How did Isaac Newton discover the laws of gravity?

Isaac Newton first published on gravity in "Principia Mathematica," which was released in July, 1687. A section of "Principia Mathematica" called "Discourse concerning Gravity and its Properties," was read to the Royal Society on April 21, 1686, in preparation for the publication of the book. read more

Newton did not "figure out" his universal law of gravitation completely on his own. He instead expanded upon the works of Galileo, Kepler, Halley, Huygens, Hooke, and others. There are issues with regard to priority for Newton's law of gravitation. Hooke, in particular, claimed that he discovered this prior to Newton. read more