English radio astronomer, founder and director (1951–81) of England's Jodrell Bank Experimental Station (Jodrell Bank Observatory).

Lovell attended the University of Bristol, from which he received the Ph.D. degree in 1936. After a year as an assistant lecturer in physics at the University of Manchester, he became a member of the cosmic-ray research team at that institution, working in this capacity until the outbreak of World War II in 1939, when he published his first book, Science and Civilization. During World War II, Lovell worked for the Air Ministry, doing valuable research in the use of radar for detection and navigation purposes for which he was awarded the Order of the British Empire in 1946.

On returning to the University of Manchester in 1945 as a lecturer in physics, Lovell acquired a surplus army radar set for use in his research on cosmic rays. Because interference from the surrounding city hampered his efforts, he moved the equipment, which included a searchlight base, to Jodrell Bank, an open field located about 20 miles south of Manchester. Shortly thereafter, authorities at the university agreed to provide him with a permanent establishment at the site, which already belonged to the university's botany department, and to sponsor the construction of his first radio telescope, for which he used the searchlight base as a mounting.

Lovell's initial investigations with the instrument involved the study of meteors (meteor and meteoroid). About 15 years earlier, when radio waves had been bounced off meteors during certain meteor showers, some astronomers had noted that the number of meteors observed visually was much smaller than the number of radio echoes received, an indication that the showers actually consisted of more meteors than could be seen. To determine if the echoes were meteoric in origin, Lovell used his new radio telescope to observe a particularly intense meteor shower on the night of Oct. 9–10, 1946. As the shower first increased and later decreased in intensity, radio signals from the instrument's transmitter were directed toward the shower. Throughout the evening, not only did the number of optical sightings coincide with the number of radio echoes being received, but the timing of the two rates was also as predicted, conclusively proving that the echoes were caused by the meteors. Having established this fact, Lovell could now apply radio techniques to meteor showers previously unknown because they occurred during daylight hours. Further experiments showed that orbits of meteors are elliptical, confirming the belief that these bodies are members of the solar system and are not of interstellar origin.

In recognition of his work and growing reputation, Lovell was appointed by the University of Manchester to the position of senior lecturer in 1947 and reader in 1949; from 1951 to 1980 he was professor of radio astronomy at the university. During this time, he had already begun planning and building a bigger and more sophisticated radio telescope, which, when it was completed in 1957, was the world's largest of its kind, with a diameter of 250 feet. The structure rotates horizontally at 20° per minute, and the reflector itself moves vertically at 24° per minute. While work on the telescope was in progress, Lovell published Radio Astronomy (1952), Meteor Astronomy (1954), and The Exploration of Space by Radio (1957).

Because of the widespread publicity given to Jodrell Bank and its director, coupled with the latter's reputation as a popularizer of science, the British Broadcasting Corporation in 1958 invited Lovell to give a series of radio talks, known as the Reith Lectures, which were published in 1959 as The Individual and the Universe. When Lovell was knighted (1961) for his pioneering work in radio astronomy, 20 investigations—mostly on radio emissions originating thousands of millions of light years away—were in progress at Jodrell Bank. Some of this work is discussed in his book The Exploration of Outer Space (1962). His research has since been concerned mainly with cosmology; radio emissions from outer space, including those from pulsars (discovered in 1968); the measurement of the angular diameters of distant quasars; and flare stars.

Lovell received a number of honorary degrees from various academic institutions as well as honorary membership in several academies and organizations. He was elected a fellow of the Royal Society in 1955, receiving its Royal Medal in 1960. From 1969 to 1971 he was president of the Royal Astronomical Society, and he received the Society's Gold Medal in 1981.