Copernican system

Copernican system

n.

the theory of Copernicus that the planets revolve around the sun and that the turning of the earth on its axis from west to east accounts for the apparent rising and setting of the stars: basis of modern astronomy

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or Copernican principle

Model of the solar system centred on the Sun, with Earth and other planets revolving around it, formulated by Nicolaus Copernicus in the mid 16th century.

Having the Sun in this central position explained the apparent motion of planets relative to the fixed stars and was truer than the Earth-centred Ptolemaic system (see Ptolemy). Scientifically, the Copernican system led to belief in a much larger universe than before (because, if the Earth revolved around the Sun, the stars would have to be very distant not to appear to alter their position); more broadly, the Copernican principle is invoked to argue against any theory that would give the solar system a special place in the universe. Dethronement of Earth from the centre of the universe caused profound shock: the Copernican system challenged the entire system of ancient authority and required a complete change in the philosophical conception of the universe.

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▪ astronomy

      in astronomy, model of the solar system centred on the Sun, with Earth and other planets moving around it, formulated by Nicolaus Copernicus (Copernicus, Nicolaus), and published in 1543. It appeared with an introduction by Rhäticus (Rheticus) as De revolutionibus orbium coelestium libri VI (“Six Books Concerning the Revolutions of the Heavenly Orbs”). The Copernican system gave a truer picture than the older Ptolemaic system, which was geocentric, or centred on Earth. It correctly described the Sun as having a central position relative to Earth and other planets. Copernicus retained from Ptolemy of Alexandria, although in somewhat altered form, the imaginary clockwork of epicycles and deferents (orbital circles upon circles), to explain the seemingly irregular movements of the planets in terms of circular motion at uniform speeds.

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