The Eclipse of 1919: How Einstein’s Theory of General Relativity Changed Our World
by Emily Arnold McCully; illus. by the author
Primary, Intermediate    Ottaviano/Little, Brown    40 pp.
7/25    9780316475525    $18.99

This picture book serves as a good introduction to the concepts of scientific theory, methodology, and history involved in the role of a 1919 eclipse in proving Einstein’s theory of general relativity. Isaac Newton’s universal law of gravity stood unchallenged for two hundred years until Albert Einstein proposed his theory that speed affects mass, time, and space. It was a revolutionary proposition, but how could one test such a notion? McCully leads up to the answer to that question with a few pages of biographical information about Einstein and a basic explanation of his theory, establishing uncertainty: “But was it correct?” She explains that the effects of relativity “can’t be observed in the everyday world because everything is closer together than in space” and that the theory could be tested only during a total eclipse of the sun. World War I interrupted much scientific inquiry, and Einstein’s 1915 publication of his theory was virtually ignored. After the war, Arthur Eddington, director of the Cambridge Observatory, tested the theory during an eclipse in 1919, setting out with a colleague to a remote island on the west coast of Africa. McCully conveys the endeavor’s considerable drama—heavy rains obscured the sun that day, with the clouds parting just long enough to allow for the photographic evidence that would prove the theory; “overnight, Albert Einstein’s name became a permanent synonym for genius.” The text is illustrated with McCully’s recognizable watercolor, pen, and ink illustrations in a variety of shapes and sizes from spot illustrations to sweeping double-page spreads. An author’s note and source notes are appended.

From the July/August 2025 issue of The Horn Book Magazine.