Amid ongoing efforts to find signs of life on Mars, NASA’s upcoming mission to collect samples from the planet is on track to wrapping up in the early 2020s. Yet, a scientist has put forward a thought-provoking idea that we might have actually come across signs of life on Mars almost fifty years ago, a meeting that might have had a sad ending.
Before the remarkable journey of the Curiosity rover, there were two earlier spacecraft vehicles that played a crucial role. NASA’s Viking program, which took off in 1975, not only gave us our first views of Mars’ surroundings but also conducted tests on its soil to search for hints of life. The main goal was to discover any signs that life could be present.
Information given by NASA’s Viking program
The information collected by these probes caused a significant change in how scientists on Earth think about water on Mars. The explorations showed many shapes in the land that looked like they were made by water moving around.
They found wide river paths in different places, and they saw signs that huge amounts of water burst through dams, made deep valleys, carved rocks, and went on for thousands of kilometers. There were also lots of twisting channels and streams all over the lower half of the planet, suggesting that it might have rained there a long time ago.
Interestingly, the sides of Mars’ volcanoes looked similar to those in Hawaii, which tells us they might have gotten wet from rain earlier. Some craters even seemed like they were made by something hitting muddy ground.
Series of tests
A set of tests led to confusing results that left scientists puzzled. The landers conducted three different experiments. The first one showed positive signs that seemed to point to life processes.
However, the following two experiments produced completely contrary results. They couldn’t find any organic stuff. This made scientists think that maybe the first positive result happened because of some chemical reactions that didn’t involve life.
In other words, the first experiment found bits of organic materials mixed with chlorine. These probably came from Earth and weren’t part of Mars.
Another part of the experiment involved adding water with nutrients and a special kind of carbon (carbon-14) to the Martian soil. The idea was that if there were tiny living things on Mars, they would eat the nutrients and turn the special carbon into gas.
The first round showed this gas, which didn’t happen in a comparison test, but the other results didn’t really provide clear answers.
If there were bacteria, more gas should have been emitted when they added additional nutrients and waited longer. Even when this was done, however, not much extra gas came out. The main reason for the first positive result was probably perchlorate, something used in rocket fuel. This perchlorate might have changed how the nutrients worked.
Alternative theory for the experiments
Professor Dirk Schulz-McKoch from the Technical University of Berlin has a different perspective. He thinks that perhaps the researchers made a mistake by adding water. This mistake might have caused the bacteria they were looking for to die.
Life on Mars was discovered 50 years ago and then eradicated -astrobiologist
— ✨FacT✨ (@_F_A_CT) August 29, 2023
In a report published in June, he talks about how some kinds of life on Earth can live in really tough places, as is the case with bacteria inside rocks with salt. These bacteria get water from the air and don’t like being underwater.
If they were put in water, they could die. This may be the reason why they didn’t see any special gas even when they added more nutrients.
Professor Schulz-McKoch has said that life on Mars could have hydrogen peroxide in its cells. He wrote about this in a study in 2007. This kind of setup could be good for life on Mars because it freezes at a low temperature, gives off oxygen, and soaks up water.
He puts forward the idea, saying, “If we consider the hypothesis that Martian life evolved to incorporate hydrogen peroxide into its cells, it could elucidate the outcomes of the Viking program’s experiments.”
He goes on to say, humorously, that the machine they used to examine the samples heated them up before checking. “If Martian cells contained hydrogen peroxide, this could have proven fatal. Additionally, it might have triggered a reaction between the hydrogen peroxide and organic molecules, generating substantial carbon dioxide—precisely what the device detected.”