Physicists have grappled with the question over whether it’s possible to exceed the speed of light, and University of Minnesota researchers are taking a closer look, the Pioneer Press reported.

Neutrinos, a type of subatomic particle, were observed surpassing the speed of light, according to the results of an experiment at CERN‘s Large Hadron Collider research facility in September. The announcement rocked the scientific community and spurred discussion over whether Albert Einstein’s Theory of Special Relativity could be wrong. The theory sets light speed as the universal limit.

Photo courtesy of Scientific American

Researchers at the University of Minnesota have been working to reproduce the experiment at the bottom of a northern Minnesota iron ore mine. The mine is a half-mile underground in the Soudan mine east of Tower, Minn. They will use equipment to detect neutrinos being fired from particle accelerators at Fermi Lab 456 miles away in Illinois.

Early experiments have suggested the neutrinos might be arriving slightly faster than the usual 2.5 milliseconds, to the tune of 126 nanoseconds. However, the margin of error for the experiment is about 70 nanoseconds, the scientists said, adding that neutrinos really can exceed light speed, Einstein’s theory would merely be rewritten instead of discarded.