French philosopher and mathematician René Descartes was the first to propose a model for the origin of the Solar System in his book The World, written from 1629 to 1633. In his view, the Universe was filled with vortices of swirling particles, and both the Sun and planets had condensed from a large vortex that had contracted, which he thought could explain the circular motion of the planets. However, this was before the knowledge of Newton's theory of gravity, which explains that matter does not behave in this way.