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{{Short description|American experimental physicist (1892–1962)}}
{{Use mdy dates|date=March 2023}}
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{{Infobox scientist
| name              = Arthur Compton
| image             = Arthur Compton 1927.jpg
| caption           = Compton in 1927
| birth_name        = Arthur Holly Compton
| birth_date        = {{Birth date|1892|09|10}}
| birth_place       = [[Wooster, Ohio]], US
| death_date        = {{Death date and age|1962|03|15|1892|09|10}}
| death_place       = [[Berkeley, California]], US
| alma_mater        = {{Plain list|
* [[University of Wooster]] ([[Bachelor of Science|BS]])
* [[Princeton University]] ([[Master of Arts|MA]], [[Doctor of Philosophy|PhD]])
}}
| known_for         = {{Plain list|
* [[Compton effect]]
* [[Compton generator]]
* [[Cosmic ray]]s
}}
| spouse            = {{Marriage|Betty McCloskey|1916}}
| children          = 2, including [[John Joseph Compton|John]]
| relatives         = [[Karl Taylor Compton|Karl Compton]], [[Wilson Martindale Compton|Wilson Compton]] (brothers)
| awards            = {{Plain list|
* [[Nobel Prize in Physics]] (1927)
* [[Matteucci Medal]] (1930)
* [[Hughes Medal]] (1940)
* [[Franklin Medal]] (1940)
* [[Medal for Merit]] (1946)
}}
| fields            = {{Flat list|
* [[Particle physics]]
* [[geophysics]]
}}
| work_institutions = {{Plain list|
* [[Washington University in St. Louis]] (1920–23, 1945–61)
* [[University of Chicago]] <br/> (1923–45)
* [[University of California, Berkeley]] (1962)
}}
| thesis_title      = The Intensity of X-Ray Reflection and the Distribution of the Electrons in Atoms <br/>
| thesis_url        = https://catalog.hathitrust.org/Record/001481182
| thesis_year       = 1917
| doctoral_advisor  = Hereward Cooke
| doctoral_students = {{Plain list|
* [[Ernest Wollan]] (1929)<ref name=PhysicsTree>{{Cite web|title=Arthur Holly Compton - Physics Tree|url=https://academictree.org/physics/peopleinfo.php?pid=36673|website=academictree.org|access-date=2025-09-01}}</ref>
* [[Robert S. Shankland]] (1935)<ref name=PhysicsTree/>
* [[Luis Walter Alvarez]] (1936)<ref name=PhysicsTree/>
* [[Piara Singh Gill]] (1940)<ref name=PhysicsTree/>
* [[Facundo Bueso Sanllehí]] (1941)<ref name=PhysicsTree/>
* [[Norman Hilberry]] (1941)<ref name=PhysicsTree/>
* [[Michel Ter-Pogossian]] (1950)<ref name=PhysicsTree/>
}}
| signature         = Arthur Compton signature.png
}}

'''Arthur Holly Compton''' (September 10, 1892 – March 15, 1962) was an American [[experimental physicist]] who shared the 1927 [[Nobel Prize in Physics]] with [[C. T. R. Wilson]] for his discovery of the [[Compton effect]], which demonstrated the [[particle physics|particle]] nature of [[electromagnetic radiation]]. It was a sensational discovery at the time: the wave nature of light had been well-demonstrated, but the idea that light had both [[Wave–particle duality|wave and particle]] properties was not easily accepted.

Compton is also known for his leadership over the [[Metallurgical Laboratory]] at the [[University of Chicago]] during the [[Manhattan Project]], and served as chancellor of [[Washington University in St. Louis]] from 1945 to 1953.

In 1919, Compton was awarded one of the first two [[United States National Research Council|National Research Council]] Fellowships that allowed students to study abroad. He chose to go to the [[University of Cambridge]]'s [[Cavendish Laboratory]] in England, where he studied the [[scattering]] and [[Absorption (electromagnetic radiation)|absorption]] of [[gamma ray]]s. Further research along these lines led to the discovery of the Compton effect.

Compton used X-rays to investigate [[ferromagnetism]], concluding that it was a result of the alignment of [[electron spin]]s, and studied [[cosmic ray]]s, discovering that they were made principally of positively charged particles.

During [[World War II]], Compton was a key figure in the [[Manhattan Project]] that developed the first [[nuclear weapon]]s. His reports were important in launching the project. In 1942, he became a member of the [[S-1 Executive Committee|Executive Committee]], and then head of the "X" projects overseeing the Metallurgical Laboratory, with responsibility for producing [[nuclear reactor]]s to convert [[uranium]] into [[plutonium]], finding ways to separate the plutonium from the uranium and to design an atomic bomb. Compton oversaw [[Enrico Fermi]]'s creation of [[Chicago Pile-1]], the first nuclear reactor, which went critical on December 2, 1942. The Metallurgical Laboratory was also responsible for the design and operation of the [[X-10 Graphite Reactor]] at [[Oak Ridge, Tennessee]]. Plutonium began being produced in the [[Hanford Site]] reactors in 1945.

After the war, Compton became chancellor of Washington University in St. Louis. During his tenure, the university formally desegregated its undergraduate divisions, named its first female full professor, and enrolled a record number of students after wartime veterans returned to the United States.

