Counter-Earth

Philolaus believed there was a "Counter-Earth" (Antichthon) orbiting the "Central Fire" (not labeled) that was not visible from Earth. The upper illustration depicts Earth at night while the lower one depicts Earth in the day.[1]

The Counter-Earth is a hypothetical body of the Solar System that orbits on the other side of the Solar System from Earth. A Counter-Earth or Antichthon (Greek: Ἀντίχθων) was hypothesized by the pre-Socratic Greek philosopher Philolaus (c. 470 – c. 385 BC) to support his non-geocentric cosmology, in which all objects in the universe revolve around a "Central Fire" (unseen from Earth and distinct from the Sun which also revolves around it).

In modern times a hypothetical planet always on the other side of the Sun from Earth has been called a "Counter-Earth",[2] and has been a recurring theme in UFO claims,[3] as well as in fiction (particularly science fiction).

  1. ^ Source: Dante and the Early Astronomers by M. A. Orr, 1913.
  2. ^ Comins, Neil F. (2010). What If the Earth Had Two Moons?: And Nine Other Thought-Provoking ... macmillan. pp. 171–172. ISBN 9781429957939.
  3. ^ Cite error: The named reference UFO was invoked but never defined (see the help page).