Martian Microbe Fossils, Not So Debunked Anymore 306
rubycodez writes "Three meteorites, including one that has been in a British museum for over a century, are going to be put under the electron microscope and ion microprobe by NASA. We're 'very, very close to proving there is or has been life [on Mars],' said David McKay, chief of astrobiology at Johnson Space Center."
somewhat better article on the subject (Score:5, Informative)
http://www.scientificamerican.com/article.cfm?id=proof-of-martians-to-come-this-year-2010-01 [scientificamerican.com]
Bad Reporting and Quote Mining (Score:3, Informative)
First of all, why bother linking to PopSci when the original story, even as quoted by PopSci, is at Spaceflight Now [spaceflightnow.com]?
(Of course, the title of the Slashdot piece is pretty bad as well, so I be too surprised.)
Second, the quote in both the blurb and the PopSci article is taken out of context. The original, from Spaceflight Now:
"But we do believe that we are very, very close to proving there is or has been life there," McKay tells Spaceflight Now.
The words at the beginning make a world of difference in terms of McKay's attitude. He's not asserting something he can't know, he's stating he, personally, feels confident. (But it is stated as an opinion.) That's just crappy reporting. (Or, in this case, not even reporting: copying and pasting.)
All that said, it'll be exciting if it turns up anything, but don't hold your breath. There are just so many ways to contaminate the samples or to produce a lot of the effects that they've seen abiotically that I don't think we'll answer this question from Earth. I suspect to get most scientists to agree that there's life, we'll have to find it in situ.
Re:Wait, huh? (Score:4, Informative)
Re:My psychic prediction (Score:4, Informative)
near complete annihilation of Drake's equation
Whoa, there! Drake's equation has quite a few terms in it and only two of those terms are subject to reevaluation: the average number of planets per star that are suitable for life, and the fraction of planets which are suitable for life that actually have life. The other numbers, speculative as they are, should remain unchanged by the discovery of microbial life on Mars.
Re:Very close to proving is not proving... (Score:3, Informative)
Because we have carefully studied every bit of the pieces of mars available on earth with the best scientific laboratories available. Whereas we have only looked at a minuscule fraction of mars on site, and done so with tools light enough to transport to mars.
Its like asking why we can not prove the nature of human metabolic functions with nothing more than a thermometer in your behind.
Re:I'd love to talk to someone knowledgeable about (Score:5, Informative)
Disclaimer: I am a planetary scientist but do not work directly on the martian meteorites.
1) We know that the rocks are from Mars because they all have consistent isotope ratios between the various meteorites that are inconsistent with those isotope ratios on Earth but consistent with isotopic ratios on Mars
http://wapedia.mobi/en/Neutron_activation_analysis [wapedia.mobi]
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6T-41WBDHD-8&_coverDate=10%2F31%2F2000&_alid=445411040&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5823&_sort=d&view=c&_acct=C000053194&_version=1&_urlVersion=0&_userid=1495569&md5=1c1b0d04dba7f06365b072655bef68b3 [sciencedirect.com] (May need a subscription)
2) The age(s) of the possible fossils are greater than the time the meteorites have been on Earth. Again, this can be calculated using various isotope ratios. In essence, these things formed while the rocks were still on Mars.
3) I agree with your discomfort with the word "prove." Most scientific study is based on the Popper philosophy of disproving something rather than proving its opposite.
A) The new instrumentation and techniques being used on these meteorites are greatly advancing our understanding of them. The press announcement that AH84001 might have evidence of life was premature (what we call "science by press release"), but the publications by the team were certainly good and valid work, whether they are falsified or not...
B) The scientific word "prove" is more about the lack of any valid competing hypotheses. If you can't come up with a reasonable alternative explanation for the data, you have to accept the presented explanation.
Re:I'd love to talk to someone knowledgeable about (Score:2, Informative)
Isotope ratios match those found by the 1970's Viking landers. Each planet has a different set of ratios, sort of like a female's breast-waste-hip measurements: 38-24-36 etc. (don't ask why I thot of that analogy first).
Occam's Razor says they are from Mars. Having 3+ meteorites that all match the Mars ratios are far more likely to have been blasted from Mars than some planet outside our solar system that happens to match Mars's ratios. But even discovering life from a distant planet is an important discovery in itself.
I believe there are at least 3 parts to this argument. The first is that all 3 meteorites have similar microbe fossils despite being from different places on Earth. Second, the frequency and composition of outside contamination would be different on the surface than in the interior of the rocks if contaminated. But the distribution is allegedly fairly uniform. Third, the chemical or structural pattern would be different if the life came after-the-fact. But, I don't know the details of this one. Hopefully the to-be-released paper will clarify these items.
