Compact Muon Solenoid magnet reaches full field: "Weighing in at more than 13,000 tons, the Compact Muon Solenoid experiment's magnet is built around a 20-foot-diameter, nearly 43-foot-long superconducting solenoid - a wire coil with multiple loops, which generates a magnetic field when electricity passes through it. The CMS solenoid generates a magnetic field of 4 Tesla, some 100,000 times stronger than the Earth's magnetic field, and stores 2.5 gigajoules of energy, enough to melt nearly 20 tons of gold. Superconductivity is achieved by chilling the coil to a temperature near absolute zero, where virtually all electrical resistance vanishes. Extremely high electrical current can then be used to generate a powerful magnetic field. "