John LoSecco, professor in the Department of Physics and Astronomy at the University of Notre Dame, was among a handful of researchers recently honored by the American Physical Society (APS), which named the Morton Salt Mine in Painesville, Ohio, the “birthplace of neutrino astronomy” and designated it as a historic landmark.

LoSecco and colleagues made a breakthrough in neutrino astronomy at the site in 1987, when they detected neutrinos being emitted from a supernova, or exploding star. Neutrinos, subatomic particles with no electric charge and very little mass, were predicted in the 1930s and were officially discovered in the 1950s, but are not well understood due to their limited interaction with other matter.

To make the discovery, LoSecco used the Irvine-Michigan Brookhaven (IMB) detector, situated 2,000 feet underground in the Morton Salt Mine to study electromagnetic radiation. Interestingly, the IMB was not originally designed to study neutrinos but was able to detect them from an unexpected supernova explosion, Supernova SN1987A.

“The goal of using the IMB Detector was actually to see if protons decay,” LoSecco said. “We didn’t find any evidence of proton decay but ended up with a neutrino discovery instead.”

While it’s estimated that 99% of the supernova’s energy is emitted as neutrinos, seeing a supernova with the naked eye is extremely rare. Supernova SN1987A was an exciting surprise for LoSecco and his team.

“This was the first supernova visible to the human eye in 400 years and the only time neutrinos have ever been directly observed coming out of a supernova,” he said.

The discovery gave a clear look into the makeup of exploding stars and to this day is used by the Department of Energy as one of the top three justifications for continued research into neutrino astronomy.

Looking back on his time with the IMB collaboration, LoSecco remembered his lifelong interest in neutrinos and how the historical landmark ceremony, which is done as part of the APS’s historic site initiative, felt like a full circle moment.

“I remember writing an undergraduate research paper on neutrino astronomy,” he said. “It’s neat to be honored at a ceremony for my contributions to the field.”

Originally published by Madison MacDougall at science.nd.edu on October 24, 2024.