== Education ==
[[File:Compton Heisenberg 1929 Chicago.jpg|thumb|left|upright|Compton and [[Werner Heisenberg]] in 1929 in Chicago]]

Arthur Holly Compton was born on September 10, 1892, in [[Wooster, Ohio]], the son of Elias Compton and Otelia Catherine Augspurger,{{sfn|Hockey|2007|p=244}} who was named American Mother of the Year in 1939 and was of German [[Mennonite]] descent.<ref>{{citeweb|url=http://www.americanmothers.org/past-national-mothers-of-the-year |title=Past National Mothers of the Year |access-date=July 23, 2013 |publisher=American Mothers, Inc. |url-status = dead|archive-url=https://web.archive.org/web/20110323130748/http://www.americanmothers.org/past-national-mothers-of-the-year |archive-date=March 23, 2011 }}</ref><ref>{{Cite GAMEO|last1=Amstutz ||last2=Steiner |first1=J. E. |first2=Samuel J. |date=February 2012 |article=Compton, Otelia Augspurger (1859-1944)}}</ref>
They were an academic family. Elias was Dean of the University of Wooster (now the [[College of Wooster]]), which Arthur also attended. Arthur's eldest brother, [[Karl Compton|Karl]], who also attended Wooster, earned a [[Ph.D.]] in physics from [[Princeton University]] in 1912, and was President of the [[Massachusetts Institute of Technology]] from 1930 to 1948. His second brother, [[Wilson Martindale Compton|Wilson]], likewise attended Wooster, earned his Ph.D. in economics from Princeton in 1916 and was President of the State College of Washington (now [[Washington State University]]) from 1944 to 1951.{{sfn|Compton|1967|p=425}} All three brothers were members of the [[Alpha Tau Omega]] fraternity.<ref>{{cite web |url=https://depaul.digication.com/atohistory/The_1920_s |access-date=August 10, 2013 |publisher=Alpha Tau Fraternity |title=The Official History of the Beta Beta Chapter of the Alpha Tau Omega Fraternity |archive-url=https://web.archive.org/web/20141016120814/https://depaul.digication.com/atohistory/The_1920_s |archive-date=October 16, 2014 |url-status = dead}}</ref>

Compton was initially interested in astronomy, and took a photograph of [[Halley's Comet]] in 1910.{{sfn|Compton|1967|pp=11–12}} Around 1913, he described an experiment where an examination of the motion of water in a circular tube demonstrated the rotation of the earth, a device now known as the [[Compton generator]].<ref>{{cite journal|journal=Science|volume=37|issue=960|doi=10.1126/science.37.960.803 |pmid=17838837|pages=803–06|title=A Laboratory Method of Demonstrating the Earth's Rotation|date=May 23, 1913|last1=Compton|first1=A.&nbsp;H.|bibcode = 1913Sci....37..803C |url=https://zenodo.org/record/1448113}}</ref> That year, he graduated from Wooster with a [[B.S.]] and entered Princeton, where he received his [[M.A.]] in 1914.<ref name="Nobel" /> Compton then studied for his Ph.D. in physics under the supervision of Hereward L. Cooke, writing his thesis on ''The Intensity of X-Ray Reflection, and the Distribution of the Electrons in Atoms''.<ref>{{cite web |url=http://library.nd.edu/chemistry/resources/genealogy/physics/documents/ComptonAH.pdf |access-date=July 24, 2013 |title=Arthur Holly Compton (1892–1962) |publisher=[[University of Notre Dame]] |archive-date=January 11, 2014 |archive-url=https://web.archive.org/web/20140111004355/http://library.nd.edu/chemistry/resources/genealogy/physics/documents/ComptonAH.pdf |url-status=dead }}</ref>

When Arthur Compton earned his Ph.D. in 1916, he, Karl, and Wilson became the first group of three brothers to earn PhDs from Princeton. Later, they would become the first such trio to simultaneously head American colleges.{{sfn|Compton|1967|p=425}} Their sister, Mary, married a missionary, C. Herbert Rice, who became the Principal of [[Forman Christian College]] in [[Lahore]].{{sfn|Allison|1965|p=82}} In June 1916, Compton married Betty Charity McCloskey, a Wooster classmate and fellow graduate.{{sfn|Allison|1965|p=82}} They had two sons, Arthur Alan Compton and [[John Joseph Compton]].{{sfn|Allison|1965|p=94}}

In 1916, Compton became a physics instructor at the [[University of Minnesota]].{{sfn|Allison|1965|p=83}} In 1917, he became a research engineer at the [[Westinghouse Electric (1886)|Westinghouse Lamp Company]] in [[Pittsburgh]], where he worked on the development of the [[sodium-vapor lamp]]. During [[World War I]], he developed aircraft instrumentation for the [[Signal Corps (United States Army)|Signal Corps]].{{sfn|Allison|1965|p=82}}

In 1919, Compton was awarded one of the first two [[United States National Research Council|National Research Council]] Fellowships that allowed students to study abroad. He chose to go to the [[University of Cambridge]]'s [[Cavendish Laboratory]] in England. Working with [[George Paget Thomson]], the son of [[J.&nbsp;J. Thomson]], Compton studied the [[scattering]] and [[Absorption (electromagnetic radiation)|absorption]] of [[gamma rays]]. He observed that the scattered rays were more easily absorbed than the original source.{{sfn|Allison|1965|p=83}}{{sfn|Compton|1967|p=27}} Compton was greatly impressed by the Cavendish scientists, especially [[Ernest Rutherford]], [[Charles Galton Darwin]] and [[Arthur Eddington]], and he ultimately named his second son after J.&nbsp;J. Thomson.{{sfn|Compton|1967|p=27}}

