Searching for the Secrets of the Universe in Sudbury, Ontario

Dark matter has never been observed directly. Canada's SNOLAB hopes to change that

The "glove box" of the DEAP-3600 dark matter detector keeps out contaminants.

Nobody wants to spend an entire day underground if they don’t have to. But buried two kilometres beneath the earth’s surface, deep in the four-billion-year-old Canadian Shield in northern Ontario, SNOLAB has been on my bucket list for nearly a decade. It was the theoretical physicist Freeman Dyson who tipped me off to the existence of the Sudbury science laboratory.

“I was happy that people in Canada had the good sense to go for the idea,” he says. Particle detectors like SNOLAB are among what Dyson describes as science’s “unfashionable pursuits”—compared with, say, the more flashy particle colliders, like the Large Hadron Collider at CERN, the vast lab that sits astride the Franco-Swiss border near Geneva. “Unfashionable pursuits don’t get the attention,” Dyson says. “But they are usually more cost-effective science. SNOLAB is a good example.”

Photos of and near SNOLAB in Sudbury, Ont.
The superstack at Vale’s Copper Cliff smelter.

With more than 500 scientists collaborating—drawn from 78 institutions and 17 countries—the enterprise first took shape in 1984, and construction of the SNO detector began in 1990. Situating the lab in the active Creighton Mine, which still produces thousands of tonnes of nickel and copper per day, offered an improved experimental setting. The “overburden” of rock has the felicitous effect of filtering out the noisy and meddlesome cosmic rays that would otherwise obscure results of the neutrinos—the pervasive subatomic particles that are everywhere and pass through everything —interacting with the clear plastic spherical tank of heavy water at the centre of the detector. With this major advantage, SNOLAB can address the most fundamental questions in science: How does the sun burn? Of what is our Universe composed and how did it evolve? What are the most basic building blocks of matter?