Since their first discovery in 1911, superconductors — materials which perfectly conduct electricity — have long beguiled and tantalized physicists. Superconductors are used in particle accelerators, nuclear fusion devices, MRI machines, and even maglev trains. Yet broader and more common applications are hampered by a forbidding temperature limit — so far, no superconductor has been proven to work at ambient pressures and temperatures. On July 22, scientists in South Korea published research claiming to have solved this problem. They say that their material, called LK-99, has an electrical resistivity, or resistance ... (full story)