The magnetic interaction of objects is one of the fundamental processes that govern everything in the Universe. Its visible manifestations are magnetic phenomena. Among them are the northern lights, the attraction of magnets, magnetic storms, etc. How do they arise? What are they?
Magnetism
Magnetic phenomena and properties are collectively referred to as magnetism. Their existence has been known for a very long time. It is assumed that as early as four thousand years ago, the Chinese used this knowledge to create a compass and navigate in sea voyages. Conducting experiments and seriously studying the physical magnetic phenomenon began only in the 19th century. Hans Oersted is considered one of the first researchers in this field.
Magnetic phenomena can occur both in Space and on Earth, and appear only within magnetic fields. Such fields arise from electric charges. When the charges are stationary, an electric field forms around them. When they move - a magnetic field.
That is, the phenomenon of the magnetic field occurs with the advent ofelectric current or alternating electric field. This is a region of space within which a force acts that affects magnets and magnetic conductors. It has its own direction and decreases as it moves away from its source - the conductor.
Magnets
A body around which a magnetic field is formed is called a magnet. The smallest of them is the electron. The attraction of magnets is the most famous physical magnetic phenomenon: if you attach two magnets to each other, they will 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 each other, while opposite 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 are magnetic. These include iron, cob alt, nickel, steel, etc. Among them there are liquids, alloys, chemical compounds. If magnets are held near a magnet, they will become one themselves.
Substances such as pure iron easily acquire this property, but also quickly say goodbye to it. Others (such as steel) take longer to magnetize but retain the effect for a long time.
Magnetizing
We have established above that a magnetic field arises when charged particles move. But what kind of movement can we talk about, for example, in a piece of iron hanging on a refrigerator? Allsubstances are made up of atoms, which contain moving particles.
Each atom has its own magnetic field. But, in some materials, these fields are directed randomly in different directions. Because of this, one large field is not created around them. Such substances are not capable of magnetization.
In other materials (iron, cob alt, nickel, steel) the atoms are able to line up so that they all point in the same way. As a result, a common magnetic field is formed around them and the body becomes magnetized.
It turns out that the magnetization of a body is the ordering of the fields of its atoms. To break this order, it is enough to hit it hard, for example, with a hammer. The fields of atoms will begin to move chaotically and lose their magnetic properties. The same will happen 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 certainly arise. But can it be the other way around? The English physicist Michael Faraday once asked this question and discovered the phenomenon of magnetic induction.
He concluded that a constant field cannot cause an electric current, but a variable one can. The current occurs in a closed circuit of the magnetic field and is called induction. In this case, the electromotive force will change in proportion to the change in the speed of the field that permeates the circuit.
Faraday's discovery was a real breakthrough and brought considerable benefits to electrical manufacturers. Thanks to him, it became possible to receive current from mechanical energy. The law deduced by the scientist was applied andused 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 hardly notice it. It is not tangible, has no taste or smell. But it is with him that magnetic phenomena in nature are associated. Such as the aurora, magnetic storms or magnetoreception in animals.
Essentially, the Earth is a huge, but not very strong magnet, which has two poles that do not coincide with the geographic ones. Magnetic lines leave the South Pole of the planet and enter the North. This means that in fact the South Pole of the Earth is the north pole of the magnet (hence why in the West the south pole is denoted in blue - S, and in red 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 heat and light, but also provokes such unpleasant magnetic phenomena as storms. Their appearance is associated with an increase in solar activity and the processes that occur inside this star.
The Earth is constantly affected by the flow of ionized particles from the Sun. They move withspeed of 300-1200 km/s and are characterized as solar wind. But from time to time, sudden ejections of a huge number of these particles occur on a star. They act like shocks on the earth's shell and cause the magnetic field to oscillate.
Such storms usually last up to three days. At this time, some inhabitants of our planet feel unwell. The vibrations of the shell are reflected in us with headaches, increased pressure and weakness. In 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 sky glow with rapidly changing colors, and occurs mainly in high latitudes (67-70 °). With strong activity of the Sun, the radiance is observed even lower.
About 64 kilometers above the poles, charged solar particles meet the far reaches of the magnetic field. Here, some of them head to the Earth's magnetic poles, where they interact with the gases of the atmosphere, which is why the aurora appears.
The spectrum of the glow depends on the composition of the air and its rarefaction. The red glow occurs at an altitude of 150 to 400 kilometers. Blue and green shades are associated with a high content of oxygen and nitrogen. They occur at an altitude of 100 kilometers.
Magnitoreception
The main science that studies magnetic phenomena is physics. However, some of them may also be related to biology. For example, the magnetic sensitivity of livingorganisms - the ability to recognize the Earth's magnetic field.
Many animals, especially migratory species, have this unique gift. The ability to magnetoreception was found in bats, pigeons, turtles, cats, deer, some bacteria, etc. It helps animals navigate in space and find their home, moving away from it for tens of kilometers.
If a person uses a compass for orientation, then animals use completely natural tools. Scientists are not yet able to determine exactly how and why magnetoreception works. But it is known that pigeons are able to find their home even if they are taken hundreds of kilometers away from it, while closing the bird in a completely dark box. Turtles find their birthplace even years later.
Thanks to their "superpowers", animals anticipate volcanic eruptions, earthquakes, storms and other cataclysms. They are sensitive to fluctuations in the magnetic field, which increases the ability to self-preservation.
