View of Mars from Viking 2 lander, September 1976. (NASA/JPL-Caltech)

Is This Proof of Life on Mars?

Article Updated: 23 Dec , 2015



The Curiosity rover is currently on its way to Mars, scheduled to make a dramatic landing within Gale Crater in mid-August and begin its hunt for the geologic signatures of a watery, life-friendly past. Solid evidence that large volumes of water existed on Mars at some point would be a major step forward in the search for life on the Red Planet.

But… has it already been found? Some scientists say yes.

Researchers from universities in Los Angeles, California, Tempe, Arizona and Siena, Italy have published a paper in the International Journal of Aeronautical and Space Sciences (IJASS) citing the results of their work with data obtained by NASA’s Viking mission.

The twin Viking 1 and 2 landers launched in August and September of 1975 and successfully landed on Mars in July and September of the following year. Their principal mission was to search for life, which they did by digging into the ruddy Martian soil looking for signs of respiration — a signal of biological activity.

A six-inch-deep trench in the Martian soil dug by Viking 1 in February 1977. The goal was to reach a foot below the surface for sampling.

The results, although promising, were inconclusive.

Now, 35 years later, one team of researchers claims that the Viking landers did indeed detect life, and the data’s been there all along.

“Active soils exhibited rapid, substantial gas release,” the  team’s report states. “The gas was probably CO2 and, possibly, other radiocarbon-containing gases.”

By applying mathematical complexities to the Viking data for deeper analysis, the researchers found that the Martian samples behaved differently than a non-biological control group.

“Control responses that exhibit relatively low initial order rapidly devolve into near-random noise, while the active experiments exhibit higher initial order which decays only slowly,” the paper states. “This suggests a robust biological response.”

While some critics of the findings claim that such a process of identifying life has not yet been perfected — not even here on Earth — the results are certainly intriguing… enough to bolster support for further investigation into Viking data and perhaps re-evaluate the historic mission’s “inconclusive” findings.

The team’s paper can be found here.

Image credits: NASA/JPL-Caltech. Also, read more on Irene Klotz’s article on Discovery News.

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35 Responses

  1. Very exciting! Even if particular exploratory ramifications come with it. Can’t wait for MSL to gather samples and data, hopefully confirming many of these deductions and/or elaborating… 🙂

  2. Jason Carr says:

    This debate has been going on for years. I suspect the only real way we’ll ever know for sure is to send new bots to Mars that can provide conclusive evidence (one way or the other). Let’s hope this happens soon because I’d hate to see this debate go on for another decade. Great post Jason!

    • Jordan Davis says:

      what makes you think theyd let us see them? how do we know there isnt proof already?

      • .. .__. says:

        Tell us what medications you are on and who exactly you think “they” are.

      • John Stock says:

        So by default everything is a conspiracy and you trust noone? Give me a break and give your head a shake.

      • Matt Colonna says:

        What makes YOU think that they would keep microbial life a secret??
        What would be the purpose of hiding bacteria?

      • Jeremy says:

        Religion. In case you guys are not aware, the religious right is very afraid of findings that might hurt their religious story. For example, most teachings in the bible hint that any life outside of earth, would be angels, therefore if we find stuff other than angels, well, god lied. I’m not saying there is a conspiracy, but come on, all you have to do is research Pythagoras to see what I’m talking about.

  3. DengFing says:

    Sounds pretty real to me dude. Wow.
    http://www.Total-Privacy dot US

  4. David Krauss says:

    “By applying mathematical complexities to the Viking data for deeper analysis”… uh-oh, skeptic alarm… how well was this experiment repeated by Phoenix, and will we get more relevant results from Curiosity?

    • Ethan Walker says:

      Phoenix did not attempt to recreate this experiment, although its unexpected discovery of perchlorates in the soil settled some mysteries from the Viking data. Curiosity also does not carry anything like the infamous Viking experiment, although I think it does have a pair of chiral columns for the GCMS which could potentially (extreme long shot) provide some evidence for life. But generally Curiosity is more focused on chemistry than and mineralogy than exobiology. The main lesson drawn from Viking seems to be that without a much better understanding of martian soil chemistry, its hard to say much of anything conclusively from that sort of experiment.

    • Torbjörn Larsson says:

      The Phoenix data made a complete prediction of the Viking experiments possible, since the perchlorates predicts the absence of organics in the thermal decomposition experiments used at both sites.

