Physics Notes - Herong's Tutorial Notes - v3.24, by Herong Yang
What Is World Line
This section provides a quick introduction of world line, which is the path of an object left in a spacetime frame of reference.
What Is World Line? A world line is the path of an object left in a spacetime frame of reference.
For example, if we define a spacetime frame of reference fixed on Sun and uses only 2 dimension x and y on the Ecliptic plane, the world line of Sun will be a straight line along the t-Axis as shown on the right hand side of the picture below.
In the same spacetime frame, the world line of Earth will be a helix line.
As comparison, if we look at a space frame of reference fixed on Sun and uses only 2 dimension x and y on the Ecliptic plane, the trajectory of Sun will be a stationary point and the trajectory of Earth will be a circle. See the left hand side of the picture.
Table of Contents
Introduction of Frame of Reference
Introduction of Special Relativity
Time Dilation in Special Relativity
Length Contraction in Special Relativity
The Relativity of Simultaneity
Moving Frames and Galilean Transformation
Galilean Diagram of Moving Frames
Minkowski Spacetime and Diagrams
Introduction of Generalized Coordinates