Most of us know that if alien life is found in the near future, it will not look like the little green men We partner with UFOs and cheesy science fiction stories. Based on the location of life's building blocks on other celestial bodies, humans are much more likely to locate the kind of life that requires a microscope to see: bacteria, archaea and other “extremophiles” capable of withstanding harsh conditions. To help us find those tiny organisms, scientists are turning to those beneath the Earth's surface for a little guidance.
Scientists have detected extremophiles in some of the most unfriendly environments on Earth: nestled in the salt flats from the Puna de Atacama desert in Argentina, in the midst of the cutting cold of Antarctica and around the incessantly arid Mojave Desert. With confirmation that organisms can survive in conditions we would otherwise consider uninhabitable, researchers have sought and found other extremophiles deep beneath the Earth's surface. More than 4 meters (13 feet) below the Atacama Desert lie microbial communities full of life; ecosystems thrive under hydrothermal vents in the depths of the sea. In fact, up to 70% Archaea and bacteria biomass is thought to be found in the “deep biosphere,” the region between the Earth's surface and its core, including millions of undiscovered species.
If life can exist in the depths of the Atacama Desert, perhaps it can also exist beneath the surface of Mars.
Credit: Diego Delso/Wikimedia Commons
But what does this have to do with Mars? The red planet It's not what we would normally call forgiveness.:Its thin atmosphere, low gravity, arid landscape and frigid temperatures would make it difficult for mammals and other large creatures to survive. But if hyper-hardy bacteria and archaea can exist in extreme underground conditions on Earth, similar organisms could do the same on Mars. That's convenient, because scientists discovered this year that liquid water, one of the basic necessities of life, is likely to exist there. between layers of the Martian crust.
“We know that water is a prerequisite for life as we know it,” said Karen Lloyd, a subsurface microbiologist at the University of Southern California (USC). said On Thursday, the BBC reported that water isn't the only thing life needs to thrive. “It needs energy and somewhere to be, so it needs a habitat.” Mysterious microbes inhabiting Earth's soil could help us redefine what counts as “habitat.”
“The same kind of processes that occur in our subsurface can occur on Mars,” said Cara Magnabosco, a geobiologist at ETH Zurich, Switzerland.
Magnabosco was referring to the Martian. earthquakes, erosionand volcanic eruptions that mimic geologic movements on Earth. On Earth, these events push water and substrate to the surface, a process that, if it occurred on Mars, could allow explorers to more easily collect samples that might contain life.
“Mars has mud volcanoes,” Lloyd said. “There are places on Mars you can go where you find subsurface samples that have been exhumed and brought to the surface.”
If life is found on Mars, there's a chance it will arrive dead: preserved organic remains that prove life was once possible, but may no longer be. When MIT scientists announced they had I found signs of water. Last week, on rocks from Mars, one suggested that fragments of extinct life might be “very well preserved… it's like pickling something in salt.”
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