The Large Hadron Collider circulated its first beam

On September 10, 2008, an international team at CERN injected the first beam of protons into the Large Hadron Collider, the world’s largest and most powerful particle accelerator. The beam was launched at 9:30 a.m.; just under an hour later, at 10:28, it had been steered the full 27 kilometers clockwise around the underground ring straddling the French–Swiss border.

The moment was a milestone after roughly two decades of design and construction. It was also a genuine media spectacle, reaching an estimated audience of more than a billion people, with thousands of broadcasts and press articles on what CERN dubbed “first-beam day.”

Two yellow dots on a screen signalled that protons had finally completed the lap.

The triumph was brief. Nine days later, a faulty electrical connection between two magnets damaged a sector of the machine, forcing months of repairs. The LHC would not deliver its first collisions until late 2009, on its way to confirming the Higgs boson in 2012.