PSR B1919+21

PSR B1919+21 is the first discovered pulsar, a highly dense and rapidly rotating neutron star. It emits regular beams of radio waves from its magnetic poles, which sweep across Earth like a lighthouse beam, creating precise pulses detected by astronomers. Located about 2,000 light-years away, it rotates approximately 1,800 times per minute. Its discovery in 1967 provided crucial insight into extreme states of matter and confirmed the existence of neutron stars, revolutionizing astrophysics. The pulsar's consistent signals also serve as cosmic clocks, aiding in tests of fundamental physics and gravitational theories.