Are we alone in the universe? This must be the deepest question in human history. Since its creation, NASA and other space agencies have invested billions of US dollars in missions, such as Perseverance, to search for traces of past life on the red planet. However, there is a story from the scientific community that is often told on obscure websites and that you will not find on NASA’s official website. Almost half a century ago, a historic discovery may have proven that life exists on Mars… But what happened next has always been the subject of intense debate.
This refers to the Viking 1 and Viking 2 missions, launched by NASA in the 1970s. These were the first direct and sophisticated attempts to search for microbial life beyond Earth. The whole conspiracy dates back to 1976, when one of the three experiments aboard the landing modules found a result as ambiguous as it was promising: positive signals compatible with the presence of life—at least, according to what was expected before this space mission left Earth.
The “positive” experiment on Mars
It was 1976, and apart from hippies everywhere, the United States and the Soviet bloc were in the midst of the Cold War. The space race against the Soviet Union drove the United States to achieve anything before its rival. The Viking probes arrived on Mars that year, carrying with them an entire miniature biological laboratory. The most intriguing of the three experiments was the Labeled Release (LR), whose principal investigator was scientist Gilbert V. Levin.
This experiment was specifically designed to detect the metabolism of living organisms. The process consisted of taking a small sample of Martian soil and feeding it with a soup of special nutrients. These nutrients were labeled with a well-known radioactive marker: carbon-14.
If Martian microbes consumed nutrients, they would inevitably exhale carbon dioxide—in other words, CO2—which would also contain the radioactive marker and could be easily detected by a sensor. The initial result was quite astonishing: a strong and rapid burst of radioactive gases was recorded in the first test cycle with the probes, separated by 4,000 miles to validate this finding.
The crucial control test was also carried out: a duplicate soil sample was sterilized with intense heat (approximately 160 °C) before receiving the nutrient. The curious thing is that this sterilized sample did not produce any reaction… So it meets all the criteria for detecting microbial life that had been proposed in the forecast phase.
The initial logical conclusion was that life on Mars had been detected and then destroyed by heat. But why didn’t they say anything to the public?
Chemistry vs. biology clash
It offers a lot to the module, since other instruments on board began to give contradictory results. This second experiment, which was tasked with searching for organic molecules, found no significant traces of organic matter in the soil. According to the LR experiment, there was life, but where are the essential components to build it?
However, the doctor who had been in charge of the laboratory that did give an affirmative answer spent the rest of his life dedicated to this cause. He maintained until the day he died that the LR was biological, and that the absence of organics was a technological problem, not one of the red planet. Dr. Gilbert V. Levin argued that the second laboratory heated the soil, destroying any organic molecules before they could be detected, or that Martian life was simply of low density.
However, the prevailing official explanation was that the Martian soil contained highly reactive chemicals that reacted violently with the experiment’s nutrient solution. These oxidants, very similar to cleaning products or hydrogen peroxide, released CO2 from biogenetics. In other words, they had a reaction similar to that of an organism with metabolism, without actually being one. Ultimately, NASA concluded that the results of the Biking waves were officially inconclusive, but we will always be left with a nagging doubt, since the official director of one of the experiments always gave another version of events.
In any case, it would not be the first time—nor the last—that a government agency has hidden information from the public. Elon Musk, Jeff Bezos and other billionaires to get to Mars and see if Dr. Levin was right.