The scientists who announced they had recorded subatomic particles called neutrinos breaking the speed of light last year have found a small problem.
The results could have been skewed by a dodgy cable, according to the physicists at Cern, home of the Large Hadron Collider particle accelerator.
Their experiment sent the science world into uproar as they appeared to have blown open Einstein's 1905 theory of relativity - a cornerstone of physics.
It states that no particle can travel as fast as light in a vacuum because light has no mass.
In September they beamed neutrinos over 450 miles from their base in Geneva to a laboratory in Gran Sasso in the Italian Alps.
The neutrinos beat light by 60 nanoseconds - or billionths of a second - raising science-fiction-style scenarios blurring the lines between past and present. When they repeated the experiment, known as Opera, two months later just to make sure, they got the same result.