An American engineer who worked in NASA space research talks about the experiment of the Viking program, which proves the existence of life on Mars. The article also describes how Mars and Earth share microbes - scientists call this process "the exchange of saliva."
The Viking space program's labeled particle experiment yielded positive results, although most were recognized as inorganic chemical reactions.
Now we can look into the past and imagine how our universe was born. We have learned a lot about the laws of nature that govern countless celestial bodies, are responsible for their evolution and movement in space and determine their future fate. However, oddly enough, we still have not decided whether there is life on other planets or whether we, like the old sailor from the poem by Samuel Coleridge, are "alone, alone, always alone, alone in the swell." Until now, we have made only one attempt to reveal this primordial secret. I had the opportunity to participate in this historic experiment in 1976 - the introduction of labeled substances was carried out as part of the NASA Viking program.
On July 30, 1976, we received the first results from Mars, where the Viking spacecraft landed at a distance of almost 6,500 kilometers from each other. The samples, surprisingly, were positive. In the Labeled Release (LR) experiment, four samples and five controls were positive. This indicated microbial respiration on the Red Planet. Similar curves were obtained during experiments with the earth's soil. It seemed that the answer to the burning question had been found.
However, molecular analysis of organic matter - that is, the essence of life - was not found, and NASA concluded that the find only "mimics life, but it is not." Amazingly, in all the 43 years that have passed since then, none of the NASA spacecraft has been equipped with devices for detecting organic matter. Instead, the agency ran a series of experiments to determine if life existed on Mars - and if so, bring samples back to Earth for biological analysis.
NASA continues to prioritize the search for alien life. On February 13, 2019, NASA Director Jim Bridenstine announced that we might soon be able to find evidence of microbial life on Mars. Our country intends to send a manned spacecraft to Mars. And any life there is a potential threat to the astronauts - and upon their return, to all of us. Thus, the question of life on Mars is now of fundamental importance.
On the one hand, life on Mars is hard to even imagine. On the other hand, for the planet to be completely sterile is also a miracle, this does not happen. NASA scientist Chris McKay once said that Mars and Earth "exchanged saliva" for billions of years - that is, when comets or large meteorites hit the planet, their particles fell into space. A small part of them eventually ended up on another planet, potentially infecting it with microbiological hitchhikers. A number of laboratories have proven that some types of terrestrial microbes survive perfectly in the Martian environment. The International Space Station (ISS) reports that some microorganisms survive even in outer space.
Not wanting to conduct a direct search for microorganisms, NASA seems to forget about the simple experiment that Louis Pasteur conducted back in 1864. He infected the nutrient medium with microbes and got gas bubbles that were not there before the introduction of living organisms. So Pasteur established that heating - or pasteurization - destroys germs. This simple but elegant experiment is still being carried out by health authorities in the study of drinking water - unless the culture medium is taken more modern. Thus, billions of people are protected from microbial pathogens.
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In fact, the same experiment was carried out on Mars, except that other nutrients were added to increase compatibility with alien organisms, and they were tagged with radioactive carbon. These improvements increased sensitivity to even small microbial populations, if any, and reduced the time to detect microorganisms to about one hour. On Mars, each labeled particle experiment lasted seven days. Plus, Pasteur temperature control was added to distinguish a biological response from a chemical one.
The goal of the LR experiment was to detect and monitor metabolism, a simple and reliable indicator of living organics. In total, this experiment was carried out thousands of times - both before and after the "Viking", with terrestrial soils and microbial cultures, both in the laboratory and in extreme natural conditions. No false positive or false negative results were recorded. This indicates the reliability of the LR data, although they can be interpreted in different ways.
In her recent book, To Mars with Love, my scientific colleague in the experiment, Patricia Ann Straat, explains its scientific details in plain language. Scientific articles about the labeled substance experiment are also available on my website.
In addition to direct evidence collected during the LR, a number of subsequent programs and terrestrial experiments support microbial life on Mars.
- Surface water in quantities sufficient for the life of microorganisms was discovered on Mars by Vikings and the Mars Pathfinder, Phoenix and Curiosity rovers.
- The LR reaction was not provoked by ultraviolet radiation, as was initially assumed. A similar activity was found on material protected by rock.
- The Curiosity rover discovered complex organic matter on Mars, up to kerogen of possibly biological origin.
- The Phoenix and Curiosity rovers have found evidence that ancient Mars may have been inhabited.
- The excess of carbon-13 compared to carbon-12 in the Martian atmosphere speaks in favor of biological activity.
- The Martian atmosphere is in a nonequilibrium state: in theory, its carbon dioxide should have long ago been converted into carbon monoxide under the influence of solar ultraviolet radiation. However, carbon dioxide is somehow restored - perhaps with the participation of microorganisms, as on Earth.
- Some terrestrial microorganisms survived in outer space outside the ISS.
- Particles of rock with living microbes could well have got to Mars from Earth.
- Residual methane was found in the Martian atmosphere, presumably of microbial origin.
- The rapid disappearance of methane from the Martian atmosphere suggests the possible existence of methanotrophs that coexist with methanogens on the planet's surface.
- On the surface of Mars, wandering lights, similar to those of the earth, were found. They are formed during spontaneous combustion of methane.
- Formaldehyde and ammonia are found in the Martian atmosphere, each of which indicates a biological origin.
- An independent analysis of the complexity of the positive LR data established its biological nature.
- Six-channel spectral analysis found that the color, saturation, hue and intensity of green spots on the Martian rocks coincide with terrestrial lichens.
- One of the photos from the Curiosity rover shows a worm-like shape.
- The Curiosity rover has discovered large structures resembling terrestrial stromatolites (formed by microorganisms). Statistical analysis of their complex variables showed a chance of coincidence of less than 0.04%.
- Not a single factor hostile to life has been found on Mars.
- Thus, we have: positive results of widely used microbiological experience; positive results of control tests; duplication of LR results from both Viking modules; and, finally, the inability to provide, experimentally or theoretically, a comprehensive non-biological explanation for 43 years.
What is the evidence that life on Mars is impossible? Oddly enough, there is none. Moreover, laboratory studies have shown that some terrestrial microorganisms successfully survive and reproduce even on Mars.
NASA has already announced that the new rover, which will travel to the planet in 2020, will also lack the tools to detect living microorganisms. In keeping with well-established scientific protocol, I believe that every effort should be made to conduct proper life detection experiments as soon as possible. My scientist colleague and I proposed - both officially and unofficially - to conduct an experiment on Mars, similar to LR, but sensitive to chiral metabolism. Nonbiological chemical reactions, unlike living organisms, do not distinguish between right and left-handed molecules.
A chiral experiment would make it possible to confirm or expand the conclusions of the LR experiment. We would be able to determine whether life originated in the same way as on Earth, or in a different way. The mechanism for this has already been developed and tested experimentally. The equipment is easy to install on board.
In the meantime, the group of experts will review all data collected during the Viking program, along with others that are more recent. Perhaps such an impartial court will come to the same conclusions as me: the Viking program did indeed find signs of life on Mars. Either way, NASA will receive important support on the path to its holy grail.
Gilbert Levine is an engineer and inventor in the 1970s, Principal Investigator of NASA's Viking Space Program, responsible for the labeled substance experiment.