Famous American Scientists Of The 20th Century

The 20th century America was one of the major hubs of scientific and technological developments in the world. In the early part of the century, many prominent European scientists including Hans Bethe, Albert Einstein, Enrico Fermi, Leó Szilárd, Edward Teller, and Felix Bloch migrated to the United States where they accomplished several important achievements. During this era, scientists in the US made one highly controversial yet commendable accomplishment—the harnessing of nuclear energy. Gerald Woodrow Johnson, William Howard Arnold, and Charles Kincaid Bockelman were some of the established nuclear scientists of 20th century. America was also a pioneer in computer technology and information technology. Pioneers like John McCarthy who was one of the founders of the discipline of artificial intelligence played a major role in accelerating America’s progress in the area of computer science. Grace Brewster Murray Hopper, born in the early 20th century, was one of the first programmers of the Harvard Mark I computer. Americans have led the world in physics as well with the likes of Alan Harvey Guth, Steven Weinberg, and Sam Bard Treiman making important contributions to the field. Read on to learn more about the life and works of famous American scientists of the 20th century.

This ranking is based on an algorithm that combines various factors, including the votes of our users and search trends on the internet.

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 1 Albert Einstein

Albert Einstein.
46
Famous As: Physicist
Birthdate: March 14, 1879
Sun Sign: Pisces
Birthplace: Ulm, Germany
Died: April 18, 1955
Deemed as the most influential physicist of the 20th century, the German-born physicist Albert Einstein was one of the greatest minds to have ever lived. Even his name is now synonymous with the term genius. The father of Modern Physics is credited with developing the theory of relativity and explaining the photoelectric effect. The latter won him the Nobel Prize.

 2 Nikola Tesla

Nikola Tesla.
20
Famous As: Inventor
Birthdate: July 10, 1856
Sun Sign: Cancer
Birthplace: Smiljan, Croatia
Died: January 7, 1943

Inventor, engineer and futurist, Nikola Tesla, is best remembered for his contribution to the development of the modern alternating current (AC) electricity supply system. A prolific inventor, he had around 300 patents for his inventions. Even though he earned a considerable amount of money, he had poor money management skills and died a poor man.

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 3 Neil deGrasse Tyson

Neil deGrasse Tyson.
18
Famous As: Astrophysicist
Birthdate: October 5, 1958
Sun Sign: Libra
Birthplace: Manhattan, New York, United States

Public Welfare Medal-winning astrophysicist and academic Neil deGrasse Tyson hosted shows such as NOVA ScienceNow, Cosmos: A Spacetime Odyssey, and Star Talk. He is the director of Hayden Planetarium and contributed to the dismissal of Pluto’s status as the ninth planet. He has also written a monthly column as "Merlin.”

 4 Carl Sagan

Carl Sagan.
26
Famous As: Astronomer, Astrophysicist, Writer
Birthdate: November 9, 1934
Sun Sign: Scorpio
Birthplace: Brooklyn, New York, U.S.
Died: December 20, 1996
Pulitzer- and Emmy-winning astrophysicist and author Carl Sagan was best known for co-writing the TV series Cosmos: A Personal Voyage. His novel Contact was adapted into a film. He was known for his extensive research on extra-terrestrial life, had taught at major universities, and written countless papers and science books.

 5 Bill Gates

Bill Gates.
6
Famous As: Co-Founder of Microssoft
Birthdate: October 28, 1955
Sun Sign: Scorpio
Birthplace: Seattle, Washington, United States

Leading American technologist, business leader and philanthropist, Bill Gates is the co-founder of the world’s largest software company, Microsoft. His passion for computers made him one of the richest in the world and through his charity foundation, Bill & Melinda Gates Foundation, he and his ex-wife, Melinda, use this money generously to help people world over live a better life.

 6 John Forbes Nash Jr.

John Forbes Nash Jr..
16
Famous As: Mathematician
Birthdate: June 13, 1928
Sun Sign: Gemini
Birthplace: Bluefield, West Virginia, United States
Died: May 23, 2015
The inspiration behind the movie A Beautiful Mind, John F. Nash was a legendary mathematician whose work in the area of game theory earned him the Nobel Memorial Prize in Economic Sciences. In his later years, he was riddled with mental illness. He later died in a car crash.

