'Life on Mars' Meteorite Rejected After 10 Years

An anonymous reader writes "Ten years ago, NASA announced that the Martian meteorite ALH84001 showed evidence of life on Mars. The announcement made headlines around the world, and even prompted President Clinton to make a statement. Ten years later, most scientists believe that everything in the meteorite can be explained by non-biological processes. "We certainly have not convinced the community, and that's been a little bit disappointing," said David McKay, a scientist behind the 'life on Mars' paper. Unfortunately, David McKay's own brother is one of his critics. "He [David] got a little testy about the results we were getting," said Gordon McKay. "What we have shown is that it is possible to form these things inorganically.""

Comments

The hard truth

[canuck57]

No one wants to admit life started out there somewhere. For all we know the meteorites seeded life on Earth... and elsewhere. Why is it so hard for people to believe life exists beyond earth? The probabilities and facts dictate the earth is not the center of the universe.

I for one think it would be good for mankind to have a significant first contact with a superior race. At least then we can then look to exploration and not war to keep us occupied while we grow up.

Re:The hard truth

[Anonymous Coward]

No one wants to admit life started out there somewhere. For all we know the meteorites seeded life on Earth... and elsewhere. Why is it so hard for people to believe life exists beyond earth?

Just because people believe life started elsewhere doesn't mean that this rock is an example of life. Wanting life to exist elsewhere does not account for good scientific judgement. I fear that Mr. McKay has much of the former but little of the latter.

Re:The hard truth

[Anonymous Coward]

This stuff is science, not religion. All that's being said in the article is that there are explanations for the contents of that chunk of rock other than life. That doesn't rule out the possibility that life was involved, but it does rule out the meteorite as proof that there was life. So, we're back where we were before: no one knows for sure.

Re:The hard truth

[Reality Master 101]

No one wants to admit life started out there somewhere. For all we know the meteorites seeded life on Earth... and elsewhere.

Er, exactly how would life begin on a meteorite? Exactly what chemistry would allow that to happen? I think it's a tad more likely that life would begin on a planet with the requisite natural resources.

The probabilities and facts dictate the earth is not the center of the universe.

We have absolutely zero evidence for life on planets other than earth. On the other hand, we have considerable evidence that we're alone in the galaxy (other galaxies are too far away to know anything about).

I for one think it would be good for mankind to have a significant first contact with a superior race. At least then we can then look to exploration and not war to keep us occupied while we grow up.

I for one think magic wands would be good for mankind as well. Then we could keep busy with our wands and not war. It would also eliminate resource limitations, which are fundamentally the reason for war. Magic wands are about as likely as alien life, so why not go for broke?

Re:The hard truth

[starseeker]

Science has to be skeptical about anything. For example, let's take two statements:

1. Life had its origins on Earth, and is not to be found elsewhere.
2. Life started elsewhere, and is only present on Earth by virtue of some metorite hitting the right spot.

Science will accept NEITHER of these without proof. Science (good science anyway) is always testing EVERY hypothesis. Anything in science is ALWAYS open to being challenged, revisited, updated, or thrown out if contradicted. If it isn't, it's not science.

This is a very uncomfortable thing for lots of people, who want certainties in their lives. But science is what it is - certainties last only as long as the evidence supports them. F=ma could go out the window tomorrow if conclusive experimental evidence indicates it isn't true. (Now, after a certain point, things are assumed to be correct until proven otherwise, in order to make progress possible. But EVERYTHING in science is ALWAYS subject to challenge. Your challenge had better be good for F=ma though, since there is a VERY large body of evidence suggesting that relationship is a useful description of part of the natural world.)

So I'd say that instead of it being hard for people to believe there is life beyond Earth, it is important that any evidence of such life be subject to skeptical and rigorous test. This is why you have people looking for ways something could NOT be a sign of life - to make sure we don't overlook something in our hope that there IS other life out there. Good science has no favorites, and the facts will ALWAYS overrule wishful thinking (one way or the other.) If someone gets a result they want, one of the best things for them to do is sit down and think of ways this result could NOT mean what you want it to mean.

