动量概念的建立和动量守恒的思想源自于对碰撞现象的研究.动量守恒和能量守恒有效地解释了碰撞这一类复杂的力学问题.但是,从宏观物体的碰撞中得到的动量守恒定律,也就是在牛顿运动定律不适用的领域中,近代物理已经证实其仍然有效.这表明,守恒定律更深刻的基础是自然界普遍存在的时空对称性. The concept of momentum and conservation of momentum originate from the study of collision phenomena. Momentum conservation and energy conservation effectively explain such complex mechanical problems as collision. However, the law of conservation of momentum derived from the collision of macroscopic objects, That is, in the field where Newton's laws of motion do not apply, modern physics has proved that it is still valid. This shows that the more profound foundation of the conservation law is the universal space-time symmetry of nature.