 7 Richard Feynman

Richard Feynman.
17
Famous As: Physicist
Birthdate: May 11, 1918
Sun Sign: Taurus
Birthplace: Manhattan, New York City, New York, United States
Died: February 15, 1988

Theoretical physicist Richard Feynman won the Nobel Prize in Physics in 1965, along with Julian Schwinger and Shin'ichirō Tomonaga, for his research on quantum electrodynamics. He also contributed to the development of the atomic bomb. Feyman made it to Physics World’s list of the 10 greatest physicists of all time.

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 8 Steve Wozniak

Steve Wozniak.
6
Famous As: Co-founder of Apple Computer (Apple Inc.)
Birthdate: August 11, 1950
Sun Sign: Leo
Birthplace: San Jose, California, United States

Widely recognized as one of the two important pioneers of the personal computer revolution, Steve Wozniak is credited with co-founding Apple Inc. along with Steve Jobs. Not surprisingly, he has been described as one of the men that changed the course of history through technology. Apart from being a programmer and technology entrepreneur, Steve Wozniak is also a well-known philanthropist.

 9 J. Robert Oppenheimer

J. Robert Oppenheimer.
14
Birthdate: April 22, 1904
Sun Sign: Taurus
Birthplace: New York City, United States
Died: February 18, 1967

Hailed as a brilliant scientific mind, American physicist J Robert Oppenheimer, led the Manhattan Project which resulted in the development of atomic bomb during the World War II. The bombs were dropped on the Japanese cities of Hiroshima and Nagasaki in 1945. However, Oppenheimer was in a constant conflict over the moral issue of the weapons of mass destruction and rallied against nuclear proliferation.

 10 John von Neumann

John von Neumann.
6
Famous As: Mathematician, Computer Scientist
Birthdate: December 28, 1903
Sun Sign: Capricorn
Birthplace: Budapest, Hungary
Died: February 8, 1957
Hungarian-American scientist John von Neumann contributed to the development of game theory and the concept of self-replication. His work covered vast areas including math, economics, physics, and computer science. His research on nuclear physics led him to be part of the advisory committee of the U.S. Atomic Energy Commission.

 11 Claude Shannon

Claude Shannon.
4
Famous As: Mathematician, Cryptographer
Birthdate: April 30, 1916
Sun Sign: Taurus
Birthplace: Petoskey, Michigan, United States
Died: February 24, 2001

Claude Shannon was an electrical engineer, mathematician, and cryptographer. He is credited with publishing the article A Mathematical Theory of Communication which gave rise to the field of information theory. Hence, Shannon is considered the father of information theory. He is also credited with founding digital circuit design theory. During World War II, he contributed to the field of cryptanalysis.

 12 Enrico Fermi

Enrico Fermi.
4
Famous As: Nobel Laureate in Physics
Birthdate: September 29, 1901
Sun Sign: Libra
Birthplace: Rome, Italy
Died: November 28, 1954
Italian physicist Enrico Fermi created the Chicago Pile-1, the world's first nuclear reactor. Known widely as the "architect of the atomic bomb," he was equally proficient in theoretical and experimental physics, and won the 1938 Nobel Prize in Physics for his work on radioactivity and for discovering transuranium elements.

 13 Rachel Carson

Rachel Carson.
4
Famous As: Marine biologist
Birthdate: May 27, 1907
Sun Sign: Gemini
Birthplace: Springdale
Died: April 14, 1964

Rachel Carson was a conservationist, marine biologist, and author. She is credited with authoring an influential book titled Silent Spring, which played a significant role in advancing the global environmental movement. Carson is also remembered for her book, The Sea Around Us, which earned her a U.S. National Book Award. She was posthumously honored with the Presidential Medal of Freedom.

