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Taylor, Joseph (Hooton)

pulsar hulse binary gravitons

(1941– ) US physicist: co-discoverer of first binary pulsar; detected gravitons in 1978.

Educated at Harvard, Taylor held a post at the University of Massachusetts at Amherst from 1969 until 1980 when he returned to Harvard as professor of physics. In 1974 with his research student Russell A Hulse (1950– ) a search was made for new pulsars using the giant 300 m fixed radio telescope at Arecibo in Puerto Rico. These small, ultra-dense neutron stars had first been detected in 1967 by through their emission of regular pulses at radio wavelengths as they rotate.

Taylor and Hulse detected a new pulsar with a period between pulses of 0.05903 s. Their precise study of the slightly varying period showed that they had detected the first binary pulsar, consisting of two bodies of comparable mass and small size rotating about one another; the radio-emitter of the pair taking less than 8 hrs to complete a revolution around the invisible companion.

In 1977 Hulse moved to Princeton to work in plasma physics, but Taylor continued to study the binary pulsar. By the 1970s it was widely agreed that the force of gravity must be transmitted by gravitational waves, which could also be considered as massless particles, gravitons (just as light can be thought of as waves or as photons, depending on the experimental situation). Taylor realized that the two heavy bodies of the binary pulsar were close enough together to cause emission of gravitons in accord with Einstein’s prediction of 1916: and this should cause a slowdown in the orbital period, of 75 millionths of a second per year. By 1978 Taylor could report detection of a measurable change, in good agreement with this figure. Taylor and Hulse shared the Nobel Prize for physics in 1993.

Joseph Weber (1919–2000) had made an earlier claim for detection of gravity waves in 1969. Weber had a US naval career before becoming professor of electrical engineering at the University of Maryland. His detection system used 3½ tonne aluminium bars, hung in pairs several hundred miles apart, which responded to graviton events by vibrating: these results were not accepted by some physicists, and Taylor’s work established gravitons more firmly.

Taylor, Lily Ross (1886–1969) - Roman History [next] [back] Taussig, Helen (Brooke)

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