> Binary neutron star merger > A LIGO / Virgo gravitational wave detection with associated electromagnetic events observed by over 70 observatories. > Distance > 130 million light years > Discovered > 17 August 2017 > Type > Neutron star merger > 12:41:04 UTC > A gravitational wave from a binary neutron star merger is detected. > gravitational wave signal > Two neutron stars, each the size of a city but with the at least the mass of the sun, collided with each other. > gamma ray burst > A short gamma ray burst is an intense beam of gamma ray radiation which is produced just after the merger. > kilonova > Decaying neutron-rich material creates a glowing kilonova, producing heavy metals like gold and platinum. > radio remnant > As material moves away from the merger it produces a shockwave in the interstellar medium - the tenuous material between stars. This produces emission which can last for years. > + 2 seconds > A gamma ray burst is detected. > +10 hours 52 minutes > A new bright source of optical light is detected in a galaxy called NGC 4993, in the constellation of Hydra. > +11 hours 36 minutes > Infrared emission observed. > +15 hours > Bright ultraviolet emission detected. > +9 days > X-ray emission detected. > +16 days > Radio emission detected. > GW170817 allows us to measure the expansion rate of the universe directly using gravitational waves for the first time. > Detecting gravitational waves from a neutron star merger allows us to find out more about the structure of these unusual objects. > This multimessenger event provides confirmation that neutron star mergers can produce short gamma ray bursts. > The observation of a kilonova allowed us to show that neutron star mergers could be responsible for the production most of the heavy elements, like gold, in the universe. > Observing both electromagnetic and gravitational waves from the event provides compelling evidence that gravitational waves travel at the same speed as light.