coordinate time

In the framework of General Relativity, a 4-dimensional space-time reference system is described by four coordinates among which three are the spatial coordinates and the other is x₀ = ct, where c is the velocity of light in vacuum and t is the "coordinate time" in this reference system.

Coordinate time provides an unambiguous way of dating events in a specified reference system. It is the time basis (or coordinate) to be used in the theory of motions referred to this system. The relation of the observed (proper) time of an observer to the coordinate time t depends on the velocity, mass and energy.

Related terms:

• Geocentric Coordinate Time
• Barycentric Coordinate Time
• Terrestrial Time