Sir Ernest Marsden

Sir Ernest Marsden was an English-New Zealand physicist. He is recognized internationally for his contributions to science while working under Ernest Rutherford, which led to the discovery of new theories on the structure of the atom. In Marsden's later work in New Zealand, he became a significant member of the scientific community, while maintaining close links to the United Kingdom.

Born in Manchester, Marsden lived in Rishton and attended Queen Elizabeth's Grammar School, Blackburn.  In 1909, as a 20-year-old student at the University of Manchester, he met and began work under Ernest Rutherford. While still an undergraduate he conducted the famous Geiger–Marsden experiment, called the gold foil experiment, together with Hans Geiger under Rutherford's supervision. This experiment led to Rutherford's new theory for the structure of the atom, with a centralized concentration of mass and positive charge surrounded by empty space and a sea of orbiting negatively charged electrons. Rutherford later described this as "almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back to hit you."  The apparatus used in the experiment was an early version of what was to become the Geiger counter.

In 1915 he moved to Victoria University College in Wellington, New Zealand to replace Thomas Laby as Professor of Physics; Rutherford recommended his appointment there. Marsden served in France during World War I as a Royal Engineer in a special sound-ranging section and earned the Military Cross. In 1922 Marsden turned from his research and position as Professor of Physics to bureaucracy. He was appointed Assistant Director of Education before accepting the position of Secretary of New Zealand's new Department of Scientific and Industrial Research (DSIR) in 1926. The new Department's focus was on assisting primary industries, and Marsden worked to organize research particularly in the area of agriculture.  Marsden initiated a number of projects that kept New Zealand in touch with international developments in the field of radiation and nuclear sciences. In 1939 he pioneered the non-medical use of radioisotopes in New Zealand, and conducted a series of experiments to determine the role of cobalt in animal metabolism.

With the outbreak of World War II Marsden was given the title of Director of Scientific Developments, and was charged with mobilizing New Zealand's scientific manpower. During the War he worked on radar research, setting up a team to develop the radar equipment for use in the Pacific. Marsden also used his scientific connections to form a team of young New Zealand Scientists who would participate in the American Manhattan Project developing the nuclear bomb, and initiated the search for uranium, the raw material needed for nuclear projects, in New Zealand. Marsden had a post-war vision of a nuclear New Zealand, with scientists working on research using local nuclear reactors, and developing connections with the British nuclear energy and weapons program. While this vision was not fully realized, in 1946 he established a team of scientists to carry out research into atomic energy and the application of nuclear science to problems in agriculture, health, and industry. Ties between Marsden and the scientific community in Britain remained strong, and in 1947 he became the DSIR's scientific liaison officer in London.

Marsden retired in 1954 and returned to Wellington, where he continued to work and travel extensively, serving on a number of committees and conducting research into environmental radioactivity. As his studies turned to the impact of fallout from radioactive bombs, Marsden came to oppose testing and the development of nuclear weapons. While Marsden had a significant role in establishing and encouraging nuclear science in New Zealand, this role of speaking out against nuclear weapons development and testing - which he only did after the British nuclear testing program was complete - is less known.

In 1966, the same year France began testing nuclear bombs in the Pacific, Marsden suffered a stroke which left him confined to a wheelchair. He later died at his home in Lowry Bay, Lower Hutt on the shores of Wellington Harbour in 1970.