How to understand the theory of relativity

As you know, the entire material universe has three dimensions: up and down, left and right, back and forth. The fourth dimension - time. Together they constitute the space-time continuum. But the rub is that our notions of space and time is directly dependent on the speed at which we are moving.

It is the relationship between time, space and a moving object describes the special theory of relativity (SRT) developed by Albert Einstein in 1905. Later on its basis the great physicist and a general theory of relativity (GR), which, in addition to time and space, and takes into account other factors such as gravity. On it, we will not speak - it would require a separate treatise. So, we proceed to the study of the special theory of relativity!

The main principles of the theory of relativity

The first thing to understand for the development of the theory of relativity: relative movement.

This means that the presence or absence of movement is always defined in relation to other objects. The movement and its speed depends on the observer (the one who looks at the object) and the frame of reference (the one where it looks).

Imagine that a passenger traveling on the train and read book. For him, the book still as immobile and seats on the train, and the other passengers (if they sit in their seats and not making their way to the dining car, of course). The speed of all fixed objects in the train, from the standpoint of our own, will be zero-reader passenger.

At this time, the platform should the other person, which whistled past the flying train. For him, and the passenger with a book and moves with seat train speed - say, 200 km / h. But passengers on the way to the dining car, located in the head of the convoy will move even faster: their speed will develop with the speed of the train.

This is the case with any addition of speeds, but there is one exception: the speed of light. The light from the projector on the nose of our train will always move at the same speed - 300 000 km / s.

Here we come close to the basic principles on which the theory of relativity:

• The principle of relativity: For those bodies which move relative to each other at a constant speed or vane (both passenger and his book), physical processes are the same.
• The principle of the constancy of the speed of light: The velocity of light is constant for all observers irrespective of their speed with respect to the light source. That is, the light from the lamp on the nose of the train or the light from the projector on the spacecraft have the same speed.

Light travels so fast that its spread seems instantaneous. But it looks very different distances in space. For example, the distance from the sun to the earth constituting 150 million kilometers, the light passes in approximately 8 minutes. This means that if the sun ever extinguishedWe will see it in just 8 minutes.

Consequences of the theory of relativity

What follows from the above principles and how they are related with time and space? The theory of relativity has three main consequences: space expands, time contracts, mass increases. We will understand with every order.

time is compressed

Einstein was the first to realize that time It is not absolute and depends on the frame of reference in which we observe it. Earth and distant galaxies at the other end of the universe are in different locations not only space, but time.

Relatively moving objects time goes slower. This fact has been verifiedAround-the-World Atomic Clocks: Predicted Relativistic Time Gains using two identical atomic clocks: one device left on Earth, and the other sent to the supersonic plane around the planet. When planting, it was noted that the clock that flew for a few thousandths of a second behind the clock at rest.

The closer the speed of the object becomes the speed of light, the slower time flows for him. In theory, if an astronaut will go on a trip on a spaceship at a speed close to the speed of light, he will get in the future. For it will take a few weeks, and in the world - for decades. This is the relativity of time.

space shrinks

Another surprising consequence of relativity: when we see an object in motion, we can observe that it becomes shorter with increasing speed. From the point of view of an observer when approaching the speed of light the object becomes shorter and shorter in the direction of movement and perpendicular to it remains in its former dimensions.

Suppose we plant astronaut in a spaceship that can travel at the speed of light, and themselves go into a cozy observatory observe his trip. As you approach the speed of light with the ship begins to be something strange. We note that it is becoming shorter. But changes are taking place only with respect to the direction of travel, vehicle width remains constant. Reaching the speed of light, it will become virtually indistinguishable in length.

Probably, our astronaut is not a lot of fun? Do not worry about him for the astronaut will be no change. He's just joy rushes toward the expanses of space and does not notice anything. The space is only compressed relative to the observer.

mass increases

Another remarkable consequence of relativity is the fact that as the speed of the object, its mass also increases.

Mass and energy are inextricably linked. It is expressed in Einstein's famous equation E = mc². This formula shows that the energy of the body is proportional to its mass. When transferring energy to the body (ie, its acceleration) and increased weight. It turns out that some of the energy goes to increase the speed, and the other part increases the weight.

Recall our astronauts who approaches the speed of light in his ship. Observing from the Earth, we see that as the vehicle speed becomes harder to accelerate it, there are more and more energy is required to push it. There comes a time when the ship reaches a weight that no power in the universe can no longer move it. That is why, in practice, time travel is not yet possible.

briefly

So, when approaching the speed of light being expanded, the space shrinks. But all this happens only in the eyes of the observer, who sees the movement of the object relative to itself. For astronauts in the spacecraft did not change (except for increasing the mass). But while both views are true. Therefore, the theory of relativity, and takes its name.

Still not very clear? It is not surprising, because Einstein himself took 10 years to form the basic tenets of the theory of relativity. There is a book that will help you to once again put these principles in mind and explain everything literally on your toes, with bright pictures and the available schedules. "Theory of Relativity" editorial "Avanta" publishing house AST addressed the students of the middle classes, but will be of interest to any adult who wishes to penetrate the mysteries of our universe. After what seems like miracles, in fact, a reality!

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