astrophysics

American  

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

noun

(used with a singular verb)

astrophysics plural

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

Derived Forms

• astrophysicist
  noun
• astrophysical
  adjective

Inflected Forms

Nouns

• astrophysics
  plural

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

"This is a lot of firsts stacked on top of each other," said Shawn Domagal-Goldman, the director of NASA's astrophysics division, during a recent call with reporters.

From Barron's • Jun. 30, 2026

It conducts research in geology, biology, engineering and physics, the latter encompassing experiments studying dark matter, astrophysics and neutrinos.

From The Wall Street Journal • Jun. 25, 2026

An ultraheavy particle may help explain one of the most puzzling mysteries in modern astrophysics: the origin of the most energetic particles ever detected.

From Science Daily • Jun. 9, 2026

For Louise Grillmair, who met her husband in an astrophysics class, she would prefer that the world know not just about his groundbreaking scientific work, but also his kind and generous character.

From BBC • Apr. 23, 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