Science & Nature • Astronomy

Arthur Eddington

Arthur Eddington (1882–1944) was an English astronomer, physicist, and mathematician known for his work in astrophysics and for helping explain relativity to English-speaking audiences.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

Arthur Stanley Eddington (28 December 1882 – 22 November 1944) was an English astronomer, physicist, and mathematician known for his work in astrophysics and for helping explain relativity to English-speaking audiences. He also led a 1919 solar eclipse expedition that provided early observational support for Einstein’s general theory of relativity.

Life and career

Eddington was born in Kendal, England, in 1882 and became one of the most prominent astrophysicists of his time. He worked on stellar physics and also helped popularize relativity in the English-speaking world.

Relativity and the 1919 eclipse expedition

In 1919, Eddington organized observations of a total solar eclipse to test whether starlight passing near the Sun was deflected by gravity. The results were widely seen as an early confirmation of general relativity.

Stellar physics

Eddington’s research addressed how stars work, including their internal structure and the relationship between mass and luminosity. He is also associated with early ideas about the source of stellar energy.

Eddington limit and legacy

The Eddington limit, named after him, refers to the maximum luminosity a star or accreting object can sustain before outward radiation pressure overcomes gravity. His name is also attached to several other scientific ideas and measures.

Key facts

Eddington was a leading British astrophysicist of the early 20th century.
He was one of the first major English-language expositors of Einstein’s relativity theory.
His 1919 eclipse expedition helped test the gravitational bending of light predicted by general relativity.
He made influential work on the internal structure, motion, and evolution of stars.
The Eddington limit is named after him.

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Canadian context

Eddington’s work is part of the history of modern astrophysics and relativity taught in Canadian astronomy and physics contexts, but he had no major direct Canadian institutional connection in the sources provided.

Frequently asked questions

Who was Arthur Eddington?

Arthur Eddington was an English astronomer, physicist, and mathematician best known for his work in astrophysics and for promoting and testing Einstein’s theory of relativity.

What is the Eddington number?

The Eddington number is a proposed count of the number of protons or electrons in the universe associated with Eddington’s speculative fundamental theory; it is not accepted in modern physics.

What did Eddington discover?

Eddington is best known for showing that light from stars near the Sun was deflected by gravity in the 1919 eclipse observations, and for influential work on stellar structure and the mass-luminosity relation.

What is the Eddington limit?

The Eddington limit is the maximum luminosity at which outward radiation pressure balances inward gravity in a star or accreting object.

What is the Eddington experiment?

The Eddington experiment usually refers to the 1919 solar eclipse observations made to test whether gravity bends starlight as predicted by general relativity.

What is Eddington's theory?

Eddington used the phrase "fundamental theory" for his later attempt to derive physical constants from first principles; the term is also sometimes used more loosely to refer to his ideas on relativity and stellar physics.

References

Encyclopaedia Britannica — https://www.britannica.com/biography/Arthur-Eddington
Supports: Birth and death dates, nationality, occupations, and major work in astrophysics and relativity exposition.
European Space Agency — https://www.esa.int/Science_Exploration/Space_Science/Studying_the_stars_testing_relativity_Sir_Arthur_Eddington
Supports: 1919 eclipse expedition, relation to relativity, stellar research, Eddington limit, and Eddington number.
MacTutor History of Mathematics, University of St Andrews — https://mathshistory.st-andrews.ac.uk/Biographies/Eddington/
Supports: Eclipse expedition and its confirmation of light bending in general relativity.
The Schools' Observatory — https://www.schoolsobservatory.org/learn/history/biographies/eddington
Supports: Eddington’s role in relativity observations, stellar physics, and early ideas about nuclear fusion in stars.
Wikipedia — https://en.wikipedia.org/wiki/Arthur_Eddington
Supports: Overview of Eddington’s writings on relativity and the 1919 Príncipe expedition.