An extraordinary burst of high-energy light in the sky has pointed astronomers to a pair of metal-forging neutron stars 900 million light years from Earth. In a study appearing today in Nature, an international team of astronomers, including scientists at MIT, reports the detection of an extremely bright gamma-ray burst (GRB), which is the most powerful type of explosion known in the universe. This particular GRB is the second-brightest so far detected, and the astronomers subsequently traced the burst’s origin to two merging neutron stars. Neutron stars are the collapsed,…