Editing Orbit (section)

===Orbital planes===
{{Main|Orbital plane}}
The analysis so far has been two dimensional; it turns out that an [[perturbation theory|unperturbed]] orbit is two-dimensional in a plane fixed in space, and thus the extension to three dimensions requires simply rotating the two-dimensional plane into the required angle relative to the poles of the planetary body involved.

The rotation to do this in three dimensions requires three numbers to uniquely determine; traditionally these are expressed as three angles.