1671, and the organization's interest encouraged Newton to publish his notes on light, optics and color in 1672; these notes were later published as part of Newton's Opticks: Or, A treatise of the Reflections, Refractions, Inflections and Colours of Light.
However, not everyone at the Royal Academy was enthusiastic about Newton's discoveries in optics. Among the dissenters was Robert Hooke, one of the original members of the Royal Academy and a scientist who was accomplished in a number of areas, including mechanics and optics. In his paper, Newton theorized that white light was a composite of all colors of the spectrum, and that light was composed of particles. Hooke believed that light was composed of waves. Hooke quickly condemned Newton's paper in condescending terms, and attacked Newton's methodology and conclusions.
Hooke was not the only one to question Newton's work in optics. Renowned Dutch scientist Christiaan Huygens and a number of French Jesuits also raised objections. But because of Hooke's association with the Royal Society and his own work in optics, his criticism stung Newton the worst. Unable to handle the critique, he went into a rage—a reaction to criticism that was to continue throughout his life.
Newton denied Hooke's charge that his theories had any shortcomings, and argued the importance of his discoveries to all of science. In the ensuing months, the exchange between the two men grew more acrimonious, and soon Newton threatened to quit the society altogether. He remained only when several other members assured him that the Fellows held him in high esteem.
However, the rivalry between Newton and Hooke would continue for several years thereafter. Then, in 1678, Newton suffered a complete nervous breakdown and the correspondence abruptly ended. The death of his mother the following year caused him to become even more isolated, and for six years he withdrew from intellectual exchange except when others initiated correspondence, which he always kept short.
During his hiatus from public life, Newton returned to his study of gravitation and its effects on the orbits of planets. Ironically, the impetus that put Newton on the right direction in this study came from Robert Hooke. In a 1679 letter of general correspondence to Royal Society members for contributions, Hooke wrote to Newton and brought up the question of planetary motion, suggesting that a formula involving the inverse squares might explain the attraction between planets and the shape of their orbits.
Subsequent exchanges transpired before Newton quickly broke off the correspondence once again. But Hooke's idea was soon incorporated into Newton's work on planetary motion, and from his notes it appears he had quickly drawn his own conclusions by 1680, though he kept his discoveries to himself.