Giacconi, Riccardo (1931– )

Italian-born US physicist. He is the head of a team whose work has been fundamental in the development of X-ray astronomy. In 1962 a rocket sent up by Giacconi and his group to observe secondary spectral emission (see spectrum) from the Moon detected strong X-rays from a source evidently located outside the Solar System. X-ray research has since led to the discovery of many types of stellar and interstellar material. Giacconi and his team developed a telescope capable of producing X-ray images. In 1970 they launched a satellite called Uhuru, devoted entirely to the detection of stellar and interstellar X-rays. He was awarded the Nobel Prize for Physics in 2002 for his discovery of cosmic X-ray sources.

Giacconi was born in Genoa and obtained his PhD from the University of Milan in 1954. He emigrated to the USA in 1956, becoming research associate first at the Indiana University at Bloomington and then at Princeton University. In 1959 he joined American Science and Engineering, Inc. as senior scientist, rising to executive vice-president in 1969. In 1973 he was made professor of astronomy at Harvard University. Later he became director of the European Southern Observatory, La Silla, Chile. Giacconi has also worked with a Cherenkov detector, by means of which it is possible to observe the existence and velocity of high-speed particles.