Editing Physics (section)

==History==
{{Main|History of physics}}
The word ''physics'' comes from the [[Latin]] {{lang|la|physica}} ('study of nature'), which itself is a borrowing of the [[Greek language|Greek]] {{lang|grc|φυσική}} ({{transliteration|grc|phusikḗ}} 'natural science'), a term derived from {{lang|grc|φύσις}} ({{transliteration|grc|phúsis}} 'origin, nature, property').<ref name="etymonline-physics">{{cite web |title=physics |website=[[Online Etymology Dictionary]] |url=http://www.etymonline.com/index.php?term=physics&allowed_in_frame=0|access-date=1 November 2016 |archive-url= https://web.archive.org/web/20161224191507/http://www.etymonline.com/index.php?term=physics&allowed_in_frame=0 |archive-date=24 December 2016 |url-status=live}}</ref><ref name="etymonline-physic">{{cite web |title=physic |website=[[Online Etymology Dictionary]] |url=http://www.etymonline.com/index.php?term=physic&allowed_in_frame=0 |access-date=1 November 2016 |archive-url= https://web.archive.org/web/20161224173651/http://www.etymonline.com/index.php?term=physic&allowed_in_frame=0 |archive-date=24 December 2016 |url-status=live}}</ref><ref name="LSJ">{{LSJ|fu/sis|φύσις}}, {{LSJ|fusiko/s|φυσική}}, {{LSJ|e)pisth/mh|ἐπιστήμη|ref}}</ref>

=== Ancient astronomy ===
{{Main|History of astronomy}}
[[File:Senenmut-Grab.JPG|thumb|right|upright=1.8|Ancient [[Egyptian astronomy]] is evident in monuments like the [[Astronomical ceiling of Senemut Tomb|ceiling of Senemut's tomb]] from the [[Eighteenth Dynasty of Egypt]].]]
[[Astronomy]] is one of the oldest [[natural science]]s. Early civilizations dating before 3000&nbsp;BCE, such as the [[Sumer]]ians, [[ancient Egypt]]ians, and the [[Indus Valley Civilisation]], had a predictive knowledge and a basic awareness of the motions of the Sun, Moon, and stars. The stars and planets, believed to represent gods, were often worshipped. While the explanations for the observed positions of the stars were often unscientific and lacking in evidence, these early observations laid the foundation for later astronomy, as the stars were found to traverse [[great circle]]s across the sky,<ref name="krupp2003"/> which could not explain the positions of the [[planet]]s.

According to [[Asger Aaboe]], the origins of Western astronomy can be found in [[Mesopotamia]], and all Western efforts in the [[exact science]]s are descended from late [[Babylonian astronomy]].<ref name ="aaboe1991">{{harvnb |Aaboe|1991}}</ref> [[Egyptian astronomy|Egyptian astronomers]] left monuments showing knowledge of the constellations and the motions of the celestial bodies,<ref name="clagett1995">{{harvnb |Clagett|1995}}</ref> while Greek poet [[Homer]] wrote of various celestial objects in his ''[[Iliad]]'' and ''[[Odyssey]]''; later [[Greek astronomy|Greek astronomers]] provided names, which are still used today, for most constellations visible from the [[Northern Hemisphere]].<ref name="thurston1994">{{harvnb |Thurston|1994}}</ref>

=== Natural philosophy ===
{{main|Natural philosophy}}
[[Natural philosophy]] has its origins in [[Greece]] during the [[Archaic Greece|Archaic period]] (650 BCE – 480 BCE), when [[Presocratics|pre-Socratic philosophers]] like [[Thales]] rejected [[Methodological naturalism|non-naturalistic]] explanations for natural phenomena and proclaimed that every event had a natural cause.<ref name="singer2008p35">{{harvnb |Singer|2008|p=35}}</ref> They proposed ideas verified by reason and observation, and many of their hypotheses proved successful in experiment;<ref name="lloyd1970pp108-109">{{harvnb |Lloyd|1970|pp=108–109}}</ref> for example, [[atomism]] was found to be correct approximately 2000 years after it was proposed by [[Leucippus]] and his pupil [[Democritus]].<ref name="about-atomism">
{{cite web |last=Gill |first=N. S. |title=Atomism – Pre-Socratic Philosophy of Atomism |url=http://ancienthistory.about.com/od/presocraticphiloso/p/Atomism.htm |url-status=live |archive-url=https://web.archive.org/web/20140710140657/http://ancienthistory.about.com/od/presocraticphiloso/p/Atomism.htm |archive-date=10 July 2014 |access-date=1 April 2014 |publisher=[[About.com|About Education]] }}</ref>

