After 16 years and $10 billion, there was joy in the meadows and tunnels of the Swiss-French countryside on Tuesday: The world’s biggest physics machine, the Large Hadron Collider, finally began to smash subatomic particles together.
After two false starts due to electrical failures, protons whipped to more than 99 percent of the speed of light and to record-high energy levels of 3.5 trillion electron volts apiece raced around a 17-mile underground magnetic track outside of Geneva.
They crashed together inside apartment-building-sized detectors designed to capture every evanescent flash and fragment from microscopic fireballs thought to hold insights into the beginning of the universe.
The soundless blooming of proton explosions was accompanied by the hoots and applause of scientists at CERN, the European Organization for Nuclear Research, which built the collider. The relief spread to gatherings of particle physicists around the world.
Among their top goals are finding the identity of the dark matter that shapes the visible cosmos and the strange particle known as the Higgs boson, which is thought to imbue other particles with mass.
The success in colliding protons marks a remarkable comeback for CERN, but the lab is still only halfway to where it wanted to be. A year and a half ago, the first attempt to start the collider ended with an explosion that left part of its tunnel enveloped in helium gas and soot when an electrical connection between two magnets that steer the protons vaporized.
An investigation found that the collider is riddled with thousands of such joints. As a result, the collider, which was designed to accelerate protons to 7 trillion electron volts, can be safely run only at half power.