If we have first contact with a superior race (what is superior, anyway? more advanced? more peaceful?) the consequences will likely be completely unpredictable. I doubt meaningful communication would be established for a VERY long time (if it even CAN be established) - science fiction grossly underestimates that difficulty, in my opinion. And no doubt a sizable percentage of the population wouldn't be able to handle it, particularly if it/they are really different from us. We have enough trouble handling ourselves, nevermind something REALLY alien.

Re:The hard truth

[4D6963]

For all we know the meteorites seeded life on Earth

So far the theory of panspermia is very far from proven, and the most widely accepted theory about the formation of life on earth is not panspermia but chemical reactions forming aminate acids, or somethnig of this kind.

Why is it so hard for people to believe life exists beyond earth?

When it comes to science, thou shalt ban the verb 'to believe' out of thy vocabulary.

I for one think it would be good for mankind to have a significant first contact with a superior race

Why do people systematically consider that an extraterrestrial race would have to be superior to us in the same way that we are superior to the rest of animals? Keep us occupied while we grow up? What's making you think that we're growing up? Our nature is immuable, the only way we can give ourselves the feeling of evolving is through the evolution of our civilization, but that's not going to make us closer to any hypothetical superior extraterrestrial race, if there even can be such a thing as animals significantly superior to us. It seems that the idea of us being probably the most evolved life form possible has went through relatively few people's minds.

Back to the topic, scientists have no trouble admitting some forms of life might exist or might have existed in the universe, even inside our very own solar system. But the object of this article is about determining whether this precise piece of rock reveals the existence of any actual extraterrestrial form of life, it's not about determining whether there could or could not have been life in the Universe, nor even on Mars.

It's all about this precise rock.

Re:The hard truth

[Fordiman]

Well, think about it. Organized crystal structures form much more readily in low-gravity, and an impact event (two asteroids violently meeting in the black) could easily produced the sort of initial chaos needed to allow for a life-formation event (formation of amino acids and proteins as the rocks cool). Smash that into the earth, and you have a similar situation. I wouldn't be surprised if an impact event is the catalyst for life on those planets which can support it.

Before people start getting uppity about silicon-based life and how it could exist on a very hot planet, keep this in mind: Yes, silicon organics are possible and have been synthesized - but what would they use instead of water? In order to be as flexible as carbon organics, they have to be much hotter (> 100C), so there is a need for a liquid that handles those temperatures with similar properties (Anyone know the properties of Li2S?)

I submit that it is no accident that earth life is carbon-based. Lower energies needed to remain pliable and adaptable at the molecular level, and it just happens to be the most promiscuous atom to be found (can handle four covalent bonds and links up far more rapidly to the next-best, silicon).

I think if we're going to find life out there, we should be looking for a planet with similar heat characteristics to earth, with an asteroid belt or cometary system that would cause likley impacts every hundered thousand years or so (often enough to produce many many high-energy impact events to stir things up enough to form life, but not often enough to kill all life before it's got a chance to go multicellular)

I mean, once you're in our temperature range, water's a no brainer. Just captured solar wind over the millenia may be enough hydrogen to allow enough water to accrete on a planetoid (especially if there's enough oxygen in the planetoid's original mass-mix).

burden of proof

[Bartmoss]

Just because these things can be formed inorganically doesn't mean they were. Still the burden of proof definitely rests on those who says it is organic in origin. Especially now.

Luckily, just because the meteor may not have signs of former life, doesn't mean mars never had any. It would be really sad if our solar system turned out to be sterile.

cool science

[fermion]

This is the kind of subtlety that people seem to miss in science. Just because something could be true, does not mean it is true. In this case the samples in question could have been formed by an organic process, but they did not have to be. And since the overwhelming evidence is that there is no life on mars, and in fact we have no real process as yet that would have developed life on mars, the reasonable person still concludes that life probably does not exist. Now some people just are going to believe for personal reasons, and that is cool. Those people need to look for evidence in an attempt to prove their case. But this particular piece of evidence appears to have been taken out of contention.

Re:cool science

[lawpoop]

I take a somewhat different tack.

