Ernest Marsden was a physicist from New Zealand who lived from 1889 until 1970. Marsden made valuable contributions to physics and chemistry by improving the understanding of the internal structure of the atom from observing the path of a-particles.
Ernest Marsden worked under Ernest Rutherford and Hans Geiger at the University of Manchester. Marsden's work comprised the premise of Rutherford's nuclear model of the atom, and this eventually led to the discovery of the proton. Marsden also influenced Rutherford's artificial transmutation of elements in 1914 and 1915 through his continued study of deflected a-particles. Marsden became a professor of physics at Victoria University in Wellington, New Zealand, in 1915 and retired in 1954.