In the history of astronomy, a handful of Solar System bodies other than Jupiter have been counted as the fifth planet from the Sun. Various hypotheses have also postulated the former existence of a fifth planet, now destroyed, to explain various characteristics of the inner Solar System.
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Hypotheses
editThere are three main ideas regarding hypothetical planets between Mars and Jupiter.
Asteroids
editDuring the early 19th century, as asteroids were discovered, they were formerly considered planets. Jupiter became the sixth planet with the discovery of Ceres in 1801. Soon, three more asteroids, Pallas (1802), Juno (1804), and Vesta (1807) were discovered. They were counted as separate planets, despite the fact that they share a single orbital spacing given by Titius–Bode law. Between 1845 and 1851, eleven additional asteroids were discovered and Jupiter had become the twentieth planet. At this point, astronomers began to classify asteroids as minor planets.[1] Following the reclassification of the asteroids in their own group, Jupiter became the fifth planet once again. Following the International Astronomical Union's (IAU) redefinition of the term planet in August 2006, Ceres is now considered a dwarf planet.[2]
Disruption hypothesis
editThe disruption hypothesis suggests that a planet which was positioned between Mars and Jupiter was destroyed, creating the asteroid belt between these planets. First proposed by astronomer Heinrich Wilhelm Matthias Olbers, scientists in the 20th century dubbed this hypothetical planet "Phaeton". Astronomers proposed various properties of Phaeton, including masses ranging from 1–8 ML and an icy composition. However, the hypothesis faced criticisms due to difficulties in adequately explaining the mechanisms behind planetary breakup.[3] The Phaeton hypothesis was eventually superseded by the accretion model, as the observed properties of the asteroid belt did not fit an origin from a single, disrupted planet.[4]
Planet V hypothesis
editBased on simulations, NASA space scientists John Chambers and Jack J. Lissauer have proposed the existence of a planet between Mars and the asteroid belt, going in a successively eccentric and unstable orbit, 4 billion years ago. They connect this planet, which they name Planet V, and its disappearance with the Late Heavy Bombardment episode of the Hadean era.[5][6] Chambers and Lissauer also claim this Planet V most probably ended up crashing into the Sun. Unlike the disruption hypothesis's fifth planet, "Planet V" is not credited with creating the asteroid belt.
Fifth planet in fiction
editA hypothetical former fifth planet that has since been destroyed has been referenced in fiction since at least the late 1800s.[7][8] In science fiction, the planet is often called "Bodia" after Johann Elert Bode.[8][9] By the pulp era of science fiction, Bodia was a recurring theme. In these stories it is typically similar to Earth and inhabited by humans, often advanced humans and occasionally the ancestors of humans on Earth.[10][9][11][12] Following the invention of the atomic bomb in 1945, stories of this planetary destruction became increasingly common, encouraged by the advent of a plausible-seeming means of disintegration.[13] Several works of the 1950s used the idea to warn of the dangers of nuclear weapons.[7][8][14] The concept has since largely been relegated to deliberately retro works.[15]
See also
editNotes
edit- ^ Hilton, James L. "When did asteroids become minor planets?". U.S. Naval Observatory. Archived from the original on 2006-05-20. Retrieved 2006-05-25.
- ^ "In Depth | Ceres". NASA Solar System Exploration. Archived from the original on 21 April 2019. Retrieved 21 April 2019.
- ^ Drobyshevski, E. M. (March 1986). "The Structure of Phaethon and Detonation of its Ice Envelope". Earth, Moon, and Planets. 34 (3): 213–222. Bibcode:1986EM&P...34..213D. doi:10.1007/BF00145080.
- ^ "Ask an Astrophysicist". imagine.gsfc.nasa.gov. Archived from the original on 2 November 2014.
- ^ "Long-Destroyed Fifth Planet May Have Caused Lunar Cataclysm". Space.com. Retrieved 2006-11-09.
- ^ "A NEW DYNAMICAL MODEL FOR THE LUNAR LATE HEAVY BOMBARDMENT" (PDF). Chambers and Lissauer, NASA Ames. Retrieved 2006-11-09.
- ^ a b Stableford, Brian; Langford, David (2023). "Asteroids". In Clute, John; Langford, David; Sleight, Graham (eds.). The Encyclopedia of Science Fiction (4th ed.). Retrieved 2023-10-06.
- ^ a b c Westfahl, Gary (2021). "Asteroids". Science Fiction Literature through History: An Encyclopedia. ABC-CLIO. pp. 139–141. ISBN 978-1-4408-6617-3.
- ^ a b Bleiler, Everett Franklin; Bleiler, Richard (1998). "The Science-Fiction Solar System". Science-fiction: The Gernsback Years : a Complete Coverage of the Genre Magazines ... from 1926 Through 1936. Kent State University Press. p. 539. ISBN 978-0-87338-604-3.
- ^ Stableford, Brian (2006). "Asteroid". Science Fact and Science Fiction: An Encyclopedia. Taylor & Francis. pp. 40–41. ISBN 978-0-415-97460-8.
- ^ Bleiler, Everett Franklin; Bleiler, Richard (1998). "Introduction". Science-fiction: The Gernsback Years : a Complete Coverage of the Genre Magazines ... from 1926 Through 1936. Kent State University Press. pp. xvii. ISBN 978-0-87338-604-3.
The "science" in science-fiction of the Gernsback period was not wholly borrowed from the outside world. Some concepts were created on a mythical level. [...] Particularly interesting is the establishment of "Bodia" (according to one cosmology of the day, a former fifth planet whose destruction formed the asteroids) as the ultimate origin of mankind and possessor of a supercivilization.
- ^ Bleiler, Everett Franklin; Bleiler, Richard (1998). "Motif and Theme Index". Science-fiction: The Gernsback Years : a Complete Coverage of the Genre Magazines ... from 1926 Through 1936. Kent State University Press. pp. 627–628. ISBN 978-0-87338-604-3.
Bode's Fifth Planet, "Bodia." (A hypothetical planet between Mars and Jupiter that broke up to form the asteroid belt. It is usually fictionally considered as Earth-like, with a human population.)
- ^ Stableford, Brian (2006). "Planet". Science Fact and Science Fiction: An Encyclopedia. Taylor & Francis. p. 375. ISBN 978-0-415-97460-8.
- ^ Hampton, Steven (Summer 2000). Lee, Tony (ed.). "Momentos of Creation: Asteroids & Comets in SF". The Planets Project: A Science Fictional Tour of the Solar System. The Zone. No. 9. pp. 6–7. ISSN 1351-5217.
- ^ Caryad; Römer, Thomas; Zingsem, Vera (2014). "Science vs. Fiction: der ganz andere Asteroidengürtel aus Roman und Film" [Science vs. Fiction: The Entirely Different Asteroid Belt from Novel and Film]. Wanderer am Himmel: Die Welt der Planeten in Astronomie und Mythologie [Wanderers in the Sky: The World of the Planets in Astronomy and Mythology] (in German). Springer-Verlag. pp. 170–172. ISBN 978-3-642-55343-1.