STO, TOE - these abbreviations conceal the term "relativity theory" that is familiar to almost everyone. In a simple language, everything can be explained, even the statement of a genius, so do not despair if you do not remember the school physics course, because in fact everything is much simpler than it seems.
The origin of the theory
So, let's start the course "Theory of Relativity for Dummies". Albert Einstein published his work in 1905, and it caused a resonance among scientists. This theory almost completely covered many gaps and inconsistencies in the physics of the last century, but also, over everything else, turned the idea of space and time upside down. It was difficult for contemporaries to believe in many of Einstein’s statements, but experiments and studies only confirmed the words of the great scientist.
Einstein's theory of relativity explained in plain language what people have been fighting for centuries. It can be called the basis of all modern physics. However, before continuing the discussion on the theory of relativity, the question of terms should be clarified. Surely many, when reading popular science articles, came across two abbreviations: STR and GR. In fact, they mean slightly different concepts. The first is a special theory of relativity, and the second stands for "general theory of relativity."
Just about complicated
SRT is an older theory that later became part of GR. In it, only physical processes for objects moving with uniform speed can be considered. The general theory can describe what happens to accelerating objects, and also explain why there are particles of gravitons and gravity.
If you need to describe the motion and laws of mechanics, as well as the relationship of space and time when approaching the speed of light, this can be done by a special theory of relativity. In simple words, one can explain this: for example, friends from the future have presented you with a spaceship that can fly at high speed. On the nose of the spacecraft is a cannon capable of shooting photons with everything that comes in front.
When a shot is fired, then these particles fly relative to the ship at the speed of light, but, logically, a stationary observer should see the sum of the two speeds (the photons themselves and the ship). But nothing of the kind. The observer will see photons moving at a speed of 300,000 m / s, as if the speed of the ship was zero.
The thing is that no matter how fast an object moves, the speed of light for it is an invariable value.
This statement is the main striking logical conclusion such as the slowdown and distortion of time, depending on the mass and speed of the object. The plots of many science fiction films and series are based on this.
General theory of relativity
A simple language can explain the more voluminous GR. To begin with, one should take into account the fact that our space is four-dimensional. Time and space are combined in such a “subject” as the “space-time continuum”. There are four coordinate axes in our space: x, y, z and t.
But people cannot directly perceive four dimensions, just as a hypothetical flat person living in a two-dimensional world is not able to look up. In fact, our world is only a projection of four-dimensional space into three-dimensional.
An interesting fact is that, according to the general theory of relativity, bodies do not change when moving. The objects of the four-dimensional world are always always unchanged, and only their projections change during movement, which we perceive as time distortion, reduction or increase in size, and so on.
Elevator experiment
The theory of relativity can be described in simple language with the help of a small thought experiment. Imagine that you are in the elevator. The cabin began to move, and you were in a state of weightlessness. What happened There can be two reasons: either the elevator is in space, or it is in free fall under the influence of planet gravity. The most interesting thing is that it is impossible to find out the cause of weightlessness if it is not possible to look out of the elevator car, that is, both processes look the same.
Perhaps, having carried out a similar thought experiment, Albert Einstein came to the conclusion that if these two situations are indistinguishable from each other, it means that in fact the body does not accelerate under the influence of gravity, it is a uniform movement that bends under the influence of a massive body (in this case, the planet ) Thus, accelerated motion is only a projection of uniform motion into three-dimensional space.
Good example
Another good example on the topic "Theory of Relativity for Dummies." It is not entirely correct, but it is very simple and visual. If you put any object on the stretched fabric, it forms a “deflection”, “funnel” underneath. All smaller bodies will be forced to distort their trajectory according to the new bend of space, and if the body has a little energy, it may not be able to overcome this funnel at all. However, from the point of view of the moving object itself, the trajectory remains straight, they will not feel the bend of space.
Gravity "demoted"
With the advent of the general theory of relativity, gravity ceased to be a force and is now content with the position of a simple consequence of the curvature of time and space. General relativity may seem fantastic, but it is a working version and is confirmed by experiments.
Many seemingly incredible things in our world can be explained by the theory of relativity. In simple terms, such things are called consequences of general relativity. For example, rays of light flying at close distances from massive bodies are bent. Moreover, many objects from outer space are hidden one after another, but due to the fact that the rays of light bend around other bodies, seemingly invisible objects are available to our gaze (more precisely, the gaze of the telescope). It's like looking through walls.
The more gravity, the slower the time flows on the surface of the object. This applies not only to massive bodies like neutron stars or black holes. The effect of time dilation can be observed even on Earth. For example, instruments for satellite navigation are equipped with the finest atomic clocks. They are in the orbit of our planet, and time is ticking there a little faster. Hundredths of a second in a day will add up to a figure that will give up to 10 km errors in calculating the route on Earth. To calculate this error allows precisely the theory of relativity.
In simple terms, one can put it this way: General relativity is the basis of many modern technologies, and thanks to Einstein we can easily find a pizzeria and a library in an unfamiliar area.