The surface chemicals and UV light make Mars an inhospitable place for any earth bacteria, which means it's likely inhospitable for any potential Mars bacteria as well.
"We need to be able to be drilling maybe 20 centimetres, maybe metres, down below the Martian regolith [the mixture of dust, soil and broken rocks] and be looking for life in the rocks and the sediments below the surface, out of the way of this UV radiation", he said.
The chances of finding aliens may be impossible, if new research is to be believed.
Researchers from the University of Edinburgh have now confirmed that when you pair the compounds with intense ultraviolet (UV) light exposure, things become grim for any life forms.
In 1976, the Viking 1 and 2 spacecraft landed on Mars and detected something called perchlorates in the soil. Adding in additional environmental factors found on Mars like low temperatures, additional minerals found on Mars and a lack of oxygen also failed to keep the bacteria alive.
Experiments by researchers at Edinburgh University have found that when this combined with compounds found in the Martian soil, they turned into potent bactericides, effectively sterilising the upper layers of the landscape. Other perchlorates found on Mars had a similar bactericidal effect.
Researchers remain hopeful that the search for life on Mars and the mission to colonize the red planet could still be pursued. The examined cells were completely sterilized within 30 seconds, while the cells that were not dipped into the solution but only radiated were wiped out after 60 seconds. As Kluger reports, the researchers found that the colder temperatures offer some small protection for the bacteria. "We show the bacteriocidal effects of UV-irradiated perchlorates provide yet further evidence that the surface of Mars is lethal to vegetative cells and renders much of the surface and near-surface regions uninhabitable". Upon adding in other components found in Martian soil, iron oxide and hydrogen peroxide, the results were even worse: Bacteria were killed 11 times faster than with just perchlorates.
But on the bright side, it means that the bacteria carried to Mars on robotic probes (of which B. subtilis is common) are unlikely to have survived for very long and been able to contaminate the environment.