hoping that they reflect life on the Red Planet, according to Lisa Pratt of Indiana University, the team's resident life scientist. "It could be the exhaled breath of a microbial community," she said today. The only places on Earth where similar methane plumes exist are where the Earth's exposed mantle meets water at a geological fracture. Since there is no evidence of those features on Mars, she said, that could cast doubt on the theory that the methane plumes are geological. However, she sought to contain her own excitement. "As a life scientist, I would love to say that it's biology," she said—but without more evidence, it's impossible to know for sure.
The only way to learn more about these plumes may be to go and physically investigate them, she said. Observing them from Earth—or even from Mars orbit—probably won't reveal whether there are microbes beneath the surface. "We're going to have to get down where they live," she said. The Mars Science Laboratory, a new rover set to launch in 2011, carries instruments that could investigate below the planet's surface—but most likely not deep enough. If microbes do exist on Mars, Mumma said, they could be buried more than a kilometer down. That would require a whole new plan, including technology that doesn't yet exist.
Whether it is life or geology stirring up martian methane, the findings confirm that it is a fascinating time to look closely at the Red Planet. "Our strategy is to pursue both [possibilities]," Mumma said. He was mum, however, when asked how the methane plumes varied over other seasons besides late spring, saying only that the team had more information that it planned to release soon but couldn't talk about now. PM will continue to follow the news and keep you posted. —Andrew MosemanEARLIER: Phoenix Mission Discovers Water on Mars