ProtoDUNE
This 11-meter (36-feet) high prototype at CERN will refine neutrino detector technology. The final DUNE detectors will be 20 times larger than this prototype and located in the new LBNF cavern in the United States. M. Brice, J. Ordan/CERN

Friday afternoon was a big moment in the field of subatomic particle physics, and potentially also a big step toward furthering our understanding of the universe. At 4:20 p.m. EDT, ground was simultaneously broken at two sites for a new neutrino detection facility — one mile underground at the Sanford Underground Research Facility near Lead, South Dakota, and at Fermilab near Chicago.

Called the Long-Baseline Neutrino Facility (LBNF), the international collaboration will feature an 800-mile-long path running between the two sites. A beam of neutrinos generated at Fermilab will travel through Earth’s mantle to Sanford lab, where an underground 70,000-ton detector will catch them. The properties of neutrinos change as they travel, and understanding those changes will provide an insight into the workings of the universe, and help answer questions like why matter exists.

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“Fermilab is proud to host the Long-Baseline Neutrino Facility and the Deep Underground Neutrino Experiment, which bring together scientists from 30 countries in a quest to understand the neutrino,” Nigel Lockyer, director of Fermilab, said in a statement Friday. “This is a true landmark day and the start of a new era in global neutrino physics.”

Neutrinos are mysterious elementary particles which are electrically neutral, and their mass is smaller than all other known elementary particles. They interact with other particles only through the weak subatomic force and gravity, making them very difficult to detect, since they simply pass through most matter. For instance, at any given moment, there are billions of neutrinos passing through your body. This property also means no tunnel is needed for them to travel between Illinois and South Dakota. They are known to exist in three different flavors, or types, and a hypothetical fourth flavor — the sterile neutrino — is a candidate for dark matter.

But we know very little about neutrinos so far, despite them being the most abundant matter particles in the universe, and that’s why LBNF is an exciting venture. The first experiment to start at the facility will be the Deep Underground Neutrino Experiment (DUNE), which will comprise of two detectors — a large one at the Sanford lab and a smaller one at Fermilab. The prototype detectors are being manufactured at CERN, the European research center at the forefront of subatomic particle physics.

“Building and testing large prototypes is a necessary intermediary step for a project as massive as LBNF/DUNE. We’re figuring out how to adapt the existing technology to thrive inside a house-sized detector. Once we’ve proven that it can work, we will then scale it up by a factor of 25 for the final DUNE detectors,” Marzio Nessi, the head of CERN’s Neutrino Platform, said in a statement Friday.

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According to the DUNE website, some of the study areas the experiment will aim to address include why the universe is made up of matter instead of antimatter; proton decay; finding a relation between the stability of matter and Einstein’s theory about the grand unification of forces; looking inside a neutron star and maybe witness the formation of a black hole.

“Today is extremely exciting for all of us in the DUNE collaboration. It marks the start of an incredibly challenging and ambitious experiment, which could have a profound impact on our understanding of the universe,” Ed Blucher, professor of physics at the University of Chicago and the Enrico Fermi Institute and co-spokesman for the DUNE collaboration, said in a statement on the university’s website.

The experiment will be built over the next 10 years, and will require removal of over 870,000 tons of rock to create the underground cavern where it will be placed. Its construction will create about 2,000 jobs at its peak, and the experiment itself will be operated by almost 1,000 scientists and engineers from 30 countries.