Reciprocity of Time Dilation

This section introduces the reciprocity of time dilation. Elapsed time of a moving clock is slower when measured by a stationary observer; and elapsed time of a stationary clock is slower when measured by a moving observer.

Time dilation is reciprocal because moving between two observers is reciprocal. So the following two statements are both true:

The first statement was demonstrated by the thought experiment presented in previous sections. The second statement can be demonstrated by modify that experiment slightly as below:

So, because of reciprocity of time dilation, Amy and Bob both will claim the other clock is slower (or dilated):

Time Dilation Reciprocity
Time Dilation Reciprocity

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

 Time Dilation - Moving Clock Is Slower

 Demonstration of Time Dilation - Amy on the Train

 Demonstration of Time Dilation - Bob on the Ground

 Demonstration of Time Dilation - Formula

 What Is Lorentz Factor?

Reciprocity of Time Dilation

 Elapsed Time between Distant Events

 Length Contraction in Special Relativity

 The Relativity of Simultaneity

 Introduction of Spacetime

 Minkowski Spacetime and Diagrams

 References

 PDF Printing Version