In our relentless pursuit to uncover the existence of extraterrestrial life, the Viking landers, launched by the US in the 1970s, presented a glimmer of hope. However, the very methods employed in our quest may have inadvertently destroyed the evidence we sought. Astrobiologist Dirk Schulze-Makuch highlights the potential destructiveness of past biological experiments on Mars and challenges us to thoroughly consider the ecological implications when planning future missions dedicated to the search for life.
When the Viking landers safely touched down on Mars in 1976, they carried a list of objectives, one of which was to conduct experiments to test Martian soil for signs of life. These experiments were pioneering, marking the first dedicated biological investigations on the red planet. However, only recently have we started to question the potential destructive nature of these experiments.
Among the Viking experiments, the gas chromatograph-mass spectrometer (GCMS) discovered chlorinated organics in the Martian soil. Initially dismissed as contamination from cleaning products used during the mission, these findings are now believed to be native to Mars. However, subsequent analysis indicated that the heating process employed by the GCMS could have incinerated the very organics it was meant to detect.
Other experiments, such as the labeled release and pyrolytic release experiments, infused Martian samples with liquid to test for signs of metabolism and photosynthesis, respectively. These experiments produced positive signals that conflicted with the null results of the gas exchange experiment. Schulze-Makuch argues that in hindsight, these release experiments were poorly conceived, as they assumed Martian life would thrive in the presence of water, neglecting the possibility of dry-adapted organisms.
Contrary to our Earth-centric assumptions, recent discoveries have proven that life can thrive under extremely dry conditions. Pouring water over these dry-adapted microbes may not invigorate them but instead overwhelm and destroy them. Schulze-Makuch intriguingly likens this scenario to an alien spaceship attempting to save a half-dead person in the desert by submerging them in the ocean. Simply put, it is an ill-fated endeavor.
Interestingly, the pyrolytic release experiment showcased stronger life signs in the dry control run, which excluded the addition of water to the samples. These conflicting results raise the question of whether we dismissed potential signs of life in our eagerness to find definitive proof.
In 2007, Schulze-Makuch proposed the idea that Mars could host dry-adapted life that incorporates hydrogen peroxide. He emphasizes that the Viking results do not contradict this hypothesis and believes that a new mission dedicated primarily to the search for life on Mars is essential to test this theory and others.
As we reflect on the Viking experiments from the 1970s, we must acknowledge the potential destructiveness of our own methods in the search for extraterrestrial life on Mars. Schulze-Makuch urges us to learn from the past and carefully consider the ecological factors of the red planet when designing future experiments. Ultimately, the quest for life on Mars demands a new mission, solely devoted to this pursuit. With anticipation, we await the opportunity to embark on this consequential journey.
Leave a Reply