On Mars, the Vikings found life. New revelations on the mystery that NASA does not want to solve
Between 14 and 15 August 1965, the U.S. probe Mariner 4, after a journey of seven and a half
months, flew over the red planet passing at a minimum distance of 9,846 kilometers,
and soon began to send the first images of the surface to Earth.
For many scientists, however, the euphoria for the complete success of the mission soon turned into a
real cold shower. They expected a planet "alive", even with possible traces of vegetation, and
instead, the first photos were there to describe a typical lunar landscape, arid and cratered.
So, goodbye "Martian civilizations", goodbye to any possibility of finding life evolved
in that desert almost without atmosphere ... It was a real disappointment for many.
Nor did things improve with the missions that followed. Mars turned out to be a very
complex planet, completely different from Earth,
but also very different from the Moon. All photos seemed to agree on one fact:
the red planet did not look like a place suitable to host higher forms of life.
In fact, even if the Mariner probes had categorically excluded the existence of
a Martian civilization, there was always the possibility that Mars could still host some form
of microbial life. Therefore nothing was lost! The task of clarifying this aspect would have
fallen a few years later to the probes Viking 1 and 2...
The Viking mission was at that time the most ambitious project undertaken by NASA
after the end of the Apollo era. The twin probes Viking 1 and Viking 2, both consisting
of an orbiter and a lander, left for Mars on August 20 and September 9, 1975, respectively.
After a quiet interplanetary cruise of ten months, Viking 1 entered orbit around Mars on June 19,
1976, and began to take a series of photographs to locate a favorable site for landing,
the point was finally identified and on July 20, 1976, the lander separated from the
orbiter and after three hours of descent landed on the Martian surface at 11:53
UT. The twin probe entered into orbit on August 7, 1976, and its lander landed on the Martian
surface at 22:38 UT on September 3 at a point located about 6500 kilometers from Viking 1.
Very soon the first splendid images and a whole series of chemical and physical data
of the Martian soil began to arrive on Earth. It was the first time ever that a probe sent back
to Earth the appearance of a Martian landscape as it could be seen by a terrestrial explorer.
But the absolute novelty of the mission was that both landers had a mechanical arm capable
of taking soil samples, and a small internal laboratory capable of performing some simple
experiments to highlight the presence of microbial life. Viking, in fact, were not only there to take
beautiful pictures, but especially to search for life! Once at NASA they used to do so ...
And to this end, the landers performed three types of experiments. The first was the "gas exchange",
whereby nutrient broth was added to Martian soil samples, then trying to detect some
kind of gaseous emission. Before the addition of nutrients the samples were exposed to water vapor
and, to the surprise of scientists, was detected an intense emission of oxygen
with traces of nitrogen and carbon dioxide. If the samples were preheated to 145 ° C,
a temperature sufficient to kill any terrestrial microbe, the emission of oxygen decreased but
did not go to zero. When the nutrient broth was added the scientists detected some gas exchange
but the situation remained somewhat confusing. The second test was the famous LR, the Labeled
Release experiment. Also in this case to a sample of Martian soil was added a nutrient broth,
only in this case the broth contained radioactive carbon.
The idea was that if the radioactive carbon had been metabolized by Martian microorganisms,
it would have been possible to see an emission of carbon dioxide radioactive and therefore
easily detectable. The experiment was conducted by both landers: the first used some soil exposed
to sunlight and Martian weather, the second took it from under a rock (so protected from UV rays,
potentially harmful to any form of life). For both Viking the results were clearly positive,
moreover, it was noted that if the samples were preheated, the emission of carbon dioxide ceased
abruptly, just as if those responsible for the emission were microbes then eliminated by heat.
The third experiment was the "assimilation of carbon dioxide": the Martian soil samples
were exposed to an atmosphere of radioactive carbon dioxide and a strong light to simulate
the light of the Sun. The purpose was to see if any Martian microorganisms extracted carbon from
carbon dioxide like terrestrial photosynthesizing organisms. The experiment gave a positive result
in several cases even if the preheating of samples did not completely zero the response.
In summary, from the point of view of the possibility of the presence of life, the
results of the experiments seemed very promising: one experiment (the Labeled Release) had given a
very positive result and the other two partially positive. Yet the scientists who followed the
experiments agreed in drawing the conclusion that Mars had to be a biologically dead planet!
This pessimistic and strangely hasty conclusion was attributed to the fact
that further analysis of the Martian soil had not found any trace of organic material.
This was very strange, in fact, regardless of the fact that on Mars there is life or not, a certain
amount of organic molecules should still come from space (think that traces of organic matter
are present even on the Moon where they arrived on board of meteorites). Therefore, according to NASA
scientists, an unusual chemistry of a strongly reactive and oxidizing soil, swept by a violent
ultraviolet radiation coming from the Sun could well explain the results of the experiments
without resorting to the hypothesis of life. "BE sure to join the Insane Curiosity Channel...
