Shape of Earth (more) Pi in Nature A visual exploration of an infinite constant Written by Manjishtha Bhattacharyya Manjishtha Bhattacharyya is an editor at Encyclopaedia Britannica. She holds a PhD in zoology from Vidyasagar University, West Bengal, and has more than seven years of experience in science communication... Manjishtha Bhattacharyya Fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors Last updated Mar. 9, 2026 •History Pi (π) is the constant that relates a circle’s circumference to its diameter. It is an irrational, transcendental number with an infinite, non-repeating decimal expansion that could contain every possible finite numerical pattern. (Read Britannica’s article on pi.) Whenever a shape is circular, spherical, or formed by rotation, pi appears in the formulas that describe it. In nature, patterns arise when forces such as gravity, pressure, motion, and growth act evenly around a center, producing...

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