Martian methane discovery fuels speculation

16 Jan 2009

A team encompassing NASA and university scientists has detected the first definitive conclusive detection of methane gas in Mars’ atmosphere last thursday, indicating that the planet is either biologically or geologically active.

Using the NASA’s Infrared Telescope Facility and the W.M. Keck telescope — both at Mauna Kea, Hawaii – the team observed the planet via many Mars years and detected the methane gas.

The team used spectrometers on the telescopes to disperse the light into its component colors, just as a prism distributes white light into a rainbow. Via this method, they discovered three spectral features called absorption lines that, coupled together, are a definitive signature of methane.

“Methane is quickly destroyed in the Martian atmosphere in a variety of ways, so our discovery of substantial plumes of methane in the northern hemisphere of Mars in 2003 indicates some ongoing process is releasing the gas,” said Michael Mumma of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“At northern mid-summer, methane is released at a rate comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, California.”

Mumma himself is lead author of a paper describing this research that will appear in Science Express next week.

“Right now, we do not have enough information to tell whether biology or geology — or both — is producing the methane on Mars,” Mumma said.




“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’.”

If microscopic Martian life is indeed producing the methane, more than likely it resides far below the surface where it is warm enough for liquid water to exist.

“On Earth, microorganisms thrive about 1.2 to 1.9 miles beneath the Witwatersrand basin of South Africa, where natural radioactivity splits water molecules into molecular hydrogen and oxygen,” Mumma said.

“The organisms use the hydrogen for energy. 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.”

According to NASA, the possibility exists that a geologic process produced the Martian methane, either now or eons ago.

On Earth, the conversion of iron oxide into the serpentine group of minerals creates methane, and on Mars this process could involve using water, carbon dioxide and the planet’s internal heat.

“We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tonnes of methane,” said co-author Geronimo Villanueva of the Catholic University of America in Washington.

“The plumes were emitted during the warmer seasons, spring and summer, perhaps because ice blocking cracks and fissures vaporized, allowing methane to seep into the Martian air.”

According to the team, the plumes were seen over areas that show evidence of ancient ground ice or flowing water.

However, It will take future missions, such as NASA’s Mars Science Laboratory, to discover the origin of the Martian methane.

The research was funded by the planetary astronomy program at NASA headquarters in Washington and the Astrobiology Institute at NASA’s Ames Research Center in Moffett Field, California.

The University of Hawaii manages NASA’s Infrared Telescope Facility.


By Carmel Doyle


Caption for prism photo: Conceptual animation demonstrating the process of spectroscopy and how it was applied to the discovery of methane in Mars’ atmosphere. Credit: Chris Smith/NASA

Carmel Doyle was a long-time reporter with Silicon Republic