Pulsar

A pulsar is a neutron star that puts out pulses of radio energy. A pulsar is a neutron star that is emitting a beam of radio waves, and spinning, and so the effect is like that of a lighthouse. Pulsars keep exceptionally good time. Most of them ‘pulse’ at a rate between ten times a second and once every three seconds; some spin around hundreds of times a second. Pulsars have a mass of about 1.4 to 3 solar masses compacted into a sphere about 10 km across.