Phaeton (hypothetical planet)

Phaeton (alternatively Phaethon or Phaëton ; from Ancient Greek: Φαέθων, romanized: Phaéthōn, pronounced [pʰa.é.tʰɔːn]) is a hypothetical planet hypothesized by the Titius–Bode law to have existed between the orbits of Mars and Jupiter, the destruction of which supposedly led to the formation of the asteroid belt (including the dwarf planet Ceres). The hypothetical planet was named for Phaethon, the son of the sun god Helios in Greek mythology, who attempted to drive his father's solar chariot for a day with disastrous results and was ultimately destroyed by Zeus.

Phaeton hypothesis

According to the hypothesized Titius–Bode law proposed in the 1700s to explain the spacing of planets in a solar system, a planet may have once existed between Mars and Jupiter. After learning of the regular sequence discovered by the German astronomer and mathematician Johann Daniel Titius, astronomer Johann E. Bode urged a search for the fifth planet corresponding to a gap in the sequence. (1) Ceres, the largest asteroid in the asteroid belt (now considered a dwarf planet), was serendipitously discovered in 1801 by the Italian Giuseppe Piazzi and found to closely match the "empty" position in Titius' sequence, which led many to believe it to be the "missing planet". However, in 1802 astronomer Heinrich Wilhelm Matthäus Olbers discovered and named the asteroid (2) Pallas, a second object in roughly the same orbit as (1) Ceres.

Olbers proposed that these two discoveries were the fragments of a disrupted planet that had formerly orbited the Sun, and predicted that more of these pieces would be found. The discovery of the asteroid (3) Juno by Karl Ludwig Harding and (4) Vesta by Olbers, buttressed his hypothesis. In 1823, German linguist and retired teacher Johann Gottlieb Radlof called Olbers' destroyed planet Phaëthon, linking it to the Greek myths and legends about Phaethon and others.

In 1927, Franz Xaver Kugler wrote a short book titled Sibyllinischer Sternkampf und Phaëthon in naturgeschichtlicher Beleuchtung (The Sybilline Battle of the Stars and Phaeton Seen as Natural History).