In 2016, an international team of scientists found definitive evidence—tiny ripples in space known as gravitational waves—to support one of the last remaining untested predictions of Einstein’s theory of general relativity. The team used the Laser Interferometer Gravitational-Wave Observatory (LIGO), which has since made several gravitational wave discoveries. Each discovery was possible in part because of a global network of supercomputer clusters, one of which is housed at Penn State. Researchers use this network, known as the LIGO Data Grid, to analyze the gravitational wave data.