 14 Kurt Gödel

Kurt Gödel.
9
Famous As: Mathematician, Philosopher
Birthdate: April 28, 1906
Sun Sign: Taurus
Birthplace: Brno
Died: January 14, 1978

Hailed as one of the greatest logicians since Aristotle, Kurt Gödel was Austrian-born American mathematician, logician, and philosopher, who earned international stardom for his incompleteness theorem. Also credited with developing a technique called Gödel numbering, he later started working on Mathematical Platonism, a philosophical theory that failed to attract wide acceptance.

 15 Vint Cerf

Vint Cerf.
4
Famous As: Engineer
Birthdate: June 23, 1943
Sun Sign: Cancer
Birthplace: New Haven, Connecticut, United States

 16 Linus Pauling

Linus Pauling.
8
Famous As: Chemist, Biochemist
Birthdate: February 28, 1901
Sun Sign: Pisces
Birthplace: Portland, Oregon, United States
Died: August 19, 1994

Only person to win two unshared Nobel Prizes, Linus Carl Pauling was an American theoretical physical chemist, who received the 1954 Nobel Prize in Chemistry for his work on nature of chemical bond and 1962 Nobel Prize for Peace for his efforts to stop nuclear weapon testing. Also a prolific writer and educator, he has published 1,200 books and papers.  

 17 Andrew Wiles

Andrew Wiles
17
Famous As: Mathematician, University teacher
Birthdate: April 11, 1953
Sun Sign: Aries
Birthplace: Cambridge

English mathematician Sir Andrew John Wiles, a Royal Society Research Professor at the University of Oxford, is best known for proving the modularity theorem for semistable elliptic curves, thereby proving Fermat's Last Theorem for which he was awarded the Abel Prize and the Copley Medal by the Royal Society. He also proved the main conjecture of Iwasawa theory.

 18 Grace Hopper

Grace Hopper.
15
Famous As: Computer Scientist
Birthdate: December 9, 1906
Sun Sign: Sagittarius
Birthplace: New York City
Died: January 1, 1992
Computer scientist and U.S. Navy rear admiral Grace Hopper was one of the first programmers of the Harvard Mark I computing system. She pioneered the machine-independent programming language technique, and the FLOW-MATIC language used by her was later used to create COBOL. She received a posthumous Presidential Medal of Freedom.

 19 Katherine Johnson

Katherine Johnson.
33
Famous As: Mathematician
Birthdate: August 26, 1918
Sun Sign: Virgo
Birthplace: White Sulphur Springs, West Virginia, United States
Died: February 24, 2020
Katherine Johnson was a physicist and mathematician, remembered as the first African-American female NASA scientist. Her calculations helped launch the space missions of Alan Shepard and John Glenn. She was crucial to the Apollo program and won a Congressional Gold Medal and a Presidential Medal of Freedom for her achievements.

 20 E. O. Wilson

E. O. Wilson.
6
Famous As: Biologist
Birthdate: June 10, 1929
Sun Sign: Gemini
Birthplace: Birmingham

E. O. Wilson is an American naturalist, biologist, and writer. An influential biologist, Wilson has earned several nicknames, such as The Darwin of the 21st century. He has also been referred to as the father of biodiversity and the father of sociobiology. In 1995, he was ranked among the most influential American personalities by Time magazine.

 21 Isaac Asimov

Isaac Asimov.
11
Famous As: Novelist, Professor
Birthdate: January 2, 1920
Sun Sign: Capricorn
Birthplace: Petrovichi, Russia
Died: April 6, 1992

Isaac Asimov was an American writer. Best known for his science fiction works, Asimov was regarded as one of the Big Three writers along with Arthur C. Clarke and Robert A. Heinlein. Asimov is credited with influencing most sci-fi writers since the 1950s. Nobel Prize winner Paul Krugman stated that one of Asimov's works inspired him to take up Economics.

 22 Dennis Ritchie

Dennis Ritchie.
9
Famous As: Computer Scientist
Birthdate: September 9, 1941
Sun Sign: Virgo
Birthplace: Bronxville, New York, United States
Died: October 12, 2011

Computer scientist, Dennis MacAlistair Ritchie, worked at Bell Labs Computing Sciences Research Center for most of his career, co-developing the Unix operating system and B programming language with Kenneth Thompson, co-winning the 1983 A.M. Turing Award for it. Earlier, he had also created C programming language and was involved with the development of the Plan 9 and Inferno operating systems.

