Illustration of the pulsar J0030+0451 showing three hotspots. The three hotspots are thought to be areas of around a million degree Celsius on the pulsar's surface. J0030+0451 is in the constellation Pisces. Pulsars form when stars collapse into dense cores that rotate rapidly and can be detected by their highly regular emissions of radio waves. The data used to produce the illustration is from NASA??? Neutron star Interior Composition Explorer (NICER), an X-ray telescope aboard the International Space Station (ISS).