« The History of Social Software | Main | Paul Hawken: The Long Green »

The Methane Mystery

The European Space Agency's Mars Express orbiter, which arrived at the Red Planet earlier this year, has been somewhat overshadowed by two successful landers and one failure: NASA's Mars Exploration Rovers 1 & 2 ("Spirit" and "Opportunity") still crawl along the Martian surface, well beyond their scheduled end-of-mission; conversely, the ESA's "Beagle II" lander, which was carried on the Mars Express, plummeted to Mars and destruction. When the lander crashed, much of the media seemed to forget about the orbiter, either focusing on the NASA missions or the controversy around the failed Beagle II. But the Mars Express mission, despite the lander disaster, has nonetheless been producing some valuable science (as well as some great photos). The most intriguing reports concern methane.

In March, scientists on the Mars Express mission reported finding small concentrations of methane in the Martian atmosphere. The discovery has been tentatively confirmed by Earth-bound observers using spectrographic equipment (although their findings have not yet been published in peer-reviewed journals). Methane in the atmosphere is odd, however, for a number of reasons. Ultraviolet light destroys atmospheric methane fairly quickly, in planetary terms -- on the order of a few centuries. That means that the methane couldn't have been a leftover from Mars' past. In addition, methane is produced on Earth from one of two sources: geological activity and biological activity. But there's little evidence of active geology on Mars: the volcanos appear dead, and surface lava is millions of years old. Still, low levels of geological activity can't be completely ruled out.

Now comes word that the Mars Express team has mapped the Martian methane concentrations and discovered that they align startlingly well with measurements (by NASA's Odyssey orbiter) of what appears to be water-ice just under areas of the Martian surface.


National Geographic and New Scientist have more details. With the possible water-methane correlation, the idea that Martian atmospheric methane has a biological origin takes on greater weight, as water would be required for microbial methane production, but not (necessarily) for geological production. In addition, the Mars Express team has very cautiously noted that they may have also identified atmospheric hydrogen sulfide and formaldehyde, which are also strongly correlated to biological activity. Those results have not yet been fully reviewed.

All of these arguments remain controversial. The Odyssey water-ice findings are based on second-hand evidence, and the methane findings haven't yet been confirmed by broadly-accepted research. It is quite possible that all of these readings are false, or have an explanation far more prosaic than continued geological activity or Martian life.

Mars researchers will evaluate any and all possible alternative explanations before accepting any of this as signs of extant Martian life. That's not out of stubbornness or a refusal to accept the possibility; it's simple due diligence. For something this big -- the discovery of life off of Earth -- they need to be certain, absolutely certain. There's a good chance that, even if life is there, scientists will come up with a well-grounded non-biological explanation for the results, and the question of Martian microbes will remain open. In that case, we keep searching.

Comments (3)

You know... assuming this pans out and there's life up there, the next question is: "is it related to us?"

DNA or RNA based would probably indicate that somehow panspermia happened: life travelled across the solar system, or bits of martian life-bearing debris fell on earth or the other way around.

Unrelated would likely mean that, well, the universe just throws up life in any odd corner! What exciting times!

OK, I must amend myself. There are two ways to end religion on Earth. I thought archaeology was it (show moderns how incredibly primitive the people who developed religion are, by comparison, and perhaps even shock them with ancient practices).

Running into aliens counts, too. So, astrophysics?

I can hear the arguments now... "Oh, that's just bacteria from Earth that we brought there ourselves"

You might be thinking of "Christianity" when you say "Religion."

Both Hinduism and Buddhism have a long tradition of belief in the existence of other world inhabited with intelligent life, and travel to and from such worlds either by meditative power (???) or in starships.


This page contains a single entry from the blog posted on October 15, 2004 1:28 PM.

The previous post in this blog was The History of Social Software.

The next post in this blog is Paul Hawken: The Long Green.

Many more can be found on the main index page or by looking through the archives.

Powered by
Movable Type 3.34