The weasel came off worse Denis Balibouse / Reuters

The world’s largest scientific experiment has been taken offline…by a beech marten.

According to internal documents placed online, the Large Hadron Collider at CERN near Geneva has suffered a power outage after the critter chewed on a 66-kilovolt electrical transformer. The unfortunate animal was fried and caused a CERN-wide power cut.

“I can confirm that we had some issues overnight with electrical trouble,” says CERN spokesperson Arnaud Marsollier. “We suspect it might be due to a small animal.”


It will likely take a few days to bring the collider back online, says Marsollier, but the equipment is fine and should be easily fixed.

The incident is reminiscent of a widely reported story in 2009 that a similar power cut at the LHC was caused by a bird dropping a piece of baguette on a substation, but Marsollier says that was a tall tale. “This was a story that was told, but we never knew exactly what happened,” he says, though as this latest incident demonstrates, it’s not impossible. “We’re in the countryside, you have wild animals.”

Before going offline, the LHC was gearing up to start colliding beams of protons again after a switch-off during the winter months. “We had collisions at low intensity recently, this is all part of the commissioning, we check that everything is working well, that the detectors are ready,” says Marsollier.

Physicists at CERN are keen to search for signs of a mysterious particle weighing in at 750 gigaelectronvolts, which was hinted at in earlier data presented before the switch-off. For now, that search will have to wait. “You never know with the LHC if it will take a few days or a bit more, but we will be back in action very soon,” says Marsollier.

When this article was first published, it misidentified the animal in question.