Nasa's Viking landers accidentally killed life on Mars, says astrobiologist

Astrobiologist Dirk Schulze-Makuch believes Nasa's Viking missions have inadvertently 'eliminated' Martian life. He also mentioned that Martian life may have adapted to the planet's dry environment

Nasa launched Viking 1 spacecraft in 1975, aiming to uncover the secrets of planet Mars. The US space agency made history when the twin landers released by the spacecraft touched down on the Martian surface. 

 

Viking was in orbit around Mars' Chryse Planitia region for over six years, while its landers collected soil samples using robotic arms and onboard laboratories to investigate the red planet for clues of life.

 

The Viking life detection experiments were modelled after culturing techniques commonly used in identifying microbes on Earth. Under this method, water and nutrients are added in the soil samples monitoring for any signs suggesting microbes might be living in the samples.

 

 

“Such signals were associated with responses to the additives — essentially an influx of components needed to complete normal life cycles as we know them – and included things like growth, reproduction and the consumption of food for energy,” writes Space.com.

 

The landers had detected signs of microbial activity in the soil, which sparked considerable interest at the time. However, the results are mostly termed as negative, or inconclusive.

Another aspect is yet to be discovered: Dirk Schulze-Makuch

Now, an astrobiologist at the Technische Universität Berlin in Germany, Dirk Schulze-Makuch, claims that there is another aspect of this mystery which is yet to be uncovered. Viking may have discovered life on Mars, but maybe the water-based nature of its life-detection experiments inadvertently killed it, he says. 

 

Drik recently published in the journal Nature Astronomy, titled “We may be looking for Martian life in the wrong place,” where he argued that Mars is even drier than most dried places on Earth, the Atacama Desert, where microbes obtain water through salts that draw moisture from the atmosphere, while martian life could be highly sensitive to the liquid water addition. 

 

The experiment assumed that any life on Mars required liquid water, like most life forms on Earth. “Schulze-Makuch believes that the results of the experiments might be best explained not as the absence of organic life, but as the human-driven destruction of arid microbial organisms exposed to too much water,” adds Space.com.

Why Schulze-Makuch reexamined Viking data after 50 years?

Recently, Schulze-Makuch was interviewed by Space.com, where he elaborated that he reexamined the Viking experiment after 50 years to better understand the Mars environment and its complexities. We’ve gained invaluable insights into extremophiles on Earth. This reexamining helped in understanding the Viking data with a new perspective. 

Viking experiment killed Martian life

When asked about why he believes that the Viking experiment might have inadvertently killed Martian life, he cited a scientific concept that salts, and organisms with the help of the salts, can pull water from the atmosphere. He further mentioned an effect where there is a sort of delay, as water is removed, called a hysteresis because this system resists crystallisation.

 

He also mentioned that this process means water can stay in salt for long periods surging the water activity on a microscopic level making it accessible to microbes. 

 

Schulze-Makuch wasn’t 100 per cent sure that there was an organism on Mars exploiting these effects. But he also stated that Mars was almost like Earth around 4 billion years ago with abundant water. It becomes drier and drier to reach its current desert state. 

Earth and Mars possesses similar minerals

Space.com also asked about the assumption that life requires water hinders the understanding of extraterrestrial life. In response to this question, he said that he would agree in general but not with the case of Mars. He said Mars and Earth were very similar and possessed the same kind of minerals, though not the same variety of Mars that Earth has because there are a lot of minerals on Earth formed by biology. But they were otherwise very much similar.

How viking experiments led to false negative results?

Dirk Schulze-Makuch explained it with an example stating that imagine an alien’s spaceship lands somewhere in the desert and says “OK, look, that's a human and it needs water” and puts you in the middle of the ocean. Would you like that? No. This is what happened with Viking life-detection experiments. 

 

The Atacama Desert conducted a study where there was torrential rain and it flooded a huge area. Then scientists found that 70 to 80 per cent of Indigenous bacteria died as they couldn't handle that much water so suddenly. The same is true with the viking experiment.