From 1926 to 1927, he taught at the department of chemistry of the [[University of the Punjab]] where he was a [[Guggenheim Fellowship|Guggenheim Fellow]].<ref>{{Cite web |title=University of the Punjab – Science |url=http://pu.edu.pk/home/department/55/Department-of-Physics#:~:text=In%20the%20academic%20year%201926,and%20latitude%20on%20Cosmic%20Rays. |access-date=2023-08-29 |website=pu.edu.pk}}</ref><ref>{{Cite web |last=Newspaper |first=the |date=2014-10-15 |title=Nobel Laureates from Lahore |url=http://www.dawn.com/news/1137982 |access-date=2023-08-29 |website=DAWN.COM |language=en}}</ref>

For a time, Compton was a deacon at a Baptist church. "Science can have no quarrel", he said, "with a religion which postulates a God to whom men are as His children."<ref name="Time">{{cite news |url=http://www.time.com/time/magazine/article/0,9171,755635-5,00.html |archive-url=https://web.archive.org/web/20121024010454/http://www.time.com/time/magazine/article/0,9171,755635-5,00.html |url-status=dead |archive-date=October 24, 2012 |newspaper=[[Time (magazine)|Time]] |title=Science: Cosmic Clearance|date=January 13, 1936}}</ref>

== Career and research ==
[[File:Time Cover Arthur H Compton.jpg|thumb|upright|Compton on the cover of ''Time'' magazine on January 13, 1936, holding his cosmic ray detector]]

=== Compton effect ===
{{Main|Compton effect}}
Returning to the United States, Compton was appointed Wayman Crow Professor of Physics, and head of the Department of Physics at [[Washington University in St. Louis]] in 1920.<ref name="Nobel" /> In 1922, he found that [[X-ray]] [[Quantum|quanta]] scattered by free electrons had longer [[wavelength]]s and, in accordance with [[Planck constant|Planck's relation]], less [[energy]] than the incoming X-rays, the surplus energy having been transferred to the electrons. This discovery, known as the "[[Compton effect]]" or "Compton scattering", demonstrated the [[particle physics|particle]] concept of [[electromagnetic radiation]].{{sfn|Allison|1965|pp=84–86}}<ref name="Compton effect">{{cite journal |last=Compton |first=Arthur H. |date=May 1923 |title=A Quantum Theory of the Scattering of X-Rays by Light Elements |journal=[[Physical Review]] |doi=10.1103/PhysRev.21.483 |doi-access=free |bibcode=1923PhRv...21..483C |volume=21 |number=5 |pages=483–502}}</ref>

In 1923, Compton published a paper in the ''[[Physical Review]]'' that explained the X-ray shift by attributing particle-like momentum to [[photon]]s, something Einstein had invoked for his 1905 Nobel Prize–winning explanation of the [[photo-electric effect]]. First postulated by [[Max Planck]] in 1900, these were conceptualized as elements of light "quantized" by containing a specific amount of energy depending only on the frequency of the light.{{sfn|Gamow|1966|pp=17–23}} In his paper, Compton derived the mathematical relationship between the shift in wavelength and the scattering angle of the X-rays by assuming that each scattered X-ray photon interacted with only one electron.  His paper concludes by reporting on experiments that verified his derived relation:
:<math>\lambda' - \lambda = \frac{h}{m_e c}(1-\cos{\theta}),</math>
where
:<math>\lambda</math> is the initial wavelength,
:<math>\lambda'</math> is the wavelength after scattering,
:<math>h</math> is the [[Planck constant]],
:<math>m_e</math> is the [[electron rest mass]],
:<math>c</math> is the [[speed of light]], and
:<math>\theta</math> is the scattering angle.<ref name="Compton effect" />

The quantity {{frac|''h''|''m<sub>e</sub>c''}} is known as the [[Compton wavelength]] of the electron; it is equal to {{val|2.43|e=-12|u=m}}. The wavelength shift {{nowrap|''λ′'' − ''λ''}} lies between zero (for {{nowrap|''θ'' {{=}} 0°}}) and twice the Compton wavelength of the electron (for {{nowrap|''θ'' {{=}} 180°}}).<ref>{{cite web |url=http://math.ucr.edu/home/baez/lengths.html#compton_wavelength |access-date=August 18, 2013 |title=The Compton wavelength of the electron |publisher=[[University of California Riverside]] |archive-url=https://web.archive.org/web/19961110050634/http://math.ucr.edu/home/baez/lengths.html#compton_wavelength |archive-date=November 10, 1996 |url-status = dead}}</ref> He found that some X-rays experienced no wavelength shift despite being scattered through large angles; in each of these cases the photon failed to eject an electron. Thus the magnitude of the shift is related not to the Compton wavelength of the electron, but to the Compton wavelength of the entire atom, which can be upwards of 10,000 times smaller.<ref name="Compton effect" />

