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

"It'll be exciting, you know, in a slightly scary way, when they go behind the moon," Derek Buzasi, a professor of astronomy and astrophysics at the University of Chicago, told AFP.

From Barron's • Apr. 5, 2026

"But those are just simulations, not the real universe. Now we have a foundation which can let us know if some of the astrophysics underpinning those simulations is correct."

From Science Daily • Mar. 8, 2026

The international research team was led by astrophysics Ph.D. student Alexander Venner of the University of Southern Queensland, Toowoomba, Australia, who is now a postdoctoral researcher at the Max Planck Institute for Astronomy, Heidelberg, Germany.

From Science Daily • Feb. 12, 2026

"The UK punches above its weight in scientific impact and in space-related industry," said Chris Lintott, professor of astrophysics at Oxford University.

From BBC • Feb. 5, 2026

I have studied astrophysics and even waste management systems in space aircraft, but I have never given any thought to the procedure for custody or guardianship of a minor in the state of California.

From "Counting by 7s" by Holly Goldberg Sloan