On 17 August, 2017, the Laser Interferometer Gravitational-Wave Observatory detected gravitational waves from a neutron star collision. Within 12 hours, observatories had identified the source of the event within the galaxy NGC 4993 and located an associated stellar flare called a kilonova. Hubble watched as the flare of light from the kilonova faded over the course of 6 days. The inset images show the decreasing brightness in observations taken on the 22nd, 26th, and 28th.
Image Credit: NASA / ESA / STScI