 23 Ken Thompson

Ken Thompson.
9
Famous As: Computer Scientist
Birthdate: February 4, 1943
Sun Sign: Aquarius
Birthplace: New Orleans, Louisiana, United States

 24 Wernher Von Braun

Wernher Von Braun.
4
Famous As: Aerospace Engineer
Birthdate: March 23, 1912
Sun Sign: Aries
Birthplace: Wyrzysk, Poland
Died: June 16, 1977

German-born American aerospace engineer and space architect, Wernher Von Braun, worked in Nazi Germany's rocket development program as a young man. After World War II, he moved to the United States where he became a pioneer of rocket and space technology in the nation. In his later career, he became director of the newly formed Marshall Space Flight Center.

 25 Jonas Salk

Jonas Salk.
5
Famous As: Medical researcher
Birthdate: October 28, 1914
Sun Sign: Scorpio
Birthplace: New York City, New York, United States
Died: June 23, 1995

If the world is successful in its fight against polio, the credit goes to American virologist Jonas Salk who developed a vaccine for the disease. Described as a “miracle worker”, his concerns for humanity were reflected in the fact that he did not claim a patent for the vaccine. He founded the Salk Institute for Biological Studies, based in California.

 26 Mary Jackson

Mary Jackson
7
Famous As: Mathematician
Birthdate: April 9, 1921
Sun Sign: Aries
Birthplace: Hampton, Virginia, United States
Died: February 11, 2005

American mathematician and aerospace engineer Mary Jackson went down in history as the first African-American woman to work as a NASA engineer. Initially a math teacher, she later joined NACA under Dorothy Vaughan and contributed to countless American space programs at a time when racial segregation was the norm.

 27 Har Gobind Khorana

Har Gobind Khorana.
4
Birthdate: January 9, 1922
Sun Sign: Capricorn
Birthplace: Punjab, India
Died: November 9, 2011

Born into a poor family in British India, Har Gobind Khorana studied on scholarships and later bagged a seat at the University of Liverpool and thus moved to England. The renowned biochemist ended up winning the Nobel Prize for his research on how nucleotides in nucleic acids control protein synthesis.

 28 Benoit Mandelbrot

Benoit Mandelbrot
19
Famous As: Mathematician, Economist, Professor, Scientist, Writer, Computer scientist
Birthdate: November 20, 1924
Sun Sign: Scorpio
Birthplace: Warsaw
Died: October 14, 2010

Noted mathematician and polymath, Benoit B. Mandelbrot is perhaps best known for his work on fractal. He not only coined the term, but also used computer-constructed images to illustrate the mathematical definition. Also credited with the discovery of Mandelbrot set and Mandelbrot law, he established that even those things which were apparently chaotic or rough had a "degree of order".

 29 Tom Lehrer

Tom Lehrer.
12
Famous As: American musician
Birthdate: April 9, 1928
Sun Sign: Aries
Birthplace: New York, Manhattan

While he grew up to be a Harvard math professor, that didn’t stop Tom Lehrer from pursuing his childhood love for music. He gained fame as a satirical composer, with songs such as So Long, Mom, I’m Off to Drop the Bomb and That Was The Year That Was.

 30 Michio Kaku

Michio Kaku
13
Famous As: Theoretical physicist, Science writer, Popularizer of science, Futurist, University teacher, Non-fiction writer, Radio personality
Birthdate: January 24, 1947
Sun Sign: Aquarius
Birthplace: San Jose

Apart from teaching at the City College of New York, theoretical physicist Michio Kaku also often pens his thoughts in blogs and has written several bestselling books, such as The God Equation. His research is focused on the string theory. He also believes in the existence of aliens.

