Collisions take place constantly near the French town of Cessy, within sight of Mont Blanc. But the reason is not icy roads or careless drivers. In fact, residents sleep very peacefully at night. Nevertheless, up to 800 million times per second, elementary particles smash into one another at inconceivable speeds some 50 to 100 meters underground. All of this takes place in a 27-kilometer ring tunnel called the Large Hadron Collider (LHC), which is operated by the European nuclear research center CERN and extends below portions of both Switzerland and France.
The collisions are produced when two proton beams crash into one another at four spots in the tunnel that are equipped with detectors. From the hail of fragments that follows such controlled impacts, physicists hope to gain deeper insights into the structure of the universe at the smallest levels. And they have been successful. In 2012, for example, they detected the Higgs boson, which imparts mass to all matter.
The process of modernizing this colossal machine began at the start of 2013. In March 2015, it will start up again, and the particle beams will then collide with twice as much energy. Following the discovery of the Higgs boson, researchers now want to delve even more deeply into the unanswered questions of the universe.