big bang theory

noun

Definition of big bang theory

: a theory in astronomy: the universe originated billions of years ago in an explosion from a single point of nearly infinite energy density — compare steady state theory

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Recent Examples of big bang theory from the Web

If the big bang theory is an explanation on how the universe was created, then what existed before the big bang occurred?

— dan vergano, Cincinnati.com, "Stephen Hawking, legendary physicist, dies at 76, family says," 14 Mar. 2018
The title came from our whole thing, which is like the big bang theory.

— andrew dansby, Houston Chronicle, "Big Boi on rapping, tap dancing and 'The Last Jedi'," 24 Jan. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'big bang theory.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.