Copernican principle

Copernican system

 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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Copernican principle [kə′pər·nə·kən ¦prin·sə·pəl]

(astronomy)

The idea that the earth occupies a typical or unexceptional position in the universe.