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James Stanley Hey, the Sun, and Extragalactic Radio

Scoping out Radio Astronomy

A blog dedicated to telling the history of radio astronomy: its evolution, its discoveries, and its telescopes

James Stanley Hey, the Sun, and Extragalactic Radio

Olivia Wilkins

About a decade after American radio engineer Karl Jansky published his findings that radio static observed at Bell Telephone Labs actually originated in the center of the Milky Way, English physicist James Stanley Hey (1909 - 2000) was investigating another type of static from across the Atlantic Ocean.

During World War II, Hey was employed by the Army Operational Research Group (AORG), beginning in 1940. During that time, he was researching anti-aircraft radar to combat the Germans who were jamming radio communications among the Allied Forces. In February 1942, there was a significant increase in radio interference at radar stations along the south coast of England, presumably the result of interference from Axis operatives along the French coast. However, the source of the jam in communications could not be verified.

The German battleship charnhorst was one of two Axis vessels that were able to pass through the English Channel after radar communications were jammed on the southern coast of England.

After observing the patterns in the radio interference, Hey noted that the direction of the strongest bouts of interference came from the direction of the Sun, following it as it traversed the sky. Initially met with skepticism that the sun was partially responsible for jamming Allied communications, Hey consulted with the Royal Observatory in Greenwich in the southeast part of greater London. Astronomers there divulged that the sun was experiencing particularly strong sunspot activity, providing further evidence that radio waves from the sun were in fact interfering with Allied communications.

Greenwich Royal Observatory, by Kjetil Bjørnsrud

Hey did not investigate the solar radio waves further until the end of World War II. In 1946, the Sun became active again, and Hey led a team of researchers to formally investigate the correlation of solar activity with bursts of radiation observed on Earth. Meanwhile, Hey's team tuned in to other parts of the sky in an attempt to observe the same phenomena reported by Karly Jansky and Grote Reber. They observed radiation not only from solar flares but from Cygnus—which contains what is known as the Northern Cross&mdsh;as well. These radio signals "twinkled," having a period of a few seconds. This twinkling initially earned the signals the name "radio stars," but later these radio waves were found to originate from supernova remnants and other galaxies.

Map of the constellation Cygnus, from Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)

Despite observing the first detection of extragalactic radio waves, Hey's contributions to the young field of radio astronomy were not widely recognized at first, much like those of his predecessors in the field. For a decade after hypothesizing the Sun was a source of radio waves, Hey remained in the AORG, ultimately becoming its head 1949. In 1952, he left to join the physics department at the Telecommunications Research Establishment (which merged with the Royal Radar Establishment a year later to become the Royal Research Establishment), where he continued his radio astronomy work for 17 years. During that time, Hey made significant contributions to radio astronomy, for instance by collaborating with Sir Bernard Lovell, influencing the observatory at Jodrell Bank. It wasn't until 1978 that Hey was recognized by the Fellowship of the Royal Society, with a nomination and immediate election to the Society, for advancing radio astronomy from its infancy.