Tullis Onstott: Subterranaut

Finding life in the underworld could lead to possible discoveries in other worlds.

Imagine a young boy standing deep inside the imposing chasms of Carlsbad Caverns, disappointed he couldn’t spelunk any deeper than 1,000 feet. When the advertised “bottomless” pit revealed itself to be a mere 140 feet, its actual bottom concealed in darkness, Tullis Onstott became more than intrigued. Already enthralled with the wonders of indigenous life in the terra above him, he hungered for knowledge about this fascinating underworld. He found his life’s quest: the search for subsurface life.

Caves for a Neighbor

Onstott was born in otherworldly Carlsbad, New Mexico; the very town named for the epic chasms that would draw him to a career far beneath the earth’s surface. Thousands of visitors pass through the monstrous caves every year jaws agape at the sheer size of it. But Onstott had other fascinations. He wanted to see what lived there, if anything. And if it did hold life, what kind? His life’s work would soon provide the answer not just for himself, but the world.

The Science of Rigorous Curiosity

Real, provable discovery first demands years of academic study. Onstott began his formal education at the California Institute of Technology in 1976. After graduating with a bachelor’s in geophysics he moved on to Princeton for his master’s and doctorate in geology before beginning a post-doctorate fellowship in Toronto. The next few years were all about geochronology; determining the age of rocks via radiometric dating methods. Argon-argon (40Ar/39Ar) is quite a specific science and critical for the next phase of Onstott’s career.

The Earth Beckoned

Following his fellowship, Onstott returned to Princeton as a popular and successful professor. Much like the oft-absent professor Indiana Jones he hungered for discovery. Teaming up with researchers from Indiana Bloomington University he began a search for subterranean microorganisms that could survive without help from the sun; something all other life on the planet requires. Traveling to South Africa in 2012, Onstott and his colleagues descended into the gold mines of the African continent not in search of precious metal, they were after something much more valuable to scientists: new life.

Hot, Gassy Mine Shafts

Onstott and fellow researchers descended into the deepest mines in South Africa carved from 3-billion-year-old rock. Getting to their work place was nothing short of harrowing. Crammed into a cage the size of a walk-in closet with 30 miners, the team descends to 1.8 kilometers on the first leg of their deep earth voyage. It stops at this depth to avoid stressing the cables which could break if they’re made any longer. A second elevator nearby takes them deeper and a third deeper still until they finally arrive at the target depth of just under 3 miles below the earth’s surface.

Take a look at this video featuring excerpts from The Sacred Balance and see what it’s like for Onstott and David Suzuki to document ancient life forms deep within the Earth…

Endolithic Detective

What was it like down there? Onstott described it in a Princeton interview for the course Imagining Other Earths. “It’s hot, it’s obviously dark and there’s this acrid smell in the air, almost like a burnt rock. That’s because of all the dynamiting that’s going on, but also because of the weird gases that are coming out of these fractures we sampled.”

He continued, “The water that comes out, you know it’s like 70 degrees centigrade, it’s so hot that it’s scolding. You have to wear gloves in order to collect water samples.”

The team was there to find something, anything alive. The presence of microorganisms in unlikely environments wasn’t new. They’re already known to survive in the deepest parts of the ocean and hydrothermal vents. Finding something alive miles beneath the surface surrounded by complete darkness and super high humidity wouldn’t just be new, it would be mind-blowing.

Photo courstesy of Lisa M. Pratt, Indiana University/NASA National Science Foundation.

Well Hello There, Nematode

The microscopic creature Onstott co-discovered is the deepest living nematode ever found. A nematode is essentially a round worm; a microscopic insect with a smooth body. This one had about 1,000 cells, much more than he ever expected any life down here to have. In fact it scared him to death when he first saw it and described it as being a “black swirly thing.” Not exactly a quote for the science journals but we understand his shocked enthusiasm completely.

The Possibility of Microscopic Martians

Photo courtesy of Gaetan Borgonie, University of Ghent.

What Onstott co-discovered was a rock-dwelling bacterium that powers its survival by converting water molecules using radioactive uranium. So not only did they discover new life, this new life was tougher than Chuck Norris and John Wick combined. It was aptly named Halicephalobus Mephisto after Mephistopheles, Faust’s Lord of the Underworld. Pondering this momentous discovery, Onstott’s scientific brain lit up with what-ifs. If such a thing is possible on earth, why not on other planets in the solar system? Thus began his voracious appetite for finding life on Mars, too.

Spelunking Mars. Let’s Talk About It.

What followed was the stuff of every young boy’s dreams. Onstott met with colleagues, some of the world’s top scientists, to discuss exploration beneath the surface of Mars. From 1996 through 2016 he was involved with numerous NASA workshops designed to make a real Mars mission work. For Onstott, it’s more about what happens after we get there. In his mind, the impossible discovery of feisty microbial life miles deep raised the possibility of it on Mars significantly.

Photo by Brian Wilson

Mission: New Life

To find life on Mars would require drilling deep through the icy cryosphere to a depth several kilometers down. Besides reminding me of Bruce Willis in Armageddon, it reminds me of Onstott’s triple “elevator to hell” experience in South African gold mines and his fond recollection of it. I suspect he would be the most eager and capable passenger on the Mars shuttle. It would be a fitting task for Onstott and well deserved. What took him to deepest inner earth could also take him the furthest away anyone’s ever been.

Learn more about Onstott and his work at onstott.princeton.edu.