Newton discovered gravity, and argued that it was a main force in the universe.
Newton reflected on the fact that bodies weighed on the Earth and that the astronomical objects revolved around others (the Moon around the Earth, the Earth and the other planets around the Sun, and so on) and imagined that there was a universal force (acting everywhere) that made bodies attract each other. This force would be manifested both in the attraction of a body by the Earth - its weight - and in the attraction between bodies of the Solar System (and the entire universe) that makes them spin around each other. He called it "universal gravitational force" or "gravity."
