Magnetic phenomena. Magnetic phenomena in nature

The magnetic interaction of objects is one of the fundamental processes that guide everyone in the universe. Its visible manifestations are magnetic phenomena. Among them you can name the northern lights, the attraction of magnets, magnetic storms, etc. How do they arise? What is characterized?

Magnetism

Magnetic phenomena and properties in the aggregate are called magnetism. Their existence was known for a long time. It is assumed that already four thousand years ago, the Chinese used this knowledge to create a compass and navigate in sea trips. To conduct experiments and seriously study the physical magnetic phenomenon began only in the XIX century. One of the first researchers in this field is Hans Oersted.

Magnetic phenomena can occur both in the Cosmos and on the Earth, and appear only within magnetic fields. Such fields arise from electric charges. When the charges are stationary, an electric field is formed around them. When they move - the magnetic field.

That is, the phenomenon of a magnetic field arises with the appearance of an electric current or an alternating electric field. This is a region of space within which a force acts on magnets and magnetic conductors. It has its direction and decreases with distance from its source - the conductor.

Magnets

The body around which a magnetic field is formed is called a magnet. The smallest of them is an electron. The attraction of magnets is the most well-known physical magnetic phenomenon: if two magnets are applied to each other, they either attract or repel. It's all about their position relative to each other. Each magnet has two poles: north and south.

Poles of the same name repel, and unlike poles, on the contrary, attract. If you cut it in two, the north and south poles will not separate. As a result, we will get two magnets, each of which will also have two poles.

There are a number of materials that have magnetic properties. These include iron, cobalt, nickel, steel, etc. Among them there are liquids, alloys, chemical compounds. If the magnetics are held near the magnet, then they themselves will become it.

Such substances as pure iron, easily acquire a similar property, but also quickly say goodbye to it. Others (for example, steel) are magnetized longer, but they retain the effect for a long time.

Magnetization

We have established above that a magnetic field arises when charged particles move. But what movement can there be, for example, in a piece of iron hanging on the refrigerator? All substances consist of atoms in which the moving particles are located.

Each atom has its own magnetic field. But, in some materials these fields are directed chaotically in different directions. Because of this, one large field is not created around them. Such substances are not able to be magnetized.

In other materials (iron, cobalt, nickel, steel), atoms are able to line up so that they are all directed in the same way. As a result, around them a common magnetic field is formed and the body is magnetized.

It turns out, the magnetization of the body is the ordering of the fields of its atoms. To break this order, hit him hard enough, for example, with a hammer. Fields of atoms will start chaotic motion and will lose magnetic properties. It also happens if the material is heated.

Magnetic induction

Magnetic phenomena are associated with moving charges. So, around a conductor with an electric current, a magnetic field will inevitably arise. But can it be vice versa? This question was once asked by the English physicist Michael Faraday and discovered the phenomenon of magnetic induction.

He concluded that a constant field can not cause an electric current, but an alternating current can. The current arises in a closed loop of the magnetic field and is called induction. The electromotive force in this case will vary in proportion to the change in the field velocity that the contour is permeating.

The discovery of Faraday was a real breakthrough and brought great benefit to the manufacturers of electrical engineering. Thanks to him, it became possible to receive current from mechanical energy. The law, deduced by the scientist, was applied and applied in the device of electric motors, various generators, transformers, etc.

Earth's magnetic field

Jupiter, Neptune, Saturn and Uranus have a magnetic field. Our planet is no exception. In ordinary life, we almost do not notice it. It is not tangible, has no taste or smell. But it is with it that magnetic phenomena are associated in nature. Such as polar lights, magnetic storms or magnetoreception in animals.

In fact, the Earth is a huge, but not very strong magnet, which has two poles that do not coincide with the geographic. Magnetic lines emerge from the South Pole of the planet and enter the North Pole. This means that, in fact, the South Pole of the Earth is the north pole of the magnet (so in the West, the blue pole is designated in blue as S, and the red pole denotes the north pole-N).

The magnetic field extends hundreds of kilometers from the surface of the planet. It serves as an invisible dome that reflects powerful galactic and solar radiation. During the collision of radiation particles with the Earth's shell, many magnetic phenomena are formed. Let's look at the most famous of them.

Magnetic storms

The Sun has a strong influence on our planet. It not only gives us warmth and light, but also provokes such unpleasant magnetic phenomena as storms. Their appearance is associated with an increase in solar activity and processes that occur within this star.

The earth constantly experiences the influence of the flow of ionized particles from the Sun. They move at a speed of 300-1200 km / s and are characterized as a solar wind. But from time to time on the star there are sudden emissions of a huge number of these particles. They act on the earth's shell as jerks and cause the magnetic field to oscillate.

Such storm lasts usually up to three days. At this time, some inhabitants of our planet are unwell. Oscillations of the shell are reflected on us by headaches, increased pressure and weakness. For a lifetime, a person experiences an average of 2,000 storms.

Northern Lights

There are also more pleasant magnetic phenomena in nature - the northern lights or the Aurora. It manifests itself in the form of a glow of the sky with rapidly changing colors, and occurs predominantly in high latitudes (67-70 °). With strong activity of the sun, the brightness is observed even lower.

About 64 kilometers above the poles, charged solar particles meet with distant magnetic field boundaries. Here, some of them are directed to the magnetic poles of the Earth, where they interact with the gases of the atmosphere, which is why the radiance appears.

The spectrum of luminescence depends on the composition of the air and its rarefaction. Red glow occurs at an altitude of 150 to 400 kilometers. Blue and green shades are associated with a large content of oxygen and nitrogen. They occur at an altitude of 100 kilometers.

Magnetoreception

The basic science that studies magnetic phenomena is physics. However, some of them may also affect biology. For example, the magnetosensitivity of living organisms is the ability to recognize the Earth's magnetic field.

This unique gift is possessed by many animals, especially migratory species. The ability to magnetoreception was found in bats, pigeons, turtles, cats, deer, some bacteria, etc. It helps animals to navigate in space and find their habitation, moving away from it for tens of kilometers.

If a person uses the compass for orientation, then the animals use quite natural tools. Scientists can not determine exactly how and why magnetoreception works. But it is known that pigeons can find their home even if they are taken away from it for hundreds of kilometers, while closing a bird in an absolutely dark box. Turtles find their birth place even years later.

Due to their "super abilities", animals anticipate volcanic eruptions, earthquakes, storms and other cataclysms. They thinly feel the vibrations in the magnetic field, which increases the ability to self-preservation.