Albert Einstein, the Principle of Relativity, was put forward by Galileo Galilei 300 years ago, in 1905, when he proposed the On the Electrodynamics of Moving Bodies.
Galileo's Relativity Principle does not have an absolute reference system. Think of the A and B observers to better understand this. According to the observer A, the observer B is going to the right with v speed. In the same way, according to the B observer, the A observer goes to the left v speed. Both observers are right to say that the other observer is moving, since there is no absolute reference system, it is possible to switch between fixed reference systems. The notion of a "fixed reference system" is a reference system that does not move with acceleration because it does not change its speed because it can not be regarded as an accelerated observer reference system in Galileo Transformations.
Imagine yourself in a train to understand why, the windows of the train are covered with a black screen (you are not in the dark because there is light inside the train). Assume that there is no accelerating movement such as swinging, turning, accelerating or slowing down the train. How do you know if such a trending train is going at a constant speed or is it stopping? The answer is pretty simple: you can not understand. You can do any kind of experiment in the train but you can not understand if the train is moving unless you look out. If you look out of the window in the same way, you can say that the whole world is going to the other side because you do not move the train (and therefore you) because the transition between fixed reference systems can be done as we have said before.
But you can not say the same thing on an accelerating train. Suppose your train speeds up to understand this. As you know, if you've already filled up, you've been on the metro, you feel a backward force. But you do not feel such a force in an experiment in which the train (and you) are stopped, but the whole world accelerates to the other side. For this reason, you can understand when you are in a train, "I do not feel the force in any direction, then the train does not accelerate" or "I sense a direction force, then the train accelerates".
In another thought experiment, suppose you turn your arms around you and turn around. Since you feel centrifugal because you are accelerating as you turn, you feel a force out of your arms (and your head is turning, but not your position). But when you stand, you will not feel such a force when the whole world turns around you.
The three jurisdictions published by Isaac Newton in Principia (now known as the Newtonian Laws) are consistent with the Galileo transformations. However, the four equations (now known as Maxwell Equations) that combine electrical and magnetism introduced by James Clerk Maxwell in his book The Dynamical Theory of the Electromagnetic Field, published in 1865, were incompatible with Galileo's transformations. Consider, for example, a charged object, which emits an electric field as the object is loaded. Let's say this body is a skateboarder with a certain speed for you. Charged objects form a magnetic field as they travel at a constant speed. According to you, you can find the magnetic field that is based on your speed, but the result is different when you calculate this magnetic field from the skater's reference system.
Another problem with Maxwell Equations' Galileo Transforms is related to the speed of electromagnetic waves. According to Maxwell's equations, electromagnetic waves propagate at light velocity (even so it is understood that there is some kind of electromagnetic wave in visible light) but it remains a question mark as to which reference system this velocity is based. For this reason, scientists think that space is with an object called ether, that the light is scattered within this matter and that this material has spread at the speed of light according to the reference system. For this reason, Michelson and Morley designed an experiment (known today as the Michelson-Morley Experiment) to show their presence in 1887. In this experiment, a beam of light has been sent to the side of the Earth, and a beam of light has been sent to the other side. It was expected that the speed of the light sent to the side of the world would be higher than the speed of the light to the other side. But as a result of the experiment, Michelson and Morley met with a different result. The speed of light sent to both sides remained as the speed of light.
As a result of the experiment, the speed of the light seemed to be independent of the speed of the light source. Some scientists thought that the work moved with the Earth and that the speed of light was constant. Hendrik Lorentz tried to solve this problem by revealing that objects near the speed of light were shortening in space. But all these solutions alone were not enough. In 1905, young Albert Einstein, a civil servant at the Swiss Patent Institute in those years, published the article entitled On the Electrodynamics of Moving Bodies, defined as annus mirabilis (miracle year). In his paper he showed his equations over two postulates:
• Physics laws are the same in every fixed reference system (Galileo Principle)
• The speed of light is the same for each stationary reference system (Michelson-Morley Experiment)
Based on these two postulates, Einstein, who made up his equations, showed that time and space are not invariant since Newton's thought and may be different for each reference system. Let's look at the results of the Special Relativity Theory, which radically changes our ideas about space and time and opens our horizon:
• Space and time can not be handled separately. Space - time is a whole and each object moves in space - time at light speed. For this reason, an object moving in space moves at a slower pace.
• If the B observer moves at a constant speed relative to the A observer, then the time for the B observer is slower than the observer. But according to B observer, time is slower for him and not for him.
• Synchronism can vary between observers. An event that occurs at the same time for an observer may not occur at the same time for another observer
• According to a certain observer, the cismin going at constant speed gets shorter in the direction it goes.
• They never reach the speed of light because they require infinite momentum and energy to bring mass objects to light speed. Non-mass objects have to go at light speed.
• When an object is in a stationary state (without a velocity), mass increases as the mass of the light velocity is divided (E = mc 2 ).
This theory, however, failed to account for the accelerated reference frames. Einstein developed the General Theory of Relativity in 1915 and showed that space-time objects were bent and twisted and that what we actually called the "gravitational force" was the only way space-time moving objects took in space.