"When I presented my results at a meeting of the [[American Physical Society]] in 1923", Compton later recalled, "it initiated the most hotly contested scientific controversy that I have ever known."{{sfn|Compton|1967|p=36}} The wave nature of light had been well demonstrated, and the idea that it could have a dual nature was not easily accepted. It was particularly telling that diffraction in a crystal lattice could only be explained with reference to its wave nature. It earned Compton the [[Nobel Prize in Physics]] in 1927.{{efn| The 1927 Nobel Prize was also awarded to [[C. T. R. Wilson]] for the invention of the [[Wilson cloud chamber]].<ref>{{cite web|title=The Nobel Prize in Physics 1927|publisher=The Nobel Foundation| url=https://www.nobelprize.org/prizes/physics/1927/summary/}}</ref>}} Compton and Alfred W. Simon developed the method for observing at the same instant individual scattered X-ray photons and the [[recoil]] [[electron]]s. In Germany, [[Walther Bothe]] and [[Hans Geiger]] independently developed a similar method.{{sfn|Allison|1965|pp=84–86}}

=== X-rays ===
[[File:Alvarez and Compton.jpeg|thumb|Compton at the University of Chicago in 1933 with graduate student [[Luis Walter Alvarez|Luis Alvarez]] next to his cosmic ray telescope]]

In 1923, Compton moved to the [[University of Chicago]] as Professor of Physics,<ref name="Nobel">{{cite web |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1927/compton-bio.html  |title=Arthur H. Compton – Biography |publisher=Nobel Foundation |access-date=March 19, 2013}}</ref> a position he would occupy for the next 22 years.{{sfn|Allison|1965|pp=84–86}} In 1925, he demonstrated that the scattering of 130,000-volt X-rays from the first sixteen elements in the [[periodic table]] (hydrogen through sulfur) were [[Polarization (waves)|polarized]], a result predicted by J. J. Thomson. [[William Duane (physicist)|William Duane]] from [[Harvard University]] spearheaded an effort to prove that Compton's interpretation of the Compton effect was wrong. Duane carried out a series of experiments to disprove Compton, but instead found evidence that Compton was correct. In 1924, Duane conceded that this was the case.{{sfn|Allison|1965|pp=84–86}}

Compton investigated the effect of X-rays on the sodium and chlorine nuclei in [[salt]]. He used X-rays to investigate [[ferromagnetism]], concluding that it was a result of the alignment of [[electron spin]]s.{{sfn|Allison|1965|pp=87–88}} In 1926, he became a consultant for the Lamp Department at [[General Electric]]. In 1934, he returned to England as Eastman visiting professor at [[Oxford University]]. While there, General Electric asked him to report on activities at [[General Electric Company plc]]'s research laboratory at [[Wembley]]. Compton was intrigued by the possibilities of the research there into [[fluorescent lamp]]s. His report prompted a research program in America that developed it.{{sfn|Allison|1965|pp=88–89}}<ref>{{cite web |url=http://www.americanrhodes.org/info.html |title=Eastman Professorship |publisher=The Association of American Rhodes Scholars |access-date=July 26, 2013 }}</ref>

Compton's first book, ''X-Rays and Electrons'', was published in 1926. In it he showed how to calculate the densities of diffracting materials from their X-ray diffraction patterns.{{sfn|Allison|1965|pp=87–88}}  He revised his book with the help of [[Samuel K. Allison]] to produce ''X-Rays in Theory and Experiment'' (1935). This work remained a standard reference for the next three decades.{{sfn|Allison|1965|p=90}}

=== Cosmic rays ===
By the early 1930s, Compton had become interested in [[cosmic ray]]s. At the time, their existence was known but their origin and nature remained speculative. Their presence could be detected using a spherical "bomb" containing compressed air or argon gas and measuring its electrical conductivity. Trips to Europe, India, Mexico, Peru and Australia gave Compton the opportunity to measure cosmic rays at different altitudes and latitudes. Along with other groups who made observations around the globe, they found that cosmic rays were 15% more intense at the poles than at the equator. In September 1932, Compton attributed this to the effect of cosmic rays being made principally of charged particles, rather than photons as [[Robert Millikan]] had suggested, with the latitude effect being due to [[Earth's magnetic field]]. This resulted in a public altercation between Millikan and Compton in December. Ultimately, Compton was proven correct.{{sfn|Compton|1967|pp=157–163}}<ref>{{cite web |title=How the First American Science Writer Found (Then Lost) God in the Cosmic Ray  |publisher= Science History Institute |url=https://www.sciencehistory.org/stories/magazine/cosmic-rays-william-laurence-robert-millikan-arthur-compton/ |access-date=27 March 2025}}</ref><ref>{{cite news |newspaper=The New York Times |title=Millikan Retorts Hotly to Compton in Cosmic Ray Clash; Debate of Rival Theorists Brings Drama to Session of Nation's Scientists |first=William L. |last=Laurence |author-link=William L. Laurence  |date=31 December 1932 |url=https://timesmachine.nytimes.com/timesmachine/1932/12/31/100886110.html |access-date=27 March 2025}}</ref>

== Manhattan Project ==
[[File:Compton ID badge.JPG|thumb|left|upright|Arthur Compton's ID badge from the Hanford Site. For security reasons he used a pseudonym.]]
In April 1941, [[Vannevar Bush]], head of the wartime [[National Defense Research Committee]] (NDRC), created a special committee headed by Compton to report on the NDRC uranium program. Compton's report, which was submitted in May 1941, foresaw the prospects of developing [[radiological weapon]]s, [[nuclear propulsion]] for ships, and [[nuclear weapons]] using [[uranium-235]] or the recently discovered [[plutonium]].{{sfn|Hewlett|Anderson|1962|pp=36–38}} In October he wrote another report on the practicality of an atomic bomb. For this report, he worked with [[Enrico Fermi]] on calculations of the [[critical mass]] of uranium-235, conservatively estimating it to be between {{convert|20|kg}} and {{convert|2|t}}. He also discussed the prospects for [[uranium enrichment]] with [[Harold Urey]], spoke with [[Eugene Wigner]] about how plutonium might be produced in a [[nuclear reactor]], and with [[Robert Serber]] about how the plutonium produced in a reactor might be separated from uranium. His report, submitted in November, stated that a bomb was feasible, although he was more conservative about its destructive power than [[Mark Oliphant]] and his British colleagues.{{sfn|Hewlett|Anderson|1962|pp=46–49}}

