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."
I'd love to talk to someone knowledgeable about... (Score:5, Interesting)
...this topic. Any here on Slashdot?
For example, how did we determine that Allan Hills 84001 [wikipedia.org] came from Mars and not anywhere else? Not even a Mars-like planet in a nearby solar system? How?
How do we know that the signs of life on that rock are from before it was landed, rather than after? I see wikipedia mention that 'some argue', but there's almost no meat on these bones.
There are more questions, but I guess I'm uncomfortable with the word 'prove'. If this were in a court of law, for example, all of this would be 'circumstantial'. There generally needs to be a lot of it, and it needs to be compelling, before this sort of evidence would get a verdict. This leads me to suspect one of these scenarios:
A) There's more detail here. (I'm rooting for this one)
B) The scientific word 'prove' isn't the same as other uses of 'prove' (which would be sad, since they already have their own words - e.g. hypothesis)
Anyway if you either are a third party with sources or someone who actually works with this kind of thing, please do comment below. I'm in the mood to learn something today.
Re:My psychic prediction (Score:3, Interesting)
Re:My psychic prediction (Score:5, Interesting)
Well I could give a crap about theology. What I want to know is some of the biochemical properties of these organisms. Did they use DNA, RNA or some entirely different set of molecules of protein encoding? Did they share a common ancestor with life on Earth? Is it possible that life had evolved on Earth prior to the collision with the Mars-sized body that produced the Earth, and we have a sort of limited panspermia going on (or maybe it's visa-versa, maybe life began on Mars)? If life was on Mars, is it quite possible as its atmosphere slipped away and its surface became incredibly hostile that somewhere below their surfaces, or perhaps even in deeper valleys and rift zones like Valles Marineris, where atmospheric pressure would be higher and the potential for a more habitable zone might be found?
Of course, this infinitely increases the potential for life elsewhere in the solar system. Europa becomes target #2, and, potentially a far more likely place than Mars to find a complex ecology.
I suppose, in consideration of theology, it depends on who you're asking. Some of the IDers (Michael Behe and his ilk) and Theistic Evolutionists (Catholics tend to this one) will not have any epiphanies. For Old Earth Creationists, it probably won't sway them. But YECs, well, that's a group who has heavily painted themselves into a corner. Now, on top of having to claim the earth is only 6,000 years old, they have to deal gyrations over the age of Mars. They'll probably start by denying all of it, claiming it to be a hoax by evil evilushionists. Then they'll come around to the idea that God planted life there, but no later than 6000 years ago! The people who will change views are the fence sitters at any of these levels.
As for space exploration, well the push for a long-term manned mission to Mars is going to get a major bump. We simply do not have the probes complex enough for more than a bit scouring of the few top inches of Mars' crust. I'm not putting them down, the Mars Landers have been an overwhelming success, but the kind of science any probe sent there, or any probe they're planning to send there, is still pretty limited.
Maybe we should put off any notions of getting humans there in the next two or three decades, and stretch it out to 2050 or 2060, working on self-sustaining long-term bases for humans, so we can send people there for a few years at a time. I'm sure you would have no lack of volunteers among the scientific community.
Re:Very close to proving is not proving... (Score:3, Interesting)
Because we are only rolling around our RC toys and they lack an electron microscope powerful enough?
But we will never get to Mars, because we need all funds we ever had on other things, like that interesting branch of science where we can clearly prove anything and where isolated experiments to the contrary don't disprove anthing. The science there is settled, folks. For. Ever.
Now excuse me while save some CO2 and pay some taxes.
Re:Cannot prove (Score:3, Interesting)
You have Popper backwards.
You can prove a Black Swan exists by finding one. (Finding proof of life on Mars)
You cannot disprove a Black Swan by only finding white ones. (Finding life only on Earth, thus "proving" life does not exist elsewhere)
Re:I'd love to talk to someone knowledgeable about (Score:3, Interesting)
For Martian meterorites, they can look at a few other things. You can first check to see if it's igneous [wikipedia.org]. That indicates that it might have come from a place with molten rock and it solidified at some point. That in turn indicates that this came from a planetary body. Now that you've established it came from a planet or a moon and not the asteroid belt, you examine other things. The meterorite might have gas bubbles in it, so you compare the composition of the gas with your knowledge of the atmosphere of other planets. In the case of ALH84001, they may have seen that the rock had lots of Fe, like Mars, and that it had gas bubbles which matched what previous landers on the planet may have observed. They then come to the conclusion that the meteorite in question is probably from Mars.
As for your other questions, the wikipedia article rightly points out that ALH84001 might have been contaminated. That's why you see articles like this peppered with maybe and probably every few words.
Re:My psychic prediction (Score:3, Interesting)
Really. We already count the "golden zone", orbits hospitable to life as we know it, extending from the orbit of Venus to the orbit of Mars. Nothing changes here. It's also pretty clear that either of these planets might well have supported life before we came along.. Venus with an earlier atmosphere, Mars before it cooled off and lost most of its atmosphere, might have supported life. This term, ne, is not changed by finding life on Mars. It's definitely affected by our greater understanding of where habitable planets might be, such as large moons around warm gas giants.
The real question is a simple one: how likely is life on a planet that could support life. If we find that Mars had life, and it couldn't have been that which begat life here much later, then we have a fairly profound datapoint. Not a huge sample, obviously, but this would suggest life is fairly likely to show up on planets that can support life. This is the f term in the Drake Equation, and finding independent life on Mars impacts the Drake Equation only here.
That's a very different question than "are we alone", at least in the sense of other intelligent life. You need a planet stable enough for life to evolve into intelligence, and ecosystems that support the very high energy cost of intelligence (that's fi term in Drake's Equation... no changes here, either).
Re:I'd love to talk to someone knowledgeable about (Score:3, Interesting)
You're welcome! It's good to see people genuinely interested instead of automatically dismissing because they think they thought of the one thing wrong with the analysis that was missed by the possibly hundreds of scientists who do this day-in and day-out...
A clarification on my post:
A) I don't think it was misunderstood, but want to clarify that the "whether they are falsified or not..." statement was meant to say that whatever the final conclusion about the possible fossils, the initial (1996) work raising the possibility that AH84001 had fossilized martian life was good work, not that the authors might have faked their data. They did not.
I'm of two minds about holding press releases about these kinds of conclusions. 1) It's important to share this with the world. 2) It's important to be sure you've accounted for as many of the possible controversies with your data before going to the public who may not understand the details.
Re:I don't know anything about this but.. (Score:3, Interesting)
I suspect we will have to wait significantly less than "centuries" for larger dataset regarding life in the Universe. I wouldn't be terribly surprised if in less than two decades we will have telescopes capable of resolving Earth-like planets and analyzing their atmospheres (and highly active biospheres probably tend to heavily influence those)
Even in our system the list of suspect places is quite long, giving us plenty opportunities for exploration. Not only Mars, but also Europa, Ganymede, Callisto, even Enceladus of high atmosphere of Venus; at the least.
Re:My psychic prediction (Score:3, Interesting)
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.
Re:I don't know anything about this but.. (Score:4, Interesting)
Rocks may have a greater chance of falling towards the Sun.
But don't discount the Solar Wind. I believe I've read similar discussions that suggest the overall probability is greater for life pushing outward from the Sun due to Solar Wind. We have found microbes very high up in our biosphere. And there tends to be a larger dust trail around Earth.
So dust particles carrying life may get a free ride outwards.