Gravitational waves are ripples in spacetime generated by the acceleration of astrophysical objects; a direct consequence of general relativity, they were first directly observed in 2015. Here, I review the first 5 years of gravitational-wave detections. More than 50 gravitational-wave events have been found, emitted by pairs of merging compact objects such as neutron stars and black holes. These signals yield insights into the formation of compact objects and their progenitor stars, enable stringent tests of general relativity, and constrain the behavior of matter at densities higher than that of an atomic nucleus. Mergers that emit both gravitational and electromagnetic waves probe the formation of short gamma-ray bursts and the nucleosynthesis of heavy elements, and they measure the local expansion rate of the Universe.

引力波是由天体物理物体加速产生的时空涟漪；作为广义相对论的直接结果，它们于 2015 年首次被直接观测到。在这里，我回顾了引力波探测的前 5 年。已经发现了 50 多个引力波事件，它们是由成对合并的致密天体（例如中子星和黑洞）发出的。这些信号有助于深入了解致密天体及其前身恒星的形成，能够对广义相对论进行严格的测试，并限制密度高于原子核的物质的行为。发射引力波和电磁波的合并探测短伽马射线暴的形成和重元素的核合成，并测量宇宙的局部膨胀率。