Final answer:
The concept of the atom as a miniature solar system, or the planetary model of the atom, was developed by Ernest Rutherford. Niels Bohr later refined this model, incorporating quantum mechanics to address its limitations.
Step-by-step explanation:
The concept of the atom as a miniature solar system was developed by Ernest Rutherford, who proposed the planetary model of the atom. This model describes the atom as having a tiny, dense, positively charged nucleus with lighter, negatively charged electrons orbiting it, similar to planets orbiting the Sun. Although this classical view of the atom as a stable, solar system-like entity was compelling, it had its limitations, as it could not explain why the orbiting electrons would not lose energy and spiral into the nucleus.
The planetary model of the atom served as a precursor to Niels Bohr's refined model that incorporated quantum mechanics to explain the stability of atoms and the atomic spectra of hydrogen. Bohr's model expanded on Rutherford's description by introducing quantized electron orbits, thus preventing the collapse of the electron into the nucleus.