Carl David Anderson (September 3, 1905 – January 11, 1991) was an American

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

. He is best known for his discovery of the positron in 1932, an achievement for which he received the 1936

Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...

, and of the muon in 1936.

Biography

Anderson was born in

New York City New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the Un ...

, the son of Swedish immigrants. He studied physics and

engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more speciali ...

Caltech The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...

(

B.S. A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University ...

, 1927;

Ph.D. A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is ...

, 1930). Under the supervision of

Robert A. Millikan Robert Andrews Millikan (March 22, 1868 – December 19, 1953) was an American experimental physicist honored with the Nobel Prize for Physics in 1923 for the measurement of the Elementary charge, elementary electric charge and for his work on ...

, he began investigations into

cosmic rays Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our ow ...

during the course of which he encountered unexpected

particle In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. They vary greatly in size or quantity, from ...

tracks in his (modern versions now commonly referred to as an Anderson)

cloud chamber A cloud chamber, also known as a Wilson cloud chamber, is a particle detector used for visualizing the passage of ionizing radiation. A cloud chamber consists of a sealed environment containing a supersaturated vapour of water or alcohol. An ...

photographs that he correctly interpreted as having been created by a particle with the same mass as the

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...

, but with opposite

electrical charge Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...

. This discovery, announced in 1932 and later confirmed by others, validated

Paul Dirac Paul Adrien Maurice Dirac (; 8 August 1902 – 20 October 1984) was an English theoretical physicist who is regarded as one of the most significant physicists of the 20th century. He was the Lucasian Professor of Mathematics at the Univer ...

's theoretical prediction of the existence of the positron. Anderson first detected the particles in

. He then produced more conclusive proof by shooting

gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...

s produced by the natural radioactive nuclide ThC'' ( ²⁰⁸Tl) into other materials, resulting in the creation of positron-electron pairs. For this work, Anderson shared the 1936

with

Victor Hess Victor Franz Hess (; 24 June 188317 December 1964) was an Austrian- American physicist, and Nobel laureate in physics, who discovered cosmic rays. Biography He was born to Vinzenz Hess and Serafine Edle von Grossbauer-Waldstätt, in Waldstei ...

. Fifty years later, Anderson acknowledged that his discovery was inspired by the work of his Caltech classmate

Chung-Yao Chao Chung-Yao Chao (; 27 June 1902 – 28 May 1998) was a Chinese theoretical physicist. He studied the scattering of gamma rays in lead by pair production in 1930, without knowing that positrons were involved in the anomalously high scattering cro ...

, whose research formed the foundation from which much of Anderson's work developed but was not credited at the time. Also in 1936, Anderson and his first graduate student,

Seth Neddermeyer Seth Henry Neddermeyer (September 16, 1907 – January 29, 1988) was an American physicist who co-discovered the muon, and later championed the Implosion-type nuclear weapon while working on the Manhattan Project at the Los Alamos Laborato ...

, discovered a muon (or 'mu-meson', as it was known for many years), a subatomic particle 207 times more massive than the

, but with the same negative electric charge and spin 1/2 as the electron, again in

. Anderson and Neddermeyer at first believed that they had seen a

pion In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: ) is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more gene ...

, a particle which

Hideki Yukawa was a Japanese theoretical physicist and the first Japanese Nobel laureate for his prediction of the pi meson, or pion. Biography He was born as Hideki Ogawa in Tokyo and grew up in Kyoto with two older brothers, two older sisters, and two yo ...

had postulated in his theory of the strong interaction. When it became clear that what Anderson had seen was ''not'' the pion, the physicist

I. I. Rabi Isidor Isaac Rabi (; born Israel Isaac Rabi, July 29, 1898 – January 11, 1988) was an American physicist who won the Nobel Prize in Physics in 1944 for his discovery of nuclear magnetic resonance, which is used in magnetic resonance ima ...

, puzzled as to how the unexpected discovery could fit into any logical scheme of

particle physics Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...

, quizzically asked "Who ordered ''that''?" (sometimes the story goes that he was dining with colleagues at a Chinese restaurant at the time). The muon was the first of a long list of

subatomic particles In physical sciences, a subatomic particle is a particle that composes an atom. According to the Standard Model of particle physics, a subatomic particle can be either a composite particle, which is composed of other particles (for example, a pro ...

whose discovery initially baffled theoreticians who could not make the confusing "zoo" fit into some tidy conceptual scheme.

Willis Lamb Willis Eugene Lamb Jr. (; July 12, 1913 – May 15, 2008) was an American physicist who won the Nobel Prize in Physics in 1955 "for his discoveries concerning the fine structure of the hydrogen spectrum." The Nobel Committee that year awarded hal ...

, in his 1955 Nobel Prize Lecture, joked that he had heard it said that "the finder of a new elementary particle used to be rewarded by a Nobel Prize, but such a discovery now ought to be punished by a 10,000 dollar fine." Anderson spent all of his academic and research career at

. During

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

, he conducted research in

rocket A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely fr ...

ry there. He was elected a Fellow of the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, a ...

in 1950. He received the Golden Plate Award of the

American Academy of Achievement The American Academy of Achievement, colloquially known as the Academy of Achievement, is a non-profit educational organization that recognizes some of the highest achieving individuals in diverse fields and gives them the opportunity to meet ...

in 1975. He died on January 11, 1991, and his remains were interred in the

Forest Lawn, Hollywood Hills Cemetery Forest Lawn Memorial Park – Hollywood Hills is one of the six Forest Lawn cemeteries in Southern California. It is located at 6300 Forest Lawn Drive, Los Angeles, California 90068, in the Hollywood Hills neighborhood of Los Angeles. Histor ...

Los Angeles, California Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

. His wife Lorraine died in 1984.

Select publications

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References

External links

1983 Audio Interview with Carl Anderson by Martin Sherwin
Voices of the Manhattan Project *

American National Biography The ''American National Biography'' (ANB) is a 24-volume biographical encyclopedia set that contains about 17,400 entries and 20 million words, first published in 1999 by Oxford University Press under the auspices of the American Council of Le ...

, vol. 1, pp. 445–446.
Annotated bibliography for Carl David Anderson from the Alsos Digital Library for Nuclear Issues
*

*
National Academy of Sciences Biographical Memoir

Oral History interview transcript with Carl D. Anderson on 30 June 1966, American Institute of Physics, Niels Bohr Library and Archives
* {{DEFAULTSORT:Anderson, Carl David 1905 births 1991 deaths 20th-century American physicists American Nobel laureates American people of Swedish descent Burials at Forest Lawn Memorial Park (Hollywood Hills) California Institute of Technology alumni California Institute of Technology faculty Experimental physicists Fellows of the American Academy of Arts and Sciences Fellows of the American Physical Society John H. Francis Polytechnic High School alumni Nobel laureates in Physics Particle physicists Scientists from California Scientists from New York City Members of the United States National Academy of Sciences