The theory of relativity and the Pythagorean theorem

TL;DR

This paper demonstrates that key effects of relativity can be understood simply using a unit system where the speed of light is unity, and relates energy, momentum, and mass through the Pythagorean theorem.

Contribution

It introduces a simplified framework for understanding relativity effects and visually relates fundamental quantities using the Pythagorean theorem.

Findings

Relativity effects are simplified with a natural unit system.

Energy, momentum, and mass are related via the Pythagorean theorem.

The approach aids teaching and popularization of relativity.

Abstract

It is shown that the most important effects of special and general theory of relativity can be understood in a simple and straightforward way. The system of units in which the speed of light $c$ is the unit of velocity allows to cast all formulas in a very simple form.The Pythagorean theorem graphically relates energy, momentum and mass. The paper is addressed to those who teach and popularize the theory of relativity.