English: This simulation tracks the gravitational wave and density changes as two orbiting neutron stars crash together. Dark purple colors represent the lowest densities, while yellow-white shows the highest. An audible tone and a visual frequency scale (at left) track the steady rise in the frequency of gravitational waves as the neutron stars close. When the objects merge at 42 seconds, the gravitational waves suddenly jump to frequencies of thousands of hertz and bounce between two primary tones (quasiperiodic oscillations, or QPOs). The presence of these signals in such simulations led to the search and discovery of similar phenomena in the light emitted by short gamma-ray bursts.Credit: NASA's Goddard Space Flight Center and STAG Research Centre/Peter HammondComplete transcript available.Watch this video on the NASA Goddard YouTube channel.Visual description:On a black background with a faint gray grid, two multicolored blobs representing merging neutron stars circle and close. The colors indicate density. Yellow-white indicates the highest densities, at the centers of the objects. The colors change to orange and red at their periphery, with purple colors representing matter torn from and swirling with the neutron stars as they orbit. The grid shrinks as the camera pulls back to capture a wider view of the merger. A pale orange display at left shows the changing frequency of the gravitational waves generated, which is also indicated by the rising tone. As the merger occurs, the screen shows a spinning yellow blob at center immersed in a large cloud of magneta and purple debris.