Former_planets

List of former planets

List of former planets

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This is a list of astronomical objects formerly widely considered planets under any of the various definitions of this word in the history of astronomy. As the definition of planet has evolved, the de facto and de jure definitions of planet have changed over the millennia. As of 2024, there are eight official planets in the Solar System per the International Astronomical Union (IAU),[1] which has also established a definition for exoplanets. Several objects formerly considered exoplanets have been found actually to be stars or brown dwarfs.

Background

Throughout antiquity, several astronomical objects were considered Classical Planets, meaning "wandering stars", not all of which are now considered planets. The moons discovered around Jupiter, Saturn and Uranus after the advent of the telescope were also initially considered planets by some. The development of more powerful telescopes resulted in the discovery of the asteroids, which were initially considered planets. Then Pluto, the first Trans-Neptunian Object, was discovered. More Trans-Neptunian Objects of the Kuiper Belt were found with the help of electronic imaging. One of these, Eris, was widely hailed as a "new planet", which prompted the 2006 recategorization of solar system bodies.

Some planetary scientists reject the 2006 definition of planet, and thus would still consider some of the objects on this list to be planets under a geophysical definition. See the list of gravitationally rounded objects of the Solar System for a list of geophysical planets.

List

More information Former planet, Discovery ...

See also

Notes

  1. [N 1]
    It is an aspect of the planet Venus.
  2. [N 2]
    It is an aspect of the planet Mercury.

References

  1. [1]
    IAU (August 24, 2006). "Definition of a Planet in the Solar System: Resolutions 5 and 6" (PDF). IAU 2006 General Assembly. International Astronomical Union. Retrieved January 26, 2008.
  2. [2]
    Leonard Linsky (October 1959). "Hesperus and Phosphorus". The Philosophical Review. 68 (4): 515–518. doi:10.2307/2182495. JSTOR 2182495.
  3. [3]
    "The Great Cosmic Light Called Hesperus, Brother Of Lucifer, Reaches Greatest Brilliancy". Star Gazer. Episode 09-07 (1628). February 2009.
  4. [4]
    "Planet Mercury: Some Surprising Facts for Skywatchers". Space.com. 29 April 2015.
  5. [5]
    Elizabeth Howell (23 December 2015). "What Is The Difference Between the Geocentric and Heliocentric Models of the Solar System?". Universe Today.
  6. [6]
    Holli Riebeek (7 July 2009). "Planetary Motion: The History of an Idea That Launched the Scientific Revolution". The Science: Orbital Mechanics. NASA Earth Observatory.
  7. [7]
    Eric G. Blackman (2006). "The Copernican Model: A Sun-Centered Solar System". Astronomy 104 -- The Solar System. University of Rochester, School of Arts and Sciences, Department of Physics and Astronomy.
  8. [8]
    Galileo Galilei (1610). "Sidereus Nuncius" (in Latin). {{cite journal}}: Cite journal requires |journal= (help)
  9. [9]
    Al Van Helden (1995). "Satellites of Jupiter". The Galileo Project. Rice University.
  10. [10]
    Calvin J. Hamilton (2009). "The Discovery of the Galilean Satellites". Views of the Solar System.
  11. [11]
    Jean-Pierre Luminet (31 December 2016). "Montaigne, Peiresc, Gassendi, and Cassini - The Provençal Humanists and Copernicus". Inference: International Review of Science. 2 (4).
  12. [12]
    Cristiani Hugenii (Christiaan Huygens) (1659). "Systema Saturnium" (in Latin). {{cite journal}}: Cite journal requires |journal= (help)
  13. [13]
    Jean-Dominique Cassini (Giovanni Domenico Cassini) (1673). "Découverte de deux nouvelles planètes autour de Saturne" (in French). Paris Observatory. {{cite journal}}: Cite journal requires |journal= (help)
  14. [14]
    Jean-Dominique Cassini (Giovanni Domenico Cassini) (1686–1692). "An Extract of the Journal Des Scavans. Of April 22 st. N. 1686. Giving an Account of Two New Satellites of Saturn, Discovered Lately by Mr. Cassini at the Royal Observatory at Paris". Philosophical Transactions of the Royal Society of London. 16 (179–191): 79–85. Bibcode:1686RSPT...16...79C. doi:10.1098/rstl.1686.0013. JSTOR 101844.
  15. [15]
    Herschel, W. S. (1787). "An Account of the Discovery of Two Satellites Revolving Round the Georgian Planet". Philosophical Transactions of the Royal Society of London. 77: 125–129. doi:10.1098/rstl.1787.0016. JSTOR 106717. And the heavens now displayed the original of my drawing, by shewing, in the situation I had delineated them, The Georgian Planet attended by two satellites.

    I confess that this scene appeared to me with additional beauty, as the little secondary planets seemed to give a dignity to the primary one, which raises it into a more conspicuous situation among the great bodies of our solar system.
  16. [16]
    "When did the asteroids become minor planets? — Naval Oceanography Portal". Archived from the original on 2012-04-06.
  17. [17]
    James L. Hilton (18 April 2016). "When did the asteroids become minor planets?". Astronomical Applications Department. U.S. Naval Observatory. Archived from the original on 24 March 2008.
  18. [18]
    Benamran, Bruce (4 September 2018). How to Speak Science: Gravity, Relativity, and Other Ideas That Were Crazy Until Proven Brilliant. The Experiment. ISBN 9781615194032.
  19. [19]
    Hodgson, Richard G. (March 1978). "The Discovery of Chiron: Some Reflections". The Minor Planet Bulletin. 5 (3). IAU MPC: 21–22. Bibcode:1978MPBu....5...21H.
  20. [20]
    "Chiron and the Centaurs". Emerald Visions. Mystic Visions Spiritual Astrology. 2004.
  21. [21]
    Barbara Hand Clow (1987). Chiron: Rainbow Bridge Between the Inner and Outer Planets. Llewellyn. ISBN 087542094X.
  22. [22]
    Richard Nolle (1983). Chiron: The New Planet in Your Horoscope, The Key to Your Quest. American Federation of Astrologers. ISBN 0866902368.
  23. [23]
    "In Greenwich". Popular Mechanics. Vol. 158, no. 1. January 1982. p. 28.
  24. [24]
    Robert Roy Britt (24 August 2006). "Pluto Demoted: No Longer a Planet in Highly Controversial Definition". SPACE.com.
  25. [25]
    Mike Wall (19 November 2010). "The Man Who Killed Pluto: Q & A with Astronomer Mike Brown". SPACE.com.
  26. [26]
    E. Mostra (1998). "Pluto and Charon". Voyage in the Universe. Astronomical Observatory of Padua.
  27. [27]
    Collander-Brown, S.; Maran, M.; Williams, I. P. (2000-10-11). "The effect on the Edgeworth-Kuiper Belt of a large distant tenth planet". Monthly Notices of the Royal Astronomical Society. 318 (1): 101–108. Bibcode:2000MNRAS.318..101C. doi:10.1046/j.1365-8711.2000.03640.x. ISSN 0035-8711.
  28. [28]
    Coote, Roger. / (August 2008). The earth. London. ISBN 9781842399491. OCLC 671197414.{{cite book}}: CS1 maint: location missing publisher (link)
  29. [29]
    David Whitehouse (30 July 2005). "Astronomers detect '10th planet'". BBC News.
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