Hypothetical astronomical object
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Various unknown astronomical objects have been hypothesized throughout recorded history. For example, in the 5th century BCE, the philosopher Philolaus defined a hypothetical astronomical object which he called the "Central Fire", around which he proposed other celestial bodies (including the Sun) moved.[1]
Types of hypothetical astronomical objects
[edit | edit source]Hypothetical astronomical objects have been speculated to exist both inside and outside of the Solar System, and speculation has included different kinds of stars, planets, and other astronomical objects.
- For hypothetical astronomical objects in the Solar System, see: List of hypothetical Solar System objects
- For hypothetical stars, see: Hypothetical star
- For hypothetical brown dwarfs, see: List of brown dwarfs
- For hypothetical black holes, see: Hypothetical black hole
- For extrasolar moons, all of which are currently hypothetical, see: Extrasolar moon
- For stars, planets or moons whose existence is not accepted by science, see: Planetary objects proposed in religion, astrology, ufology and pseudoscience and Stars proposed in religion
- For hypothetical planets in fiction, see: Fictional planets of the Solar System
Hypothetical planet types
[edit | edit source]Hypothetical types of extrasolar planets include:
| Type | Description |
|---|---|
| Ammonia planet [citation needed] | A planet with significant amounts of ammonia. May have lakes or oceans of ammonia. |
| Blanet | A planet that directly orbits a black hole. |
| Carbon planet | A terrestrial planet composed primarily of carbon, rather than silicon. |
| Chthonian planet | A hot Jupiter whose outer layers have been completely stripped off by its parent star. |
| Chlorine planet | A planet with significant amounts of free chlorine or hydrochloric acid.[2] |
| Coreless planet | A terrestrial planet that has no metallic core. |
| Desert planet | A terrestrial planet with little to no water. |
| Extragalactic planet | A planet that is located outside the Milky Way galaxy |
| Eyeball planet | A tidally locked planet where uneven heating of the surface induces spatial features resembling a human eye. |
| Helium planet | A gas giant composed mainly of helium instead of hydrogen. |
| Hycean planet /ˈhaɪʃən/ | A hot, water-covered planet with a hydrogen-rich atmosphere that is possibly capable of harboring extremophilic life.[3][4][5] |
| Ocean planet | A planet whose surface is covered entirely by deep oceans. |
| Superhabitable planet | A terrestrial planet that is more habitable than Earth. |
| Tidally detached exomoon | A planet that was originally a moon but has become gravitationally detached. |
| Toroidal planet | A planet whose shape resembles a torus or doughnut. |
| Trojan planet | A planet that orbits near the L4 or L5 Lagrange points of a more massive object. |
References
[edit | edit source]- ^ Marco Ceccarelli, Distinguished Figures in Mechanism and Machine Science (2007), p. 124.
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