Central Fire

The Central Fire or Hearth of the Universe is a fiery celestial body hypothesized by the pre-Socratic philosopher Philolaus to be positioned at the center of the universe, and around which all other celestial objects revolve. It is sometimes called "the house of Zeus" but more frequently "the mother of the gods" or "estia", after the goddess of fire and hearth, Hestia.

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Significance in the history of science

Like the other pre-Socratic thinkers, Philolaus operated under the common-sense idea that the world was flat. However, his astute observations of the movements of the stars and planets led him to develop the firm conviction that their apparent motion was due in part to the real motion of the observer, i.e. that the Earth must rotate around not only a central point, but also on its own axis.

Though we take it for granted today that this is in fact true, and that the central point in question is the Sun, Philolaus' Pythagorean view of the cosmos led him to believe that not only the earth must revolve around this point, but also every other body in the universe, including the sun.

This idea's monumental importance to the history of science lay not only in the fact that it was the first to identify the Earth's own rotation, but also in that it did away with the idea of the fixed directions of up and down in space. Since in his understanding, the world was flat, its revolution around a fixed point meant that down must be any direction toward the Central Fire, and up any direction away from it. This idea is even more impressive when one considers that it predated Newton's law of universal gravitation by more than 2000 years.

Implications in Pythagorean philosophy

Given the elegance and mathematical simplicity of Philolaus' ideas regarding the nature of the Earth's place in the cosmos, it is easy to understand how the idea of a central fire quickly became a fixture in the thinking of his fellow pre-Socratics. Since this celestial body was necessarily beneath the Earth at all times, its existence, at the very least, could not be disproven.

However, all this created a problem in Pythagorean cosmology. The Greek philosophers did not regard the Earth as a planet. Planets, in their understanding, were composed of a fiery or ethereal matter having little or no density, a fifth element with neither positive density like Earth and Water nor negative density like Fire and Air. Since these objects existed with zero density, they could quite easily rotate eccentric to the Earth without becoming off balance. However, the earth was obviously made of the dense elements of Earth and Water. If there were a single Earth revolving at some distance from the center of space, the universe's center of balance would not coincide with its spatial center. Since this is the point towards which things fall, the earth must have a counter-balance of the same mass or the universe would be flung apart. This problem led Philolaus to develop idea of a Counter-Earth, a second, flat Earth, identical but opposite to ours in every way.

The ideas of a flat earth, Counter-Earth, and Central Fire were all eventually superseded by the theory which is currently held by the scientific community, that is, of a spherical earth rotating around its own axis while revolving around the sun. The Counter-Earth is still a popular motif in science fiction and fantasy writing today.

See also

• Counter-Earth

Sources

Burch, George Bosworth. The Counter-Earth. Osirus, vol. 11. Saint Catherines Press, 1954. p. 267-294