Sunday, January 18, 2009
Methane On Mars – Tracks Of Life?
Methane atmospheric abundance spectrometry overlay on Martian surface. Image Credit: NASA
Methane On Mars – Tracks Of Life?
NASA has issued a press release describing the detection of methane gas on Mars and how this may be evidence of life on the red planet.
NASA cautions, "Right now, we do not have enough information to tell whether biology or geology -- or both -- is producing the methane on Mars," said Michael Mumma of NASA's Goddard Space Flight Center in Greenbelt, Md.. "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 producing the methane, it likely resides far below the surface where it is warm enough for liquid water to exist. Liquid water is necessary for all known forms of life, as are energy sources and a supply of carbon.
The process of how the methane gas was detected is in itself a good story.
Conceptual animation demonstrating the process of spectroscopy and how it was applied to the discovery of methane in Mars’ atmosphere (click photo). Image Credit: Chris Smith/NASA
This excerpted and edited from the National Aeronautics and Space Administration –
Discovery of Methane Reveals Mars Is Not a Dead Planet
By: Dwayne Brown - NASA, Nancy Neal-Jones, and Bill Steigerwald of the Goddard Space Flight Center - Jan. 15, 2009
WASHINGTON -- A team of NASA and university scientists has achieved the first definitive detection of methane in the atmosphere of Mars. This discovery indicates the planet is either biologically or geologically active.
The team found methane in the Martian atmosphere by carefully observing the planet throughout several Mars years with NASA's Infrared Telescope Facility and the W.M. Keck telescope, both at Mauna Kea, Hawaii. The team used spectrometers on the telescopes to spread the light into its component colors, as a prism separates white light into a rainbow. The team detected three spectral features called absorption lines that 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, Md. "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, Calif." Mumma is lead author of a paper describing this research that will appear in Science Express on Thursday.
Methane, four atoms of hydrogen bound to a carbon atom, is the main component of natural gas on Earth. Astrobiologists are interested in these data because organisms release much of Earth's methane as they digest nutrients. However, other purely geological processes, like oxidation of iron, also release methane.
Animation depicting two processes (geochemical and biological) that may have produced the methane plumes now seen in Mars’ atmosphere (click photo). Image Credit: Susan Twardy/NASA
"We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tons 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."
One method to test whether life produced this methane is by measuring isotope ratios.
Isotopes of an element have slightly different chemical properties, and life prefers to use the lighter isotopes.
A chemical called deuterium is a heavier version of hydrogen. Methane and water released on Mars should show distinctive ratios for isotopes of hydrogen and carbon if life was responsible for methane production.
It will take future missions, like NASA's Mars Science Laboratory, to discover the origin of the Martian methane.
Additional photo and animation assets here.