"Rutherford's discovery was the beginning of the science that came to be called nuclear physics. ...The projectiles that he used to explore the nucleus were particles produced in the disintegration of radium... discovered by Marie Curie in 1898. The particles are helium nuclei that are emitted at high speed when radium atoms decay...The twenty years between 1909 and 1929 were the era of tabletop nuclear physics. ...Small and simple experiments were sufficient to establish the basic laws of nuclear physics."