Special Relativity

Why is the speed of light constant?

Time dilation in Einsteins theory of special relativity

Electromagnetic forces and time dilation in special relativity

Lorentz-Fitzgerald contraction: Why is a moving object shortened?

Origin of the magnetic force from the perspective of special relativity

The relativity of simultaneity

Lorentz transformation

Lorentz transformation and Rotation, a comparison

Light cone



This section groups together nine articles on special relativity, in a suggested order of reading. (You may also want to read pages 177-209 of The Evolution of Physics.) While the first, the third and the fifth articles require the basic knowledge on electricity and magnetism, as covered in the section Electricity and Magnetism, the first part, others can be read without these prerequisites. The third and fifth articles show that Einstein's theory of special relativity is consistent with electromagnetism. Of course, this should be the case since light is an electromagnetic wave, and Einstein's theory of special relativity is based on the fact that the speed of light in vacuum is always constant. Nevertheless, it is exciting to check these consistencies between electromagnetism and special relativity in easy ways, since understanding them from the original construction of special relativity requires advanced knowledge. Moreover, it is always exciting to see that you arrive at the same conclusion even from very different perspectives.


The third article makes use of the relationship between electric current and magnetic force. Later, in the fifth article, this relationship is partly derived by using the special theory of relativity, but the relevant facts are stated in the third article and can be taken for granted for the purpose of understanding the point of the third article. If you dont wish to take it for granted, you may want to read the articles in the section Electricity and Magnetism, the first part, which deal with the interplay between electric fields and magnetic fields.


Unlike other articles, the last three articles related to Lorentz transformation are mathematical to some extent. Even though you only need to know the concept of square root to comprehend them, the derivation of Lorentz transformation might be complicated. Lorentz transformation and Rotation, a comparison assumes prior knowledge on "Rotation in Cartesian coordinates" covered in the section "Trigonometric functions."