Black hole formation. Animation clip 6 of 11 showing a stage in black hole formation from the merger of two neutron stars. Neutron stars are immensely dense stellar core remnants, formed after a large star runs out of hydrogen fuel and its core collapses. During the merger, part of the mass of the neutron stars is rearranged to form this disc of super_hot plasma purple around the central black hole area. This animation is part of a sequence showing the role neutron star mergers play in the occurrence of short gamma_ray bursts GRBs. Later clips in this sequence K003/2670_2660 show the process of neutron star merger in detail, as modelled by the Damiana supercomputer at Germany磗 Max Planck Institute for Gravitational Physics.