Concept

Astrophysics

Overview

Astrophysics is a science that applies the methods and principles of physics and chemistry in the study of astronomical objects and phenomena including the universe. As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space—what they are, rather than where they are", which is studied in celestial mechanics. Astrophysics is also used when designing and plotting courses for spacecraft.

Among the subjects studied are the Sun (solar physics), other stars, galaxies, extrasolar planets, the interstellar medium, and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.

In practice, modern astronomical research often involves substantial work in the realms of theoretical and observational physics. Some areas of study for astrophysicists include the properties of dark matter, dark energy, black holes, and other celestial bodies; and the origin and ultimate fate of the universe. Topics also studied by theoretical astrophysicists include Solar System formation and evolution; stellar dynamics and evolution; galaxy formation and evolution; magnetohydrodynamics; large-scale structure of matter in the universe; cosmic rays; general relativity, special relativity, and quantum and physical cosmology (the physical study of the largest-scale structures of the universe), including string cosmology and astroparticle physics.

Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).

Possible passages

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Indeed, when two things are simultaneously raised by one and the same power, the smaller quantity must of course yield more readily than the greater to the impulsive force by which they are constrained; and hence, the one is called _heavy_ and gravitating downwards, the other _light_ and tending upwards. The same thing also is observable in what we ourselves do, who inhabit this place [the earth].
Plato, The works of Plato
States what Astrophysics is; the author is tied to Astrophysics in the knowledge graph.
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That is called hard to which our flesh yields, and soft which yields to our flesh; and things are also termed hard and soft relatively to one another. That which yields has a small base; but that which rests on quadrangular bases is firmly posed and belongs to the class which offers the greatest resistance; so too does that which is the most compact and therefore…
Plato, Timaeus
States what Astrophysics is; the author is tied to Astrophysics in the knowledge graph.
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We shall see that matter has a tendency to constitute _isolable_ systems, that can be treated geometrically. In fact, we shall define matter by just this tendency. But it is only a tendency. Matter does not go to the end, and the isolation is never complete. If science does go to the end and isolate completely, it is for convenience of study; it is understood that the so-called isolated system remains subject to…
Henri Bergson, Creative Evolution
States what Astrophysics is.
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Philosophers who discussed Astrophysics

Drew Dalton

Related ideas

Place in the tradition

Part of Cosmology.

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