Scientists at CERN‘s Large Hadron Collider say they have collected data that indicates certain particles created at the laboratory traveled faster than the speed of light, which is universally considered impossible.

Neutrinos sent through the ground from Cern toward the Gran Sasso laboratory 732km away seemed to show up a tiny fraction of a second early.

The result – which threatens to upend a century of physics – will be put online for scrutiny by other scientists.

In the meantime, the group says it is being very cautious about its claims.

“We tried to find all possible explanations for this,” said report author Antonio Ereditato of the Opera collaboration.

“We wanted to find a mistake – trivial mistakes, more complicated mistakes, or nasty effects – and we didn’t,” he told BBC News.

If true this would be an enormous breakthrough, but it is likely that some error crept into the calculations.