“I am convinced that we found evidence of life on Mars in the 1970s,” said Gilbert V. Levin, who was the principal investigator of an experiment on NASA’s Viking mission to Mars.
The Labeled Release (LR) experiment on the Viking mission reported positive results of microbial respiration, although the majority ruled them out as a product of inorganic chemical reactions.
On July 30, 1976, the LR returned its initial results from Mars. Surprisingly, they were positive. As the experiment progressed, a total of four positive results, backed by five varied controls, flowed from the Viking twin spacecraft landing each other 6,000 kilometers away.
As Levin explains in an opinion article published in Scientific American, data curves pointed to the detection of microbial respiration on the red planet.
«The curves of Mars were similar to those produced by the LR tests of soils on Earth. It seemed that we had finally answered the final question, ”he says.
However, when the Molecular Analysis Experiment could not detect organic matter, the essence of life, NASA concluded that the LR had found a substance that mimicked life, but it was not life.
“Inexplicably,” says Levin, “during the 43 years since Viking, none of NASA’s subsequent Mars landers have carried a life-detection instrument to track these exciting results. Instead, the agency launched a series of missions to the red planet to determine if there was ever a suitable habitat for life and, if so, eventually bring samples to Earth for biological testing.
NASA ignores a simple test
In his view, NASA’s reservation against the direct search for microorganisms ignores the simplicity of the task carried out by Louis Pasteur in 1864. This famous French chemist and bacteriologist allowed the microbes to contaminate a broth of infusion of hay, after which bubbles of its exhaled gas appeared. Before containing live microorganisms, no bubbles appeared. (Pasteur had previously determined that heating, or pasteurizing, such a substance would kill microbes.)
This elegant and simple test, updated to replace modern microbial nutrients with hay infusion products in the Pasteur test, is used daily by health authorities around the world to examine drinking water. Billions of people are thus protected against microbial pathogens.
“In essence, it was the LR test on Mars, modified by the addition of several nutrients that are believed to expand the chances of success with foreign organisms, and the labeling of the nutrients with radioactive carbon,” says Levin. “The improvements applied made the experiment sensitive to very low microbial populations postulated for Mars, if any, and reduced the time of detection of terrestrial microorganisms to approximately one hour.”
“But on Mars,” he adds, “each LR experiment continued for seven days. A heat control, similar to Pasteur’s, was added to determine if any response obtained was biological or chemical ».
The Viking LR sought to detect and monitor the ongoing metabolism, a very simple and false-positive indicator of living microorganisms. Several thousand executions were carried out, both before and after Viking, with terrestrial soils and microbial cultures, both in the laboratory and in extreme natural environments. No false positive or false negative results were obtained.
“This strongly supports the reliability of the LR data, despite the interpretation of its interpretation,” says Levin.
More hints of Martian life
In addition to the direct evidence of life on Mars obtained by the LR instrument of the Viking mission, there are others that support or are consistent with exhaling microbial life and were obtained in subsequent missions and discoveries:
- Sufficient surface water to support microorganisms was found by Viking, Pathfinder, Phoenix, and Curiosity.
- The ultraviolet (UV) activation of the Martian surface material did not cause, as originally proposed, the LR reaction: a sample taken under a rock that projected from this type of radiation was as active as other surface elements.
- Complex organisms have been reported by scientists from the Curiosity mission, including querogen, which could be of biological origin.
- The Phoenix and Curiosity missions found evidence that the ancient Martian atmosphere was possibly habitable.
- The excess of carbon-13 over carbon-12 in the atmosphere of Mars indicates biological activity, which prefers to ingest the latter.
- The Martian atmosphere is in an imbalance: its CO2 should have long since been converted into CO by the sun’s UV light; therefore, CO2 is being regenerated, possibly by microorganisms such as on Earth.
- Terrestrial organisms have survived the outer space environment of the International Space Station.
- Ejecta that contains viable microbes has arrived from Mars to Earth.
- Methane has been measured in the Martian atmosphere; Microbial methanogens could be the source.
- The rapid disappearance of methane from the Martian atmosphere requires a sink, possibly provided by methanotrophs that could coexist with methanogens on the surface.
- Ghostly lights — as if they were fiery fires — have been sighted near from the surface, which could correspond to spontaneous methane ignitions.
- Formaldehyde and ammonia, each possibly indicative of biology, would be present in the Martian atmosphere.
- An independent analysis of complexity on the positive LR signal has identified it as biological.
- The six-channel spectral analysis of the Viking imaging system found that green lichens and mantles on the rocks of Mars have the same color, saturation, hue, and intensity.
- A worm-shaped feature appeared in an image taken by Curiosity.
- Large structures, similar to Earth’s stromatolites (formed by microorganisms), have been found by Curiosity. Statistical analysis determined that the probability that this similarity was a cause of chance is less than 0.04%.
- No adverse factors to life have been found on Mars.
Source: Scientific American