What Is Light Cone?

This section provides a quick introduction of light cone, which is a 4-dimensional surface in a spacetime frame where all events on the surface can be connected to a central event by light.

What Is Light Cone? A light cone is a 4-dimensional surface in a spacetime frame where all events on the surface can be connected to a central event by light.

If we look at it from the central event point of view, a light cone can be divided into 2 parts:

The future light cone can also be illustrated using the following example:

Again, drawing a fast growing sphere in 4 dimensions on paper is very difficult. But if we remove the z-Axis in spacetime, the light cone becomes a 3-dimensional cone shape surface as shown below:

Light Cone in a Spacetime Frame with Z-Axis Removed (wikipedia)
Light Cone in a Spacetime Frame with Z-Axis Removed

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

 What Is Spacetime?

 What Is World Line?

What Is Light Cone?

 Moving Frames and Galilean Transformation

 Galilean Diagram of Moving Frames

 Minkowski Spacetime and Diagrams

 References

 PDF Printing Version