To judge whether an object is still or in motion, you must choose the appropriate object of reference 。 Different reference objects are selected motion state It's different. Relative stillness means that two objects move in the same direction and at the same speed, and their positions relative to each other do not change.
If the person sitting in the train uses the train as object of reference , he sees that the position of the goods on the train to the train is unchanged, so the goods are opposite to the train static 。 If trees or buildings on the ground are selected as reference objects, people can see that the position of goods to buildings is constantly changing, so goods to trees relative motion 。 From the day of the formation of the cosmic explosion solid ， liquid still Gas , all move with it. Copernicus Author《 Heliocentric theory 》, which mentioned: Universal gravitation 。 Any matter in the universe causes great attraction gravitation Small, progressive, so that all things rotate. Existing on the surface of a solid, such as living things on the earth earth rotation Movement; The gas then flows, forming the wind. Dialectical materialism It is believed that motion is absolute because everything is in motion, and everything is in motion all the time, and there is no matter that does not move. Movement is universal, eternal and unconditional, so it is absolute. While recognizing the absoluteness of movement, dialectical materialism also recognizes the existence of a certain relativity of matter static Status. Relative stillness is a special state of motion and a sign Material movement Under certain conditions and within a certain range, it is temporarily stable and Equilibrium state 。 Static is conditional and temporary, so it is relative. There are two basic situations of relative static: one is that there is no movement of relative position. That is, from a certain reference system, the relationship between objects maintains a certain balance, or there is no relative position movement. Like a big tree, we can see that it does not move because it is relative to the earth Frame of reference For example, the big tree didn't happen displacement We can think of it as static. But in fact, the tree is still circling the sun with the earth at a speed of 30 kilometers per second revolution 。 The second is that there is no qualitative change. That is, from the point of view of things themselves, things still maintain their own nature, are still in an insignificant quantitative change stage and have not become other things, which temporarily appear as static Status. But even in this case, objects are moving and changing, and sooner or later they will lose their original nature and become something else. Although static is relative, it is important to recognize and recognize relative static. First of all, relative stillness is the measure of the movement of things. Movement is manifested in its opposite, that is, in stillness. Movement should find its measure from its opposite, that is, in stillness. If physics wants to describe the motion of an object, it must find a relatively stable reference system, otherwise, the object motion state It cannot be seen or measured. Secondly, relative stillness is a necessary condition for the existence and development of things. The stability of things is the premise of their existence; Quantitative change of things is a necessary preparation for qualitative change. Again, relative static It is the basis of understanding and distinguishing things. If there is no stillness, things will change rapidly, and they will become indistinguishable and unpredictable. All understanding of things will be impossible, let alone the use of things. Only when things maintain their own stability and have certain forms, properties, structures and functions can we compare, analyze and study things, and understand and use things. therefore Dialectical materialism Think absolute motion And relative stillness are dialectical unity. On the one hand, motion is absolute, while stillness is relative; On the other hand, there is relative stillness in absolute motion, and there is absolute motion in relative stillness, that is, there is stillness in motion, and there is motion in stillness. If we do not recognize that there is movement in stillness, deny the absoluteness of movement, and regard things as rigid and unchangeable, we will move towards metaphysics; On the contrary, if we do not recognize that there is stillness in motion, and deny the role of relative stillness, and regard things as changing and unpredictable, we will slide towards relativism and sophistry 。 