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An interpretation that to many scientists seemed to hide something unclear. Especially to Gilbert
V. Levin, the creator and manager of the Labeled Release experiment, who since then has always been
strongly opposed to those conclusions, arguing with arguments entirely shared that his experiment
had instead provided unequivocal evidence of the existence of Martian microbial life.
After the end of the Viking mission, Levin and his collaborator Patricia Ann Straat,
analyzed for at least a decade the data of the experiments and repeated them in the laboratory
on Earth using different types of soil from the most diverse sites, such as Antarctic soil.
In 1997, other discoveries about extremophilic bacteria and new hypotheses about environmental
conditions on Mars gave new impetus to their research, and Levin decided to publish for the
first time his conclusions, stating: "Several thousand tests have been made, both before and
after the Viking mission, with terrestrial soils and microbial cultures, both in the laboratory and
in extreme natural environments. No false positive or false negative results have ever been obtained.
This strongly supports the reliability of the Labeled Release experiment data on Mars."
In a new paper defending his thesis, recently produced, Levin now tells how both Viking
spacecraft, even though they landed thousands of miles apart, returned the same positive results,
supported by five different controls. And how, when the Viking Molecular Analysis Experiment
failed to detect any organic molecule, NASA concluded that the LR experiment
must have found a substance that "mimics the metabolism of life, but not life itself".
In his "j'accuse", Levin also denounces that, inexplicably, despite results
so controversial and therefore in need of immediate confirmation or denial, from 1976 to
date none of the subsequent NASA landers on Mars has been equipped with a life detection instrument
similar to that of Viking. And this, together with the hastily negative judgment on the results,
has always been for Levin the smoking gun, the queen proof of the fact that NASA did
not want to let the world know that something up there on Mars had been found for real...
The official NASA version has in fact never fully convinced a part of the scientific community,
and many have wondered if the outcome of those analyses was not the fault of experiments too
insensitive or conceptually wrong, rather than the real absence of life on Mars.
Levin himself, immediately after the failure to detect organic material by the Molecular Analysis
Experiment stated that the lack could be due to a sensitivity of the instrument not adequate to the
values of the Martian environment. And he brought as evidence the fact that a similar experiment
conducted on Earth in Death Valley with a copy of the same spectrometer mounted on board of Viking,
was not able to detect the presence of bacteria or other organic material!
In the meantime, other probes arrive on Mars, and with them come other good news for Levin. In 2008,
among the regolith of the northern hemisphere of Mars, the Phoenix lander finds perchlorates,
which are highly toxic and flammable salts, also used for the manufacture
of fireworks. The Mexican Navarro-Gonzalez and the American Christopher McKay of NASA have the
idea to try an experiment. They take soil from the Atacama Desert, the driest place on Earth,
with a small amount of bacteria and organic compounds, and to the soil
sample they add a small amount of perchlorates, thus simulating the composition of Martian soil.
They heat up to 500 degrees and they make analyze everything to an exact copy of the
spectrometer that in 1976 on Mars had found only the presence of a kind of solvent.
Result? No trace of organic compounds if not some molecules of chlorohydrocarbons.
Just the same found on Mars, and that NASA had baptized as contamination of terrestrial nature!
In practice, the Viking's spectrometer had destroyed, burning the perchlorate,
just those organic compounds of which it had to show the existence!
This hypothesis is also proved by the fact that Viking detected the presence of chlorobenzene,
a flammable substance that could have been originated only by the combustion
of organic material in the soil samples... And this was certainly another point in favor
of the thesis of Levin and colleagues. Also in favor was the news that a review of the Viking
experiments by neurobiologist Joseph D. Miller of the University of Southern California had led to
some puzzling conclusions. The analysis with modern statistical techniques of an experiment
conducted on Earth for more than ninety days, had in fact allowed to discover, according to Miller,
a periodic oscillation of carbon dioxide emission with a period of 24.66 hours,
coinciding with the duration of the Martian day. And according to Miller, this is a typical
circadian phenomenon, index of bacterial activity. .
To put an end, in one way or another, to this long controversy on the search for life on Mars will
probably be the next scheduled missions. Certainly not the Perseverance one, that is landing on
the planet just in these days, and it is totally lacking of an equipment for biological research...
Maybe we will have to trust in ExoMars, the mission designed by the European Space Agency,
equipped to search for life forms and able to explore the Martian subsurface. A probe that,
however, has suffered major delays in its launch schedule and will not arrive on Mars before 2023.
And we want to close with the words of the same Levin, who interviewed about these
latest revelations, when asked why in his opinion
NASA had avoided to equip its Mars probes with instruments suitable for the search for life,
he replied: "It was an absolutely intentional choice. I think that finding microbial life on
Mars could have hindered the sending of other missions because of the "planetary protection"
treaty, with the consequent loss of federal funding. I can't see any other motivation".
“Do you want to know more about the Planetary Protection Treaty ? Click on
the video “Will we be the ones contaminating the Martians?"