Descartes's Mechanical Philosophy. According to French philosopher René Descartes (1596-1650), the universe operated as a continuously running machine which God had set in motion. Since he rejected Newton's theory of gravity and idea of a vacuum in space, Descartes argued that instead the universe was composed of a "subtle matter" he named "plenum," which swirled in vortices like whirlpools and actually moved the planets by contact. Here, these vortices carry the planets around the Sun.
Taken by Prosper Henry, 1885. This photograph of the Ring Nebula in the constellation Lyra shows but a three-degree section of the firmament, 1,956 light-years from earth. Once a star similar to our own sun, the nebula was formed when the star exploded, releasing gasses from its outer shell into space.
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