The Magnetic Cathedral
In a valley north of Marseille, on a 180-hectare site carved from scrubland and vineyard, the largest scientific instrument ever built is taking shape . The central component — a magnetic coil called the central solenoid — will generate a field 280,000 times stronger than Earth's own . When energised, it will induce and sustain a current of 15 million amperes through a volume of superheated gas for up to 500 seconds at a time . The goal is modest only by comparison to its ambition: to prove that humans can replicate the physics of stellar cores, fusing hydrogen into helium and releasing energy in the process, not once or twice in a laboratory flash, but continuously, controllably, at industrial scale.