The search for life outside the Earth has a bit of a hurdle to jump over as researchers find evidence of potentially toxic Martian soil. Lab testing shows how certain chemicals found on Martian soil quickly kills organic life when activated by ultraviolet rays from the sun.
Toxic Chemicals On Martian Soil
Scientists from the University of Edinburgh investigated the behavior of a certain chemical compound with regards to its reaction to organic life when activated by ultraviolet radiation.
The compound in question is called perchlorate, which can also be found on Earth deserts but in lesser concentrations such as in the Atacama Desert. Perchlorate was initially discovered on Martian soil by the Phoenix Lander mission in 2008, and is now the focus of the current study.
What researchers did was to replicate the conditions on Mars to see the chemical compound's reaction toward the bacteria Bacillus subtilis. The Bacillus subtilis cultures were immediately killed by perchlorates, which were activated by the high heat of UV light. In fact, the bacteria cultures were killed within minutes.
What's more, the combination of perchlorates with iron oxides and hydrogen peroxide showed a 10-fold increase in bacterial cell death compared to the experiment with perchlorates alone.
Essentially, what they found is evidence that perhaps the Martian surface isn't as habitable as previously thought.
UV Conditions On Mars
Compared to the Earth today, early Earth was likely exposed to far higher levels of UV radiation, which is a known limiting factor to the development of life. This is very likely because the early Earth had limited ozone protection similar to what we have now.
Mars' ozone condition is similar to early Earth's as it also has limited ozone protection from UV radiation. Naturally, this means that Mars has higher levels of UV radiation on its surface.
In the case of perchlorates, it is actually not an inherent killer of organic life, and in fact, it can be surrounded by organic matter for years without doing them any harm. However, as per the results of the current study, it turns out that the killing only begins once perchlorate is exposed to UV radiation, something that is apparently quite abundant in Mars.
The Good News And The Bad News
Let's begin with the "bad" news. At least when it comes to searching for life and trying to build a human colony on Mars, the effects of perchlorates on organic matter is a bit of a stumbling block as it shows Mars as a less hospitable planet than previously thought.
Naturally, the researchers believe that further testing is necessary to check whether perchlorates would have the same effects on other organic cultures.
The good news is that these results do not necessarily mean that Mars is quite a harsh planet and that it is incapable of supporting life. It is entirely possible that the organic life on Mars is hardier than the life here on Earth due to the more extreme conditions of their surroundings.
What's more, this is also favorable for future Mars expeditions as it is very important not to taint the planet with earthly contaminants.
As such, authors of the study describe their new discovery on perchlorates to be an example of the compound's two-sided nature, which can be both beneficial and damaging.