Fictional planets of the Solar System
Hypothetical planets persist in fiction beyond scientific refutation.
Fictional planets of the Solar System have been depicted since the 1700s, often corresponding to hypothetical planets seriously proposed by real-world astronomers but persisting in fiction long after the underlying scientific theories were refuted. Notable examples include Vulcan, a planet hypothesized inside Mercury's orbit to explain orbital anomalies, and Counter-Earth, a planet diametrically opposite Earth. These fictional worlds have appeared in numerous works, reflecting both scientific speculation and imaginative storytelling.
- First proposed
- 1700s
- Notable examples
- Vulcan, Counter-Earth, Phaëton (Bodia), Persephone
- Key scientific basis
- Vulcan proposed 1859–1915 to explain Mercury's orbital anomalies; Counter-Earth proposed by Philolaus in 5th century BCE
- Common themes
- Satire, inhabited counterparts, destruction, resource mining, tidal locking
Lore & Background
Vulcan was hypothesized by Urbain Le Verrier in 1859 to explain anomalies in Mercury's orbit, similar to his prediction of Neptune. It was typically depicted as extremely hot, small, dense, and often tidally locked, with one side in perpetual day and the other in night. In pulp science fiction, it appeared as a source of rare materials, a prison colony, or a hollow planet. Counter-Earth, originally proposed by Philolaus in the fifth century BCE, is a planet opposite Earth in its orbit, often used for satire or depicting alternate versions of Earth's people. The asteroid belt was suggested as remnants of a destroyed planet called Phaëton or Bodia, popular in pulp era stories about its destruction. Additional outer planets, like a ninth or tenth planet beyond Neptune or Pluto, appear regularly, with 'Persephone' being a common name. Rogue planets entering the Solar System from without also appear, typically on collision courses with Earth.
Reader's Guide
Fictional planets of the Solar System hold significance as a bridge between scientific hypothesis and creative storytelling. Vulcan, for instance, was seriously considered by astronomers for decades until Einstein's general relativity explained Mercury's orbit in 1915, yet it continued to appear in fiction into the 1960s. Counter-Earth, rooted in ancient Greek philosophy, has been a vehicle for satire and alternate-history narratives since the late 1800s. The concept of a destroyed fifth planet, Bodia, gained popularity after the atomic bomb's invention in 1945, reflecting contemporary anxieties. These fictional worlds often incorporate scientific plausibility, such as tidal locking or libration, as noted by astrophysicist Elizabeth Stanway. Their legacy endures in modern works, like the Star Trek franchise's use of the name 'Vulcan' for an extrasolar planet, and in the Doctor Who serial 'The Tenth Planet' featuring a Counter-Earth called Mondas.
Did You Know?
- Counter-Earth was originally proposed by the ancient Greek philosopher Philolaus in the fifth century BCE.
- The hypothetical destroyed fifth planet between Mars and Jupiter is called Phaëton in astronomy and 'Bodia' in science fiction.
- The most common name for a hypothetical outermost planet beyond Pluto is 'Persephone'.
More in Planets and Dwarf Planets 1-24
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