Scientists suspect humans may never colonise Mars as killer chemicals on the planet’s surface pose a danger to life from Earth.
The chemicals – compounds called perchlorates – are strewn across the surface of the red planet.
Tests have shown that under UV lighting that mimics sunlight, the chemicals attack and kill bacteria commonly found on spacecraft from Earth.
The team from Edinburgh University fear that the toxic chemicals will contaminate humans and even robots on Mars.
The effect is even worse for bacteria when the perchlorates mix with two other chemicals found on Mars – iron oxide and hydrogen peroxide.
A fatal cocktail of all three was 10 times deadlier for bacteria.
The researchers in Edinburgh found that when the perchlorates were exposed to UV radiation similar to that on Mars, the chemicals quickly killed bacteria.
Their conclusion was the compounds found extensively on Mars are a potent risk for life from Earth.
“Our findings have important implications for the possible contamination of Mars with bacteria and other materials from space missions. This should be taken into account in designing missions to Mars,” said Jennifer Wadsworth of the UK Centre for Astrobiology and School of Physics and Astronomy at Edinburgh University.
A similar study was launched in London earlier in 2017 by Mars One, a company intending to colonise Mars and the Moon.
Life reflects fiction
The mission explained that introducing bacteria to soil on Mars is crucial to growing crops to feed humans migrating to the planet as they are crucial to the process of breaking down dead leaves, plants and roots into nutrients.
Mars One CEO Bas Lansdorp said: “For our mission of permanent settlement on Mars, growing food locally is important. While our astronauts will bring storable food from Earth, they will try to eat fresh food that they produce on Mars, increasing their independency from supplies from Earth and increasing the quality of life.”
The Edinburgh discovery is a strange case of real life reflecting fiction.
In 1897, HG Wells wrote about Martians invading Earth in his novel War Of The Worlds.
In the book, the aliens failed to conquer Earth because they fell victim to some common bacteria which humans were immune to. The university study reverses the story and suggests humans would face the same catastrophic consequences.