Albert Einstein's 1905 theory of relativity is one of the most fundamental pillars of physics - but now scientists say his conclusion that nothing can travel faster than light could be proven wrong.
Scientists at the European Organisation for Nuclear Research, or CERN, the world's largest physics laboratory say they have recorded sub-atomic particles, known as neutrinos, travelling faster than the speed of light.
According to Einstein's theory of special relativity - known by the equation E=mc2 - that feat is impossible. CERN says as part of its 'OPERA' experiment, a neutrino beam fired from a particle accelerator near Geneva to a lab 730 kilometres away in Italy travelled 60 nanoseconds faster than the speed of light. It revealed that neutrinos travel at a velocity of 20 parts per million above the speed of light.
Scientists calculated the margin of error at just 10 nanoseconds, making the difference statistically significant. If the findings are correct, it would force a major rethink of the fundamental laws of nature, including how the universe works.
Given the potential far-reaching consequences of such a result, CERN has decided to hold an open house shortly in which scientists can refute or confirm the results based on their measurements.
"When an experiment finds an apparently unbelievable result and can find no artefact of the measurement to account for it, its normal procedure to invite broader scrutiny, and this is exactly what the OPERA collaboration is doing, it's good scientific practice," said CERN Research Director Sergio Bertolucci.
If the result is confirmed, "it might change our view of physics, but we need to be sure that there are no other, more mundane, explanations," he said, underscoring the need for "independent measurements."
CERN spokesman James Gillies said the readings have so astounded researchers that they are asking others to verify them before claiming a discovery.
"The feeling that most people have is this can't be right, this can't be real," he said, adding they are inviting "the broader physics community to look at what they've done and really scrutinise it in great detail, and ideally for someone elsewhere in the world to repeat the measurements."
Einstein's theory states that energy is equal to mass multiplied by the speed of light squared, so firing an object faster than that would require an infinite amount of energy.
After the findings, scientists at the competing Fermilab in Chicago have promised to start such work immediately. "It's a shock," said Fermilab head theoretician Stephen Parke, who was not part of the research in Geneva. "It's going to cause us problems, no doubt about that - if it's true."
The Chicago team had similar faster-than-light results in 2007, but those came with a giant margin of error that undercut its scientific significance.
Outside scientists expressed skepticism at CERN's claim that the neutrinos - one of the strangest well-known particles in physics - were observed smashing past the cosmic speed barrier of 299,792 kilometres per second.
University of Maryland physics department chairman Drew Baden called it "a flying carpet,' something that was too fantastic to be believable.
But given the enormous implications of the find, they still spent months checking and rechecking their results to make sure there was no flaws in the experiment.
The CERN researchers are now looking to the United States and Japan to confirm the results. "The result comes as a complete surprise," said Antonio Ereditato, the spokesperson of the OPERA experiment. "After many months of studies and cross checks we have not found any instrumental effect that could explain the result of the measurement."
CERN said a series of high precision measurements of the distance between the source and the detector, and of the neutrinos' time of flight will be conducted.
President Pratibha Patil is expected to visit CERN, the European nuclear research organisation, on October 1. Patil is going to spend 90 minutes at CERN, where experiments are conducted on the Large Hadron Collider machine that will contribute to the knowing of the unknown in the formation of the universe.
In addition to the LHC experiment, scientists are simultaneously working on several other projects that include the OPERA experiment.