Editing Planetary system (section)

==History==

===Heliocentrism===
[[Heliocentrism]] is the doctrine that the Sun is at the centre of the universe, as opposed to [[geocentrism]] (placing Earth at the centre of the universe).

Some interpret [[Aryabhatta]]'s writings in [[Āryabhaṭīya]] as implicitly heliocentric although this has also been rebutted.<ref>Noel Swerdlow, "Review: A Lost Monument of Indian Astronomy," ''Isis'', 64 (1973): 239–243.</ref>

The idea was first proposed in [[Western philosophy]] and [[Greek astronomy]] as early as the 3rd century BC by [[Aristarchus of Samos]],<ref>[[#Reference-Dreyer-1953|Dreyer (1953)]], [https://archive.org/stream/historyofplaneta00dreyuoft#page/n148/mode/2up pp.135–48]; [[#CiTEREFLinton2004|Linton (2004)]], [https://books.google.com/books?id=B4br4XJFj0MC&pg=PA38 pp.38–9)].  The work of Aristarchus's in which he proposed his heliocentric system has not survived.  We only know of it now from a brief passage in [[Archimedes]]'s ''[[The Sand Reckoner]]''.</ref>https://books.google.com/books?id=B4br4XJFj0MC&pg=PA38 but received no support from most other ancient astronomers.

===Discovery of the Solar System===
{{Main|Discovery and exploration of the Solar System}}
[[File:De Revolutionibus manuscript p9b.jpg|thumb|190px|[[Heliocentric model]] of the [[Solar System]] in [[Copernicus]]' [[manuscript]]]]
''[[De revolutionibus orbium coelestium]]'' by [[Nicolaus Copernicus]], published in 1543, presented the first mathematically predictive heliocentric model of a planetary system. 17th-century successors [[Galileo Galilei]], [[Johannes Kepler]], and [[Sir Isaac Newton]] developed an understanding of [[physics]] which led to the gradual acceptance of the idea that the Earth moves around the Sun and that the planets are governed by the same physical laws that governed Earth.

===Speculation on extrasolar planetary systems===
In the 16th century the Italian philosopher [[Giordano Bruno]], an early supporter of the [[Nicolaus Copernicus|Copernican]] theory that Earth and other planets orbit the Sun, put forward the view that the fixed stars are similar to the Sun and are likewise accompanied by planets. He was burned at the stake for his ideas by the [[Roman Inquisition]].<ref>"Cosmos" in
 ''The New Encyclopædia Britannica'' (15th edition, Chicago, 1991) '''16''':787:2a. "For his advocacy of an infinity of suns and earths, he was burned at the stake in 1600."</ref>

In the 18th century, the same possibility was mentioned by [[Sir Isaac Newton]] in the "[[General Scholium]]" that concludes his ''[[Philosophiae Naturalis Principia Mathematica|Principia]]''. Making a comparison to the Sun's planets, he wrote "And if the fixed stars are the centres of similar systems, they will all be constructed according to a similar design and subject to the dominion of ''One''."<ref>
{{Cite book |last1      = Newton
 |first1     = Isaac
 |first2    = I. Bernard
 |last2     = Cohen
 |first3    = Anne
 |last3     = Whitman
 |title     = The Principia: A New Translation and Guide
 |publisher = University of California Press
 |date      = 1999
 |orig-year  = First published 1713
 |page      = 940
 |isbn      = 0-520-20217-1
 |url       = https://archive.org/details/keytonewtonsdyna0000brac
|url-access = registration
 }}
</ref>

His theories gained popularity through the 19th and 20th centuries despite a lack of supporting evidence. Long before their confirmation by astronomers, conjecture on the nature of planetary systems had been a focus of the [[search for extraterrestrial intelligence]] and [[Extrasolar planets in fiction|has been a prevalent theme in fiction]], particularly science fiction.

===Detection of exoplanets===
The first confirmed detection of an [[exoplanet]] was in 1992, with the discovery of several terrestrial-mass planets orbiting the [[pulsar]] [[PSR B1257+12]]. The first confirmed detection of exoplanets of a [[main-sequence]] star was made in 1995, when a giant planet, [[51 Pegasi b]], was found in a four-day orbit around the nearby [[G-type star]] [[51 Pegasi]]. The frequency of detections has increased since then, particularly through advancements in [[methods of detecting extrasolar planets]] and dedicated planet-finding programs such as the [[Kepler (spacecraft)|Kepler mission]].