Ernest Rutherford’s paper of 1911, which drew consequences from the experiments of Hans Geiger and Ernest Marsden at Rutherford’s laboratory in Manchester on the scattering of alpha and beta particles by matter (1909), was a game changer. It established experimentally, irrespective of any theory or model, that the atom consists of a central charged mass surrounded by mostly empty space. Planetary schemes of the atom, which until then had been mainly qualitative, now seemed to be the “obvious” interpretation of these results, although Rutherford himself refrained from endorsing any of them. In 1913 Niels Bohr introduced an “atom-model” (his expression) with no explicit planetary analogy, but calling the path of the electron an “orbit” and identifying the axes of the ellipsoid of the electron as it rotates about the central core in stationary states. In 1915 Arnold Sommerfeld further developed Bohr’s theory in which he presented a full blown planetary account of the atom, taking advantage of an analogy with Keplerian motion. Bohr accepted Sommerfeld’s analysis and, in his Nobel Lecture of 1922, Bohr made it clear that, in his view, the chemical atom is essentially planetary. He was wrong. As is well known, by 1925 Bohr’s quantum theory was replaced by quantum mechanics. In our talk we address the history of the planetary model, with attention to the methodologies that were applied. We then consider the philosophical implications of this major episode that contributed to shaping physics in the twentieth century.