=== Aristotle and Hellenistic physics ===
[[File:Aristotle Altemps Inv8575.jpg|thumb|upright|[[Aristotle]]<br />(384–322 [[BCE]])]]
During the [[Classical Greece|classical period]] in Greece (6th, 5th and 4th centuries BCE) and in [[Hellenistic civilization|Hellenistic times]], [[natural philosophy]] developed along many lines of inquiry. [[Aristotle]] ({{langx|el|Ἀριστοτέλης}}, ''Aristotélēs'') (384–322 BCE), a student of [[Plato]],
wrote on many subjects, including a substantial treatise on "[[Physics (Aristotle)|Physics]]"&nbsp;– in the 4th century BC.  [[Aristotelian physics]] was influential for about two millennia. His approach mixed some limited observation with logical deductive arguments, but did not rely on experimental verification of deduced statements.  Aristotle's foundational work in Physics, though very imperfect, formed a framework against which later thinkers further developed the field. His approach is entirely superseded today.

He explained ideas such as [[motion (physics)|motion]] (and [[gravity]]) with the theory of [[classical elements|four elements]].
Aristotle believed that each of the four classical elements (air, fire, water, earth) had its own natural place.<ref>{{Cite web |title=Daily 40 no. 2 – Aristotle and the Four Simple Bodies and Elements |website=Cal State LA |url=https://www.calstatela.edu/sites/default/files/dept/chem/09summer/158/daily40-aristotle.pdf |access-date=27 September 2023 |archive-url=https://web.archive.org/web/20230106231001/https://www.calstatela.edu/sites/default/files/dept/chem/09summer/158/daily40-aristotle.pdf |archive-date=6 January 2023 }}</ref>  Because of their differing densities, each element will revert to its own specific place in the atmosphere.<ref>{{Cite web |last=tbcaldwe |title=Natural Philosophy: Aristotle {{!}} Physics 139 |date=14 October 2012 |url=https://blogs.umass.edu/p139ell/2012/10/14/natural-philosophy-aristotle/ |access-date=17 December 2022 |language=en-US}}</ref>  So, because of their weights, fire would be at the top, air underneath fire, then water, then lastly earth. He also stated that when a small amount of one element enters the natural place of another, the less abundant element will automatically go towards its own natural place.  For example, if there is a fire on the ground, the flames go up into the air in an attempt to go back into its natural place where it belongs.  His laws of motion included: that heavier objects will fall faster, the speed being proportional to the weight and the speed of the object that is falling depends inversely on the density object it is falling through (e.g. density of air).<ref name=":1">{{Cite web |title=Aristotle |url=https://galileoandeinstein.phys.virginia.edu/lectures/aristot2.html |access-date=17 December 2022 |website=galileoandeinstein.phys.virginia.edu}}</ref> He also stated that, when it comes to violent motion (motion of an object when a force is applied to it by a second object) that the speed that object moves, will only be as fast or strong as the measure of force applied to it.<ref name=":1" />   The problem of motion and its causes was studied carefully, leading to the philosophical notion of a "[[unmoved mover|prime mover]]" as the ultimate source of all motion in the world (Book 8 of his treatise ''[[Physics (Aristotle)|Physics]]'').

