A mile under the Black Hills, science is happening with the potential to change humanity’s understanding of the universe and our place within it. At the Sanford Underground Research Facility – or SURF – any number of these experiments can have ramifications that go well beyond South Dakota.
As we all cram into “the shaft”, an old mining elevator that descends 11 minutes to the lab space nearly a mile underground, the anticipation is palpable.
While walking into the caverns of the lab might feel like a step into Area 51, this is anything but science-fiction, and a recent trip below offered a crash course into the major projects at SURF.
Instead, analysis of dark matter, neutrinos, and other particles that make up the fabric of the universe is very real, and happening right under our feet.
Standing near the Lux Zeppelin project, Markus Horn is on the hunt for dark matter, a still-unknown substance that could make up 85% of our universe.
“We always feel like we’re getting closer and closer and closer, yet at the same time – why have we still not found it,” Horn asks.
Horn said one of the beauties of science is that mystery and discovery are still very much alive.
“The challenge is not just the big elevator pitch of the standard particle or standard model," Horn said. "We are looking at a whole bunch of different models of what dark matter could be and how it can interact in our detector. Then comes the technical challenge of actually building these detectors.”
Horn explains the LZ like a proud parent at their child’s ballet recital. Each layer offers a more accurate, and more detailed, view for researchers.
“The technical challenge, and how to build it, and how to prove what you’re trying to do – that is what really fascinates me," Horn said. "So, we are building more detectors around our detectors, but making sure it’s from the outside. So, it’s basically like a Russian doll.”
Deeper into the complex come the caverns designed as the landing points for neutrinos, among the smallest, and least understood, known particles to science.
Trillions hit the earth each day, and Jolie Macier is the far detector and cryogenics project manager at DUNE – the Deep Underground Neutrino Experiment. That project beams neutrinos from 800 miles away to a single point in these caverns.
“The physicists describe them as tricky and wily," Macier said. "It’s very hard to capture them. So, liquid argon proves to be a very good medium for that. We’re really looking for that big scale, as opposed to a very small scale.”
Though neutrinos seem impossibly small, and these caverns are impossibly vast in the context of a decommissioned gold mine, this workspace exists for good reason. SURF researchers say this study can only be accomplished at SURF, one of 16 deep underground labs on earth.
“The fact is that a million (neutrinos) are passing through my fingernail every second," Macier said. "Part of the reason to be down here is to shield from solar neutrinos. That way, we know the ones we’re manufacturing from our beamline are the ones we’re capturing here.”
Finally, we reach CASPAR, a small particle accelerator. Like the Hadron Collider on a much smaller scale, CASPAR is dedicated to understanding the inner workings of star systems.
This lab is headed by Mark Hanhardt, an experimental support scientist and PhD candidate at South Dakota Mines – though he prefers the title “warrior of physics.”
When looking deep into the universe, challenging, sometimes troubling questions are bound to arise. With such a vast universe, humanity is a single pixel on a screen larger than can possibly be perceived. That, naturally, begs a profound question – ‘what’s the point of anything?’
“It’s an interesting philosophical question," Hanhardt muses. "You can take the nihilist view that nothing matters because we’re all essentially doomed. Or you can take the optimist nihilistic view that because nothing matters, we get to make our own purpose. That’s definitely the way I like to take it.”
Ultimately, Hanhardt found his purpose here, a mile underground. Unraveling the universe as he listens to Ode to Joy from his desk.
“We are just a blink of an eye as far as the universe is concerned, but we are unique in that we are the only part of the universe that is capable of appreciating the rest of it," Hanhardt said. "We are the only part that can think, as far as we know. We are the only part look out there and understand the universe. As far as we know, intelligence is the rarest phenomenon that we’ve ever discovered. At least in my mind, that gives us a responsibility to learn as much about the universe as we can.”
One of SURF’s main operating objectives is to encourage science education in the region, and the upcoming Neutrino Days event in Lead is designed to help families do just that. That event is scheduled for July 12, with a special SDPB broadcast from the underground lab coinciding with it July 11.