Lightning - Fantastic Power in the Sky!

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2 years ago

If you want, apply for one of the world's most incredible signs of unhindered power - thunder! Most people have experienced a storm at one point or another with all of its terrible aspects: rain, blinding lightning, storms, and frightening anticipation of the next blow.

Would you like to know more about the causes of this mysterious electrical phenomenon in the sky? What happens during a storm that creates such impressive forces? Since lightning is an electrical manifestation in the atmosphere, we need to know the electrical properties of air in order to understand its origin.

An electric atmosphere

We usually don't notice it, but the atmosphere we live in is very charged with electricity. The electrical potential of the atmosphere is surprisingly large. On a clear day, the potential near the ground increases an average of 150 volts per meter (45 volts per foot). The air is positive to the ground and the higher it is, the higher the tension.

This means the air on the main level can be 250 volts above the ground when you are outside of buildings and trees. Why are we not feeling the effects of this tension? A person can be electric at such a high voltage with enough current, but we don't even feel a small spark. The reason is that air is a good insulator. Our skin is a relatively good conductor of electricity and keeps our body at an equal potential. Atmospheric potential can only be measured with very sensitive instruments which are carefully isolated and protected from other electrostatically chargeable objects.

If the potential continues to increase at this speed, up to only a hundred meters, it would be 15,000 volts. However, the potential resulting from air becoming conductive at high altitudes above the stratosphere is limited. What makes this difference, that the same air that is a good insulator on the ground becomes a good conductor high in the sky? The answer lies in the phenomenon of ionization.

Air, nitrogen or oxygen molecules are generally neutral. This means that the positive charge of each atomic nucleus is exactly balanced by the negative charges of the electrons around the nucleus. However, if one of the electrons is removed from its orbit, the molecule remains positively charged. So let's say the molecule is ionized. In short, it is an ion.

This ionization effect can have several reasons, but in the lowest and clearest atmosphere, the main means are cosmic rays bombarding us from space. The energetic particles strike the air molecules with such force that electrons are released and leave positive ions behind. Free electrons can bind to other molecules and form negative ions. At altitudes of up to thirty miles, enough ions are produced to make air a good conductor.

We call this layer of conductive air the electric ball. This has sometimes been found in the ionosphere, but the latter name is correctly applied to the upper layers which reflect radio waves for more than one hundred kilometers (60 miles).

Now the ground is also a good leader. In this case, the ionic flux is transported in solution in the groundwater. Each mineral in solution in water is in the form of ions. Therefore, table salt produces positive sodium ions and negative chloride ions. Gypsum forms calcium and sulfate ions. All groundwater contains more or less dissolved minerals, and even very dry soils still have moisture. Therefore, while a small piece of earth may not have a lot of electricity, the earth's crust is so large that together it makes a very good conductor.

All parts of a good conductor must have the same electrostatic potential. If something happens that at some point increases the potential, current will flow from there to the parts with the lower potential until it is balanced. This applies to the land. This also applies to the electric ball. But the lower atmosphere is an insulator that separates the two. This way you can keep the big potential difference between them. Indeed, this system forms a gigantic electric capacitor in which the earth is negative and the electric ball is positive. The potential in the atmosphere is on average 300,000 volts. It varies considerably from hour to hour during the day and from month to month throughout the year.

Nothing is a perfect insulator. With sufficiently sensitive instruments, a small current can be detected even in the lower atmosphere. It is easily conductive due to the few cosmic rays penetrating the ground. The earth has an excess of electrons that are constantly leaking from countless points on the surface. Such point emissions occur at the tips of tree leaves, at the tips of grass leaves and even at the sharp tips of sand grains. Artificial structures that rise higher in the air compress the electric field around the top and corners of the roof, and the discharge of electrons is concentrated at these points. On the Earth's scale, these small discharges have enough total current to be able to completely empty the earth into the electrical sphere in less than an hour. Therefore, there must be a charging mechanism to keep excess electrons in the ground. And that's where the lightning comes in.

The storm as a generator

We see many types of clouds in the sky. Most are more or less flat and horizontal. But those that most arouse our admiration are the magnificent white hills that fly high in the blue sky like giant cauliflower. Under the right weather conditions, a large mound continues to grow and rises thousands of meters into the stratosphere as the base expands. Then there will be a storm cloud or thunder. When fully developed, its top is blown into a cloud that forms the familiar head of the anvil. It is still beautiful far away, but for someone during the thunderstorm it is now a dark, threatening cloud mass. Soon rain, sometimes hail, floods the land below.

It is the type of cloud that creates lightning and thunder. It is like a giant electric generator in the sky, eight to eighteen kilometers high and covers an area of ​​up to 3,000 square kilometers. There are strong ups and downs in the cloud that cause water droplets and ice crystals at speeds between forty and one hundred kilometers per hour. Countless particles of rain, ice, hail and hail remove each other as the cloud twists, swells and swells.

Obviously, gravity continues to attract water and ice, and the friction created in this way tears electrons and ions at the interfaces between air and water. and ice cream. The cargo is separated by a strong wind. These carry positive charges in the cloud, while negatively charged raindrops slide down. The potential difference between top and bottom continues to increase as the cloud matures. In the end, it is "packed" with a huge overhead. The cloud is desperate to find a way to get rid of the hundreds of millions of volts it has created within it. The quality of the air insulation can only withstand limited electrical pressure. Eventually it shatters and a dazzling flash essentially relieves stress.

