Scientists have found evidence of life in underwater rock samples they took from the deepest place on Earth. Oliver Plümper, Utrecht University

Scientists may have found evidence of life underneath the deepest point in the ocean, and that could be good news for anyone hoping to discover aliens on other planets.

It’s not life forms themselves that the researchers dug up, rather it is organic matter that could have been created by a microbe of some kind. They found those traces in samples of rock that came from a point beneath the seafloor near the Pacific Ocean’s Mariana Trench, the lowest underwater point on Earth. “We cannot pinpoint the exact origin of the organic matter,” their study in the journal Proceedings of the National Academy of Sciences says, but it is entirely possible that life exists down there.

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The place at the bottom of the ocean where the researchers found the organic sample is the South Chamorro mud volcano, one of many mud volcanoes and hydrothermal vents in the area that spew out heat and material from inside the Earth. According to the study, microbes could be living in or under the mud volcano. The heat would in those depths not be too much to handle — the researchers put the upper temperature limit for life to exist at about 250 degrees Fahrenheit, so they estimate that life could thrive as far down as 10,000 meters below the seafloor.

That area “may represent one of Earth’s largest hidden microbial ecosystems,” the scientists wrote, and would have provided protection from space impacts and dangerous climate changes through Earth’s youth that organisms wouldn’t have had on the planet’s surface. “These types of protected ecosystems may have allowed the deep biosphere to thrive, despite violent phases during Earth’s history such as the late heavy bombardment and global mass extinctions.”

The potential discovery of tiny organisms so deep within the Earth may give hope to people searching for extraterrestrials, although not necessarily intelligent ones. In addition to this recent finding of organic matter, scientists in Canada have also found evidence of bacteria that lived in underwater hydrothermal vents billions of years ago. Although the Mars surface can appear a bit like a wasteland, at one point it had similar environmental conditions. Some scientists searching for Martians — or evidence of past Martians — have been focusing their attention underground, because as climate change turned Mars’ surface from more hospitable to hot and barren, life may have gone underground to survive.

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Microbes at such Earth depths could also be important in the search for extraterrestrial life in places like Enceladus and Europa, moons of Saturn and Jupiter, respectively. Beneath their icy exteriors, astronomers believe there could be liquid oceans, and those could be potentially harboring tiny aliens.

About the possibility of life underneath the Mariana Trench, study leader Oliver Plümper, a researcher at Utrecht University in the Netherlands, told National Geographic, “It could be huge or very small, but there is definitely something going on that we don’t understand yet.”

See also:

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What Climate Change Looked Like on Mars