Copernican principle

Unsolved problem in physics:

Are cosmological observations made from Earth representative of observations from the average position in the universe?

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 are not privileged observers of the universe,^[1] that observations from the Earth are representative of observations from the average position in the universe. Named for Copernican heliocentrism, it is a working assumption that arises from a modified cosmological extension of Copernicus' argument of a moving Earth.^[2]

^ Peacock, John A. (1998). Cosmological Physics. Cambridge University Press. p. 66. ISBN 978-0-521-42270-3.
^ Bondi, Hermann (1952). Cosmology. Cambridge University Press. p. 13.

[1] Peacock, John A. (1998). Cosmological Physics. Cambridge University Press. p. 66. ISBN 978-0-521-42270-3.

[2] Bondi, Hermann (1952). Cosmology. Cambridge University Press. p. 13.

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