The quest for extraterrestrial life has always been fraught with challenges, and a new perspective suggests a crucial oversight in one of the most ambitious missions to date. Dirk Schulze-Makuch, an astrobiologist at Germany’s Technische Universität Berlin, proposes a groundbreaking reassessment of NASA’s approach to finding life on Mars, arguing that the famed Viking 1 mission, launched in 1975, may have inadvertently destroyed any Martian life it encountered.
Schulze-Makuch’s compelling hypothesis centers on the inherent limitations of NASA’s long-standing ‘follow the water’ strategy. He contends that the water-based life detection experiments conducted by Viking 1, while seemingly logical, may have been lethal to any microorganisms present. “We are water-filled bags,” he explains in an interview with Space.com, “but too much water can be detrimental, and I believe that’s precisely what occurred with the Viking experiments.”
His revolutionary alternative? A ‘follow the salts’ approach. This strategy is inspired by Schulze-Makuch’s extensive research in the Atacama Desert, a remarkably Mars-like environment on Earth. The Atacama’s extreme aridity mirrors conditions on Mars, yet surprisingly, life persists. The key, Schulze-Makuch suggests, lies in the role of salts. He explains that, in these arid environments, organisms can utilize salts to extract water directly from the atmosphere. This process is enhanced by a phenomenon known as hysteresis, where the system resists crystallization as water is drawn out, maintaining water activity at a microscopic level – crucial for microbial survival.
This understanding profoundly impacts our search for life beyond Earth. Schulze-Makuch posits that as Mars transitioned from a wetter to its current desert state, any remaining life may have adapted to exploit salts for water acquisition, making the ‘follow the water’ approach obsolete and potentially destructive. He cautions, “I can’t definitively say Martian organisms are exploiting these effects. But considering Mars’ Earth-like conditions billions of years ago, these are the adaptations I would anticipate in any surviving lifeforms.”
The implications are starkly illustrated by a study in the Atacama Desert where torrential rains led to the demise of 70-80% of indigenous bacteria, unable to cope with the sudden influx of water. This mirrors Schulze-Makuch’s concerns about the Viking mission’s approach. By flooding potential microbial habitats with water, the mission might have inadvertently eradicated the very life it sought to discover.
Schulze-Makuch’s call for a paradigm shift in our approach to extraterrestrial life exploration is not merely theoretical. It’s a call to action, urging NASA to rethink its strategies and embrace a new era of Martian investigation. The ‘follow the salts’ approach offers a potentially more effective, and certainly more considerate, method of searching for life on the Red Planet, ensuring we don’t inadvertently extinguish the very signs of life we desperately seek.
