Absolute time is not changed with any external action or observer. Relative time changes with external action or observer and can be determined by measuring the absolute time difference of the motion of the object.
According to the above concepts, it can be found that absolute time is actually unmeasurable and imperceptible. Newton believes that absolute time can only be expressed in the form of mathematics, and human beings can only observe the passage of time through the movement of objects.
As an example, if a person wants to measure a 100-meter sprint, then we are free to choose when the person is at the starting point for 0 seconds, but at this time the absolute time is unknown, and then we measure this with a stopwatch. When the person passes through the end, he knows the time it takes for the person to sprint 100 meters. In this process, we do not know the absolute time of the start and end, we only measure the absolute time difference.
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Gottfriend Wilhelm. Leibniz (1646~1716 German mathematician, physicist) believes that at the same time. Events are more basic; it is absurd to think that there is no time for things to exist. In his view, time is drawn from events, and all simultaneous events constitute a stage of the universe. And these stages are just like yesterday, today and tomorrow, one after the other. Leibniz's theory of relative time seems to be more acceptable today than Newton's theory because it is more in line with the development of modern physics.
Newton's absolute time
Newton went one step further than Galileo. Newton believes that, contrary to Aristotle's "theory," if there is nothing else to stop, the moving objects will never stand still. The falling stone will fall to the ground and will not move because it is blocked by the earth. The carriage stops so because it has friction between the wheel and the road surface. On a smooth horizontal road, the carriage with frictionless bearings , will continue to scroll. Therefore, Newton pointed out that the effect of force on an object is only to change its speed of movement with time. The amount of this change is called acceleration, which is proportional to the magnitude of the force. This is the second law of Newton's kinematics.
Newton's law of motion, together with the law of universal gravitation that he derived in 1684, laid the foundation for classical physics and had a great influence on the development of the natural sciences of the time and later. It is still widely used today and continues to play a huge role. . However, it should be seen. Newton's law is based on the concept that the time used to measure motion is an "absolute time" that traverses evenly.
Different perspectives
Historically, other physicists have different opinions on the absolute time and space proposed by Newton. Leibniz believes that space only makes sense when there is a reference point, and time only makes sense when there is motion. George Berkeley speculated that in the absence of a reference point, one sphere cannot be said to be rotating, or two spheres connected by a rope are rotating relative to their common center of mass, at most one of which is rotated relative to the other.
The Galileo transformation gives the transformation relationship between different inertial coordinate systems. This means that absolute space-time is not necessary because we only need to select an inertial coordinate system to know the results in other inertial coordinate systems, and there is no An inertial coordinate system can be isolated.
In addition, Ernst Mach proposed the Mach principle, which mentions that it is meaningless to discuss the inertia of an object without a reference point, and again that absolute time and space is an unnecessary concept. The Mach principle was later emphasized and named in Einstein's paper on general relativity.
Einstein and relativity
Time and space have always been considered as two independent physical quantities until the special theory of relativity is proposed. The special theory of relativity gives a new concept of time and space, in which the relative simultaneous existence negates the existence of absolute time, because the time of the event occurs with the speed of the observer. There is a relationship with the location where the event occurred.
The general theory of relativity further establishes the relationship between time and space using the concept of geodesic. At this point, the relationship between time and space becomes more specific.
Summary
Newton's concept of absolute time and space, because the "absolute" physical quantity itself is not measurable, plus the "relative" physical quantity, although it changes with the observer, but there is a direct transformation relationship between different observations, and becomes unnecessary.
