Hulse, Russell Alan (1950-…), an American physicist, discovered the first binary pulsar, a pair of collapsed stars, each emitting huge amounts of energy, orbiting each other. For this discovery and follow-up research work, Hulse shared the 1993 Nobel Prize for physics with fellow American Joseph H. Taylor (see Taylor, Joseph Hooton, Jr. ).
A pulsar is a rapidly spinning neutron star, a dense star composed chiefly of tightly packed neutrons. An extremely powerful magnetic field, a region where magnetic forces can be felt, surrounds the neutron star and rotates with it. This rapidly rotating magnetic field produces a strong electric field that rips electrons and protons from the star’s surface. As these particles flow from the star, they emit energy in the form of a narrow beam of radio waves. Using a giant radio telescope, an astronomer can detect a pulse of radio waves each time the pulsar rotates and the beam sweeps past the earth.
In 1974, Hulse and Taylor, using the huge Arecibo Observatory radio telescope in Puerto Rico, found a pulsar where the rate of pulsation regularly decreased and increased. Hulse and Taylor concluded that the pulsar was revolving around an unobserved companion object, the two massive bodies forming a binary system. Until the discovery of this pair of stars, called pulsar PSR 1913+16, scientists had believed that the supernova explosion in which any pulsar is formed would destroy all companion objects. Taylor went on to find more binary pulsars.
By recording the pulses from PSR 1913+16 over several years, Hulse and Taylor noted that the pulsation rate was gradually slowing. The two stars making up the pulsar were losing energy and spiraling closer together. Their studies confirmed that massive bodies in orbit around each other give off energy in the form of gravitational waves. The German-born physicist Albert Einstein had predicted the existence of gravitational waves in 1915 as part of his general theory of relativity (see Relativity ). In 2016, researchers announced that they had directly detected the existence of gravitational waves.
Hulse was born and educated in New York City. In 1970, Hulse received a bachelor’s degree in physics at Cooper Union, a college in New York City. As part of his postgraduate work at the University of Massachusetts at Amherst, he studied radio astronomy.
After earning a Ph.D. in physics in 1975, Hulse took a postdoctoral appointment at the National Radio Astronomy Observatory in Charlottesville, Virginia, until 1977. He then joined the Plasma Physics Laboratory (PPL) at Princeton University in New Jersey as a research physicist. Since the late 1970’s Hulse has conducted research on hydrogen fusion at the PPL.
