Like cosmic lighthouses , beams of radiation from surface hotspots sweep past our viewpoint creating pulses which reveal the rotation rates of these incredibly dense stellar corpses . The most famous pulsar of all is found in the nearby supernova remnant, the Crab Nebula . The Crab's young pulsar is fast. Rotating at 33 times a second, its radiation energizes the surrounding gaseous stellar debris . The image is about 1,500 light-years across.
Specific rights apply .