Concept
Celestial mechanics
Overview
Celestial mechanics is the branch of astronomy that deals with the motions and gravitational interactions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to produce ephemeris data. The computation of the motion of the bodies through orbital mechanics can be simplified by using an appropriate inertial frame of reference. This leads to the use of various different coordinate systems, such as the Heliocentric (Sun-centered) coordinate system.
In a binary system of objects interacting through gravity, Newtonian mechanics can used to produce a set of orbital elements that will predict with reasonable accuracy the future position of the two bodies. This method demonstrates the correctness of Kepler's laws of planetary motion. Where one of the bodies is sufficiently massive, general relativity must be included to predict apsidal precession. The problem becomes more complicated when another body is added, creating a three-body problem that can not be solved exactly. Perturbation theory is used to find an approximate solution to this problem.
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
In the original texts
Passages from public-domain books where Celestial mechanics is discussed.
In Ptolemy's system, the motions of the heavenly bodies can not be explained by the action of central forces, celestial mechanics is impossible. The intimate relations that celestial mechanics reveals to us between all the celestial phenomena are true relations; to affirm the immobility of the earth would be to deny these relations, that would be to fool…
Henri Poincaré, The Foundations of Science
states what it is; names the idea; opens on it
The theory of gravity, connected together, in the most accurate manner, by the different actions of the Sun and the Earth, all those irregular motions; and it appears, by calculation, that the time, the quantity, and the duration of those direct and retrograde motions of the Nodes, as well as of their stationary appearances, might be expected to be exactly such, as the observations of Astronomers have determined…
Adam Smith, The Essays of Adam Smith
states what it is
The motion at each instant is determined by the amount and direction of the motion, and the amount and direction of the sun’s action, at the previous instant; and if we speak of the entire revolution of the planet as one phenomenon (which, as it is periodical and similar to itself, we often find it convenient to do), that phenomenon is the progressive effect of two permanent and progressive causes, the central force…
John Stuart Mill, A System of Logic, Ratiocinative and Inductive
states what it is
Since the form of the orbits of heavenly bodies and their velocities could not be considered to be the results of their masses and of their relative positions with reference to one another; since it was not possible to calculate the velocities and orbits from the physical characters of the bodies, since in a word these physical characters did not enter into the problem of calculating the positions of the bodies nor…
John Dewey, Creative Intelligence
names the idea; opens on it
For this system, which is called that of _occasional causes_ (because it teaches that God acts on the body at the instance of the soul, and _vice versa_), besides introducing perpetual miracles to establish communication [157] between these two substances, does not obviate the derangement of the natural laws obtaining in each of these same substances, which, in the general opinion, their mutual influence would cause.
Gottfried Wilhelm Leibniz, Theodicy Essays on the Goodness of God, the Freedom of Man and the Origin of Evil
states what it is; author linked in the graph
Related ideas
- General relativity
- Gottfried Wilhelm Leibniz
- Differential equation
- Isaac Newton
- Johannes Kepler
- Kepler's laws of planetary motion
- Urbain Le Verrier
- Algebra
- Moon
- Classical mechanics
- Astronomia nova
- Planet
- Physics
- Paris
- Ptolemy
- Newton's law of universal gravitation
- Scientific law
- Sun
- Solar System
- Space
- Nicolaus Copernicus
- Pierre-Simon Laplace
- Ancient Greek astronomy
- Vulcan (hypothetical planet)
Place in the tradition
Part of Cosmology.