Sunday, July 23, 2017

Mars Might Not be Habitable (At Least on the Surface)

Right now, the hunt is on to locate possible alien life on Mars. Additionally, many organizations are looking to land probes on Mars, and quite possibly people in the near future. With all of this exploration going on that's directed towards the red planet, we've heard of water possibly existing on the planet (an earlier article reported here at Science Bureau). We've gathered samples from the surface of Mars for observation. And there just might be a new discovery that could change the way we look at Mars.

Turns out, there's a toxic cocktail of chemicals on the surface that completely sterilize the planet.


Yep, the toxic soil shows no signs of life, and the compounds within the soil are turned into potent bactericides by the ultraviolet light. A bactericide is a substance that kills bacteria, effectively sterilizing whatever surface it is touching. And the compounds found in the soil are located all over the entire planet. So chances are there's nothing in terms of alien life on the surface of Mars.


Granted, this is only the surface. There still exists the possibility of life that could exist at some point beneath the surface. Due to the current onslaught of ultraviolet light and radiation on the surface, the most hospitable area on the planet could be a couple feet below the surface. “At those depths, it’s possible Martian life may survive,” said Jennifer Wadsworth, a postgraduate astrobiologist at Edinburgh University who completed this research. Back in the 1970s, the Viking landers on Mars made the discovery of detecting perchlorates on the surface. Perchlorates are powerful oxidants that are often used in propellants for rockets. In short, they are not the best for human health if they are consumed. And in 2015, the Mars Reconnaissance Orbiter spotted signs of perchlorates that streaked on the surface, suggesting possible liquid movement on Mars.


At first, the notion was that alien bacterial life might have trouble existing in an environment with these perchlorates, but they could maybe exist in some form that could utilize the perchlorates as energy. With this in mind, Wadsworth worked with a fellow astrobiologist named Charles Cockell, and put the bacteria Bacillus subtilis through an experiment to simulate the surface on Mars. B. subtilis is a common soil bacterium and a contaminant found on many space probes. When the bacteria was mixed with perchlorates like the ones on Mars and blasted with UV light, the bacteria was found to die twice as fast when the perchlorates were present. In addition, the UV light also was observed breaking down the perchlorates into hypochlorite and chlorite, which are also destructive to bacteria.


The study also focused on other compounds found on the surface of Mars, such as iron oxides and hydrogen peroxide. When these were hit with UV light, the bacteria was found to die 11 times faster than combined with the perchlorates. So as of now, life on the surface seems like a dismal possibility. “I can’t speak for life in the past,” said Wadsworth. “As far as present life, it doesn’t rule it out but probably means we should look for life underground where it’s shielded from the harsh radiation environment on the surface.”


Luckily, that's what many space agencies plan to do. The European Space Agency plans to launch its ExoMars rover to the planet so that it can bore down 2 meters into the soil to retrieve samples and observe them for possible alien life. But for now, especially on the surface of the red planet, any alien life - if it did exist in the past - probably has no chance now thriving or even existing on the surface of Mars. Again, we may find something in the planet, but we are going to need to wait a few more years for some more answers.


A news article on this topic posted at The Guardian can be read here:


https://www.theguardian.com/science/2017/jul/06/mars-covered-in-toxic-chemicals-that-can-wipe-out-living-organisms-tests-reveal


The research paper published in the journal Nature can be found here:

https://www.nature.com/articles/s41598-017-04910-3