 31 Vera Rubin

Vera Rubin
4
Famous As: Astronomer
Birthdate: July 23, 1928
Sun Sign: Leo
Birthplace: Philadelphia, Pennsylvania
Died: December 25, 2016

American astronomer Vera Rubin is best known for her pioneering discoveries on galaxy rotation rates, her groundbreaking work confirming the existence of dark matter and for her life-long advocacy for women in science. She studied the galactic rotation curves and provided strong evidence of the existence of dark matter. The Vera C. Rubin Observatory in Chile is named after her.

 32 Dorothy Vaughan

Dorothy Vaughan
28
Famous As: Mathematician
Birthdate: September 20, 1910
Sun Sign: Virgo
Birthplace: Kansas City, Missouri, United States
Died: November 10, 2008

American mathematician Dorothy Vaughan was also known as a "human computer." Initially a math teacher, she became the first African-American supervisor of NACA, later part of NASA, at a time when racial segregation was rampant in the U.S. Her contribution to the early American space programs is invaluable.

 33 Murray Gell-Mann

Murray Gell-Mann.
6
Famous As: Physicist
Birthdate: September 15, 1929
Sun Sign: Virgo
Birthplace: Manhattan, New York City, U.S.
Died: May 24, 2019

Nobel Prize-winning American physicist Murray Gell-Mann is best remembered for his research on elementary particles. The Yale and MIT alumnus later taught at Caltech and is credited with coining the terms "quark" and "strangeness" in quantum physics. A linguistic enthusiast, he also co-established the Evolution of Human Languages program.

 34 John McCarthy

John McCarthy
6
Famous As: Mathematician, Computer scientist, Engineer, University teacher
Birthdate: September 4, 1927
Sun Sign: Virgo
Birthplace: Boston
Died: October 24, 2011

 35 Glenn T. Seaborg

Glenn T. Seaborg.
4
Famous As: Chemist
Birthdate: April 19, 1912
Sun Sign: Aries
Birthplace: Ishpeming, Michigan
Died: February 25, 1999

 36 Alan Kay

Alan Kay.
6
Famous As: Computer Scientist
Birthdate: May 17, 1940
Sun Sign: Taurus
Birthplace: Springfield, Massachusetts

 37 John G. Trump

John G. Trump
5
Famous As: Scientist
Birthdate: August 21, 1907
Sun Sign: Leo
Birthplace: New York, New York, United States
Died: February 21, 1985

Better known as former U.S. president Donald Trump’s uncle, John G. Trump was an MIT physicist and engineer. Though he had initially aspired to be an architect and join his brother Fred’s real-estate business, John later concentrated on his research that led to the invention of high-voltage generators.

 38 Cecilia Payne-Gaposchkin

Cecilia Payne-Gaposchkin
4
Famous As: Astronomer, University teacher
Birthdate: May 10, 1900
Sun Sign: Taurus
Birthplace: Buckinghamshire
Died: December 7, 1979

After losing her father at 4, Cecilia Payne-Gaposchkin was raised singlehandedly by her mother. The incredibly talented Cecilia studied at Cambridge but failed to secure a degree because of her gender. She later joined Harvard and opposing prevalent beliefs, proposed that stars were mainly made of hydrogen and helium. 

 39 Norman Borlaug

Norman Borlaug.
6
Famous As: Father of the Green Revolution
Birthdate: March 25, 1914
Sun Sign: Aries
Birthplace: Cresco, Iowa
Died: September 12, 2009

Norman Borlaug was an American agronomist who played a key role in the Green Revolution, a set of research technology transfer initiatives that increased agricultural production, for which he won the Nobel Peace Prize in 1970. Nicknamed the Father of the Green Revolution, Borlaug was also honored with the Congressional Gold Medal and Presidential Medal of Freedom for his work.

 40 James Watson

James Watson.
11
Famous As: Molecular Biologist
Birthdate: April 6, 1928
Sun Sign: Aries
Birthplace: Chicago, Illinois, United States

James Watson is a geneticist, molecular biologist, and zoologist. He is credited with co-authoring the academic paper that propounded the double helix structure of nucleic acids such as DNA for which he was awarded the Nobel Prize in 1962. In 1977, he was honored with the Presidential Medal of Freedom. In 1997, he was awarded the National Medal of Science.

