A scientist recently claimed that NASA could have inadvertently discovered life on Mars almost 50 years ago after which unintentionally killed it before realizing what it was. But other experts are split on whether the brand new claims are a far-fetched fantasy or an intriguing possible explanation for some puzzling past experiments.
After landing on the Red Planet in 1976, NASA’s Viking landers could have sampled tiny, dry-resistant life-forms hiding inside Martian rocks, Dirk Schulze-Makuch, an astrobiologist at Technical University Berlin, suggested in a June 27 article for Big Think.
If these extreme life-forms did and live on, the experiments carried out by the landers could have killed them before they were identified, since the tests would have “overwhelmed these potential microbes,” Schulze-Makuch wrote.
That is “a suggestion that some people surely will find provocative,” Schulze-Makuch said. But similar microbes do live to tell the tale Earth and will hypothetically live to tell the tale the Red Planet, in order that they cannot be discounted, he added.
Nevertheless, other scientists imagine the Viking results are far less ambiguous than Schulze-Makuch and others make them out to be.
Viking experiments
Each of the Viking landers — Viking 1 and Viking 2 — carried out 4 experiments on Mars: the gas chromatograph mass spectrometer (GCMS) experiment, which searched for organic, or carbon-containing, compounds in Martian soil; the labeled release experiment, which tested for metabolism by adding radioactively traced nutrients to the soil; the pyrolytic release experiment, which tested for carbon fixation by potential photosynthetic organisms; and the gas exchange experiment, which tested for metabolism by monitoring how gases which can be known to be key to life (corresponding to oxygen, carbon dioxide and nitrogen) modified surrounding isolated soil samples.
The outcomes of the Viking experiments were confusing, and have continued to perplex some scientists ever since. The labeled release and pyrolytic release experiments produced some results that supported the concept of life on Mars: In each experiments, small changes within the concentrations of some gases hinted that some form of metabolism was going down.
The GCMS also found some traces of chlorinated organic compounds, but on the time, mission scientists believed the compounds were contamination from cleansing products used on Earth. (Subsequent landers and rovers have since proved that these organic compounds occur naturally on Mars.)
Nevertheless, the gas exchange experiment, which was deemed an important of the 4, produced a negative result, leading most scientists to eventually conclude that the Viking experiments didn’t detect Martian life.
And in 2007, NASA’s Phoenix lander, the successor to the Viking landers, found traces of perchlorate — a chemical that is utilized in fireworks, road flares and explosives, and naturally occurs inside some rocks — on Mars.
The final scientific consensus is that the presence of perchlorate and its byproducts can adequately explain the gases detected in the unique Viking results, which has essentially “resolved the Viking dilemma,” Chris McKay, an astrobiologist at NASA’s Ames Research Center in California, told Live Science in an email.
But Schulze-Makuch believes a lot of the experiments could have produced skewed results because they used an excessive amount of water. (The labeled release, pyrolytic release and gas exchange experiments all involved adding water to the soil.)
An excessive amount of of a very good thing
“Since Earth is a water planet, it seemed reasonable that adding water might coax life to point out itself within the extremely dry Martian environment,” Schulze-Makuch wrote. “In hindsight, it is feasible that approach was an excessive amount of of a very good thing.”
In very dry Earth environments, corresponding to the Atacama Desert in Chile, there are extreme microbes that may thrive by hiding in hygroscopic rocks, that are extremely salty and attract tiny amounts of water from the air surrounding them. These rocks are present on Mars, which does have some level of humidity that might hypothetically sustain such microbes. If these microbes also contained hydrogen peroxide, a chemical that’s compatible with some life-forms on Earth, it could help them to further attract moisture and in addition could have produced a number of the gases detected within the labeled release experiment, Schulze-Makuch proposed.
But an excessive amount of water may be deadly to those tiny organisms. In a 2018 study published within the journal Scientific Reports, researchers found that extreme floods within the Atacama Desert had killed as much as 85% of indigenous microbes that might not adapt to wetter conditions.
Due to this fact, adding water to any potential microbes within the Viking soil samples could have been reminiscent of stranding humans in the midst of an ocean: Each need water to survive, but within the unsuitable concentrations, it will probably be deadly to them, Schulze-Makuch wrote.
Alberto Fairén, an astrobiologist at Cornell University and co-author of the 2018 study, told Live Science in an email that he “totally agrees” that adding water to the Viking experiments could have killed potential hygroscopic microbes and given rise to Viking’s contradictory results.
Controversial claim
This just isn’t the primary time that scientists have proposed that the Viking experiments could have inadvertently killed Martian microbes. In 2018, one other group of researchers proposed that when soil samples were heated up, an unexpected chemical response could have burned and killed any microbes living within the samples. This group claims that this might also explain a number of the puzzling results from the experiments.
Nevertheless, as McKay suggested, scientists who proceed to chip away on the landers’ results are wasting their efforts. “I disagree with their logic,” he said. “There is no such thing as a must invoke an odd recent sort of life to elucidate the Viking results.”