Editing Hyperbolic orthogonality (section)

{{short description|Relation of space and time in relativity theory}}
[[File:Orthogonality and rotation.svg|thumb|350px|Euclidean [[orthogonality]] is preserved by rotation in the left diagram; hyperbolic orthogonality with respect to hyperbola (B) is preserved by [[hyperbolic rotation]] in the right diagram.]]

In [[geometry]], the relation of '''hyperbolic orthogonality''' between two lines separated by the asymptotes of a [[hyperbola]] is a concept used in [[special relativity]] to define simultaneous events. Two events will be simultaneous when they are on a line hyperbolically orthogonal to a particular timeline. This dependence on a certain timeline is determined by velocity, and is the basis for the [[relativity of simultaneity]]. Furthermore, keeping time and space axes hyperbolically orthogonal, as in Minkowski space, gives a constant result when measurements are taken of the speed of light.