New art installation ‘The Radiant Stranger’ is launched in School of Physics

The School of Physics has officially welcomed a new sculpture to the Fitzgerald building. Launched by the renowned theoretical physicist Sir Michael Berry FRS on 24 May, the sculpture, entitled The Radiant Stranger, is a model of conical refraction.  It was designed by Professor James Lunney and fabricated by David Grouse in the Mechanical Workshop in the School of Physics. The artwork was jointly funded by the School of Physics and the TCD Association & Trust.

The Radiant Stranger was the name given by the Irish poet Aubrey de Vere (1814-1902) to conical refraction, an optical effect predicted in 1832 by William Rowan Hamilton (1805-1865) and observed by Humphrey Lloyd (1800 – 1881) in the same year. This was a major sensation, a prime example of a theoretical prediction using the wave theory of light, quickly confirmed by observation.

Professor Lunney noted: “The Radiant Stranger is a celebration of the discovery of conical refraction in Trinity College Dublin in 1832.  The combination of theoretical prediction by William Rowan Hamilton, followed shortly by the experimental observations of Humphrey Lloyd, was a sensational moment in the development of optics in the 19th century.”

William Rowan Hamilton was one of the world’s great mathematicians. Hamilton, a child prodigy, became Andrews Professor of Astronomy at Trinity even before he had completed his undergraduate degree. Hamilton is famous for predicting, on the basis of sophisticated calculation, a new physical phenomenon: Conical Refraction. The prediction, made in October 1832, was experimentally confirmed by Hamilton’s colleague Humphrey Lloyd (and former Trinity Provost) later that year.

In conical refraction a beam of light directed along either of the optical axes of a biaxial crystal spreads out as a hollow cone inside the crystal, and emerges as a hollow cylinder of light. Sample rays of the cones are highlighted in orange in the sculpture, which is a scaled-up version of a small wire model recently discovered at Trinity, possibly made in Dublin in the 19th century.  It was the discovery of this model which inspired Professor Lunney to propose the making of The Radiant Stranger.