English radio astronomer who was awarded, with Martin Ryle, the Nobel Prize for Physics 1974 for his work on pulsars, rapidly rotating neutron stars that emit pulses of energy.
The discovery by Jocelyn Bell Burnell of a regularly fluctuating signal, which turned out to be the first pulsar, began a period of intensive research. Hewish discovered another three straight away, and more than 170 pulsars have been found since 1967.
Hewish was born in Cornwall and studied at Cambridge. He worked at the Cavendish Laboratory there, and became professor at Cambridge 1972.
Before 1950, Hewish used radio telescopes mainly to study the solar atmosphere. When new instruments became available, radio observations were extended to sources other than the Sun. Before the discovery of pulsars, Hewish examined the fluctuation in such sources of the intensity of the radiation (the scintillation) resulting from disturbances in ionized gas in the Earth's atmosphere, within the Solar System, and in interstellar space.
Hewish has patented a system of space navigation using three pulsars as reference points, which would provide coordinates in outer space accurate up to a few hundred kilometres.