The flash was detected by the LUX-ZEPLIN detector, buried nearly 1.5 kilometres underground in a former gold mine in the United States. The findings were presented today at the 2026 TeV Particle Astrophysics conference in Japan and published on the preprint server arXiv, where they are yet to be peer reviewed.

Dr Theresa Fruth, an Australian physicist from the University of Sydney working on the experiment, described the result as "very exciting". "This event just won't go away even after many, many checks," she said. "It's also kind of scary to think, 'Oh, this could be it'." But she stressed that more detections were required to confirm the result.

Dark matter is estimated to make up 85 per cent of the observable universe, but no one has directly observed it. Scientists infer its existence from the way galaxies move. One leading theory posits that dark matter consists of weakly interacting massive particles (WIMPs), which are slow-moving particles larger than atoms. LUX-ZEPLIN uses a vat of super-cooled liquid xenon and 494 light sensors to detect the tiny collisions between WIMPs and normal particles.

Until now, the detector had not found any signal that looked like dark matter. The only other experiment to claim a detection is the DAMA/LIBRA experiment in Italy, which has reported an annual signal, but it has not been replicated by other detectors.

Professor Nicole Bell, a theoretical physicist at the University of Melbourne not involved in the research, called it an "interesting observation" but said it was "very early days." "If it's really dark matter, we'll see more events soon, and that would be a huge breakthrough," she said.

The team now needs additional events to confirm whether the flash truly signals dark matter or is a statistical fluke. If verified, it would mark the first direct detection of the substance that has puzzled physicists for decades.