=== Medieval European and Islamic ===
{{main|European science in the Middle Ages|Physics in the medieval Islamic world}}

[[File:Ibn al-Haytham crop.jpg|thumb|right|upright|[[Ibn al-Haytham]] ({{Circa|965|1040}}) wrote of his ''camera obscura'' experiments in the ''Book of Optics''.{{sfn|Smith|2001|loc=Book I [6.85], [6.86], p. 379; Book II, [3.80], p. 453}}|alt=Ibn Al-Haytham (Alhazen) drawing]]

The [[Western Roman Empire]] fell to invaders and internal decay in the fifth century, resulting in a decline in intellectual pursuits in western Europe. By contrast, the Eastern Roman Empire (usually known as the [[Byzantine Empire]]) resisted the attacks from invaders and continued to advance various fields of learning, including physics.{{sfn|Lindberg|1992|page=363}}  In the sixth century, [[John Philoponus]] challenged the dominant Aristotelian approach to science although much of his work was focused on Christian theology.<ref>{{Cite web |last=Wildberg |first=Christian |date=2021 |editor-last=Zalta |editor-first=Edward N. |title=John Philoponus |url=https://plato.stanford.edu/entries/philoponus/ |access-date=2025-02-06 |publisher=Metaphysics Research Lab, Stanford University}}</ref>

In the sixth century, [[Isidore of Miletus]] created an important compilation of [[Archimedes]]' works that are copied in the [[Archimedes Palimpsest]].
[[Science in the medieval Islamic world|Islamic scholarship]] inherited [[Aristotelian physics]] from the Greeks and during the [[Islamic Golden Age]] developed it further, especially placing emphasis on observation and ''[[A priori and a posteriori|a priori]]'' reasoning, developing early forms of the [[scientific method]].

The most notable innovations under Islamic scholarship were in the field of [[optics]] and vision,<ref>{{cite book |last= Dallal|first=Ahmad  |author-link= |date= 2010|title=Islam, Science, and the Challenge of History |url= |location=New Haven |publisher= Yale University Press|page=38 |isbn=|quote = Within two centuries, the field of optics was radically transformed}}</ref> which came from the works of many scientists like [[Ibn Sahl (mathematician)|Ibn Sahl]], [[Al-Kindi]], [[Ibn al-Haytham]], [[Kamāl al-Dīn al-Fārisī|Al-Farisi]] and [[Avicenna]]. The most notable work was ''[[Book of Optics|The Book of Optics]]'' (also known as Kitāb al-Manāẓir), written by Ibn al-Haytham, in which he presented the alternative to the ancient Greek idea about vision.<ref>{{Cite journal |last1=Tbakhi |first1=Abdelghani |last2=Amr |first2=Samir S. |date=2007 |title=Ibn Al-Haytham: Father of Modern Optics |journal=Annals of Saudi Medicine |volume=27 |issue=6 |pages=464–467 |doi=10.5144/0256-4947.2007.464 |issn=0256-4947 |pmc=6074172 |pmid=18059131}}</ref> His discussed his experiments with [[camera obscura]], showing that light moved in a straight line; he encouraged readers to reproduce his experiments making him one of the originators of the [[scientific method]]<ref>{{Cite journal |last=Al-Khalili |first=Jim |date=February 2015 |title=In retrospect: Book of Optics |url=https://www.nature.com/articles/518164a |journal=Nature |language=en |volume=518 |issue=7538 |pages=164–165 |doi=10.1038/518164a |bibcode=2015Natur.518..164A |issn=1476-4687}}</ref><ref>{{harvnb |Howard|Rogers|1995|pp=6–7}}</ref>

[[File:Pinhole-camera.svg|thumb|left|upright|The basic way a pinhole camera works]]
{{clear}}
=== Scientific Revolution ===
{{further|History_of_physics#Scientific_Revolution}}

Physics became a separate science when [[early modern Europe]]ans used experimental and quantitative methods to discover what are now considered to be the [[laws of physics]].<ref name="benchaim2004">{{harvnb |Ben-Chaim|2004}}</ref>{{Page needed|date=November 2016}}

