astronomer

American  

[uh-stron-uh-mer] / əˈstrɒn ə mər /

noun

1. an expert in astronomy; a scientific observer of the celestial bodies.

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astronomer British  

/ əˈstrɒnəmə /

noun

1. a scientist who studies astronomy

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Etymology

Origin of astronomer

First recorded in 1325–75; Middle English; see origin at astronomy, -er ¹

Explanation

A scientist who studies the objects in the sky, including planets, galaxies, black holes, and stars, is called an astronomer. These days, the terms astronomer and astrophysicist are used interchangeably, to talk about any physicist who specializes in celestial bodies and the forces that affect them. Astronomers use telescopes and cameras to observe the stars and other objects in the sky, and they often use complicated math to make predictions and solve puzzles about their movements and locations. The Greek root, astronomia, literally means "star arrangement."

Example Sentences

Researchers say the famous comet known as Halley's Comet may have been identified as a repeating object centuries before British astronomer Edmond Halley gave it his name.

From Science Daily • May 13, 2026

“There’s really no one signature that can indicate life,” says Lisa Kaltenegger, an astronomer at Cornell University.

From The Wall Street Journal • Apr. 23, 2026

She later earned a doctorate in astronomy from Harvard and in 1927, she became the youngest astronomer ever to have a star of distinction next to her name in the publication American Men of Science.

From BBC • Apr. 22, 2026

Coined in the 1960s by a Soviet astronomer, the futurist term refers to a civilization able to use all of the energy from its home system's star.

From Barron's • Apr. 21, 2026

Only a few astronomers, notably Gerard Kuiper, the Dutch-born astronomer for whom the Kuiper belt of comets is named, took any interest in the solar system at all.

From "A Short History of Nearly Everything" by Bill Bryson

Related Words

• astrophysicist
• cosmologist