An estimated 3,000 storms occur on Earth simultaneously. Most of these events take place in the area.

Most lightning strikes occur in the cloud itself, but the accumulated negative charge at the bottom of the cloud so exceeds the earth's normal potential that the lightning strikes also hit the ground and carry electrons to the ground. When the cloud dissolves, the positive charge is over it in the electrical sphere. Then, in good weather, the positive ions escape from the atmosphere to the earth to neutralize its negative charge, and the negative ions rise to the electric sphere to neutralize it. This ends the cycle.

How the beam rises

It is difficult to study lightning in the cloud. It is not a very pleasant environment for the researcher and his sensitive instruments. But lightning strikes on the ground can be seen and photographed with high-speed cameras. Thanks to these results, researchers learned a lot about the gradual formation of rays. Here is the picture shown.

It is known from laboratory tests of the electrical breakdown of air that lightning begins when the electric field reaches an intensity of about three million volts per meter (75,000 volts per inch). What happens is that the few electrons ever released by cosmic rays are pushed hard enough at this voltage to push other electrons out of the neutral molecules they hit. These in turn accelerate, collide with new molecules and ionize them. This forms a true flow of electrons moving away from the negative charge on the cloud, leaving a trail of positive ions. This weakens the air resistance and paves the way for lightning to reach the insulation blanket.

Cameras designed to stop the action in moments measured in a million seconds (microseconds) show that it is progressive action. A "shifted conductor" crosses the cloud at a point where air resistance is temporarily lower and the flow of electrons shifts about fifty meters. So, so to speak, “breathe” and take a temporary break when the potential is at its peak. After about fifty microseconds, it will burst again, possibly in a different direction, depending on the local resistance of the ionized air. Step by step, the conductors cut a highly ionized airway 1 to 10 meters wide towards the ground.

The air is more ionized in some places than in others. The rider's descent path turns to take advantage of any favorable variations. Thus, lightning takes on the familiar forked appearance when it shoots one way or the other, exploring different branches, always looking for the easiest way to reach earth. As you approach fifty yards to your destination, a banner will climb from a convenient spot on the ground to find you. The circuit is now ready! The cloud has a pipeline to release its unbearable excess electronic load.

The electrons rise first in the channel closest to the ground, immediately followed by those which rise. Then the back track, which now shines brightly, hits the cloud at a speed that approaches the light itself. Although it may have taken 20,000 microseconds for the guides to touch the ground, the returning team made the trip in just 70 microseconds. Now the cloud discharges a current of 10,000 to 20,000 amperes or more for about 40 microseconds. During that brief moment, it produces electricity in billions of kilowatts, more energy than all the power plants on Earth combined. It really is a fantastic show of strength!

The blow passes quickly, but it is rarely the end of the action. The path of the beam in air is still strongly ionized. Other parts of the cloud that are still heavily charged flash above the discharged area, and this continues through the channel, which is still open to the ground. So there are usually three or four hits in a row that repeat so quickly that it looks like a single lightning bolt. Sometimes it takes more than a dozen results to clear the cargo cloud.

Now, in just a fifth of a second, lightning does its job. "It's over, but the cry", as they say. The cry in this case is thunder. You may hear a slap, bang, or bang depending on how far you are from the beam. A narrow, curved cylinder of air, only a few inches (about an inch) thick when lightning passed, was heated to over 30,000 degrees Celsius (55,000 ° F). As soon as the flow is interrupted, this column of superheated air expands explosively at supersonic speed. The shock wave of this extension makes it possible to hear thunder up to a distance of twenty-five kilometers.

You may wonder why the Creator thought it was better to create lightning in the clouds. Good? Really do. It plays a crucial role in nature's nitrogen cycle. Nitrogen is essential for life and there is a large reserve in the atmosphere. But living things cannot use it directly. In the event of a lightning strike, the intense heat splits nitrogen and oxygen molecules into atoms, and as they cool, many combine to form nitrogen oxides. These compounds dissolve with rain and are transported to the ground. There, converted into nitrates, they provide an important fertilizer for growing plants. This is an important process for the natural fixation of nitrogen. Lightning storms are estimated to supply hundreds of millions of tonnes of nitrates each year.

Live with the rays

You have reason to be upset when lightning strikes. It has a very strong destructive ability. Lightning strikes trees and telephone poles, pierces ceilings and walls, and fires fires in forests and buildings. The electrical current in a tree is often so strong that it immediately evaporates moisture from the wood and the hot steam splits the tree.

In fact, lightning can also kill. Animals seeking shelter under a tree during storms are often electrocuted when lightning strikes a tree. People often have similar problems, especially on beaches and golf courses. Trees isolated in these areas can be electrocuted. If you are facing a storm, do not seek refuge under a special tree. Stay away from tall trees in the forest. And avoid metal fences, pipes, and train tracks. You are safer in the valley than on the hill.

If you live in an area where storms are common, protecting your home from electric shocks can be a good idea. To be effective, they must be anchored. Painted posts, connected by thick wires (insulated from the building) to a metal cable or well-buried plate, attract electricity and run it securely on the ground. Television and power lines leading to homes can be protected by electric rods.

If you’re in a car or train during a storm, there’s nothing to worry about. The metal body of the rotating car distributes the electric current and carries it down. The occupants of the aircraft are also protected from electricity. The birds are regularly beaten and sometimes have small holes in the metal skin. However, there were no reports of plane crashes directly caused by lightning. In fact, severe storms bring danger, which the pilot deliberately provides ample space.

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