Major developments in this period include the replacement of the [[geocentric model]] of the [[Solar System]] with the heliocentric [[Copernican model]], the [[Kepler's laws|laws governing the motion of planetary bodies]] (determined by [[Johannes Kepler]] between 1609 and 1619), Galileo's pioneering work on [[telescope]]s and [[observational astronomy]] in the 16th and 17th centuries, and [[Isaac Newton]]'s discovery and unification of the [[Newton's laws of motion|laws of motion]] and [[Newton's law of universal gravitation|universal gravitation]] (that would come to bear his name).<ref>{{harvnb |Guicciardini|1999}}</ref> Newton, and separately [[Gottfried Wilhelm Leibniz]], developed [[calculus]],<ref name=bblank> See also [[Leibniz–Newton calculus controversy]]. {{cite journal | last = Blank| first =Brian E. |date=May 2009 | title = The Calculus Wars reviewed by Brian E. Blank | journal = [[Notices of the American Mathematical Society]] | volume = 56 | issue = 5 | pages = 602–610 | url = https://www.ams.org/notices/200905/rtx090500602p.pdf }}</ref>  the mathematical study of continuous change, and Newton applied it to solve physical problems.<ref name="allen1997">{{harvnb |Allen|1997}}</ref>
<gallery mode=packed heights=200px>
Justus Sustermans - Portrait of Galileo Galilei, 1636.jpg|[[Galileo Galilei]] (1564–1642) related mathematics, theoretical physics, and experimental physics.
JKepler.jpg|[[Johannes Kepler]] (1571–1630) explained [[Kepler's laws|planetary motions]], formulating the first "natural laws" in the modern sense<ref>{{cite web |last1=Gould |first1=Alan |title=Johannes Kepler: His Life, His Laws and Times |url=https://www.nasa.gov/kepler/education/johannes/ |website=[[NASA]] |date=24 September 2016 |access-date=25 February 2025 |archive-url=https://web.archive.org/web/20210624003856/https://www.nasa.gov/kepler/education/johannes |archive-date=24 June 2021}}</ref>
GodfreyKneller-IsaacNewton-1689.jpg|[[Isaac Newton]] discovered the [[Newton's laws of motion|laws of motion]] and [[Newton's law of universal gravitation|universal gravitation]]
</gallery>

=== 19th century ===
{{further|History_of_physics#19th_century}}
The discovery of laws in [[thermodynamics]], [[chemistry]], and [[electromagnetics]] resulted from research efforts during the [[Industrial Revolution]] as energy needs increased.<ref name="schoolscience-industrialrevolution">{{cite web
 |title       = The Industrial Revolution
 |publisher   = Schoolscience.org, [[Institute of Physics]]
 |url         = http://resources.schoolscience.co.uk/IoP/14-16/biogs/biogs5.html
 |access-date  = 1 April 2014
|url-status=live
 |archive-url  = https://web.archive.org/web/20140407083354/http://resources.schoolscience.co.uk/IoP/14-16/biogs/biogs5.html
 |archive-date = 7 April 2014
|df          = dmy-all
}}</ref> By the end of the 19th century, theories of thermodynamics, [[classical mechanics|mechanics]], and electromagnetics matched a wide variety of observations. Taken together these theories became the basis for what would later be called [[classical physics]].<ref name=Krane-2019>{{Cite book |last=Krane |first=Kenneth S. |title=Modern physics |date=2020 |publisher=John Wiley & Sons, Inc |isbn=978-1-119-49548-2 |edition=4 |location=Hoboken, New Jersey}}</ref>{{rp|2}}

A few experimental results remained inexplicable. Classical electromagnetism presumed a medium, an [[luminiferous aether]] to support the propagation of waves, but this medium could not be detected. The intensity of light from hot glowing [[blackbody radiation|blackbody]] objects did not match the predictions of thermodynamics and electromagnetism. The character of [[photoelectric effect|electron emission]] of illuminated metals differed from predictions. These failures, seemingly insignificant in the big picture would upset the physics world in first two decades of the 20th century.<ref name=Krane-2019/>

