Exposing PseudoAstronomy

January 17, 2009

Life on Mars? Lots of Methane Means Cow Farts?


Introduction

Over the last week, there have been lots of headlines floating around. “Methane Could Signal Life on Mars,” claims InformationWeek. “Life on Mars is a Possibility,” says the Dispatch Online. “Methane on Mars. Does that Mean … Life?” asks the Christian Science Monitor. And “Gas ‘May Be Sign of Life’ on Mars,” adds the CBBC Newsround.

What’s the news? And why are people excited about gas that we’ve all smelled around farms? And why am I not thrilled and jumping up and down that we now have proof of life?

Why Methane Is Important

Methane is a molecule that is a gas under most circumstances. You need to get to temperatures like those of the outer planets’ moons to get methane to freeze. It’s a simple molecule, composed of one atom of carbon and four of hydrogen (CH4).

A discovery of methane on a body without much of an atmosphere is important because it does not last long. Methane will relatively quickly react with ultraviolet radiation and photo disintegrate into – I think – ethane – by losing a hydrogen atom (and then boding with another CH3 to form ethane, C2H6). It can also be destroyed in Mars’ atmosphere by other mechanisms.

What all that means is that in order for there to be methane present today in Mars’ atmosphere, there must be a very recent (as in within the last ~100 years) source of it. At least in the atmosphere.

Why this is interesting regardless is that it means that something likely created the methane recently. On Earth, the bulk of methane is produced by methanogenic bacteria (bacteria that release methane as a byproduct of metabolism). And, as the title of this post suggests, a lot of this is seriously from cows farting (or flatulating for my more refined readers). Methanogenic bacteria live in many mammalian gastrointenstinal tracts, including cows, but also humans. And that’s as far as I’ll go with that line of thought.

However, there are other sources of methane that do not involve life. Among them is the process of converting iron oxide (rust) into another group of minerals, and this releases methane in the process (along with using water, carbon dioxide, and a heat source).

So Does This Mean Cows Are Farting on Mars?

Not likely.

In all seriousness, this is an interesting discovery. It could indicate that there are or recently were methanogenic bacteria on Mars. If they’re not there now, then they could have been there in the very recent past, produced the methane, and it is now being released, slowly.

However, and I hate to agree with the folks over at Answers in Genesis on this one, the history of “life on Mars” is fraught with announcements and then retractions. And often, the media make a sensational headline, get people all worked up, and then don’t follow-up with the story when it turns out to be less interesting. Seriously, does anyone remember the media owning up to ALH84001 NOT having bacterial fossils?

Regardless of the source of the methane, however, this is an interesting discovery because Mars is effectively saying, “Hey, I’m still an active planet! I’m not telling you what is going on right now, but I’m dropping little teasers like this.” Methane is a teaser. Because it has a short lifetime in Mars’ atmosphere, it needs to have a very recent source. This indicates either active geology and/or active biology. Either one is interesting.

Final Thoughts

The reason that I’m not jumping on the “Life on Mars” bandwagon – unlike UFO people who say this is just prepping us for Obama disclosing the UFO presence on our planet, or the Hoagland crowd who say NASA knew all along – is that life on Mars should, in my opinion, be the last conclusion, reached only after all the other known possibilities are exhausted.

Why? Well, to quote a clich├ęd phrase from Carl Sagan, “Extraordinary claims require extraordinary evidence.” Life on Mars would be amazing – it would redefine humanity’s role in our li’l corner of the universe. But, it’s an extraordinary claim, and it needs more evidence than methane that could have other sources.

That’s why this is very interesting news, but most headlines are very premature. If you would like to read the actual real, original NASA press release, click here.

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