      So you can say that Phoenix rejected instead of confirmed the Viking experiment.

      • Hans Peter Uhrig says:

        The Viking LR didn’t rely on pyrolysis (heating) as the other experiments who failed to get positives.
        The LR just checked for gas release in case of the (radio-labeled)nutrient solution would be metabolized by microbes in the soil samples. In all cases the LR measured a steady (radioactive) gas release in the active samples which was expected as sign of respiration. The same samples didn’t show any gas release after they were heat-sterilized (160°C) or after sample storage for 3-4 months in the dark but otherwise ambient but isolated conditions. Interestingly the soil samples showed a lower release of gas after the sterilization temperature for the control run had been altered to ~46°C and 50°C respectively. The 50°C control almost eliminated the gas release like the 160°C controls.
        Any biologists and especially astrobiologist should become keen-eared by this kind of data shouldn’t they?

        The LR data was dismissed after the Viking GC/MS instrument failed to detect organics – here comes the Phoenix finding of perchlorate into the game.

        Alltogether the Phoenix findings strengthened the biologic interpretation of the LR as it explained the failure of the Viking GC/MS to detect organics…

        so the choice still is either a false positive of the Viking LR or a false negative of the GC/MS (like it got in antarctic dry valley test runs where the Viking LR readily detected microbes with a positive result).

  5. lcrowell says:

    The one problem is that I don’t know what is meant by “mathematical complexities to the Viking data for deeper analysis.” However, I did read about 10 years ago that the gasses produced in the Viking experiment had a diurnal cycle. That tends to give me some reason to suspect there might indeed have been life after all.


    • Torbjörn Larsson says:

      But the capsule and the experiments had a diurnal voltage and temperature cycle too. The experiments were too poorly designed to control for that.

      • lcrowell says:

        I should have thought with a $billion program they would have thermostatic controlled the experiment. With a little insulation and a simple device that should have been rather easily covered.


  6. Shandooga says:

    Ridiculous. Mars is and always has been a barren rock. Get over it. All the planets are “formless and waste”…except for Earth. Just accept it.

    • Corey Sioui says:

      Mars hasn’t always been a barren rock, it does have an atmosphere and there is ice at the polar caps. If it is and always has been barren rock then you wouldn’t have either.

    • squidgeny says:

      Yeah, Science. Just accept this thing some guy somewhere said this one time. Stop trying to investigate things and find facts!

    • Tommy Deblieck says:




      SO SCARY !!! SO I KNOW 1 THING FOR SURE… WE ARE NOT ALONE !!!!!!!!!!!!!!!!!!!!!!!

    • Torbjörn Larsson says:

      Of course, “don’t look”. So what are you afraid of.

    • TheMan says:

      This is true. There is a reason there is life on Earth and not on other planets within our solar system.

      • Torbjörn Larsson says:

        Nothing that is raised in astrobiology, and since you don’t give references there likely is none even posed.

        The rapidity with which life arose on Earth implies that it is an easy enough process. Anything from large enough asteroids so that their wet zone migrates slowly enough, through ice ocean moons to habitable terrestrials should likely have life.

        In our system this means Venus and Mars may have had it, Earth has it, there are some 14 ice moons that may have oceans and there are some 20 asteroids and probably as many moons (including our own) that may have had it deep in their crust.

        And, joy, we can go looking!

    • Rolando Pacheco says:

      Well i don’t think so, i think that in some way it is life in mars, bacterial or germs, because in the past of mars it was equal to earth whit wather and oxigen, so life can breack true on it own way…

  7. Superluminal2 says:

    Until we can either go to Mars ourselves or have a sample return mission, MSL will probablly find more questions than it answers.

  8. Dampe says:

    I think it’s time to move on from the Viking data. If there ‘is’ or ‘has been’ life on Mars, other missions WILL detect it eventually. The data was inconclusive in the 80’s.
    Even if the math may suggest life, it’s not direct evidence.

  9. Duncan Ivry says:

    Regarding “applying mathematical complexities to the Viking data”

    In the paper the authors say: “We have applied complexity analysis to the Viking LR data. Measures of mathematical complexity permit deep analysis of data structure along continua including signal vs. noise, entropy vs.negentropy, periodicity vs. aperiodicity, order vs. disorder etc.”

    There are indeed a lot of proposals for measures of the complexity of data (or of algorithms as well — usually data is implemented with algorithms for manipulating the data).