The final draft of Compton's November report made no mention of using plutonium, but after discussing the latest research with [[Ernest Lawrence]], Compton became convinced that a plutonium bomb was also feasible. In December, Compton was placed in charge of the plutonium project.{{sfn|Hewlett|Anderson|1962|pp=50–51}} He hoped to achieve a controlled [[chain reaction]] by January 1943, and to have a bomb by January 1945. To tackle the problem, he had the research groups working on plutonium and nuclear reactor design at [[Columbia University]],  Princeton University and the [[University of California, Berkeley]], concentrated together as the [[Metallurgical Laboratory]] in Chicago. Its objectives were to produce reactors to convert uranium to plutonium, to find ways to chemically separate the plutonium from the uranium, and to design and build an [[atomic bomb]].{{sfn|Hewlett|Anderson|1962|pp=54–55}}

In June 1942, the [[United States Army Corps of Engineers]] assumed control of the nuclear weapons program and Compton's Metallurgical Laboratory became part of the Manhattan Project.{{sfn|Hewlett|Anderson|1962|pp=74–75}} That month, Compton gave [[Robert Oppenheimer]] responsibility for bomb design.{{sfn|Hewlett|Anderson|1962|p=103}} It fell to Compton to decide which of the different types of reactor designs that the Metallurgical Laboratory scientists had devised should be pursued, even though a successful reactor had not yet been built.{{sfn|Hewlett|Anderson|1962|pp=180–181}}

When labor disputes delayed construction of the Metallurgical Laboratory's new home in the [[Palos Forest Preserves|Argonne Forest preserve]], Compton decided to build [[Chicago Pile-1]], the first nuclear reactor, under the stands at [[Stagg Field]].{{sfn|Hewlett|Anderson|1962|pp=108–109}} Under Fermi's direction, it went critical on December 2, 1942.{{sfn|Hewlett|Anderson|1962|p=174}} Compton arranged for [[Mallinckrodt]] to undertake the purification of uranium ore,{{sfn|Allison|1965|p=92}} and with [[DuPont]] to build the plutonium semi-works at [[Oak Ridge, Tennessee]].{{sfn|Hewlett|Anderson|1962|pp=190–191}}

A major crisis for the plutonium program occurred in July 1943, when [[Emilio Segrè]]'s group confirmed that plutonium created in the [[X-10 Graphite Reactor]] at Oak Ridge contained high levels of [[plutonium-240]]. Its [[spontaneous fission]] ruled out the use of plutonium in a [[gun-type nuclear weapon]]. Oppenheimer's [[Los Alamos Laboratory]] met the challenge by designing and building an [[implosion-type nuclear weapon]].{{sfn|Hewlett|Anderson|1962|pp=46–49}}

[[File:Arthur H. Compton House (7373049818).jpg|thumb|right|Compton's house in Chicago, now a national landmark]]
Compton was at the [[Hanford site]] in September 1944 to watch the first reactor being brought online. The first batch of uranium slugs was fed into Reactor B at Hanford in November 1944, and shipments of plutonium to Los Alamos began in February 1945.{{sfn|Hewlett|Anderson|1962|pp=304–310}} Throughout the war, Compton would remain a prominent scientific adviser and administrator. In 1945, he served, along with Lawrence, Oppenheimer, and Fermi, on the Scientific Panel that recommended military use of the atomic bomb against Japan.<ref>{{cite web |url=http://www.nuclearfiles.org/menu/key-issues/nuclear-weapons/history/pre-cold-war/interim-committee/interim-committee-recommendations_1945-06-16.htm |title=Recommendations on the Immediate Use of Nuclear Weapons |publisher=nuclearfiles.org |access-date=July 27, 2013 |archive-date=December 22, 2017 |archive-url=https://web.archive.org/web/20171222190536/http://www.nuclearfiles.org/menu/key-issues/nuclear-weapons/history/pre-cold-war/interim-committee/interim-committee-recommendations_1945-06-16.htm |url-status=dead }}</ref> He was awarded the [[Medal for Merit]] for his services to the Manhattan Project.{{sfn|Allison|1965|p=93}}

== Return to Washington University ==
After the war ended, Compton resigned his chair as Charles H. Swift Distinguished Service Professor of Physics at the University of Chicago and returned to Washington University in St. Louis, where he was inaugurated as the university's ninth chancellor in 1946.{{sfn|Allison|1965|p=93}} During Compton's time as chancellor, the university formally desegregated its undergraduate divisions in 1952, named its first female full professor, and enrolled record numbers of students as wartime veterans returned to the United States. His reputation and connections in national scientific circles allowed him to recruit many nationally renowned scientific researchers to the university. Despite Compton's accomplishments, he was criticized then, and subsequently by historians, for moving too slowly toward full [[racial integration]], making Washington University the last major institution of higher learning in St. Louis to open its doors to [[African American]]s.<ref>{{cite journal |first=Amy M. |last=Pfeiffenberger |title=Democracy at Home: The Struggle to Desegregate Washington University in the Postwar Era |journal=Gateway-Heritage |publisher=Missouri Historical Society|volume=10 |issue=3 |date=Winter 1989 |pages=17–24}}</ref>

