Rutherford continued to make ground-breaking discoveries long after receiving the Nobel prize in 1908. Along with Hans Geiger and Ernest Marsden in 1909, he carried out the Geiger–Marsden experiment, which demonstrated the nuclear nature of atoms by measuring the deflection of alpha particles passing through a thin gold foil. Rutherford was inspired to ask Geiger and Marsden in this experiment to look for alpha particles with very high deflection angles, which was not expected according to any theory of matter at that time. Such deflection angles, although rare, were found. It was Rutherfords interpretation of this data that led him to formulate the Rutherford model of the atom in 1911that a very small charged nucleus, containing much of the atoms mass, was orbited by low-mass electrons.
In 1912, Rutherford was joined by Niels Bohr (who postulated that electrons moved in specific orbits). Bohr adapted Rutherfords nuclear structure to be consistent with Max Plancks quantum theory, and the resulting Rutherford–Bohr model is considered valid to this day.