# What are relativistic effects?

Classical physics holds the view that any observers, regardless of location, will receive the same results in their time and length measurements. The principle of relativity says that observers can receive different results, and similar distortions are called "relativistic effects." When approaching the speed of light, Newtonian physics departs to the side.

## Speed of light

Scientist A. Michelson, who in 1881 carried out measurements of the speed of light, realized that these results will not depend on the speed with which the source of radiation moves. Together with E.V. Morley Michelson conducted another experiment in 1887, after which it became clear to the whole world: it does not matter in which direction the measurement is being made, the speed of light is everywhere and always the same. The results of these studies ran counter to the ideas of physics of that time, because if the light moves in a certain medium (ether) and the planet moves in the same medium, measurements in different directions can not be the same in any way.

Later, the French mathematician, physicist and astronomer Jules Henri Poincaré became one of the founders of the theory of relativity. He developed the theory of Lorentz, according to which the existing ether is stationary, so the speed of light relative to it does not depend on the speed of the source. In moving frames of reference, Lorentz transformations are performed , and not Galilean transformations (Galileo transformations adopted until then in Newtonian mechanics). From now on, Galilean transformations became a special case of Lorentz transformations, when changing to another inertial frame of reference for a small (in comparison with the speed of light) velocity.

The relativistic effect of shortening of length, also called the Lorentz contraction, is that for an observer objects moving relative to it will have a shorter length.

Albert Einstein made a significant contribution to the theory of relativity. He completely abolished the term "ether", which until then had been present in the arguments and calculations of all physicists, and he shifted all concepts of the properties of space and time into kinematics.

After Einstein's work came to light, Poincare not only stopped writing scientific papers on this subject, but did not even mention his colleague's name in any of his works, except for the only case of reference to the theory of photoeffect. Poincaré continued to discuss the properties of the ether, categorically denying any publications by Einstein, although at the same time he treated the greatest scientist with respect and even gave him a brilliant description when the administration of the Higher Polytechnic School in Zurich wanted to invite Einstein to become professor of the educational institution.

## Theory of relativity

Even many of those who are completely at odds with physics and mathematics, at least in general terms, represent what is the theory of relativity, because this is perhaps the most famous of the scientific theories. Her postulates ruin everyday ideas about time and space, and although all schoolchildren study the theory of relativity, but to understand it in its entirety it is not enough just to know the formulas.

The effect of time dilation was tested in an experiment with a supersonic aircraft. The exact atomic clock on its board, after returning, fell behind for a split second. If there are two observers, one of which stands still and the other moves at a certain speed relative to the first, the time for the observer who is motionless will go faster, and for a moving object the minute will last a little longer. However, if the moving observer decides to go back and check the time, it turns out that his watch shows slightly less than the first. That is, having passed a much larger distance on the scale of space, he "lived" less time while moving.

## Relativistic effects in life

Many believe that it is possible to observe relativistic effects only when the speed of light is reached or when approaching it, and this is true, but you can observe them not only by dispersing your spacecraft. On the pages of the scientific journal Physical Review Letters you can read about the theoretical work of Swedish scientists. They wrote about the fact that relativistic effects are present even in a simple battery for the car. The process is possible due to the rapid movement of electrons in lead atoms (by the way, they are the reason for most of the voltage in the terminals). This also explains why, despite the similarity of lead and tin, tin-based batteries do not work.

## Unusual metals

The speed of rotation of electrons in atoms is rather low, and therefore the theory of relativity simply does not work, but there are some exceptions. If we move farther and farther along the periodic table, it becomes clear that there are quite a few elements heavier than lead in it. The large mass of nuclei is balanced by increasing the velocity of the electrons, and it can even approach the light velocity.

If we consider this aspect from the theory of relativity, then it becomes clear that the electrons in such a case must have a huge mass. This is the only way to preserve the angular momentum, but the orbital will contract along the radius, and this is actually observed in heavy metal atoms, but the orbitals of the "slow" electrons do not change. This relativistic effect is observed in the atoms of some metals in s-orbitals having a regular, spherically symmetric shape. It is believed that it is as a result of the theory of relativity that mercury has a liquid aggregate state at room temperature.

## Space travel

Objects in space are at great distances from each other, and even when traveling at the speed of light, it will take a very long time to overcome them. For example, to get to Alpha Centauri - the closest star to us, a spacecraft with the speed of light, it will take four years, and to reach our neighboring galaxy - the Great Magellanic Cloud - it will take 160 thousand years.

It's still possible to fly to Alpha Centauri and back, it will take only eight years, and for the ship's inhabitants, feeling the effect of slowing down time, this period will be much less, but upon returning from a trip to the neighboring galaxy, the astronauts will find that on their native planet it has been three hundred and twenty Thousands of years, and human civilization, perhaps, has long ceased to exist. Thus, relativistic effects allow people to move in time. This is considered one of the main problems of space exploration, because what is the point of conquering outer space, if there is no possibility to return?

## Other Activities

In addition to the famous time delay, there is also a relativistic Doppler effect, according to which, if the wave source starts moving, then the waves propagated towards this movement will be perceived by the observer as "compressed", and in the direction of removal, the wavelength will be increased.

A similar phenomenon is characteristic of any wave, so it can be observed using the example of sound in everyday life. The contraction of the sound wave is perceived by the human ear as an increase in tone. Therefore, when the signal of a train or car is heard from afar, it is lower, and if the train passes by the observer, while producing a sound, then its height will be higher at the moment of approach, but as soon as the objects are leveled and the train starts to move away, the tone will drop sharply And will continue on lower notes.

These relativistic effects are due to the classical analog of the frequency variation during the motion of the receiver and source, as well as the relativistic time delay.

Among other things, modern physicists are increasingly discussing the magnetic field as a relativistic effect. According to this interpretation, the magnetic field is not an independent physical material entity, it is not even one of the forms of manifestations of the electromagnetic field. The magnetic field from the point of view of the theory of relativity is just a process that arises in the space around point charges because of the transfer of an electric field.

Adherents of this theory believe that if C (the speed of light in vacuum) were infinite, then the propagation of interactions over velocity would also be unlimited, and as a result, no manifestations of magnetism could arise.