It has been more than 100 years since the advent of special relativity, but the reasons behind the related phenomena are still unknown. This article aims to inspire people to think about such problems. With the help of Mathematica software, I have proven the following problem by means of statistics: In 3-dimensional Euclidean space, for point particles whose speeds are c and whose directions are uniformly distributed in space (assuming these particles’ reference system is \(\mathcal {R}_{0}\), if their average velocity is 0), when some particles (assuming their reference system is \(\mathcal {R}_{u}\)), as a particle swarm, move in a certain direction with a group speed u (i.e., the norm of the average velocity) relative to \(\mathcal {R}_{0}\), their (or the sub-particle swarm’s) average speed relative to \(\mathcal {R}_{u}\) is slower than that of particles (or the same scale sub-particle swarm) in \(\mathcal {R}_{0}\) relative to \(\mathcal {R}_{0}\). The degree of slowing depends on the speed u of \(\mathcal {R}_{u}\) and accords with the quantitative relationship described by the Lorentz factor \(\frac{c}{\sqrt{c^2-u^2}}\). Base on this conclusion, I have deduced the speed distribution of particles in \(\mathcal {R}_{u}\) when observing from \(\mathcal {R}_{0}\).

狭义相对论问世至今已有100多年，但相关现象背后的原因仍不得而知。本文旨在启发人们思考此类问题。借助Mathematica软件，我通过统计学证明了以下问题： 在3维欧氏空间中，对于速度为c且方向在空间中均匀分布的点粒子（假设这些粒子的参考系为\（ \mathcal {R}_{0}\)，如果它们的平均速度为 0），当一些粒子（假设它们的参考系是\(\mathcal {R}_{u}\)），作为一个粒子群，移动在某个方向上以相对于的群速度u（即平均速度的范数）\(\mathcal {R}_{0}\)，它们（或子粒子群的）相对于\(\mathcal {R}_{u}\)的平均速度比粒子（或相同相对于\(\mathcal {R}_{0}\)在\(\mathcal {R}_{0}\) 中缩放子粒子群）。减速程度取决于\(\mathcal {R}_{u}\)的速度u，符合洛伦兹因子\(\frac{c}{\sqrt{c^2-u ^2}}\)。基于这个结论，我推导出了从\(\mathcal {R}_{0}\)观察时\(\mathcal {R}_{u}\)中粒子的速度分布。