View source for Sublunary sphere

{{Short description|Region in the geocentric cosmos below the Moon}}
{{incomplete citations|date=January 2025}}
[[File:Simplified outline of the Platonic cosmos.png|thumb|Simplified outline of the sublunary sphere.]]
In [[Aristotelian physics]] and [[Greek astronomy]], the '''sublunary sphere''' is the region of the [[geocentric]] [[cosmos]] below the [[Moon]], consisting of the four [[classical elements]]: [[Earth (classical element)|earth]], [[Water (classical element)|water]], [[Air (classical element)|air]], and [[Fire (classical element)|fire]].<ref>Aristotle, ''Ethics'' (1974) p. 357–58</ref><ref>Stephen Toulmin, ''Night Sky at Rhodes'' (1963) p. 38 and p. 78</ref>

The sublunary sphere was the realm of changing nature. Beginning with the Moon, up to the limits of the universe, everything (to classical astronomy) was permanent, regular and unchanging—the region of [[Aether (classical element)|aether]] where the [[Naked eye planets|planets]] and [[star]]s are located. Only in the sublunary sphere did the powers of physics hold sway.<ref>C. C. Gillespie, ''The Edge of Objectivity'' (1960) p. 14</ref>

==Evolution of concept==
[[File:Albertus Magnus. Philosphia naturalis - caelum.jpg|thumb|The [[seven heavens]] and the sublunar spheres, from an engraving of [[Albertus Magnus]]' ''Philosophia naturalis''.]]
[[Plato]] and [[Aristotle]] helped to formulate the original theory of a sublunary sphere in antiquity,<ref>Gillespie, pp. 13–15</ref>{{missing long citation|date=January 2025}} the idea usually going hand in hand with [[geocentrism]] and the concept of a [[spherical Earth]].

[[Avicenna]] carried forward into the Middle Ages the Aristotelian idea of generation and corruption being limited to the sublunary sphere.<ref>J. J. E. Garcia, ''Individuation in Scholasticism'' (1994) p. 41</ref> [[Scholasticism|Medieval scholastics]] like [[Thomas Aquinas]], who charted the division between celestial and sublunary spheres in his work ''Summa Theologica'', also drew on [[Cicero]] and [[Lucan]] for an awareness of the great frontier between Nature and Sky, sublunary and aetheric spheres.<ref>W. Hooper, ''C. S. Lewis'' (1996) pp. 529–531</ref> The result for medieval/Renaissance mentalities was a pervasive awareness of the existence, at the Moon, of what [[C. S. Lewis]] called "this 'great divide'&nbsp;... from aether to air, from 'heaven' to 'nature', from the realm of gods (or angels) to that of daemons, from the realm of necessity to that of contingence, from the incorruptible to the corruptible".{{cn|date=January 2025}}

However, the theories of [[Copernicus]] began to challenge the sublunary/aether distinction. In their wake, [[Tycho Brahe]]'s observations of a new star (nova) and of comets in the supposedly unchanging heavens further undermined the Aristotelian view.<ref>R. Curley, ''Scientists and Inventors of the Renaissance'' (2012) pp. 6–8</ref> [[Thomas Kuhn]] saw scientists' new ability to see change in the 'incorruptible' heavens as a classic example of the new possibilities opened up by a paradigm shift.<ref>Thomas S. Kuhn, ''The Structure of Scientific Revolutions'' (1970) pp. 116–17</ref>

==Literary offshoots==
[[Dante]] envisaged Mt Purgatory as being so high that it reached above the sublunary sphere, so that "These slopes are free from every natural change".<ref>Dante, ''Purgatory'' (1971), p. 235</ref>

[[Samuel Johnson]] praised Shakespeare's plays as "exhibiting the real state of sublunary nature, which partakes of good and evil, joy and sorrow, intermingled".<ref>Samuel Johnson, ''Selected Writings'', Penguin, p. 266</ref>

== See also ==
{{Columns-list|colwidth=22em|
* [[Celestial spheres]]
* [[Firmament]]
* [[Sphere of fire]]
* [[Unmoved mover]]
}}

==References==
{{reflist|25em}}

==Further reading==
* J. Barnes, ''Aristotle'' (1982)
* M. A. Orr, ''Dante and the Medieval Astronomers'' (1956)
* Thomas Kuhn, ''The Copernican Revolution'' (1957)

== External links ==
* [http://msuweb.montclair.edu/~furrg/mel/ptolemaic.html The Geocentric or Ptolemaic Notion of the Universe]

{{Ancient Greek astronomy}}
{{Aristotelianism}}


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[[Category:Ancient Greek astronomy]]
[[Category:Obsolete theories in physics]]