Einstein can rest easy. New findings show that the light particles - not neutrinos - are still the fastest in the cosmos. (Photo: Library of Congress)

The news last September that the nearly-massless subatomic particles called neutrinos traveled faster than light rocked the physics world. The finding threatened to upend Einstein's rules of relativity, which describe the speed of light as the maximum possible speed in the universe, and brought with it the potential for exciting new physics.

But the workgroup at CERN that made the measurement last Fall announced Friday at the Neutrino 2012 conference in Kyoto, Japan, that after repeated tests by both collaborators and competitors, neutrinos don't break the cosmic speed limit.  

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"Although this result isn't as exciting as some would have liked, it is what we all expected deep down," said CERN Research Director Sergio Bertolucci in a statement.

"The story captured the public imagination, and has given people the opportunity to see the scientific method in action - an unexpected result was put up for scrutiny, thoroughly investigated and resolved in part thanks to collaboration between normally competing experiments. That's how science moves forward," Bertolucci said.

The controversial original measurement has been blamed on a faulty fiber-optic cable connection and a malfunctioning clock, which resulted in an error of 0.00000006 seconds when scientists were timing the journey of neutrinos traveling a 732-mile route through the Earth's crust from CERN's underground lab in Geneva, Switzerland to a the Gran Sasso Laboratory in Italy.

Four experiments, including the collaboration at CERN that made the original faster-than-light measurements, found that after new tests, neutrinos "respect the cosmic speed limit," according to the Christian Science Monitor.

Neutrinos still fascinate physicists because they may be the key to understanding why the universe has more matter than antimatter - and therefore is able to exist without annihilating as matter and antimatter do when they meet. Neutrinos come in flavors, and can switch spontaneously between them, which may prove they have some mass afterall. The OPERA collaboration at CERN continues to study these neutrino oscillations.

But after Friday's announcement, we know they aren't the speedsters we once thought they were.