Methane points
to a lively Mars

By Leonard David

Senior space writer

updated 11:44 a.m. ET April 20, 2005

BOULDER, Colo. - Evidence for intense local enhancements in methane on Mars has been bolstered by ground-based observations. The methane, as well as water on Mars, was detected using state-of-the-art infrared spectrometers stationed atop Mauna Kea, Hawaii, and in Cerro Pachón, Chile.

Scientific teams around the globe are on the trail of methane seeping out of Mars. And for good reason: The methane could be the result of biological processes. It could also be an "abiotic" geochemical process, however, or the result of volcanic or hydrothermal activity on the Red Planet.

Many types of microbes here on Earth produce a signature of methane. Indeed, the tiny fraction of atmospheric carbon found as methane on our planet is churned out almost entirely biologically, with only a very small contribution from abiotic processes, scientists say.

Lingering methane
New information on Mars methane was acquired using NASA’s Infrared Telescope Facility atop Mauna Kea, Hawaii, as well as from the Gemini South telescope sitting on a mountain in the Chilean Andes.

Michael Mumma, a lead investigator at the Center for Astrobiology and Solar System Exploration Division at the NASA Goddard Space Flight Center in Greenbelt, Md., presented the findings during the biennial meeting of the NASA Astrobiology Institute, held here April 10-14 and hosted by the University of Colorado at Boulder.

Mumma and his research colleagues have used ground-based spectrometers to carry out a simultaneous search for methane and water vapor. "Pronounced enhancements" of methane have been detected over several equatorial regions on Mars, consistent with "enhanced local release," Mumma reported.

In scientific terms, the methane line detected is "very strong indeed," Mumma noted. Using the high-tech infrared spectrometers, spectra of six narrow longitudinal bands across the face of Mars were taken. Such spectra involve analyses of light broken into its rainbow of colors.

"Every one of these longitudes shows a very substantial enhancement in the equatorial zone," Mumma explained. "So this is a very intense source of methane on Mars in this region. It also requires a very rapid decay of methane … more rapid than photochemistry would allow."

On Mars, the photochemical lifetime of methane is very short — roughly 300 years. Therefore, any methane now lingering within the Martian atmosphere must have been released recently.

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