Evolution of LIGO's binary neutron star (BNS) detection range between iLIGO (2002) and O4 (2023). The base map (drawn by Richard Powell, Atlas of the Universe) shows the nearest superclusters of galaxies within a 500 million-light-year radius (~153 megaparsecs or Mpc) of the Virgo Supercluster, in which our Milky Way Galaxy resides. Hundreds of thousands of large galaxies reside within this volume of space.

In its fourth observing run, O4, LIGO could potentially detect BNS mergers as far as 620 million light years (190 Mpc) away, beyond the confines of this map. Binary neutron star mergers are among the 'weakest' gravitational wave signals that LIGO can detect, so detecting them at these great distances means that LIGO's ability to detect the much more powerful black-hole collisions will also expand to include unimaginably vast reaches of the Universe. (Credit: Base map by Richard Powell. Animation: Caltech/MIT/LIGO Lab/Kim Burtnyk)