Copernican principle
Channel: all the knowledge of the universe PRINCIPIA
Date: 2021-12-10

Copernican principle, by Wikipedia https://en.wikipedia.org/wiki?curid=7327 / CC BY SA 3.0

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Figure 'M' （for Latin Mundus） from Johannes Kepler's 1617–1621 Epitome Astronomiae Copernicanae, showing the Earth as belonging to just one of any number of similar stars.
In physical cosmology, the Copernican principle states that humans, on the Earth or in the Solar System, are not privileged observers of the universe.
Named for Copernican heliocentrism, it is a working assumption that arises from a modified cosmological extension of Copernicus's argument of a moving Earth.
Hermann Bondi named the principle after Copernicus in the mid-20th century, although the principle itself dates back to the 16th-17th century paradigm shift away from the Ptolemaic system, which placed Earth at the center of the universe.
Copernicus proposed that the motion of the planets could be explained by reference to an assumption that the Sun is centrally located and stationary in contrast to the then currently upheld belief that the Earth was central.
He argued that the apparent retrograde motion of the planets is an illusion caused by Earth's movement around the Sun, which the Copernican model placed at the centre of the universe.
Copernicus himself was mainly motivated by technical dissatisfaction with the earlier system and not by support for any mediocrity principle.
In fact, although the Copernican heliocentric model is often described as "demoting" Earth from its central role it had in the Ptolemaic geocentric model,
it was successors to Copernicus, notably the 16th century Giordano Bruno, who adopted this new perspective.
The Earth's central position had been interpreted as being in the "lowest and filthiest parts".
Instead, as Galileo said, the Earth is part of the "dance of the stars" rather than the "sump where the universe's filth and ephemera collect".
In the late 20th Century, Carl Saga...