In 1976, the Viking 1 and 2 probes landed on Marte with an ambitious mission: search for traces of life on the Martian soil. At one point, one of the probes tested positive for biological traces, but then everything was attributed to natural compounds on the planet that were not exactly from a life form.
Now almost 50 years later, a recent hypothesis by the German astrobiologist Dirk Schulze-Makuch suggests that the NASA may have found life on Mars during the 1970s, but that the research methods used by the Viking probes they would have destroyed the evidence of their existence.
This theory, raised in several scientific publications and conferences, reopens the debate about the possibility of life on the red planet and underlines the importance of designing more careful experiments for future missions.
Going back to 1976, among the experiments carried out, the gas chromatograph-mass spectrometer (GCMS) detected chlorinated organic compounds, a signal that was then discarded as contamination from the instruments themselves. However, later research confirmed that these compounds originated from Mars.
According to Schulze-Makuch, the problem was that The experiments required heating the samples to high temperatures to separate their componentswhich could have destroyed the very organic compounds that were sought. This could explain why the results yielded carbon dioxide rather than conclusive biological signals.
The experiments carried out by the Viking probes were based on the assumption that any life form on Mars would need water to survive, just as it does on Earth. Therefore, some procedures, such as In the pyrolytic release experiment, they added water to the samples to observe chemical reactions. Nevertheless, Schulze-Makuch he claims in the magazine Nature that this excessive amount of water could have “drowned” Martian microorganisms adapted to extremely dry conditions.
In the scientist’s words, “It would be as if an alien ship found a dehydrated human in a desert and, to save him, decided to throw him into the ocean. “That approach wouldn’t work.”
A key indication that reinforces this Our hypothesis is that the biological signals observed in the experiments were stronger in the dry tests, where no water was added to the samples. This suggests that Martian life, if it exists, could be optimized to survive in extremely dry conditions, something the Viking methods did not contemplate.
To support his hypothesis, Schulze-Makuch compares the conditions of Mars with those of the Atacama Desert, in Chile, one of the driest regions on Earth. There, microorganisms manage to survive within salt rocks using hygroscopicity, a process by which salts capture water from the humidity in the air.
The scientist points out that the equatorial regions of Mars, where the Viking probes landed, present conditions similar to those of the Atacama, which reinforces the possibility that microbial life adapted to dryness exists on the red planet.
Schulze-Makuch and other scientists have argued that the Viking methods were ill-conceived from the beginning. assume that life on Mars would be identical to that on Earth. This anthropocentric perspective could have led to a misinterpretation of the results.
The hypothesis does not necessarily imply that life has been found on Mars, but it raises the possibility that the experiments were able to detect signals that were discarded or destroyed. Furthermore, it underscores the need to reconsider how we design experiments to search for life in extraterrestrial environments.
After almost 50 years since the Viking missions, Schulze-Makuch believes that It’s time to send a mission dedicated exclusively to detecting life on Mars. According to the scientist, this new mission should explore regions such as Southern Highlands, where salt rocks near the surface could harbor microorganisms.
An important approach would be to “follow hydrated and hygroscopic compounds, such as salts,” rather than focusing solely on the search for liquid water. This strategy, combined with an experimental design that is more respectful of the Martian environment, could increase the chances of finding life.
The Schulze-Makuch hypothesis revives fundamental questions about the search for life beyond Earth. If the Viking experiments did destroy biological evidence, this demonstrates how easy it is to miss signs of life by imposing terrestrial criteria on extraterrestrial environments.
Additionally, it raises the need to consider the unique ecology of each planet when designing experiments. For example, If Martian microorganisms really use hydrogen peroxide as a survival strategy, as Schulze-Makuch suggested in 2007, this would require a completely different approach in future analyses.
The debate about the existence of life on Mars remains speculative, but hypotheses like this reinforce the importance of continuing to explore. According to Schulze-Makuch, sending a specific mission with current technology could provide definitive answers and potentially change our understanding of the universe.
“It’s time for another life detection mission, now that we have a much better understanding of the Martian environment,” concludes the scientist.
With better preparation and an approach more tailored to the unique conditions of Mars, humanity could be closer to solving one of the biggest riddles of space exploration: are we alone in the universe?
Scientists have raised the possibility that small pools of melt water could exist under the ice sheets on Mars, even amid its extreme conditions. According to computational models, the sunlight passing through the Martian ice would be enough to support photosynthesis in these bodies of water, an essential process for life on Earth.
Although no direct evidence of life has been found on Mars, the results of this study suggest that these puddles could be one of the most promising places to look for signs of life on the red planet. “If we are looking for life anywhere in the universe today“The ice exhibits on Mars are probably one of the most accessible places we should look,” he said. Aditya Khullerlead author of the study, in a statement from NASA.
One of the notable findings is that certain types of ice on Mars could allow the formation of small bodies of melt water in the subsurface. Mars features two main types of ice: water ice and carbon dioxide ice. While carbon dioxide ice goes directly from solid to gas, water ice can melt under specific conditions, even with the planet’s low temperatures and thin atmosphere.
The researchers used computer simulations to analyze how sunlight could penetrate up to 3 meters beneath the Martian ice, allowing small pockets of water to form. These bags could create the necessary conditions for photosynthesis, the process on Earth that converts sunlight into chemical energy, essential for life.
A similar phenomenon occurs on Earth. In icy regions, dust particles trapped in the ice create small spaces known as cryoconite holeswhere heat generated by absorbed sunlight melts ice, forming pools of water that harbor microbes and other simple organisms. According to the NASA team, a comparable process could be occurring on Mars.
Dust embedded in the Martian ice would absorb sunlight, generating enough heat to melt the surrounding ice and creating environments that could be habitable for microscopic life forms.
