Definition:Orbit (Physics)

This page is about Orbit in the context of Physics. For other uses, see Orbit.

Definition

Let $A$ and $B$ be bodies in space.

The orbit of $A$ around $B$ is the path taken by $A$ as it travels around $B$ under the influence of the force acting between $A$ and $B$.

Period of Orbit

The period of the orbit is the length of time it takes for $A$ to travel once around $B$ and return to its original position.

Radius of Orbit

Let $\mathbf r$ be the position vector of the center of mass of $A$ with respect to the center of mass of $B$ at a particular point in time.

The radius of the orbit of $A$ around $B$ is defined as:

the position vector $\mathbf r$

or

the length of $\mathbf r$.

Context will determine which is meant.

Also see

• Results about orbits in the context of physics can be found here.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): orbit: 1.
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): orbit: 1.
• 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): orbit