For the first time, astronomers have observed a cosmic event using both gravitational waves and optical light, a major step forward in the new era of gravitational wave astronomy. Signals from the Laser Interferometer Gravitational Wave Observatory (LIGO) in the United States and the Advanced Virgo Interferometer in Italy pinpointed the location of two merging neutron stars in a galaxy 130 million light-years away. Astronomers then used some 70 ground- and space-based telescopes across all seven continents to study the collision in X-ray, ultraviolet, optical, infrared, and radio waves.
Neutron stars are among the densest objects in the universe, packing half a million times the mass of the Earth into an area the size of Manhattan. They sometimes occur in pairs, often resulting in an eventual collision. These mergers produce gamma ray bursts, electromagnetic radiation, and gravitational waves, ripples in the fabric of spacetime predicted by Einstein more than 100 years ago. “Already it is transforming our understanding of the universe with a fresh narrative of the physics of stars in their death throes,” France Cordova, director of the National Science Foundation, said at a press conference.