Did the Viking landers find life on Mars 25 years ago?

July 30, 2001 12:00 AM

Did the Viking landers find life on Mars 25 years ago? Some scientists think so. I have too much faith in planetary scientists and the newly minted field of exobiology, to believe this is a just a ploy to rekindle waning public interest in space exploration. I think this is genuine 20/20 hindsight coupled with better scientific understandings of life existing in the extreme hinterlands of possibility. . .
posted by crasspastor (29 comments total)

It's interesting how the headline of this article reads in no uncertain terms: Scientists Say Mars Viking Mission Found Life.

Not "may now have found" or "upon further scrutiny". I find this quite interesting and exciting. I want to believe.

Also, this would be good time to bring up publicly, that as a kid I would stare into those famous Viking surface photos for hours, in simple awe of the foreignness, the familiarity, the nearer horizons and just stare and think. Those are my most favorite photos of all time. Anybody else do the same or have another neat science trinket they've never stopped being in awe of?

Pathfinder was freakin' awesome too.
posted by crasspastor at 12:10 AM on July 30, 2001

"I found that the gas release was indeed rhythmic, with a period of precisely 24.66 hours, a Martian day," Miller said. This finding, along with other painstaking assessments about LR operations, the scientist feels that a Martian circadian rhythm in the experiment may constitute a biosignature - a sign of life.

When I read this I couldn't help thinking that this guy's fooling himself.

Surely a circadian rhythm shouldn't match exactly with the length of a Martian day. Nearly would be interesting, exactly makes me think that it's probably being caused by something else like sunlight raising and lowering the temperature or something like that.

But what the hell would I know?
posted by lagado at 12:26 AM on July 30, 2001

Here's another article on Miller's circadian rhythms.

"I think, basically, that it's bugs''
posted by lagado at 12:31 AM on July 30, 2001

It is too large a universe for us to be alone. Then again, I have always subscribed to von Daniken's explanations.

I am always in awe of the Discovery/TLC, National Geographic, Animal Planet documentaries, especially those about under water life. How on earth do they get those cameras in there and shoot such neat footage? How do they shoot those inside the reptile's egg, or those mother's womb footage? I am more in awe of people's skills than any other thing. [Anyhow, if anyone knows how these video are shot, don't hesitate to post.

And while at it, if anyone knows of any website that has the recipes, step-by-step cooking instructions from the show Iron Chef, post them as well. How do they make 4-6 course fully cooked meal in just 60 minutes? I'd like to replicate those, if I can ever find a set of instructions.]
posted by tamim at 12:38 AM on July 30, 2001

Mars has always assumed a place in popular lore as the planet aliens come from, and I'm wondering to what extent that is influencing and spinning the scientific discoveries.
posted by brucec at 4:51 AM on July 30, 2001

James Lovelock has made a good explanation about why he didn't believe that there was any life on the red planet.

He simply asked whether or not the atmosphere was in equilibrium. That is, whether combustible gases were around in large supply or were scarce. On earth, volatile gases like oxygen are constantly being continuously produced and consumed (by life). Carbon dioxide is very scarce.

On Mars the opposite is true. The atmosphere is close to equilibrium. Carbon dioxide predominates and oxygen is very scarce. Mars' atmosphere looks more like what you exhale than what you inhale.

He went on to say that you could (in the 1970's) determine the composition of the Martian atmosphere by observing its spectrum. In other words it was possible to know that there was no life on Mars without even leaving Earth!

Needless to say his contrarian views were not very welcome at NASA.
posted by lagado at 5:35 AM on July 30, 2001

Or perhaps life on Mars might be different, chemically, than Earth life.
posted by skyline at 5:55 AM on July 30, 2001

Lovelock's argument doesn't wash because it would require broadscale life. Rare and quite unsuccessful life wouldn't have the ability to cause broad ecological effects.

No-one on either side of this debate is claiming that the evidence is conclusive. I myself lean towards the pessimistic. There were three experiments on Viking which looked for life and two were negative. The third, at issue here, was the broadest spectrum and most susceptible to non-organic effects, and a plausible case can be made for the results of that experiment being caused by action of inorganic catalysts in the Martian soil. But the fact that we didn't find something with three piddle-dunk tests performed in just two locations doesn't mean that there is no life. It's much too soon to close the book on this subject.
posted by Steven Den Beste at 6:38 AM on July 30, 2001

I've had several arguments with people on this, but my position is not only will there probably be life on Mars, but on Venus and Europa as well; maybe Jupiter. And throughout the universe in quantity. Because life finds a way to survive and thrive. Look at those deep sea heat vent films, or the inside of a volcano stuff - even in the worst places on Earth, there is life. Now you can make the argument that Earth's worst places are still better than Mars best places, but skyline has it right, we can't count on non-Earth life to follow Earth life rules. I think we're going to find that the universe is full of life; it is one of humanity's greatest conceits, to believe that so large a space belongs to us alone.
posted by UncleFes at 6:54 AM on July 30, 2001

