Astrobiologist Dirk Schulze-Makuch of the Technical University of Berlin has come up with a bold hypothesis: NASA missions in the 1970s may have inadvertently destroyed life on Mars. His assumption is based on the results of experiments conducted during the Viking-1 mission in 1976.
Viking’s experiment
Two NASA spacecraft landed on Mars and conducted a series of tests to search for life. In one experiment, Martian soil was mixed with water and nutrients. It was assumed that, as on Earth, life on Mars depended on liquid water. The first results gave hope: the analysis showed possible signs of biological activity. However, they were later recognized by most scientists as false positives.
Schulze-Makuch offers a different explanation. He believes that life on Mars could have existed, but be adapted to extreme conditions. He cites microbes from the Atacama Desert in Chile as an example. In this driest place on Earth, microorganisms survive using salts that absorb moisture from the air. The scientist believes similar salt-dependent life forms could have existed on Mars, and excess water during the experiment could have destroyed them.
Why are salts important?
In a commentary for Nature, Schulze-Makuch emphasizes that the search for life on Mars should focus on the study of hydrated salts. He suggests that the Martian environment is more supportive of organisms that survive with hygroscopic compounds rather than liquid water. “The Viking experiments may have accidentally killed Martian life by applying too much water for analysis,” the astrobiologist notes.
This hypothesis challenges NASA’s traditional “follow the water” strategy. Instead, Schulze-Makuch suggests focusing efforts on researching hygroscopic compounds such as sodium chloride, the main salt that is present on Mars.
The scientist cites an example from the Atacama Desert, where heavy rains destroyed 70-80% of the local microbes, which simply could not cope with so much moisture. He suggests that something similar may have happened during the Viking experiments.
New missions and perspectives
Nearly 50 years after the Viking missions, the scientist is emphasizing the need for a new expedition to search for life on Mars. “Today we have a better understanding of the Martian environment and can use a variety of independent methods to obtain conclusive data,” said Schulze-Makuch.
Although his hypothesis remains a theory, it opens new perspectives for the study of Mars. Perhaps future missions will help provide a final answer to the question of whether there is life on the Red Planet.
Earlier we reported on the top 5 false signs of extraterrestrial life in the history of science.
Provided by space.com
