In all our explorations of Mars thus far, no proof has been discovered that meets the rigorous requirements to assert that we’ve conclusively discovered life.
However, many years in the past within the Seventies, when the Viking landers turned the primary US mission to securely land on and discover the crimson planet, we might have been shut.
One researcher raises the likelihood that life existed in a pattern of Martian soil. After which, in our quest to smell it, we snuffed it out. Identical to that.
In response to astrobiologist Dirk Schulze-Makuch of the Technical College Berlin in Germany, an experiment to detect the indicators of microbial life on Mars may have been lethal.
In a column posted to Large Assume final yr, and in a commentary printed in Nature Astronomy in September, he speculates that our very strategies might have been harmful in and of themselves.
In that case, it is important for us to contemplate totally the ecology of Mars when designing future experiments. And, Schulze-Makuch advises, humanity must ship one other mission, devoted primarily to the seek for life, with these issues in thoughts.
Once they landed on Mars in 1976, the 2 Viking landers had an inventory of aims. A kind of was to carry out a set of experiments designed to check the Martian filth for biosignatures – traces of molecules that point out the presence of life.
To this point, these have been the one devoted organic experiments carried out on Mars.
A kind of experiments, the gasoline chromatograph-mass spectrometer (GCMS), discovered chlorinated organics. On the time, that outcome was interpreted as contamination from human cleansing merchandise, and thus a null detection for indicators of biology.
We all know now that chlorinated organics are native to Mars, though whether or not they’re produced by organic or non-biological processes stays unknown.
There was some hypothesis lately concerning the destructiveness of the Viking organic experiments. The GCMS wanted to warmth the samples to separate out the assorted supplies therein. That, subsequent evaluation revealed, may have incinerated the very organics it hoped to seek out.
Now, Schulze-Makuch means that different experiments may have destroyed proof likewise; particularly, the labeled launch and pyrolytic launch experiments, which concerned infusing Martian samples with liquid, then testing the outcomes for proof of metabolism and photosynthesis, respectively.
The outcomes advised a optimistic sign, which appeared at odds with the null outcomes of the fourth experiment, the gasoline trade. This was, and stays, complicated, Schulze-Makuch writes.
However the launch experiments have been probably poorly conceived, on reflection. On the time, we assumed that life on Mars could be like life on Earth and thrive within the presence of water – the extra the merrier.
However, as we’ve extra just lately discovered, life can optimize itself to thrive below very dry situations. And Mars could be very dry.
Change these situations, and the thriving might very properly cease.
“Now let’s ask what would happen if you poured water over these dry-adapted microbes. Might that overwhelm them? In technical terms, we would say that we were hyperhydrating them, but in simple terms, it would be more like drowning them,” Schulze-Makuch defined in his column.
“It would be as if an alien spaceship were to find you wandering half-dead in the desert, and your would-be saviors decide, ‘Humans need water. Let’s put the human in the middle of the ocean to save it!’ That wouldn’t work either.”
Curiously, he factors out, the life indicators recognized within the pyrolytic launch experiment have been a lot stronger within the dry management run, which didn’t add water to the pattern. So it appears pure to surprise, as others have: did these experiments detect indicators of life that we dismissed?
These indicators, to be clear, are nonetheless contradictory and much from conclusive. Nevertheless, they could warrant additional investigation.
Schulze-Makuch proposed again in 2007 that Mars might host dry-adapted life that comes with hydrogen peroxide. The Viking outcomes, he and his co-author Joop Houtkooper assert, should not incompatible with this speculation.
“If these inferences about organisms surviving in hyperarid Martian conditions are correct, then rather than ‘follow the water,’ which has long been NASA’s strategy in searching for life on the red planet, we should in addition follow hydrated and hygroscopic compounds – salts – as a way to locate microbial life,” Schulze-Makuch concludes.
“Nearly 50 years after the Viking biology experiments, it is time for another life detection mission – now that we have a much better understanding of the Martian environment.”
The commentary is printed in Nature Astronomy.
An earlier model of this text, previous to the brand new Nature commentary, was printed in August 2023.
