Astrophysics (index)about


(world line)
(path of an object through space and time)

A worldline (or world line) is the path of an object through time and space, i.e., its position as a function of time. Given relativity, particularly general relativity, the above simple definition depends upon the frame of reference. A path defined in a 4-dimensional spacetime does allow a line to be defined such that the equivalent line in any frame of reference can be produced through a transformation implied by the relativity theories.

Spacetime diagrams attempt to show some of the characteristics of worldlines.