 41 Zbigniew Brzezinski

Zbigniew Brzezinski.
4
Famous As: Former Diplomat, Political Scientist
Birthdate: March 28, 1928
Sun Sign: Aries
Birthplace: Warsaw
Died: May 26, 2017
Polish-American diplomat Zbigniew Brzezinski had been a counselor to President Lyndon B. Johnson and the National Security Advisor to President Jimmy Carter. He believed in the realist school of international relations. He also taught foreign policy and was seen in programs such as The NewsHour with Jim Lehrer.

 42 Lynn Margulis

Lynn Margulis.
7
Famous As: Author
Birthdate: March 5, 1938
Sun Sign: Pisces
Birthplace: Chicago
Died: November 22, 2011

Lynn Margulis was an evolutionary theorist, biologist, educator, and science author. She was a modern proponent of the significance of symbiosis in evolution. Along with British chemist James Lovelock, Margulis was the co-developer of the Gaia hypothesis. She was a strong critic of neo-Darwinism. In 2001, she was honored with the Golden Plate Award of the American Academy of Achievement. 

 43 Retta

Retta
9
Famous As: Stand-up Comedian
Birthdate: April 12, 1970
Sun Sign: Aries
Birthplace: Newark, New Jersey, U.S.

 44 James Harris Simons

James Harris Simons.
9
Famous As: Mathematicians & Hedge Fund Manager
Birthdate: 1938 AD
Birthplace: Newton

The son of a shoe factory owner, mathematician-turned-hedge-fund-manager James Harris Simons studied math at MIT and helped the U.S. break codes during the Vietnam War. He later founded his own hedge fund firm, Renaissance Technologies. He supports autism research and funds Math for America. In 2021, he was America’s 23rd-richest person.

 45 Hilary Putnam

Hilary Putnam
4
Famous As: Mathematician, Philosopher, University teacher, Non-fiction writer, Computer scientist
Birthdate: July 31, 1926
Sun Sign: Leo
Birthplace: Chicago
Died: March 13, 2016

 46 Robert Stroud

Robert Stroud
4
Famous As: Writer
Birthdate: January 8, 1890
Sun Sign: Capricorn
Birthplace: Seattle, Washington, USA
Died: November 21, 1963

 47 Marvin Minsky

Marvin Minsky
15
Famous As: Mathematician, Computer scientist, University teacher
Birthdate: August 9, 1927
Sun Sign: Leo
Birthplace: New York City
Died: January 24, 2016

 48 Ronald McNair

Ronald McNair
9
Famous As: Physicist, Astronaut
Birthdate: October 21, 1950
Sun Sign: Libra
Birthplace: Lake City
Died: January 28, 1986

A doctorate in physics from MIT Cambridge, Ronald McNair worked on chemical lasers before joining NASA and in 1984 flew as a mission specialist on STS-41-B aboard Challenger, becoming the second African-American to do so. In January 1986, he was selected to fly on STS-51-L, but was killed along with rest of the crews when Challenger disintegrated soon after liftoff.

 49 Sally Ride

Sally Ride.
17
Famous As: First American Woman To Go in Space, Physicist
Birthdate: May 26, 1951
Sun Sign: Gemini
Birthplace: Encino, Los Angeles, California, United States
Died: July 23, 2012
Astronaut and physicist Sally Ride was the first American woman and the youngest American astronaut to enter space. Following her death, it was revealed that she had been in a 27-year lesbian relationship with tennis player and professor Tam O'Shaughnessy. Sally herself was a ranked junior tennis player, too.

 50 Kip Thorne

Kip Thorne.
5
Famous As: Physicist
Birthdate: June 1, 1940
Sun Sign: Gemini
Birthplace: Logan

American theoretical-physicist Kip Thorne, who is noted for his contributions in gravitational physics and astrophysics, is known for Thorne-Żytkow object, Thorne-Hawking-Preskill bet, LIGO, gravitational waves and the book Gravitation. Thorne along with Rainer Weiss and Barry C. Barish received the Nobel Prize in Physics in 2017 for their contributions to the LIGO detector and the observation of gravitational waves.