Compton retired as chancellor in 1954, but remained on the faculty as Distinguished Service Professor of Natural Philosophy until his retirement from the full-time faculty in 1961. In retirement he wrote ''Atomic Quest'', a personal account of his role in the Manhattan Project, which was published in 1956.{{sfn|Allison|1965|p=93}}

== Philosophy ==
Compton was one of a handful of scientists and philosophers to propose a two-stage model of [[free will]]. Others include [[William James]], [[Henri Poincaré]], [[Karl Popper]], [[Henry Margenau]], and [[Daniel Dennett]].<ref>{{cite web |url=http://www.informationphilosopher.com/freedom/two-stage_models.html |title=Two-Stage Models for Free Will |publisher=The Information Philosopher |access-date=July 27, 2013}}</ref> In 1931, Compton championed the idea of human freedom based on [[quantum indeterminacy]], and invented the notion of amplification of microscopic quantum events to bring [[Indeterminism|chance]] into the macroscopic world. In his somewhat bizarre mechanism, he imagined sticks of dynamite attached to his amplifier, anticipating the [[Schrödinger's cat]] paradox, which was published in 1935.<ref>{{cite journal|journal=Science|volume= 74|issue=1911|pmid=17808216|doi=10.1126/science.74.1911.172 |page=172|title=The Uncertainty Principle and Free Will |date=August 14, 1931|last1=Compton|first1=A. H.|bibcode = 1931Sci....74..172C |s2cid= 29126625}}</ref>

Reacting to criticisms that his ideas made chance the direct cause of people's actions, Compton clarified the two-stage nature of his idea in an ''[[Atlantic Monthly]]'' article in 1955. First there is a range of random possible events, then one adds a determining factor in the act of choice.{{sfn|Compton|1967|p=121}}{{blockquote|A set of known physical conditions is not adequate to specify precisely what a forthcoming event will be. These conditions, insofar as they can be known, define instead a range of possible events from among which some particular event will occur. When one exercises freedom, by his act of choice he is himself adding a factor not supplied by the physical conditions and is thus himself determining what will occur. That he does so is known only to the person himself. From the outside one can see in his act only the working of physical law. It is the inner knowledge that he is in fact doing what he intends to do that tells the actor himself that he is free.{{sfn|Compton|1967|p=121}}}}

==Religious views==
Compton was a [[Presbyterianism|Presbyterian]].<ref name="Blackwood 1988">{{cite journal|author=Blackwood, James R.|year=1988|title=Arthur Compton's Atomic Venture|journal=American Presbyterians|url=https://www.jstor.org/stable/23330520|volume=66|issue=3|pages=177–193|jstor=23330520}}</ref> His father Elias was an ordained Presbyterian minister.<ref name="Blackwood 1988"/>

Compton lectured on a "Man's Place in God's World" at [[Yale University]], [[Western Theological Seminary]] and the [[University of Michigan]] in 1934–35.<ref name="Blackwood 1988"/> The lectures formed the basis of his book ''The Freedom of Man''. His chapter "Death, or Life Eternal?" argued for Christian immortality and quoted verses from the Bible.<ref name="Blackwood 1988"/><ref>Eikner, Allen V. (1980). ''Religious Perspectives and Problems An Introduction to the Philosophy of Religion''. University Press of America. pp. 194–203. {{ISBN|978-0-8191-1215-6}}</ref> From 1948 to 1962, Compton was an elder of the [[Second Presbyterian Church (St. Louis, Missouri)|Second Presbyterian Church]] in St. Louis.<ref name="Blackwood 1988"/> In his later years, he co-authored the book ''Man's Destiny in Eternity''. Compton set [[Jesus]] as the center of his faith in God's eternal plan.<ref name="Blackwood 1988"/> He once commented that he could see Jesus' spirit at work in the world as an aspect of God alive in men and women.<ref name="Blackwood 1988"/>

== Death and recognition ==
[[File:CGRO s37-96-010.jpg|thumb|The [[Compton Gamma Ray Observatory]] released into Earth's orbit in 1991]]

Compton died of a [[cerebral hemorrhage]] on March 15, 1962, in [[Berkeley, California]], at the age of 69. He was outlived by his wife (who died in 1980) and sons. Compton is buried in the Wooster Cemetery in [[Wooster, Ohio]].{{sfn|Allison|1965|p=94}} Before his death, he was professor-at-large at the [[University of California, Berkeley]] for spring 1962.<ref>{{cite web|title=Arthur Holly Compton: Systemwide|url=http://texts.cdlib.org/view?docId=hb0580022s&doc.view=frames&chunk.id=div00003&toc.depth=1&toc.id=|publisher=California Digital Library|access-date=May 24, 2017}}</ref>

