Mars Methane Mystery
October 24, 2008
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HowStuffWorks: Life on Mars? |
Science Channel: Is There New Life on Mars? |
If research in the next few years nails it, history will record that at the beginning of the 21st century the first extraterrestrial life we encountered didn’t express itself by a flying saucer landing at the White House (as so many UFO fanatics fantasize). It was instead the “humblest of God’s creations,” As British science fiction author H.G. Wells once wrote. In other words, bacteria.
The evidence has been accumulating for the past several years and it has been, in my opinion, an underreported story due to the deserved caution of the researchers involved. It’s a big deal when you say the “L” word in astronomy.
A potential biomarker has been detected on Mars in the form of plumes of methane rising off the surface. On Earth, the smelly methane comes largely from methanogenic bacteria living in wetland, landfills, and cow stomachs. Methane can also be produced by volcanic process, by reactions between water and hot carbon-bearing rocks, or by the natural decay of coal and petroleum.
Since 2003 several teams of scientists detected the faint spectral fingerprint of methane from ground-based telescopic observations of the Red Planet, as well as from data collected by ESA’s Mars Express orbiter.
The elusive methane is very dilute, peaking at 60 parts per billion, as opposed to Earth’s 1800 parts per billion. But unlike on Earth, the methane is very localized to a few “hotspots” hundreds of miles across and perhaps not coincidentally stretching along the warmest part of Mars, the equator. What’s very tantalizing is that atmospheric water vapor and underground water ice are more concentrated in these regions, making them a potential oasis for microbes.
The real game-changer, reported earlier this month by Mike Mumma of NASA’s Goddard Space Flight Center, is that the methane plumes are very short-lived. Something is replacing the methane, and quickly.
Mumma found that the methane is chemically broken down by sunlight within a year. This requires that millions of tons of methane must be being pumped into the martian atmosphere to sustain the quantity observed. That’s a lot of flatulent Mars-cows!
The methane could be produced by chemical reactions from buried volcanic rocks soaking in subsurface water, or subsurface deposits of methane ice from Mars’ distance past.
If the methane is instead biologically produced as a waste product, it could come from subsurface microbes living in aquifers deep below the permafrost near the surface. The localization of the methane might mean that life is not very mobile on Mars, but concentrated in a few underground microhabitats where it has sought shelter for billions of years on a planet growing increasingly hostile.
What to do next? It turns out that one of the hotspots is a candidate landing site for NASA’s Mars Science Laboratory. This beefy nuclear powered, Volkswagen-sized rover will be launched in 2009. It carries equipment to gather samples of rocks and soil, crush them, and place them into onboard test chambers. MSL will look for organic compounds and anything that might indicate the action of an organism.
Though it may not be able to reach any microbes, should they exist, its onboard lab could analyze the carbon isotopes in the atmospheric methane. As organisms build organic molecules they use the isotope carbon-12 more readily than carbon-13. Compounds that arise from Earthly biological processes have distinctive carbon 12:13 ratios that are different from that found in methane produce by a non-biological process.
If this were found on Mars it would be strongly suggestive of life with a similar Earth biochemistry.
The potential MSL landing site that is a source of methane plumes is Nili Fossae, a fractured terrain to the northeast of the great volcanic chain on the Tharsis plateau. It is made up of curved faults and down-dropped blocks of crust between the faults. The area is rich in clays that must have been under pools of warm water in the distant past.
Depending on What MSL finds, this region may be a target for a Mars sample return mission in the next decade. This will be the only way to definitely prove the existence of life on Mars.
Until then the mystery of the methane plumes will tantalize us with the prospect we are directly seeing a biotracer of Mars’ ancient inhabitants – but just can’t be absolutely sure without bringing back a physical Mars bug.
Comments
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GOODDD
Posted by: xcbgdfg | October 25, 2008 at 03:52 PM
Sounds like an opening to study more on this subject. I watched "Crystal Caves" on the history channel. I got an idea what Nasa and the ESA are up to too. Be prepared for a shock to alter our world; they might actually find humans or aliens living underneath the surface, or even evidence of past civilizations that were once there as well. Sounds like a reason to go. Possibly A Rescue mission...
Posted by: Jim Tasker | October 30, 2008 at 03:23 PM
Hey, Anyone look at the data from the first probes on Mars (Viking 1 and 2) Funny that it takes 33 years to pay attention. Chemical or biological, an investigation was needed even if the answer might be controversial.
UncleVern (really old guy with no life)
Posted by: UncleVern | January 18, 2009 at 02:29 AM
Dear sir,
I understand the desire to know if we are alone in the universe or not, but even if we can answer the question with a yes, their is life out there, then what? What do we hope to accomplish by establishing the fact that there is life on mars?
What questions do we hope to answer?Or learn?
Posted by: patrick donathan | April 24, 2009 at 06:45 PM