Editor’s note: Este artículo está traducido al español.

A trio of Nevada professors is working with NASA to investigate what drives life deep underground, hoping to create a better understanding of how ecosystems can thrive miles beneath the surface of Earth— and potentially on other planets.

Led by Desert Research Institute microbiologist Duane Moser, who is joined by UNLV microbiologist Brian Hedlund and UNR planetary scientist Wendy Calvin, the team will be looking at a phenomenon Moser has studied for decades: underground ecosystems powered by radiation instead of the sunlight that allows life as we know it.

The findings could help guide NASA’s search for life beneath the surfaces of other rocky planets, like Mars.

“Without all these things that we take for granted on this planet, you can’t really have a surface ecosystem on any body in the solar system that we’re aware of, so you have to go underground,” Moser said. “If you’re underground, the sun’s useless to you. You’ve got to come up with something completely different.”

The Nevada System of Higher Education secured a $750,000 grant from NASA’s Established Program to Stimulate Competitive Research for the study.

“By studying how radiation fuels life in underground environments on Earth, we can better target where and how to search for life on Mars and icy worlds,” said Eric Wilcox, the project director for Nevada NASA Established Program to Stimulate Competitive Research. “The work also has the potential to shed light on how life began on Earth, which is one of the most profound questions in science.”

Moser was a postdoctoral researcher in 1997 when he traveled to South Africa to look for life forms in some of the world’s deepest mines. He had an opportunity to study more than 3 kilometers — or about 2 miles — beneath the surface, mainly in “ultradeep” gold mines where the rock is billions of years old.

At the time, scientists thought the biosphere — where any kind of living organism can be found on or near Earth — only extended about 10 to 100 meters beneath the surface, he said.

In subsurface environments like these African mines, scientists will drill boreholes. The extracted cores of rock provide a variety of critical information about what lies ahead or beneath — the presence of fractures, pressurized water or minerals such as gold.

Some of the holes drilled during Moser’s early project did produce water, which was hundreds of millions, or even billions, of years old, he said. To his surprise, it contained bacteria.

“We look at these ancient water samples, and we’re finding microbial life. They should be sterile — how could life be there,” he said. “We thought it was tens of meters. Here we are 2, 3, 4 kilometers underground, and we’re still finding life.”

Life as we know it on Earth depends on the sun. Plants, algae and some bacteria convert energy from sunlight into the energy needed for life-sustaining metabolism. Water splits during photosynthesis, breaking down into hydrogen and oxygen.

But the sun’s energy doesn’t reach 3 kilometers below the surface. And nature provides only so many sources of energy, Moser said.

The sun’s rays didn’t penetrate that far down in the South African gold mines, but the rock did contain uranium. The alpha radiation from the uranium, instead of the sun’s light, split water into hydrogen and oxygen compounds, Moser said. Microbes use these byproducts to survive in what are called radiolytic ecosystems.

Nevada is a long way from South Africa, but Moser and his colleagues will sample in locales that are close to home and that he said were just as good, like the Nevada Test Site.

Except for Earth, all known planetary surfaces are often too harsh for life. Many scientists believe that the best chance of finding extraterrestrial life in the solar system — microscopic aliens, as it were — is beneath the surface.

As miniscule and isolated as these life forms may be, they represent something great and even existential.

“I think what we’re really getting at is, is kind of the fundamentals of what life is. At its core, you need some source of energy that somehow can fuel the biosphere. We think we know. We look outside and we see cows and trees. We think we know what it is, but we actually don’t,” Hedlund said.

“Only by stepping back and thinking, ‘life can work this way, but life can also work that way’ — what’s in common, what are the basics?” he added. “And then how do we extend that to think about deeper time or deeper space?”