This is a rendition of a pulsar, which is a rapidly spinning neutron star, the collapsed remains of a dead star's core. Some spin hundreds of times per second. As they do, beams of radiation – usually radio waves but often, and as seen here, optical light – sweep across our line of sight and we see the star blink on and off with the precision of an atomic clock. The surrounding nebula is the shattered remains of the dead star left over from the supernova that created the pulsar.