WHAT THE GRAVITATIONAL WAVE DISCOVERY CONFIRMED. Leah Crane in this post on the New Scientist blog lists what she considers the five biggest discoveries resulting from the discovery of the gravitational wave resulting from a neutron star merger. The fifth “discovery” —critical for science—is that the predictions from existing theory were “pretty good”. She gives as examples of confirmed predictions: “We knew that black holes theoretically existed, and roughly how they should orbit and collide. We were pretty sure that neutron star collisions would make heavy elements and short gamma ray bursts.” The discovery “was able to measure the expansion of the universe, and its measurement was consistent with calculations made with other methods.”
So theories and hypotheses were tested and roughly confirmed in accordance with good science.