They can tell by radiation damage patterns that a given rock has been in space relatively recently. This means that likely the rocks have been close to the surface of Earth rather than being deep underground. But the Mars fossils resemble underground life (as found on Earth).
Re:I'd love to talk to someone knowledgeable about (Score:2, Informative)
Mod parent up: it's a good, concise, balanced reply.
I'd also recommend that anyone interested in following up this story look up some of the stuff by (e.g.) John Bradley on this as well, to provide a bit of a counterpoint, as the headline-grabbing articles tend to lack scientifi balance. The following link's a good few years old, and the work has moved on a bit, but it is a pretty good potted summary of the arguments for and against a biological origin of these structures.
http://www.psrd.hawaii.edu/Dec97/LifeonMarsUpdate2.html [hawaii.edu]
(Disclaimer: I'm an astrophysicist that works on astrochemistry, but I also don't personally do lab work on meteorites).
Re:My psychic prediction (Score:4, Informative)
Theistic Evolutionists(Catholics tend to this one) will not have any epiphanies
You're right, it has been addressed by the Vatican. Catholics believe aliens could exist. No epiphanies required.
http://news.bbc.co.uk/2/hi/7399661.stm [bbc.co.uk]
Re:I'd love to talk to someone knowledgeable about (Score:3, Informative)
Dangit! Missed another point I wanted to make..
When we say we have "proved" something, we generally mean we've shown, to our satisfaction, that the competing hypotheses are not as strong as the hypothesis we have "proven."
So, what these guys are doing is working to show why these possible fossils are not likely to have formed on Earth, are not likely to have formed as precipitates, etc. Eventually, they expect to show that all of the competing hypotheses for the formation are weaker than (or have even been falsified) their hypothesis that they were formed by microbial life on Mars.
Re:My psychic prediction (Score:3, Informative)
Well, we're still even thinking "life as we know it"... the "golden zone" where earth-like life can exist. There might be other possibilities... we have not travelled anywhere near enough to rule this out.
"We" have actually been to two other worlds... Luna and Mars. A few short-haired dudes went to the moon, and I think we're all pretty satisfied enough there's no life on the Moon. I'll absolutely concede that one. But even in looking for life on Mars, our space probes have often been flawed: http://science.slashdot.org/article.pl?sid=09/05/25/1442231 [slashdot.org]. If they can't find life on Earth, there's a problem.
In short, we don't have a bloody clue about life in this solar system. We know there might have been as many as three planets capable of supporting it at some point throughout their history. One is a definite yes today, one a pretty damn definite no (Venus), barring the extremest of extremeophiles living that heat. Mars is more like a "was" than an "is". And we know very little about possibilities, in any practical terms... space probes only help so much, if the expected zone of life is a thousands meters below the moon's surface, as suggested of Europa. The probes to check out Europa, Io, Callisto, and Ganymede won't launch until 2020, with an arrival sometime in 2026, see:http://opfm.jpl.nasa.gov/europajupitersystemmissionejsm/.
Then there's Titan... no liquid water seen so far, but a cold climate (94K), with liquid hydrocarbon seas, a relatively thick atmosphere of nitrogen and methane, weather, rain, and earth-like features. Earth life, no. A different kind... well, I haven't been there to say for certain....
Re:What about contamination (Score:3, Informative)
Because they're looking at mineralized "footprints". I doubt very much in a single century an Earth-based microbial colony could live, die and then leave mineralized evidence.
Re:My psychic prediction (Score:4, Informative)
we already have the means to kill every man, woman, and child on the planet if the wrong kind of fight breaks out.
unless the actual goal is to kill everyone and everyone is in on the plan and cooperates, we don't have the means to kill everyone. Things like the "peace activist" line about having enough "bombs" to "destroy the earth (x) times over" are hyperbole. The planet is extremely large, and we are extremely small in comparison. Humans are ridiculously adaptable. There are too many of us spread out over too large an area for us to do much beyond temporarily stall technological advancement, much less throw us into the stone age or oblivion.
The problem isn't technological retardation, but a nuclear winter [wikipedia.org].
Re:My psychic prediction (Score:3, Informative)
How often does this happen to you? Evangelicals generally dislike Catholics nearly as much as they dislike atheists. They think that the Catholics aren't even really Christians. If they were old-fashioned enough they'd call them "papists".
Re:I don't know anything about this but.. (Score:3, Informative)
Like I said in the title, I know zip about how all this works, but once you've got some water sloshing around on your planet, what else do you need?
Carbon and Nitrogen. And an energy source. And time, a billion years or so should do the trick.