Neutron star
In 1974, Hulse and Taylor discovered binary pulsar PSR B1913, which is made up of a pulsar and black companion star. Neutron star rotation emits impulses that are extremely regular and stable in the radio wave region and is nearby condensed material body gravitation (non-detectable in the visible field). Hulse, Taylor, and other colleagues have used this first binary pulsar to make high-precision tests of general relativity, demonstrating the existence of gravitational radiation. An approximation of this radiant energy is described by the formula of the quadrupolar radiation of Albert Einstein (1918).