A mile down in an unused mine tunnel, scientists guided by helmet lamps trudged through darkness and the muck of a flooded, uneven floor.
In the subterranean world of the Beatrix gold mine, they shed their backpacks, taking out tools and meticulously prepared test tubes to collect samples.
Leaning a ladder against the hard rock wall, Tullis C. Onstott, a geosciences professor at Princeton, climbed to open an old valve about a dozen feet up.
Out flowed water chock-full of microbes, organisms flourishing not from the warmth of the sun, but by heat generated from the interior of the planet below.
These tiny life-forms — bacteria and other microbes and even little worms — exist in places nearly impossible to reach, living in eternal darkness, in hard rock.
Scientists like Dr. Onstott have been on the hunt for life in the underworld, not just in South Africa but in mines in South Dakota and at the bottom of oceans.
What they learn could provide insights into where life could exist elsewhere in the solar system, including Mars.
Microbial Martians might well look like what lives in the rocks here at a deep underground mine.
The same conditions almost certainly exist on Mars. Drill a hole there, drop these organisms in, and they might happily multiply, fueled by chemical reactions in the rocks and drips of water.
“As long as you can get below the ice, no problems,” Dr. Onstott said. “They just need a little bit of water.”
Mars has long been a focus of space exploration and science fiction dreams. NASA has sent more robotic probes there than any other planet. But now there is renewed interest in sending people as well. NASA has been enthusiastically promoting its “Journey to Mars” goal to send astronauts there in the 2030s. Elon Musk, the billionaire founder of SpaceX, is promising that he will be able to get there a decade sooner and set up colonies.
Astronauts on Mars would be able to greatly accelerate the quest for answers to the most intriguing questions about the red planet. Was there ever life on Mars? Could there be life there today?
It was not that long ago that scientists had written off Mars as lifeless.
Forty years ago, NASA spent nearly $1 billion on its Viking mission, which revealed a cold, dry world seemingly devoid of organic molecules that are the building blocks of life.
But more recent missions have discovered compelling evidence that Mars was not always such an uninviting place. In its youth, more than three billion years ago, the planet was warmer and wetter, blanketed with a thick atmosphere — possibly almost Earthlike.
A fanciful but plausible notion is that life did originate on Mars, then traveled to Earth via meteorites, and we are all descendants of Martians.
Eventually, Mars did turn cold and dry. Radiation broke apart the water molecules, and the lighter hydrogen atoms escaped to space. The atmosphere thinned to wisps.
But if life did arise on Mars, might it have migrated to the underworld and persisted?
For a couple of decades, Dr. Onstott has been talking his way into South African gold mines, regaling the mine managers with the wonder of deep Earth life to overcome their wariness. In many ways, the mines provide easy access to the depths — a ride in a cagelike elevator, jammed against miners starting their shift, descending quickly as lights from the different levels zip past. Think of it as traveling through a 450-story skyscraper, going down.
Dr. Onstott and his colleagues had made repeated pilgrimages to this particular tunnel in this particular mine, Beatrix, 160 miles southwest of Johannesburg.
When miners carve out new tunnels, they poke holes through the rock to see what surprises might lie ahead. Sometimes the borehole taps into a section of fractured rock with water coursing through. Then the fracture is drained and plugged.
But this particular tunnel at Beatrix never entered production, so the borehole valve remains, allowing the scientists to return to draw samples from the same place.
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At this level, almost a mile underground, the elevator gates open to a well-lit, concrete cavern with the unremarkable plainness of a parking garage. A minirailway system transports miners and ore back and forth. The side tunnel, though, is pitch black save for the helmet lamps, and the trek to the valve is a slosh through muck and over tangles of mangled electrical cabling.
Scientists led by Dr. Onstott made their most recent trip to South Africa in June last year. Over a couple of hours, they took their fill of the water and set up an apparatus that remains attached to the valve, trapping microbes, which were retrieved later in the summer. Since then, they have been analyzing the samples to understand this assemblage of life.
[Source: The New York Times]
