Constancy of Speed of Light in Minkowski Diagram
This section provides a demonstration of constancy of speed of light using a Minkowski diagram.
The main assumption of the special theory of relativity is that
the speed of light has the same value c measured in all inertial frames.
This assumption can be easily demonstrated by the Minkowski diagram.
Let's follow a simple thought experiment described below:
- A light pulse travels from Bob's location for 6 seconds.
- The trajactory of the light pulse can be represented by a diagonal
line between event O and event E, (X,cT)=(6,6), in Bob's stationary frame.
- So according to Bob's stationary frame, the speed of the light pulse is
X/cT = 6/6 = 1 (c).
Now let's assume that Amy's frame is moving at a speed of v=0.6*c:
- The event E would be observed at (X',cT')=(3,3) in Amy's moving frame
based on the Minkowski diagram given below.
- So according to Amy's moving frame, the speed of the light pulse is
X'/cT' = 3/3 = 1 (c).
So the speed of light is 1 (c) in both Bob's frame and Amy's frame.
Last update: 2014.
Table of Contents
About This Book
Introduction of Space
Introducion of Frame of Reference
Introducion of Time
Introduction of Speed
Newton's Laws of Motion
Introduction of Special Relativity
Time Dilation in Special Relativity
Length Contraction in Special Relativity
The Relativity of Simultaneity
Introduction of Spacetime
►Minkowski Spacetime and Diagrams
What Is Minkowski Spacetime?
Events Interval and Relations
What Is Lorentz Transformation?
What Is Minkowski Diagram?
►Constancy of Speed of Light in Minkowski Diagram
Time Dilation in Minkowski Diagram
Length Contraction in Minkowski Diagram
Relativity of Simultaneity in Minkowski Diagram
Invariant Spacetime Interval in Minkowski Diagram
Multiple Reference Frames in Minkowski Diagram
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