A recent study of a fissure on the surface of Mars reveals what looks like volcanic activity as recently as 50,000 years ago. This could mean that warm magma beneath the surface, and groundwater we suspect is there, could provide a habitat for alien life.
This raises the question, if Mars has indigenous life, should humans go there?
Scientists at the University of Arizona Lunar and Planetary Laboratory found a dark deposit around a fissure that's more than 30 kilometres long on the surface of Mars known as the Cerberus Fossae system, that may be the most recent volcanic activity on the planet.
The scientists speculate that magma explosively erupted when the magma from below either came into contact gases already present in the magma or encountered ice in the Martian permafrost that was then vapourized.
Mars has the largest volcanic mountains in the solar system, but they have been extinct for millions if not billions of years.
This recent eruption took place in a relatively flat region known as Elysium Planitia and suggests Mars is not as geologically dead as previously thought.
Recent volcanic activity raises possibility of life
If that is so, the possibility exists that magma close to the surface could provide enough heat to melt some of the permafrost and allow liquid water to seep through cracks and pores in rock. This warm, wet environment could provide a habitat for underground life.
This fits with work done on Earth by the Earth 4D project co-founded by Dr. Barbara Sherwood Lollar at the University of Toronto. This international group has found life many kilometres underground on Earth that does not require sunlight.
Deep inside our planet, microscopic organisms thrive in groundwater and harvest energy from minerals in the rock.
Could similar life exist underground on Mars?
So far, no signs of life have been found on the surface of Mars, which is not entirely surprising since the atmosphere of the red planet is extremely thin and has no ozone layer, so deadly ultraviolet light reaches right down to ground level. But underground life would be shielded from that radiation and also protected from the extremely cold Martian weather.
Avoiding potential contamination
Scientists are proposing future missions that would drill down to explore the subsurface and continue the search for life there. If Mars turns out to be alive, those planning to send humans there will have to consider the implications of contamination, both of the alien life by humans and vice versa.
Ice will be a valuable resource on Mars, both for water and for making rocket fuel. That means it will be mined out of the ground, which opens the door to contact with underground life.
One of the biggest unknowns about alien life is whether it is based on the same biology as us or something different. Does it have similar DNA, or is it based on some other chemistry?
If humans were infected with Martian microbes, would their immune systems recognize it? If a Martian explorer did become infected, should they be allowed to return to Earth, or would they be marooned on an alien world stricken by an alien disease?
Then there is the possibility that humans could infect Martian life, which might not have any resistance, starting a pandemic that completely wipes it out. It wouldn't be the first time colonists from another land brought disease to native populations.
Finding life on Mars would be one of the biggest discoveries in modern science, proving that we are not alone in the universe and increasing the chances that other planets around other stars could harbour life as well. But before the first human boot print is made in the red Martian soil, it would be good to know that we are not stomping on our first contact with alien life.
ABOUT THE AUTHOR
Bob McDonald is the host of CBC Radio's award-winning weekly science program, Quirks & Quarks. He is also a science commentator for CBC News Network and CBC-TV's The National. He has received 12 honorary degrees and is an Officer of the Order of Canada.
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