Contemporary New Zealand scientists
Astronomy
An aurora as seen at the Mt John Observatory, at Lake Tekapo, Fraser Gunn
Astronomy
The current understanding of the origins of the universe is that it really is a random fluctuation in nothing. When you look at pure nothing, before there was even a universe, just emptiness, probably what there is is this foamy structure, with little patches where just by chance there’s too much of something, and other patches with too little of something.
Gerry Gilmore, professor of experimental philosophy at Cambridge University, in an interview in Eureka, National Radio, 6 November 2004
A century ago, the Milky Way constituted the entire universe for most astronomers. However, the emergence of quantum physics and relativity, coupled with bigger telescopes, better instrumentation and new ‘windows’ on the universe through radio and other wavelengths, led to some remarkable discoveries.
Among the most significant were the detection of cosmic background radiation, the Big Bang origin of the universe, an array of high-energy particles and celestial objects such as black holes. Several New Zealanders have been part of these continuing advances.
Southern skies
The University of Canterbury’s Mt John Observatory, led by John Hearnshaw, is the centre of astronomical research and training in New Zealand. Despite its modest size, MJO’s southern location, clear skies, high-tech resources and passionate staff have enabled it to make significant contributions to astronomy, particularly in the fields of stellar spectroscopy and photometry, minor planet discovery, and microlensing observations.
Microlensing, a technique pioneered by New Zealander Charles Alcock, who is currently director of the Harvard-Smithsonian Center for Astrophysics, occurs when light from a distant star or galaxy is bent by the gravity of an intervening star passing directly in front. This produces a magnified, distorted image, the ‘Einstein ring’, which registers as a temporary brightening of the star. Small ‘defects’ in the brightening indicate planets around the star.
Alan Gilmore and Pam Kilmartin have lived and worked at the hilltop observatory since 1980 and both played a lead role in the discovery and tracking of minor planets. Phil Yock, at the University of Auckland, and Ian Bond, at Massey University, lead the New Zealand contingent of an international collaboration, Microlensing Observations in Astrophysics or MOA. It uses the world’s largest dedicated microlensing telescope, the 1.8m MOATEL, funded by Nagoya University, to search for dark matter and extra-solar planets.
Through participation in another international consortium, the 11m South African Large Telescope or SALT, Canterbury staff and students have access to observing time on the world’s largest optical telescope. This project, led by Peter Cottrell, employs high resolution spectroscopy, which means that SALT is capable of detecting a ‘candle flame on the moon’.
Planet finders
More than 150 planets outside our solar system have been found since the first was detected in 1995. Most such planets are ‘hot Jupiters’ – massive planets in close orbits around their host stars – and were discovered through the radial velocity technique, the gravitational ‘wobble’ the planet induces in the parent star.
Microlensing is more sensitive to finding Earth-like planets, orbiting at larger distances around their stars. Canterbury astronomers Michael Albrow and Karen Pollard, founding members of the international microlensing collaboration PLANET, were part of a recent discovery, and in 2005, Grant Christie and Jennie McCormick, members of MicroFUN, became the first amateur astronomers to contribute to the discovery of a planet since William Herschel discovered Uranus in 1781.
In 1999, Denis and Tiri Sullivan, at Victoria University of Wellington, confirmed the existence of an extra-solar planet when they recorded a drop in luminosity as a planet passed in front of the star HD209458. Detecting such planetary transits is extremely& rare because the plane of the planet’s orbit has to be precisely& aligned with the observer.
Into the cosmos
Back in the 1950s, Beatrice Tinsley was one of few women to study mathematics, physics and chemistry at the University of Canterbury. Not long after her graduation, she moved to Texas with her husband, but was unable to find work and eventually decided to leave her family in order to fulfil her scientific promise. She became a leader in her field for her work on stellar and galactic evolution, and her model for galactic evolution became a cornerstone of modern cosmology.
In 1963, Roy Kerr’s solution to Einstein’s field equations, which describe the space around a rotating black hole, was hailed as ‘the most important exact solution to any equation in physics’. The theoretical physics of black holes, in relation to gravitation and cosmology, is a rich area of research for leading relativists Matt Visser, at Victoria University, and David Wiltshire, at the University of Canterbury.
Gerry Gilmore, at Cambridge University, discovered a new component of the galaxy – the ‘thick disk’ – and he is a lead scientist for the European Space Agency’s astrophysical mission Gaia.
The invisible universe
Although New Zealand did not join Australia and Britain in pioneering the development of radio astronomy after the Second World War, it can boast the world’s first female radio astronomer, Elizabeth Alexander, who led wartime investigations of solar interference with communications systems, and the first postgraduate thesis in solar radio astronomy by Alan Maxwell.
In 1957, Robert Unwin developed a series of auroral radars operating from Bluff Hill, and almost 50 years later, the UNWIN array, which is part of an international auroral radar network, began operations in Southland.
More recently, Sergei Gulyaev at the Centre for Radiophysics and Space Research, at the Auckland University of Technology, has conducted experiments with New Zealand, Australia and Japan, using a technique called Very Long Baseline Interferometry (VLBI) which links several radio antennas that can be hundreds of kilometers apart to operate as one giant radio telescope.
By Marilyn Head
Medals and awards
Grant Christie: FRASNZ, MBE
Jennie McCormick: MBE
Alan Gilmore: Murray Geddes Prize, FRASNZ, co-discoverer of naked-eye Nova Velorum in 1999
Pam Kilmartin: FRASNZ
John Hearnshaw: Murray Geddes Prize
Roy Kerr: Rutherford Medal, Marcel Grossman Prize
Beatrice Tinsley: Annie J Cannon Prize, Beatrice M Tinsley Prize for outstanding contributions to astronomy or astrophysics was created in her honour in 1986
Charles Alcock: Beatrice Tinsley Prize
Gerry Gilmore: Smithson Fellow Royal Society, London, Academia Europaea Fellow
Further reading and websites
J B Hearnshaw, The Analysis of Starlight: 150 years of astronomical spectroscopy, Cambridge University Press, 1986
J B Hearnshaw, The Measurement of Starlight: two centuries of astronomical photometry, Cambridge University Press, 1996
Image courtesy Fraser Gunn
