Editing Tychonic system (section)

== History and development ==
Tycho's system was foreshadowed, in part, by that of [[Martianus Capella]], who described a system in which Mercury and Venus are placed on [[deferent and epicycle|epicycles]] around the Sun, which circles the Earth. [[Nicolaus Copernicus|Copernicus]], who cited Capella's theory, even mentioned the possibility of an extension in which the other three of the six known planets would also circle the Sun.<ref>{{Cite web|url=http://webexhibits.org/calendars/year-text-Copernicus.html|title=Nicholas Copernicus &#124; Calendars}}</ref> This was foreshadowed by the Irish Carolingian scholar [[Johannes Scotus Eriugena]] in the 9th century, who went a step further than Capella by suggesting both Mars and Jupiter orbited the sun as well.<ref>[http://plato.stanford.edu/entries/scottus-eriugena/ Stanford Encyclopedia of Philosophy]. "John Scottus Eriugena." First published Thu Aug 28, 2003; substantive revision Sun Oct 17, 2004. Accessed April 30, 2014.</ref> In the 15th century by [[Nilakantha Somayaji]], an [[Indian astronomy|Indian astronomer]] of the [[Kerala school of astronomy and mathematics]], presented a geoheliocentric system where all the planets (Mercury, Venus, Mars, Jupiter and Saturn) orbit the Sun, which in turn orbits the Earth.<ref name="Ramasubramanian">{{cite journal |last1=Ramasubramanian |first1=K. |date=1994 |title=Modification of the earlier Indian planetary theory by the Kerala astronomers (c. 1500 AD) and the implied heliocentric picture of planetary motion |url=http://www.physics.iitm.ac.in/~labs/amp/kerala-astronomy.pdf |journal=[[Current Science]] |volume=66 |pages=784–90}}</ref>{{sfn|Joseph|2000|p=408}}<ref>{{cite journal |title=Model of planetary motion in the works of Kerala astronomers |last=Ramasubramanian |first=K. |journal=[[Bulletin of the Astronomical Society of India]] |year=1998 |volume=26 |pages=11–31 [23–4] |url=http://adsabs.harvard.edu/full/1998BASI...26...11R |bibcode=1998BASI...26...11R |access-date=2010-03-05}}</ref>

The Tychonic system, which was announced in 1588,<ref>{{cite web |last1=Hatch |first1=Robert |title=EARLY GEO-HELIOCENTRIC MODELS |url=http://users.clas.ufl.edu/ufhatch/pages/03-Sci-Rev/SCI-REV-Home/resource-ref-read/chief-systems/08-0TYCHO5-WSYS.html |website=The Scientific Revolution |publisher=Dr. Robert A. Hatch |access-date=11 April 2018}}</ref> became a major competitor with the Copernican system as an alternative to the Ptolemaic. After [[Galileo]]'s observation of the phases of [[Venus]] in 1610, most cosmological controversy then settled on variations of the Tychonic and Copernican systems. In a number of ways, the Tychonic system proved philosophically more intuitive than the Copernican system, as it reinforced commonsense notions of how the Sun and the planets are mobile while the Earth is not. Additionally, a Copernican system would suggest the ability to observe [[stellar parallax]], which could not be observed until the 19th century. On the other hand, because of the intersecting [[deferent and epicycle|deferents]] of Mars and the Sun (see diagram), it went against the Ptolemaic and [[Aristotelianism|Aristotelian]] notion that the planets were placed within nested spheres. Tycho and his followers revived the ancient [[Stoicism|Stoic]] philosophy instead, since it used fluid heavens which could accommodate intersecting circles.{{Citation needed|date=February 2008}}

=== Legacy ===
After Tycho's death, [[Johannes Kepler]] used Tycho's observations to demonstrate that the [[orbit]]s of the planets are [[ellipse]]s and not [[circle]]s, creating the modified [[heliocentrism|Copernican]] system that ultimately displaced both the Tychonic and Ptolemaic systems. However, the Tychonic system was very influential in the late 16th and 17th centuries. In 1616, during the [[Galileo affair]], the papal [[Congregation of the Index]] banned all books advocating the Copernican system, including works by Copernicus, Galileo, Kepler and other authors until 1758.<ref name=retrying>{{cite book|last=Finochiario|first=Maurice|title=Retrying Galileo|date=2007|publisher=University of California Press}}</ref><ref name=h218>Heilbron (2010), pp. 218–9</ref> The Tychonic system was an acceptable alternative as it explained the observed phases of Venus with a static Earth. [[Jesuit]] astronomers in China used it, as did a number of European scholars. Jesuits (such as [[Clavius]], [[Christoph Grienberger]], [[Christoph Scheiner]], [[Odo Van Maelcote]]) supported the Tychonic system.<ref>{{cite journal |last1=Pantin |first1=Isabelle  |date=1999 |title=New Philosophy and Old Prejudices: Aspects of the Reception of Copernicanism in a Divided Europe |journal=[[Stud. Hist. Philos. Sci.]] |volume=30 |issue=237–262 |page=247 |doi=10.1016/S0039-3681(98)00049-1 |bibcode=1999SHPSA..30..237P}}</ref>

The discovery of [[Aberration (astronomy)|stellar aberration]] in the early 18th century by [[James Bradley]] proved that the Earth did in fact move around the Sun and Tycho's system fell out of use among scientists.<ref>{{cite journal |last1=Bradley |first1=James |title=IV. A letter from the Reverend Mr. James Bradley Savilian Professor of Astronomy at Oxford, and F. R. S. to Dr. Edmond Halley Astronom. Reg. &c. giving an account of a new discovered motion of the fix'd stars |journal=Phil. Trans. |date=January 1728 |volume=35 |issue=406 |pages=637–661 |doi=10.1098/rstl.1727.0064 |location=London |doi-access=free}}</ref><ref>Seligman, Courtney. ''Bradley's Discovery of Stellar Aberration''. (2013).  http://cseligman.com/text/history/bradley.htm</ref> In the modern era, some [[Modern geocentrism|modern geocentrists]] use a modified Tychonic system with elliptical orbits, while rejecting the concept of relativity.<ref>Plait, Phil. (Sept. 14, 2010). Geocentrism Seriously? ''Discover Magazine.'' http://blogs.discovermagazine.com/badastronomy/2010/09/14/geocentrism-seriously/#.UVEn7leiBpd {{Webarchive|url=https://web.archive.org/web/20191025232051/http://blogs.discovermagazine.com/badastronomy/2010/09/14/geocentrism-seriously/#.UVEn7leiBpd |date=2019-10-25 }}</ref><ref>Musgrave, Iam. (Nov. 14, 2010). Geo-xcentricities part 2; the view from Mars. ''Astroblog.'' http://astroblogger.blogspot.com/2010/11/geo-xcentricities-part-2-view-from-mars.html</ref>