Author: Jessica Kloss
Institution: Princeton University
A team of NASA and university scientists have found methane on Mars which shows that the red planet is either geologically or biologically active. Since the carbon and hydrogen compound is typically destroyed quickly in the Martian atmosphere, the team concludes that something on Mars must be actively releasing this methane, refuting previous notions that Mars is a "dead planet."
Of course, the most exciting possible source of methane would be living organisms, but Mars is a difficult place for life. It has so little atmosphere that any organisms on the planet's surface would be exposed to and killed by the Sun's ultraviolet radiation, unlike on Earth, where we are protected by the thicker atmosphere.
However, specialists think that microorganisms could possibly survive beneath the surface of Mars, where they would be protected from these damaging rays. The general opinion among astrobiologists is that if there is life on Mars, it would be here, shielded and far enough down for it to be warm enough for liquid water to exist. In fact, such sub-surface dwellers are known to exist on Earth.
Lead author Michael Mumma, from NASA's Goddard Space Flight Center and lead author of the paper on this discovery says, "It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon. Gases, like methane, accumulated in such underground zones might be released into the atmosphere if pores or fissures open during the warm seasons, connecting the deep zones to the atmosphere at crater walls or canyons."
But underground microorganisms are certainly
not the only explanation for the observed methane levels. Geological processes such as the oxidation of iron could also be a source of Martian methane a chemical reaction possible with a combination of the sub-surface water, carbon dioxide, and the planet's internal heat. Another possibility is that the methane was produced in ancient volcanic eruptions, but remained trapped in "cages" of ice called clathrates, until the cages slowly melted away during the planet's summer months.
"Right now, we do not have enough information to tell whether biology or geology -- or both -- is producing the methane on Mars. But it does tell us the planet is still alive, at least in a geologic sense. It is as if Mars is challenging us, saying, 'hey, find out what this means,' " explains Mumma.
The observations for this study were made with NASA's Infrared Telescope Facility and the W.M. Keck telescope in Hawaii. However, probing for the specific mechanisms involved may be a job best completed on location. As there are currently two operational rovers on the surface of Mars, three observational spacecrafts in orbit around the planet, and several more planned for launch in the next few years, definitive answers are on the way.
Written by: Jess Kloss
Edited by: Jeff Kost (News and Features Editor) and Nira Datta (Professional Reviewer)
Published by: Hoi See Tsao