Neutron Star Merger Animation Ending with Kilonova Explosion FriendsofNASA.org: This artist’s impression video shows how two tiny but very dense neutron stars merge and explode as a kilonova. Such a very rare event is expected to produce both gravitational waves and a short gamma-ray burst, both of which were observed on August 17, 2017, by LIGO–Virgo and Fermi/INTEGRAL respectively. Subsequent detailed observations with the NASA/European Space Agency Hubble Space Telescope and other telescopes