By now, many of us have heard of gravitational wave detection. Many have even heard about the combined gravitational wave and electromagnetic detection and observation of a neutron star merger last year -- the first of its kind to make use of synergistic data from more than one path of information about an event, and which marked the official birth of "multi-messenger astronomy".
But we're not done. not by a long shot.
@JWilliams The neutron star merger (GW170817) gave us a wealth of data that we couldn't have acquired without both sources of information. because we knew that the event WAS the merger of two neutron stars, and because we knew basically in what direction to look, optical, radio, and gamma-ray observatories didn't have to start from scratch in their observations.
@JWilliams When the gamma ray signal was received at nearly the same time as the gravitational wave signal, it confirmed important predictions in General Relativity, and disproved others. we now know with great certainty that gravity as a force, and gravitational waves, travel at the speed of light.
We also have a pretty good idea now that merging neutron stars are at least one cause of gamma-ray bursts.
@JWilliams A clarification to the above: GW170817 did not disprove General Relativity predictions. But it DID do damage to some theories that involved modified gravity. Some such theories predicted gravitational waves would travel much more slowly than light.
@JWilliams Whoa, nice thread