    The authors compare the complexity — defined through the measures mentioned above — of the Viking data to (a) biological data on the one hand and to (b) purely physical (non-biological) data on the other hand. The comparisons are done “via cluster analysis and other multivariate techniques”, i.e. via a collection of statistical methods. This results, as far as I can see, in rejecting the null-hypothesis of the Viking data being purely physical.

    One — commonplace — shortcoming of this approach is that statistical methods inherently do not allow any conclusions into the direction of causal relationships.

    Another shortcoming is, that the interaction of several, usually complicated, statistical methods, when applied to the same hypothesis, is complicated to a degree, that, as far as I know, nobody has been able to calculate the relevant — and crucial! — error probabilities of the combined application. So, we don’t know much about making an error, when *rejecting* the null-hypothesis of the Viking data being purely physical *because* the authors apply impressingly many statistical methods.

    But, don’t get it wrong, these are only minor caveats.

    • Torbjörn Larsson says:

      They don’t give much in the way of a conclusive method to distinguish between biological and physical systems, especially since their reference physical systems are simple references so low complexity.

      But I note that Levin claims he has looked at superoxidants but can’t find that they repeat all the conditions of the test. Still, we would need for someone to repeat that work and to look more closely to the possible variations of the capsule environment. As it is, the oxidants are known to be there, and in that case Levin’s experiment oddly did not pick them up at all. That is possibly even worse for the robustness of conclusions from it. =D

  10. jjbreen says:

    Will I be surprised to find ‘microbial’ or “cellular” or “germ” traces or evidence that such existed on Mars? No. Why should that be a surprise?

    Will we find evidence of advance life forms – Seriously doubt it. It would be “sweet” if such did exist.

    Heck I would be excited if we found traces of something like a ‘bird’ or ‘insect’/’bug’ or even vegetation/plant life forms!

    But I don’t think we will find anything beyond the microbial – cellular – germ size/complexity.

    But understand – That too would be FANTASTIC!! I don’t think it would be kept quiet – Why?

    “Hush we found dead non-complex life signs.” (The stuff dreams are made of – but nothing more!) But nothing that would cause major chaos on Earth. It would be like finding that Jupiter has a Ring System … 😉

  11. Torbjörn Larsson says:

    No, it is not enough. Reanalyzing data for 35 years will turn up correlations with the pattern you search for. The right thing to do is to reconstruct the experiment so it can yield an observation.

    This is something the Viking scientists has failed to do, mainly because the initial experiment was so poorly constructed that these non-conclusive observations were possible. The current program has found water and the next rover Curiosity will look for organics. It may find extant or extinct life, but not by a dedicated experiment.

  12. TheMan says:

    Why don’t they just send Google up there? They’d have that shit mapped in two weeks tops! With Streetview!

  13. Aqua4U says:

    Yes, there IS life on Mars – without a doubt. Unfortunately, that life came from Earth. Our landers all have had residual biological detritus or ‘fluff’ on them. We have contaminated Mars!

    Reviewing Viking data after all these years sounds like rereading an old pulp fiction detective story – “40 year old murder case finally solved – the butler did it!”

    “For much of the history of living things, organisms were exclusively primitive, single-celled forms such as bacteria and cyanobacteria. Then as now, these simple prokaryotic cells lacked a nucleus and were relatively small, but they already contained the same basic hereditary materials found in all life today—DNA and RNA. Many of these early life forms relied on chemosynthesis for their energy, deriving it from the chemicals around them instead of from sunlight or other organisms. Some inhabited environments that seem hostile, such as deep-sea hydrothermal vents.” – Smithsonian Nat’l Museum of Natural History – Dept. of Paleobiology

    Simple prokaryotic cells relying on chemosynthesis to survive within the Martian crust seems most likely… organisms surviving on the surface, not so likely. Harsh UV and temp. swings would disrupt most exposed life form(s).

    Subsurface springs near one of the volcano’s would be the best place to look. Prob. is that it would be VERY difficult to get into one of the lava tubes to explore further. The rover would have to spool out a data/com/power wire as it descended…. but it could be done!

  14. Neeraj Jangale says:

    NASA is worthless money pit in a dozen or so lunar missions they found no traces of water , Indian ISRO with its Lunar mission found water on its first try
    I hope ISRO and ESA have missions scheduled for MARS and find something

  15. I believe Mars was just like Earth , striving with Life !! wonder what The dominant Life form did to ruin it ? oh well , Im sure we will see first hand soon enough

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