November 10, 2020

Lightning, Regarded as Divine Punishment to People, but as God’s Grace to Plants


When the sky is covered with thick clouds, most people feel scared. What if there are also lightning and thunder? The fear will be doubled. In order to encourage terrifying and scary atmosphere in the visual media, thunder and lightning are not omitted. Also, about those who have committed grave crimes or done something harmful to society, Korean people say, “They are going to be hit by thunderbolt.”

Here, thunderbolt means punishment from heaven. Although thunderbolt, lightning, and thunder are common natural phenomena, people have felt dreadful about them.

Lightning happens when the electric charge, generated by clouds, flows in the air. Lightning is usually created in a cumulonimbus cloud, a vertically long cloud, on rainy days. Caused by various factors, if the air makes a sharp upward movement, its temperature drops. Then the vapors in the air cool and condense into droplets. These droplets gather and form a cloud. The cloud that is suddenly made becomes a towering cumulonimbus cloud.

A cumulonimbus cloud is so thick that the temperature difference between its top and bottom is great. That’s why droplets are formed on the bottom where the temperature is rather high, and ice crystals are formed on the upper part where the temperature is much low. As the droplets and ice crystals move fast, they rub against each other, exchange electrons, and become electrified with large charges. Generally, electricity does not flow in the air well, but it’s possible if there is the voltage of over three million.

Between electrically charged clouds, or between a cloud and the ground, the voltage of about 0.1 to 1 billion volts is made and the electric current flows simultaneously. The flash that occurs at this time is lightning.

A lightning generated between the cloud and the ground

Thunderbolts and lightning are slightly different. A thunderbolt is a lightning which strikes something on the surface of the earth. As it refers to electric discharges only between a cloud and the ground, lightning is a more generic term.

When there is lightning, a sound of thunder is created as powerful electricity flows in the air. When electricity flows in the air, it instantaneously heats the air and causes it to expand explosively. This expansion of the air produces a powerful shock wave that is heard as thunder. Balloon popping sound is the same kind of air collision like thunder.

We hear the rolling of thunder after lightning every time. Actually, as the lightning creates a shock wave audible as thunder, thunder and lightning start at the same time. However, compared with the light which travels at 300,000 km/s, sound travels slowly at 340 m/s. Since the speed of sound and that of light are different, we see lightning, which is light, first, and then we hear a clap of thunder.

Through the time lapse between lightning and thunder, it is possible to measure the distance between the lightning occurrence spot and its observation point. For example, if you hear thunder three seconds after lightning, the place where the lightning and thunder occurred can be estimated to be about 1 km [0.6 miles] away from you. In this case, it is better to go inside a building as quickly as possible. Because as the lightning occurred at a comparatively close distance, you might get hit by lightning in a state of being exposed to the outside.

If a man is hit by lightning, an electric current of tens of thousands of amperes flows inside the body instantaneously. If the current flows through the heart, the man dies on the spot. Even if the current doesn’t flow through the heart, the body parts where the current flowed will be badly damaged, either burnt or shocked. Like this, lightning is terrifying and dangerous for people. However, it is very precious and indispensable for plants because lightning disassembles nitrogen in the air and provides it to plants.

Plants cannot live without nitrogen. All living creatures are composed of organic compounds such as protein, lipid, carbohydrate, nucleic acid, etc. Among them, the most essential substance for the growth of living creatures is protein. To make cells through cell division, protein is essential because it is the main component of cells. Therefore, living creatures must constantly ingest or synthesize protein. The necessary element to make protein is nitrogen.

Animals ingest nitrogen by eating other living creatures, but plants can’t do that. From a long time ago, providing nitrogen to plants was important for farming crops. That’s why people made fertilizer by using human feces or urine and provided it to plants. It’s because human feces and urine have ammonium and nitrate which contain nitrogen. As nitrogen fertilizer was produced in the early 20th century, crops grew faster in a short period of time and the amount of harvest increased, which developed agriculture rapidly.

Then what about non-crop plants? Plants can absorb nitrogen from remains of animals and plants, but there is a limit in its amount. The easiest way for plants to take in nitrogen is from the air. Air is composed of 78% of nitrogen, 21% of oxygen, and 1% of other gases such as argon and carbon dioxide. But plants cannot absorb nitrogen directly from the air, because nitrogen molecules are unreactive in the air.

Some plants get help from nitrogen-fixing bacteria in order to obtain nitrogen. Root nodule bacteria, which are symbiotic in the roots of legumes, are a typical example. Instead of obtaining carbon and other breeding materials from legumes, these bacteria fix nitrogen in the air and produce nitrogenous compounds, and provide them to the roots of the plants. Thanks to these bacteria, legumes produce high quality protein.

However, for most other plants, lightning is an additional source of nitrogen supply. Lightning changes nitrogen in the air into a form that plants can absorb. When the high energy of lightning is applied to the nitrogen molecules in the air, the nitrogen molecules dissociate and combine with oxygen. Then they become the form of nitrate, go into the ground, and get absorbed by plants.

One of the proverbs holding the ancestors’ wisdom said, “A year with a lot of lightning is a year of abundance.” Lightning is an object of fear for people, but it is an indispensable blessing for plants. There is a reason for everything to exist.

“He aquí que sobre él extiende su luz [“relámpago” en la versión Dios Habla Hoy], y cobija con ella las profundidades del mar. Bien que por esos medios castiga a los pueblos, a la multitud él da sustento.”Job 36:30-31