America’s nuclear arsenal relies on this brand-new supercomputer

In an expansive white-tiled room in Livermore, California sits Sierra, the world’s second most powerful supercomputer. Sierra looks like an unassuming server farm, but is actually a massive connected hive of 190,000 processing cores. It was completed earlier this year, and has been on a shakedown cruise since then: researchers at the Lawrence Livermore National Laboratory ran astrophysics, climate, and precision medicine simulations on Sierra while ferreting out bad components and other t