Two Black Holes Merge . ... Inspired by the first direct detection of gravitational waves by LIGO, this simulation video plays in slow motion but would take about one third of a second if run in real time. ... The otherwise invisible gravitational waves generated as the massive objects rapidly coalesce cause the visible image to ripple and slosh both inside and outside the Einstein rings even after the black holes have merged. ... NASA Web Site Statements, Warnings, and Disclaimers . ...