Frankly, if I were Michael Mumma, I'd be going nuts right now. The NASA scientist and his colleagues have either found evidence of life on Mars, or are getting fooled by some weird geochemistry.
The researchers today today are reporting that in 2003 and 2006, they recorded plumes of methane rising from the surface of the Red Planet. Working back from their measurements of methane in the air, the researchers pinpointed some particular spots on Mars where the methane came from. And it's a lot of methane they're talking about--19,000 metric tons of the stuff in one plume. It's coming out of Mars at the same rate seen at methane-producing spots on Earth.
Those places on Earth happen to be places where microbes are churning the gas out. There might be other ways of getting plumes of methane into the air--generating it from magma, for example. But in a paper published today by Science, Mumma and his colleagues point to the possibility that microbes buried a mile or two under the surface of Mars might be responsible. There are certainly analogs here on Earth--or here under Earth. On our planet, scientists can study these deep microbes by traveling down through mine shafts. Sending the equipment to dig a mine shaft on Mars might be a wee bit expensive, unfortunately.
So--what's going on? I've just tuned into a 2 pm press conference at NASA, and I'll do a little live-blogging for you and update this post.
Press conference notes:
2:01 Mars is "active." Diplomatic, I guess.
2:03 Mumma shows a cool demonstration of how they measured the gas by looking at how light passed through it. What blows me away about this is that all this was done from Earth, with ground-based telescopes. Between this and the discovery of exoplanets, ground-based telescopes are doing some awesome stuff these days.
2:05 Mumma points out that this methane comes and goes. So, it's coming from somewhere and being removed and being replaced. Also, this is the first definitive identification of methane on Mars.
2:06 Mumma's choices: volcanoes or bugs.
2:07 Now Geronimo Villaneuva from Catholic University is explaining how they found where the stuff is coming from. These places have a "rich history." Water flowed there before. So maybe water is underground there now (supporting life)?
2:09 Measuring isotopes in the future could help determine wha's making this stuff.
2:10 Sushil Atreya from the University of Michigan who wasn't involved in the research is commenting. Offering up possibilities--geology, ie water and rock; or biology. Could be stored in the past and being released now.
2:12 Atreya is talking about how Mars may be getting rid of methane. Light can knock it out over centuries. Or maybe oxidants in the atmosphere.
2:14 Lisa Pratt of Indiana University is talking biology. She is stoked.
2:15 Okay, I mean as stoked as scientists get at press conferences where they talk about photic zones. You can see it in the rise of her eyebrows.
2:15 Subpermafrost brines on Earth are a good model. Or radioactive minerals splitting water to hydrogen, reacts it with carbon dioxide to make methane deep underground.
2:16 Pratt wants to look for life on Mars that's exhaling methane. I think she just called it prudent to look for it. What a fascinating word to choose...
2:17 Reporters are now asking questions.
2:18 Mumma points out that if volcanoes were making the methane, you'd expect other gases too, which they don't see. NASA will look for other things that would be consistent with biology.
2:21 Mumma is explaining some of the backstory--first reports of observations were in 2003. We knew we had methane since late 2003, he says. But they've been working to make the data "unassailable." We'll see...
2:22 Mike Meyer of NASA: Mars Science Laboratory, a planned probe to the surface of Mars could do a better job of measuring the methane--including the balance of isotopes. (Methane from life has a slightly different balance than methane from volcanoes.)
2:24 Seth Borenstein from AP is asking about picking where to drop MSL. Four sites have already been named finalists, but Meyer is saying that they've "reset the clock" on the selection process.
2:25 A question on digging: Lisa Pratt says we'd have to go down to where water stays melted. A shallow drill won't cut it. A "very thin nearly invisible film" of bacteria may be spread over fractured rocks.
2:27 Mumma seems to be suggesting a deep drill isn't the only possibility. Maybe just peek under permafrost.
2:27 Pratt is talking about how much water you have to filter to find microbes from the deep Earth. So this won't be a cake-walk on Mars.
2:28 A question about methane from comets. Atreya says that the comet would have to be several kilometers across and hit in the past few centuries. "We would have known it." We don't. So probably comets can be ruled out.
2:31 Mumma: what is the right strategy to exploit this discovery? We need to measure Mars surface all the time to find all the active vents, figure out what's coming out of them, find the most likely to be biological, and decide where we really want to go.
2:33 [Let's just note that this announcement comes from NASA right before a new administration comes in, at a time when spending priorities are in serious flux. Just sayin'.]
2:35 Back to the science: Lisa Pratt says methane from rock (serpentinization) is rare on Earth and actually plugs up active sites. This is why she takes biology seriously as "slightly more plausible."
2:39 If life is deep underground, the water released with the methane may be very old. Age of water can also be estimated from isotopes.
2:41 Pratt says we need to find a haze of biomarkers in the atmosphere or drill. [She has done an admirable job of resisting the urge to say Drill, baby, drill. ; ) ]
2:42 Ken Chang at the Times has an article up--no comments from outside researchers.
2:45 Mumma: How to study an active Mars? [It's not a dead museum now.]
2:47 These guys are talking to each other now, not to the reporters. Hey--maybe we missed some other evidence from our orbiters--maybe we could do certain tests on minerals, etc....
2:48 In the comments, Joe asked if they found helium. Nothing in the paper or the press conference so far.
2:49 Atreya says, "Just remember, we're talking about life as we know it." A shout-out for weird life--excellent!
2:51 Jason asks in the comments if it's enough methane for astronauts to use for energy. No.
2:53 I mean, no, not the plume they found. Mumma is making the point that we don't know how much methane Mars is belching. (Do microbes belch? Is this Martian flatus?)
2:54 If we don't know if the production is geo or bio, we know it's easier to live by consuming methane. "It gives us a bull's eye to look for." Sulfate reduction coupled to methane consumption looks very attractive now--also happens to be one of the oldest ways of making a living on Earth.
2:56 Ken Chang gets the last question: is this a seasonal release? Mumma: We aren't at liberty to discuss the release in other seasons. [In case you wondered why press embargoes are a bad idea.]
---Well, they're done. I'm reminded of the press conference long ago when NASA scientists announced that they might have found Martian fossils in meteorites that landed on Earth. Didn't pan out so well. This time around, the scientists were pretty open about the two different options. And lucky for them, if this is evidence of life, it's life that's alive right now, not fossilized for billions of years. It will be easier to find because there's more of it and it's letting us know it's there. Of course, if part of your research programm is getting a two-mile drill to Mars, "easier" is a most relative term.