At least one of the Large Hadron Collider’s more than 1700 superconducting magnets failed, springing a leak and spewing helium gas into the subterranean tunnel that houses the atom smasher, report officials at the European particle physics laboratory, CERN, near Geneva, Switzerland.

Once it’s running at full capacity, the project’s researchers say, the $5.3 billion Large Hadron Collider, the biggest particle accelerator ever built, will be able to answer questions physicists never thought they’d get answers to, like why the universe formed the way it did and why matter has mass. Critics of the project say it could have the opposite effect, leading not to knowledge but instead humanity’s demise.