Compton received many awards in his lifetime, including the [[Nobel Prize in Physics]] in 1927, the [[Matteucci Medal]] in 1930, and the [[Hughes Medal]] and the [[Franklin Medal]] in 1940.{{sfn|Allison|1965|p=97}} He was elected to the [[American Philosophical Society]] in 1925,<ref>{{Cite web |title=APS Member History |url=https://search.amphilsoc.org/memhist/search?creator=Arthur+H.+Compton&title=&subject=&subdiv=&mem=&year=&year-max=&dead=&keyword=&smode=advanced |access-date=2023-08-14 |website=search.amphilsoc.org}}</ref> the [[National Academy of Sciences]] in 1927,<ref>{{Cite web |title=Arthur H. Compton |url=http://www.nasonline.org/member-directory/deceased-members/20001724.html |access-date=2023-08-14 |website=www.nasonline.org}}</ref> and the [[American Academy of Arts and Sciences]] in 1928.<ref>{{Cite web |date=2023-02-09 |title=Arthur Holly Compton |url=https://www.amacad.org/person/arthur-holly-compton |access-date=2023-08-14 |website=American Academy of Arts & Sciences |language=en}}</ref> He is commemorated in various ways. [[Compton (crater)|Compton crater]] on the [[Moon]] is co-named for Compton and his brother, Karl.<ref>{{cite web |url=https://the-moon.us/wiki/Compton |title=Compton |publisher=Tangient LLC |access-date=July 27, 2013}}</ref> The physics research building at Washington University in St Louis is named in his honor,<ref>{{cite web |url=http://wustl.edu/community/visitors/tour/danforth/compton-laboratory.html |title=Arthur Holly Compton Laboratory of Physics |publisher=[[Washington University in St. Louis]] |access-date=July 27, 2013}}</ref> as is the university's top fellowship for undergraduate students studying math, physics, or planetary science.<ref>{{cite web |url=https://admissions.wustl.edu/Financial_Aid_Scholarships/First_Year_Academic_Scholarships/Pages/Honorary-Scholars-Program.aspx |title=Honorary Scholars Program in Arts and Sciences |publisher=[[Washington University in St. Louis]] |access-date=March 25, 2018 |archive-url=https://web.archive.org/web/20180215155111/https://admissions.wustl.edu/Financial_Aid_Scholarships/First_Year_Academic_Scholarships/Pages/Honorary-Scholars-Program.aspx |archive-date=February 15, 2018 |url-status = dead}}</ref> Compton invented a more gentle, elongated, and ramped version of the [[speed bump]] called the "Holly hump", many of which were installed on the roads of the Washington University campus. However, they were later removed.<ref>{{Cite web |title=What are the Compton Speed Bumps? - Ask Us! |url=https://libanswers.wustl.edu/faq/76174 |access-date=2025-12-18 |website=libanswers.wustl.edu}}</ref> The University of Chicago remembered Compton and his achievements by dedicating the [[Arthur H. Compton House]] in his honor.<ref>{{cite web|url=http://compton-house.uchicago.edu |archive-url=https://web.archive.org/web/20051201170053/http://compton-house.uchicago.edu/ |url-status = dead|archive-date=December 1, 2005 |title=Compton House |publisher=[[University of Chicago]] |access-date=July 27, 2013 }}</ref> It is now listed as a [[National Historic Landmark]].<ref>{{cite web|url=http://tps.cr.nps.gov/nhl/detail.cfm?ResourceId=1613&ResourceType=Building |title=Compton, Arthur H., House |access-date=July 27, 2013 |work=National Historic Landmark summary listing |publisher=National Park Service |url-status = dead|archive-url=https://web.archive.org/web/20120212012307/http://tps.cr.nps.gov/nhl/detail.cfm?ResourceId=1613&ResourceType=Building |archive-date=February 12, 2012 }}</ref> Compton also has a star on the [[St. Louis Walk of Fame]].<ref>{{cite web|url=http://www.stlouiswalkoffame.org/inductees/?view=achievement|title=St. Louis Walk of Fame Inductees|last=St. Louis Walk of Fame|publisher=stlouiswalkoffame.org|access-date=April 25, 2013|archive-url=https://web.archive.org/web/20121031162946/http://www.stlouiswalkoffame.org/inductees/?view=achievement|archive-date=October 31, 2012|url-status = dead}}</ref> [[NASA]]'s [[Compton Gamma Ray Observatory]] was named in honor of Compton. The Compton effect is central to the [[gamma ray]] detection instruments aboard the observatory.<ref>{{cite web |url=http://heasarc.gsfc.nasa.gov/docs/cgro/index.html |publisher=[[NASA]] |title=The CGRO Mission (1991–2000) |access-date=July 27, 2013}}</ref>

