Thomas Gold - Astrophysics Research

Astrophysics Research

In 1951, at a meeting of the Royal Astronomical Society, Gold proposed that the source of recent radio signals detected from space was outside the Milky Way galaxy, much to the derision of radio astronomer Martin Ryle and several mathematical cosmologists. However, a year later, a distant source was identified and Gold announced at an International Astronomical Union meeting in Rome that his theory had been proven. Ryle would later take Gold's argument as proof of extragalactic evolution, claiming that it invalidated the Steady State theory.

Gold left Cambridge in 1952 to become the chief assistant to Astronomer Royal Harold Spencer Jones at the Royal Greenwich Observatory in Herstmonceux, Sussex, England. While there, Gold attracted some controversy by suggesting that the interaction between charged particles from the Sun with the Earth's magnetic field in creating magnetic storms in the upper atmosphere was an example of a collisionless shock wave. The theory was widely disputed, until American scientists in 1957 discovered that Gold's theory held up to mathematical scrutiny by conducting a simulation using a shock tube.

Gold resigned from the Royal Observatory following Spencer-Jones's retirement and moved to the United States in 1956, where he served as Professor of Astronomy (1957–1958) and Robert Wheeler Wilson Professor of Applied Astronomy (1958–1959) at Harvard University. In early 1959, he accepted an appointment at Cornell University, which had offered him the opportunity to set up an interdisciplinary unit for radiophysics and space research, and take charge of the Department of Astronomy. At the time, there was only one other faculty member in the department. Gold would serve as director of the Center for Radiophysics and Space Research until 1981, establishing Cornell as a leading hub of scientific research. During his tenure, Gold hired famed astronomers Carl Sagan and Frank Drake, helped establish the world's largest radio telescope at the Arecibo Observatory in Puerto Rico and the Cornell-Sydney University Astronomy Center with Harry Messel. In addition, Gold served as Assistant Vice President for Research from 1969–1971 and the John L. Wetherill Professor of Astronomy from 1971 until his retirement in 1986.

In 1959, Gold expanded on his previous prediction of a collisionless shock wave, arguing that solar flares would eject material into magnetic clouds to produce a shock front that would result in geomagnetic storms. He also coined the term "magnetosphere" in his paper "Motions in the Magnetosphere of the Earth" to describe "the region above the ionosphere in which the magnetic field of the Earth has a dominant control over the motions of gas and fast charged particles ... known to extend out to a distance of the order of 10 Earth radii". In 1960, Gold collaborated again with Fred Hoyle to show that magnetic energy fueled solar flares and that flares were triggered when opposite magnetic loops interact and release their stored energy.

In 1968, a Cambridge radio astronomy postgraduate student Jocelyn Bell Burnell and her doctoral adviser Antony Hewish discovered a pulsing radio source with a period of 1.33 seconds. The source – which was termed "pulsar" – emitted beams of electromagnetic radiation at a very short and consistent interval. Gold proposed that these objects were rapidly rotating neutron stars. Gold argued that due to their strong magnetic fields and high rotational speed, pulsars would emit radiation similar to a rotating beacon. Gold's conclusion was initially not well received by the scientific community; in fact, he was refused permission to present his theory at the first international conference on pulsars. However, Gold's theory became widely accepted following the discovery of a pulsar in the Crab Nebula using the Arecibo radio telescope, opening the door for future advancements in solid-state physics and astronomy. Anthony Tucker of The Guardian remarked that Gold's discovery paved the way for Stephen Hawking's groundbreaking research into black holes.