Bryan McAllister’s personal reference notebook
July 31, 2026Short & citedBlog
Civic Viewpoint.
A quiet encyclopedia with a personal desk
Field Notes • 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.

Updated July 31, 20261 min readCited sources

Arthur Eddington (1882–1944) was an English astronomer, physicist, and mathematician who helped explain Einstein's relativity to English-speaking audiences and led a 1919 solar eclipse expedition that provided early observational support for general relativity.

What it is

Eddington was a leading British astrophysicist of the early 20th century, known for his work on stellar structure, the mass-luminosity relation, and the Eddington limit—the maximum luminosity a star can sustain before radiation pressure overcomes gravity. He also proposed early ideas about stellar energy generation, later understood as nuclear fusion.

Why it matters

Eddington's 1919 eclipse expedition tested whether starlight passing near the Sun was deflected by gravity, as predicted by general relativity. The results were widely seen as a key confirmation of Einstein's theory, transforming how we understand gravity and spacetime. His work on stellar physics remains foundational in astrophysics.

Key details

Born in Kendal, England, Eddington became one of the first major English-language expositors of relativity. He also proposed the Eddington number—a speculative count of particles in the universe—though it is not accepted in modern physics. His name is attached to several scientific concepts, including the Eddington limit and the Eddington experiment.

In short

  • Led 1919 eclipse expedition that supported general relativity
  • Pioneered work on stellar structure and the Eddington limit
  • Helped popularize relativity in English-speaking world
  • Early ideas on stellar energy generation
Canadian angle

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.

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

Sources

  1. Encyclopaedia Britannicahttps://www.britannica.com/biography/Arthur-Eddington
    Supports: Birth and death dates, nationality, occupations, and major work in astrophysics and relativity exposition.
  2. European Space Agencyhttps://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.
  3. MacTutor History of Mathematics, University of St Andrewshttps://mathshistory.st-andrews.ac.uk/Biographies/Eddington/
    Supports: Eclipse expedition and its confirmation of light bending in general relativity.
  4. The Schools' Observatoryhttps://www.schoolsobservatory.org/learn/history/biographies/eddington
    Supports: Eddington’s role in relativity observations, stellar physics, and early ideas about nuclear fusion in stars.
  5. Wikipediahttps://en.wikipedia.org/wiki/Arthur_Eddington
    Supports: Overview of Eddington’s writings on relativity and the 1919 Príncipe expedition.