=== 20th century ===
{{see also|History of special relativity|History of quantum mechanics}}
{{further|History of physics#20th century: birth of modern physics}}
[[File:Max Planck Nobel 1918.jpg|thumb|left|[[Max Planck]] (1858–1947), proposed [[quantum|quanta]] to explain the [[blackbody spectrum]],<ref>{{cite web |url=https://www.esa.int/Science_Exploration/Space_Science/Planck/Max_Planck_Originator_of_quantum_theory |title=Max Planck: Originator of quantum theory |date=2012-08-12 |quote="He renounced previous physics and introduced the concept of ‘quanta’ of energy."|work=esa.int |access-date=2025-03-04}}</ref> originating [[quantum mechanics|quantum theory]].<ref>{{Cite web|url=https://www.esa.int/Science_Exploration/Space_Science/Planck/Max_Planck_Originator_of_quantum_theory|title=Max Planck: Originator of quantum theory|website=www.esa.int}}</ref><ref>{{Cite web|url=https://www.britannica.com/biography/Max-Planck|title=Max Planck &#124; Biography, Discoveries, & Quantum Theory &#124; Britannica|date=19 April 2025|website=www.britannica.com}}</ref>]]
[[File:Einstein1921 by F Schmutzer 2.jpg|thumb|right|[[Albert Einstein]] (1879–1955), discovered the [[photoelectric effect]] and [[theory of relativity]].]]
[[Modern physics]] began in the early 20th century with the work of [[Max Planck]] in quantum theory and [[Albert Einstein]]'s theory of relativity. Both of these theories came about due to inaccuracies in classical mechanics in certain situations. [[Classical mechanics]] predicted that the [[speed of light]] depends on the motion of the observer, which could not be resolved with the constant speed predicted by [[Maxwell's equations]] of electromagnetism. This discrepancy was corrected by Einstein's theory of [[special relativity]], which replaced classical mechanics for fast-moving bodies and allowed for a constant speed of light.<ref name="oconnorrobertson1996-relativity">{{harvnb |O'Connor|Robertson|1996a}}</ref> [[Black-body radiation]] provided another problem for classical physics, which was corrected when Planck proposed that the excitation of material oscillators is possible only in discrete steps proportional to their frequency. This, along with the [[photoelectric effect]] and a complete theory predicting discrete [[energy levels]] of [[Atomic orbital|electron orbitals]], led to the theory of quantum mechanics improving on classical physics at very small scales.<ref name="oconnorrobertson1996-quantum">{{harvnb |O'Connor|Robertson|1996b}}</ref>

Quantum mechanics would come to be pioneered by [[Werner Heisenberg]], [[Erwin Schrödinger]] and [[Paul Dirac]].<ref name="oconnorrobertson1996-quantum"/> From this early work, and work in related fields, the [[Standard Model of particle physics]] was derived.<ref name="donut2001">{{cite web |website=[[DONUT]] |title=The Standard Model |publisher=[[Fermilab]] |date=29 June 2001 |url=http://www-donut.fnal.gov/web_pages/standardmodelpg/TheStandardModel.html |access-date=1 April 2014 |archive-date=31 May 2014 |archive-url=https://web.archive.org/web/20140531012204/http://www-donut.fnal.gov/web_pages/standardmodelpg/TheStandardModel.html |url-status=live }}</ref> Following the discovery of a particle with properties consistent with the [[Higgs boson]] at [[CERN]] in 2012,<ref name="cho2012">{{harvnb |Cho|2012}}</ref> all [[fundamental particles]] predicted by the standard model, and no others, appear to exist; however, [[physics beyond the Standard Model]], with theories such as [[supersymmetry]], is an active area of research.<ref>{{cite magazine |last=Womersley |first=J. |url=http://www.symmetrymagazine.org/sites/default/files/legacy/pdfs/200502/beyond_the_standard_model.pdf |date=February 2005 |title=Beyond the Standard Model |magazine= Symmetry |volume=2 |issue=1 |pages=22–25 |archive-url=https://web.archive.org/web/20150924114111/http://www.symmetrymagazine.org/sites/default/files/legacy/pdfs/200502/beyond_the_standard_model.pdf |archive-date=24 September 2015 |url-status=live}}</ref> Areas of mathematics in general are important to this field, such as the study of [[probability amplitude|probabilities]] and [[Group theory#Physics|groups]].