In the 1970s, NASA sent the two Viking landers to Mars, during the Viking program.
The trip to the Red Planet gave scientists a better understanding of Mars, and also delivered some surprising results. One experiment gave the first possible hint that we’d detected traces of life on Mars. Back then the evidence was found “inconclusive”, but one of the experimenters, Dr Gilbert Levin, says that he’s convinced that we did find alien life back then…
The experiment, called Labeled Release, involved a sample of Martian soil that was given a drop of diluted nutrients tagged with a radioactive carbon isotope, and if lifeforms were emitting carbon dioxide on Mars, they would release the radioactive tag and it would be detected.
“Both Viking landers conducted the experiment. One collected a sunlight exposed sample, the other collected a sample from under a rock. Both experiments reported a detection. The experiment was then repeated after a week using the same sample, but this time, nothing was detected. In 1976, Levin and his partner in the experiment Dr Patricia Ann Straat deemed the results inconclusive.”
The landers were sent to Mars in the 1970’s.
Considering that the Viking Molecular Analysis Experiment failed to detect organic matter, NASA decided that whatever caused the detection was a chemical reaction mimicking life. Over the last few years, Levin and Straat have actually reconsidered the findings, arguing that this was our first detection of alien life, and noting that this and many other findings from the last 43 years make life on Mars a strong possibility.
“What is the evidence against the possibility of life on Mars? The astonishing fact is that there is none,” Levin writes in Scientific American. “Furthermore, laboratory studies have shown that some terrestrial microorganisms could survive and grow on Mars.”
“In keeping with well-established scientific protocol, I believe an effort should be made to put life detection experiments on the next Mars mission possible,” Levin writes. “I and my co-experimenter have formally and informally proposed that the LR experiment, amended with an ability to detect chiral metabolism, be sent to Mars to confirm the existence of life: non-biological chemical reactions do not distinguish between ‘left-handed’ and ‘right-handed’ organic molecules, but all living things do.”
We are yet to have certainty about the existence of life on the Red Planet, but maybe some proof has already been discovered.
