### celestial mechanics

(study of forces and motion of celestial objects)

**Celestial mechanics** is the application of **mechanics**
to celestial objects, e.g., planets, galaxies, moons,
etc. *Mechanics*, in turn is the branch of physics dealing
with forces and motion. More specifically, **dynamics** is the
study of forces and resulting motions, e.g., orbits,
and **statics** is the study of forces in the absence of motion,
e.g., why the inside of the Moon doesn't collapse to allow
it to grow smaller, and **kinematics** is the study of motion
without regard to the forces that cause it.

For example, Kepler's laws, which describe orbits
(Keplerian orbit) fall under the heading of *kinematics*,
whereas **Newton's laws**, which describe how forces
bring about orbits, fall under *dynamics*.
*Celestial mechanics* as "mechanics focused on astronomical phenomena",
includes some focus on the dynamics of orbiting bodies, and has
developed techniques of determining long-term (secular) changes,
i.e., perturbation theory.

(*astrophysics,mechanics,kinematics,dynamics*)
http://en.wikipedia.org/wiki/Celestial_mechanics

http://www.scholarpedia.org/article/Celestial_mechanics

https://farside.ph.utexas.edu/teaching/celestial/Celestial/Celestial.html

http://orca.phys.uvic.ca/~tatum/celmechs.html

**Referenced by:**

Lie transform

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