One thing I've never understood and maybe someone can explain this to me - How do we define "life"? Maybe Mars and Venus have life that look like rocks and sit there for 1000 years until they move. Why do scientists also seem to expect that in order for there to be life there must be an atmosphere identical to earth. Maybe aliens on other planets are living and breathing their atmosphere which is toally unlike ours or maybe they don't breath at all. I'm just trying ot understand what it is that we as humans are looking for when determining if there is "life" on other planets.
posted by suprfli at 8:27 AM on July 30, 2001

A totally abstract definition of life, free of terrestrial bias, would be any process that decreases entropy within a certain area, at the expense of increasing entropy around it. When you build or maintain new cells and make babies, you're decreasing your own entropy; and you've aquired the energy (or, er, "order points"?) to do so by either consuming a fellow process or absorbing energy from a high order source, like the sun. Emitting heat and smelly low-order waste products as well. Life is thus a contest to amass order in a world of increasing chaos.

There are a few exceptions, such as simple chemical processes, virii, and prions. The key here is duration and self-preservation ... both are subjective.
posted by skyline at 8:54 AM on July 30, 2001

Emitting heat and smelly low-order waste products as well

Excuse me :)

Skyline's right - so long as the object in question decreases entropy and doesn't violate any scientific laws, you've got yourself some animalcules. It cracks me up when I hear people say "Well, there can't be any life on [insert planet name here], there's no oxygen!" Oxygen breathers will be a minority in the universe, because oxygen is a highly flammable, highly corrosive gas. Any safety-conscious methane breather would be very careful around oxygen.
posted by UncleFes at 9:03 AM on July 30, 2001

Skyline, the problem with your definition is that growing crystals (e.g. quartz) fit it. (The Third Law of Thermodynamics defines a crystal as being the state of lowest entropy.)

It isn't possible to rigorously define life, but self replication is generally considered a good start. It's not just decrease in local entropy (by growth) but actual duplication which is critical. Making a crystal bigger is different than making two crystals where only one was found before (or three where there used to be two).

However, we don't need to go that far. I think there is a decent chance of actually finding things on/in Europa which actually have DNA or something very close chemically to it.
posted by Steven Den Beste at 9:15 AM on July 30, 2001

I always found that fascinating in David Brin's Uplift series: the concept of Hydrogen breathers. But why the hell shouldn't there be such animals? Just because our bodies function a certain way doesn't mean every being's would. Is xenocentrism a word? :)
posted by Kafkaesque at 9:20 AM on July 30, 2001

Is xenocentrism a word? :)

It is now, you rabid xenocentrist!
posted by UncleFes at 9:29 AM on July 30, 2001

Regarding the choice of respiratory elements, corrosive == quality (because corrosive means reactive). Nonreactive elements aren't useful; you can't do anything with them.
posted by aramaic at 9:36 AM on July 30, 2001

"Foreigner - Centricts"? Um... doesn't seem to fit.

Terracentric... Gaiacentric... maybe.
posted by silusGROK at 9:42 AM on July 30, 2001

oxycentric? carbocentric?
posted by aramaic at 9:44 AM on July 30, 2001

Nonreactive elements aren't useful; you can't do anything with them.

What if the extraterrestrial in question has a system that does not need a reactive gas process? What if their respiration has more to do with, say, a temperature maintenance system than the transport of energy? You're using earth-life as a model.

I think that you'll find the animals use whatever's locally available, regardless of it's relative value to earth-life.
posted by UncleFes at 9:45 AM on July 30, 2001

Um, no. The inability to utilize reactive chemicals means the absence of life, regardless of the format it takes.

Reactive chemicals are necessary for the metabolic process, regardless of *which* reactive chemicals they are. Without reactive chemicals, nothing happens.

...unless you're saying that life can exist without a metabolism? Pure energy beings exist only in Star Trek, where they were constructed as a plot device, not as an actual exobiological theory.
posted by aramaic at 9:57 AM on July 30, 2001

These damn scientists! I just want to believe in things! Stop being right! Crop circles are fun to believe in. It only gets a little weird when you start talking about Zurich gnomes and chupacabras.

And besides, Star Trek taught us that aliens are going to look pretty much exactly like us, but perhaps with some hitherto undreamed of ear deformity or even a stylish forehead growth. I can't wait!

harboring a secret belief that Jesus was a shaven Yeti

k
posted by Kafkaesque at 10:08 AM on July 30, 2001

Reactive chemicals are necessary for the metabolic process, regardless of *which* reactive chemicals they are. Without reactive chemicals, nothing happens.