It is true that we do find life in some rather inhospitable places, like highly radioactive nuclear reactor cores, inside solid rock, in boiling steam vents, metabolizing sulfur -- but does that mean life can arise in such places, or does it require particular conditions to arise, and then it is capable of evolving to adapt to such harsh environments? The basic amino acids that constitute life do not survive in such environments. The living organisms which live in such environments have special mechanisms to protect and repair their delicate parts.

But the places where we find the most diversity of life is in the oceans and the tropical rain forests. That tells me there are a few elements that life really wants -- a relatively small temperature window, light, and most importantly water. The oceans are water, and the tropical rain forests are almost always at 100% humidity. I would even say that the temperature range that life wants is the range of liquid water. Taking this a step further, I would say that anywhere we find liquid water, we will find life.

Let's hear it for the scientific process!

[iguana]

1. Unexplained evidence.
   
2. Testable hypothesis.
   
3. Testing of the hypothesis.
   
4. Alternative explanation for the evidence.
   
5. Revision or rejection of the hypothesis.
   
6. Goto step 3.
   

Compare to Creationism. *Cough* excuse me, "Intelligent Design".

1. Unexplained evidence.
   
2. God did it.
   
3. End of discussion. Or else.
   

If I may inject a personal note, I do believe in God. But I don't believe He created an existance so simple that anything we don't understand must have His hand directly involved.

Re:Only now?

[shawnce]

I think the tin foil hat is a little tight... it appears to be cutting off blood supply to your brain affecting your reasoning abilities. =P

Basically from the word go their has been many many scientist that questioned the theory presented for the origin of the features in the meteorite. A handful of those scientist did experiments over the _years_ since (research takes time) to see if any non-organic processes could have produced similar structures and they have found ones that can.

Tough Day to be a Martian

[DumbSwede]

Coming in the wake of this recent news about atmospheric hydrogen-peroxide possibly scouring Mars's surface of microbial life it looks like the odds of finding life easily on Mars are dwindling. Subsurface drilling still holds out hope.

Regardless of current life conditions I still hold out hope for past life fossil discoveries, multi-cellular past life. Several of the Mars rover pictures look to show fossils, but NASA is being very cautious in it assessments. Not sure what the ID camp or Creationists will make of bring back criniod like fossils from Mars estimated to be 1-2 billion years old. Actually I already pretty much do know, so consider the question rhetorical.

McKays

[FuturePastNow]

David....Gordon

Their third brother, Rodney, was unfortunately too far away to comment on the possibility of life on other worlds.

So...

[CiXeL]

Can we start trying to put it there now?

Unnecessary Evidence.

[crhylove]

Whether that little rock had evidence or not, I agree with Einstein: There is no logical number between 0 and infiniti. Therefore if there is life HERE, there is and has been life all over the damned place. One little rock doesn't change the statistical likelihood of that.

rhY

Superior races

[mangu]

it would be good for mankind to have a significant first contact with a superior race

Yet, even assuming such races exist, the probability for our meeting them is exceedingly small. Consider that it took about ten thousand years for us to go from the stone age to space exploration. Viable planets for developing life had existed for several billion years before life arose in the Earth.

Therefore, for us to meet a race that's more advanced than us, but not so advanced for that contact to become completely irrelevant, we would have to meet a race that developed just a tiny bit of time, percentage wise, before we did.

If and when we find life outside the Earth, it will most probably be either very primitive or very advanced relative to us. Baring extreme coincidence, any more advanced race we are likely to meet will have as much to teach us as we have to teach to a garden slug.

I can't help but think of using this for religion

[deft]

NOT getting the results that most of the scientific community would REALLY want as such a cool discovery that could advance thinking is a great example to show religious types.

This is what it looks like when the process beats an idea with logic and testing and eventually disproves what they really wanted to be true. In things like "intelligent design" it could never ever come out with such a neutral result agreed upon by people who may have been very much for the idea the entire time. No lying, not falsifying, no BS logic.... just the truth through science.

I applaud their dilligence, and wonder if that guy in Vegas who one the "when will life on other planets be dicovered" jackpot gets to keep his $$$ :)