astrophysics

American  

[as-troh-fiz-iks] / ˌæs troʊˈfɪz ɪks /

noun

(used with a singular verb)

1. the branch of astronomy that deals with the physical properties of celestial bodies and with the interaction between matter and radiation in the interior of celestial bodies and in interstellar space.

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astrophysics British  

/ ˌæstrəʊˈfɪzɪks /

noun

1. (functioning as singular) the branch of physics concerned with the physical and chemical properties, origin, and evolution of the celestial bodies

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astrophysics Scientific  

/ ăs′trō-fĭz′ĭks /

1. The branch of astronomy that deals with the physical and chemical processes that occur in stars, galaxies, and interstellar space. Astrophysics deals with the structure and evolution of stars, the properties of interstellar space and its interactions with systems of stars, and with the structure and dynamics of clusters of stars such as galaxies.

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astrophysics Cultural  

1. The branch of astronomy devoted to the study of the physical characteristics and composition of objects in the sky. Typical concerns of astrophysics are how much light the stars give off and the size, mass, and temperature of planets and stars.

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Other Word Forms

• astrophysical
  adjective
• astrophysicist
  noun

Etymology

Origin of astrophysics

First recorded in 1885–90; astro- + physics

Explanation

Astrophysics is the study of stars and other objects in space, and the way they move and change over time. If you're fascinated with black holes, you may want to go into astrophysics. Complicated subjects like galaxy formation, the possibility of time travel, and the way the solar system has evolved are all included in the branch of astronomy known as astrophysics. When you study astrophysics, you apply the concepts and theories of physics to astronomic observations. Astrophysicist came first, from the Greek aster, or "star," and ta physika, "the natural things," or "natural science."

Example Sentences

After receiving an email Friday afternoon, Keivan Stassun, a professor of physics and astronomy at Vanderbilt University and director of the Vanderbilt Initiative in Data-intensive Astrophysics, said he reached out to fellow board members.

From Los Angeles Times • Apr. 26, 2026

This research is presented in a paper titled "The Local Distance Network: A community consensus report on the measurement of the Hubble constant at ∼1% precision" to published in Astronomy & Astrophysics.

From Science Daily • Apr. 12, 2026

I asked Chris Lintott, Professor of Astrophysics at the University of Oxford and co-host of BBC's series The Sky at Night for his opinion.

From BBC • Apr. 5, 2026

The study was published in The Astrophysical Journal and led by scientists from the Institute for Advanced Study and the Flatiron Institute's Center for Computational Astrophysics.

From Science Daily • Dec. 22, 2025

He’s studying Astrophysics at a university in California, having finished his undergraduate degree in two years instead of four.

From "Cat's Eye" by Margaret Atwood