Sure. But the rules as to HOW an extraterrestrial makes use of chemical reaction are not engraved in the stone of earth-life. Is it impossible to conceive of a extraterrestrial that does not have a metabolism as we understand it? Or one that is so radically different from our own as to beggar the term? My point is that most people speculate on the design of extraterrstrials based on the design parameters set up by earth conditions. Extraterrestrials, by their definition, would be designed by a different set of parameters.
posted by UncleFes at 11:15 AM on July 30, 2001

and you've aquired the energy (or, er, "order points"?) to do so by either consuming a fellow process or absorbing energy from a high order source...

That is TOO sexy.
posted by rushmc at 11:30 AM on July 30, 2001

crasspastor, the answer is in looking again at that headline. The operative part, here, is scientists say, which is headlinese for "claim" or "assert". It doesn't read Mars Viking Mission Found Life.

As to whether they actually found it, that is likely to be a highly-contended bone for some time to come.

These scientists know that their result isn't going to be taken at face value by more than a small contingent of wanna-believes. Most likely, what is going to happen is that they or some other group will develop a more sophisticated test around this question that will travel on a future lander.
posted by dhartung at 12:14 PM on July 30, 2001

Steven Den Beste:Lovelock's argument doesn't wash because it would require broadscale life. Rare and quite unsuccessful life wouldn't have the ability to cause broad ecological effects.

Uncle Fes:My point is that most people speculate on the design of extraterrstrials based on the design parameters set up by earth conditions.

While we could go on speculating about rare or exotic or even non-chemical forms of life, I still think Lovelock's argument is more likely to be correct.

Life is a global phemonema, there is no "rare and unsuccessful" life only plentiful and vibrantly successful life. It changes the planet it lives on to make it habitable. It maintains temperatures, regulates the atmosphere and controls useful and toxic chemical concentrations. These processes started very early on earth (at least 3.5 billion years ago) and never stopped.

Without life, earth today would have lost all of its hydrogen to solar winds and have no oceans. All of its oxygen would be locked up in carbon dioxide. In other words, it would be like Mars.

There certainly may be other kinds of metabolisms out there (based on methane and so on), but if they exist one characteristic of them will be that they will be be easy to detect as Earth's.

This may sound to Star Trek fans as being a little earthcentric but Earth is the only planet that we know has life on it. That alone is very significant, all the other rocks in the solar system share more in common with each other than they do with Earth. The more we find out them the more that this is cofirmed.

I'm more interested (although not optimistic) about how exploration of Titan and Europa pan out. To find life we probably will need to look at new solar systems.
posted by lagado at 4:51 PM on July 30, 2001

Lagado, if there was life on Mars then the potential scenario is that it once had an ocean and a thick atmosphere, and potentially a fairly vibrant ecosystem as well (though probably not achieving multicellular forms). Then over time because of the small size of Mars the atmosphere escaped and wasn't replaced due to inadequate vulcanism, and without an atmosphere the oceans boiled and the water mostly escaped or froze, and most of the life died. Such life as remains, if any, would be about like the native life which is found in the deserts of Antarctica, where just a few cyanobacteria live embedded in the surface of the bottom sides of rocks. They're alive but the mass of life per square kilometer is tiny and they would not be able to cause any appreciable ecological effects.

There's no logical requirement that if life exists it must be robust and widespread. Changing conditions, such as the loss of the atmosphere of a planet, could cause a massive decline (even to extinction, which may also have happened), and if, for instance, the total current biomass of Mars was perhaps a thousand tons operating at a very low metabolic level, then it wouldn't have any effect on the environment there which could be measured with any instrument we've sent so far.
posted by Steven Den Beste at 5:06 PM on July 30, 2001

I'll buy that argument.

It's certainly possible that Mars had life in the distant past. It also seems likely that such life would have done whatever it could to survive such a deterioration in its conditions.

The question then becomes one of whether such a remnant life could survive (probably in a dormant state) under those conditions. The prospect makes living under an Antarctican rock look positively inviting.
posted by lagado at 5:50 PM on July 30, 2001

"such" usage overload *sigh*
posted by lagado at 5:52 PM on July 30, 2001

The operative part, here, is scientists say, which is headlinese for "claim" or "assert". It doesn't read Mars Viking Mission Found Life.

Right. But it would have been more accurate then, like I suggested, were it followed by a qualification of veracity of just how widespread this belief is. Obviously we find that out in the article that follows. Perhaps we could call it an ill written headline then?

Yet what was most poignant to me, was that I thought the case was closed, long ago, and I found it surprising to be making news yet again. That's why I started this thread actually.
posted by crasspastor at 7:24 PM on July 30, 2001