== Bibliography ==
* {{cite book |last=Compton |first=Arthur |year=1926 |title=X-Rays and Electrons: An Outline of Recent X-Ray Theory |url=https://archive.org/details/in.ernet.dli.2015.222780 |location=New York |publisher=D. Van Nostrand Company, Inc |oclc=1871779 |ref=none }}
* {{cite book |last1=Compton |first1=Arthur |year=1935 |last2=with Allison |first2=S. K. |author-link2=Samuel King Allison |title=X-Rays in Theory and Experiment |location=New York |publisher=D. Van Nostrand Company, Inc. |oclc=853654 |ref=none }}
* {{cite book |last=Compton |first=Arthur |year=1935 |title=The Freedom of Man |location=New Haven |publisher=Yale University Press |oclc=5723621 |url = https://archive.org/details/freedomofman0000arth |url-access = registration   |ref=none  |via = [[Internet Archive]]}}
* {{cite book |last=Compton |first=Arthur |year=1940 |title=The Human Meaning of Science |location=Chapel Hill |publisher=University of North Carolina Press |oclc=311688|ref=none }}
* {{cite book |last=Compton |first=Arthur |year=1949 |title=Man's Destiny in Eternity |url=https://archive.org/details/mansdestinyinete0000unse/page/n5/mode/2up |url-access= registration  |location=Boston |publisher=Beacon Press |oclc=4739240 |ref=none }}
* {{cite book |last=Compton |first=Arthur |year=1956 |title=Atomic Quest |url=https://archive.org/details/atomicquestperso0000comp |url-access=registration |location=New York |publisher=Oxford University Press |oclc=173307 |ref=none }}
* {{cite book |last=Compton |first=Arthur |year=1967 |title=The Cosmos of Arthur Holly Compton |url= https://archive.org/details/cosmosofarthurho00comp |url-access=registration |location=New York |publisher=Alfred A. Knopf |editor-first=Marjorie |editor-last=Johnston |oclc=953130 }}
* {{cite book |last=Compton |first=Arthur |year=1973 |title=Scientific Papers of Arthur Holly Compton |location=Chicago: University of Chicago Press |url= https://archive.org/details/scientificpapers0000comp |url-access= registration |editor-first=Robert S. |editor-last=Shankland |editor-link=Robert S. Shankland |isbn=978-0-226-11430-9 |oclc=962635 |ref=none |publisher=University of Chicago Press }}

==Footnotes==

{{notelist-la}}
== Notes ==

{{reflist}}

== References==
* {{cite journal |last=Allison |first =Samuel K. |author-link=Samuel King Allison |year=1965 |title=Arthur Holly Compton 1892–1962 |journal=Biographical Memoirs |volume=38 |pages=81–110 |publisher=National Academy of Sciences |issn=0077-2933 |oclc=1759017}}
* {{cite book |last=Gamow |first=George |author-link=George Gamow |year=1966 |title=Thirty Years That Shook Physics: The Story of Quantum Theory |publisher=Doubleday |location=Garden City, New York |isbn=0-486-24895-X |oclc=11970045}}
* {{cite book |last1=Hewlett |first1=Richard G. |author-link=Richard G. Hewlett |last2=Anderson |first2=Oscar E. |title=The New World: A History of the United States Atomic Energy Commission, Volume I 1939–1946 |url=https://www.governmentattic.org/5docs/TheNewWorld1939-1946.pdf |access-date=March 26, 2013 |location=University Park |publisher=[[Pennsylvania State University]] Press |year=1962 |oclc=637004643}} {{isbn|0-520-07186-7 }}
* {{cite book |last=Hockey |first=Thomas |title=The Biographical Encyclopedia of Astronomers  |year=2007 |publisher=[[Springer Publishing]] |isbn=978-0-387-31022-0 |access-date=August 22, 2012 |url=https://books.google.com/books?id=t-BF1CHkc50C&pg=PA244 |oclc=263669996}}

==Further reading==
* {{cite journal |last=Bernstein |first=Barton J. |author-link=Barton J. Bernstein |title=Four Physicists and the Bomb: The Early Years, 1945–1950  |journal=Historical Studies in the Physical and Biological Sciences |year=1988 |volume=18 |issue=2 |pages=231–263 |doi=10.2307/27757603 |jstor=27757603 |ref=none}}; covers Oppenheimer, Fermi, Lawrence and Compton. 
* {{cite journal |last1=Galison |first1=Peter |author-link1=Peter Galison |last2=Bernstein |first2=Barton J. |author-link2=Barton J. Bernstein |title=In any light: Scientists and the decision to build the Superbomb, 1952–1954 |journal=Historical Studies in the Physical and Biological Sciences |volume=19 |issue=2 |year=1989 |pages=267–347 |doi=10.2307/27757627 |jstor=27757627  |ref=none}}

== External links ==
*{{Commons category-inline}}
{{Wikiquote}}
{{Portal|Biography|History of Science|Nuclear technology|Physics}}
* [https://books.google.com/books?id=QSgDAAAAMBAJ "Strange Instrument Built to Solve Mystery of Cosmic Rays", April 1932, ''Popular Science''] article about Compton on research on cosmic rays
* [https://web.archive.org/web/20130303214641/http://www.wustl.edu/about/facts/chancellors/compton.html Arthur Compton biographical entry] at Washington University in St. Louis
* [https://web.archive.org/web/20051125115411/http://alsos.wlu.edu/qsearch.aspx?browse=people%2FCompton%2C+Arthur Annotated bibliography for Arthur Compton from the Alsos Digital Library for Nuclear Issues]
* [http://www.informationphilosopher.com/solutions/scientists/compton/ Arthur Holly Compton on Information Philosopher]
* {{Nobelprize}}
* [http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/compton-arthur-h.pdf National Academy of Sciences Biographical Memoir]
* {{find a Grave|22551}}
*[https://www.lib.uchicago.edu/e/scrc/findingaids/view.php?eadid=ICU.SPCL.COMPTONAH Guide to the Arthur Holly Compton Papers 1918–1964] at the [https://www.lib.uchicago.edu/scrc/ University of Chicago Special Collections Research Center]
*{{Internet Archive author |sname = Arthur Compton}}

{{Nobel Prize in Physics Laureates 1926–1950}}
{{1927 Nobel Prize winners}}
{{Presidents of the American Physical Society}}
{{Presidents of the American Association for the Advancement of Science}}
{{Manhattan Project}}
{{Washington University in Saint Louis chancellors}}
{{Authority control}}

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[[Category:1892 births]]
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