Lightning

Lightning is a fascinating natural phenomenon that happens when there are strong electrical charges in the atmosphere. It occurs when these charges discharge between two regions—one often in the sky and the other sometimes on the ground. This discharge happens very quickly and releases a lot of energy.

When lightning strikes, the air around it heats up very fast to about 30,000 °C—hotter than the surface of the sun! This quick heating creates a shock wave that we hear as thunder. Lightning also gives off bright flashes of light and affects the Earth’s atmosphere and weather patterns.

Lightning is most commonly seen during thunderstorms, but it can also happen during other intense weather events like volcanic eruptions. It plays a role in starting wildfires and helps scientists learn more about our planet’s electrical system. Studying lightning is called fulminology, and it helps us understand our atmosphere and climate better.

Forms

Main articles: Types of lightning and Thunderstorm

There are three main types of lightning, based on where they happen:

• Intra-cloud (IC) or in-cloud – This occurs within a single thundercloud.
• Cloud-to-cloud (CC) or inter-cloud – This happens between two clouds.
• Cloud-to-ground (CG) – This occurs between a cloud and the ground, and is called a lightning strike.

Other types include volcanic lightning, which happens during volcanic eruptions; “heat lightning”, seen from far away but not heard; dry lightning, which can start forest fires; and ball lightning, a rare phenomenon.

Cloud-to-ground lightning is the main type that affects people and property, even though the other two types are more common.

Formation

Lightning happens when warm air mixes with cold air, creating storms. These storms can make lightning and thunder, called thunderstorms. Lightning is not just in thunderstorms. It can also happen during dust storms, forest fires, tornadoes, volcanic eruptions, and even in winter as thundersnow. Hurricanes often have lightning in their rainbands.

Big forest fires can make their own weather. They create a special kind of lightning called fire lightning. These fires make heat that pushes air up fast, making pyrocumulonimbus clouds. These clouds can make dry lightning and other weather effects.

Distribution, frequency and properties

Main article: Distribution of lightning

Lightning happens all the time on Earth. It strikes about 44 times every second, which means nearly 1.4 billion flashes each year. Most lightning occurs over warm land areas near the equator, where the air moves a lot. Lightning is usually made by big storm clouds called cumulonimbus clouds. These clouds can be very tall, reaching up to 15 kilometers high.

Sometimes, lightning can travel very far. These are called megaflashes. They can stretch for about 100 kilometers or more and last longer than normal lightning. Scientists have seen these megaflashes in parts of North and South America. Lightning is not just on Earth; it has also been seen on other planets like Jupiter and Saturn.

Effects

A lightning strike can cause many different effects, both temporary and long-lasting. It can create bright light, loud sounds, and electromagnetic waves. It can also lead to damage to nature, buildings, aircraft, and living beings.

Lightning can harm nature in several ways. It can cause trees to catch fire or split apart. It can also create special glass-like structures called fulgurites in the ground. For buildings, lightning can cause damage if it strikes them directly. Special lightning rods and surge protectors help protect buildings and their electrical systems from this damage. Aircraft are generally safe from lightning because their metal bodies act like protective shields, though lightning can sometimes affect instruments.

Lightning can also affect living beings. While most people who are struck by lightning survive, it can still cause serious injuries. Thunder, the sound that follows lightning, is created when the air rapidly expands from the heat of the lightning. The distance to a lightning strike can be estimated by counting the seconds between the flash and the sound of thunder. Lightning also creates electromagnetic waves, including radio waves and, sometimes, high-energy X-rays and gamma rays. These can travel far from the strike and affect electronic devices.

Lightning has lasting effects on the environment. It can change the chemistry of the atmosphere, creating ozone and nitrogen oxides. It also plays a role in the nitrogen cycle by creating nitrates that fertilize the soil. The strong magnetic fields created by lightning can sometimes magnetize rocks and soil, leaving a lasting mark.

Detection and monitoring

Lightning can be found using special tools. One of the first tools was the lightning bell, which Benjamin Franklin used in his home. Today, tools can watch lightning from far away by catching the radio waves it makes. These tools help scientists learn where and when lightning happens.

Scientists can also make lightning happen in a safe way using rockets or strong lasers. Rockets with wires can make a path for lightning, and lasers can make a line in the air that might lead the lightning. These ways help researchers study lightning safely.

Impact of climate change and air pollution

Lightning patterns are changing because of climate change, especially in places like the Arctic, where lightning happens more often. Scientists find it tricky to know exactly how lightning will change because it depends on complicated cloud actions. In some places, like Africa, there might be more days with lightning and stronger storms.

Air pollution can also change lightning. Some pollution can make lightning happen more, but too much pollution can actually make it happen less. When lightning strikes, it can make things that either warm the planet or help clean the air by breaking down bad gases.

Lightning and climate change feedbacks

Lightning affects the climate in several ways. It can make gases that warm the planet and also destroy gases that clean the air. This creates a balance that scientists are still learning about. Lightning is also a big natural reason for wildfire, which can change the climate by releasing more gases and altering plants. In polar areas, fires caused by lightning might affect permafrost and plants, though what happens in tropical areas is still not clear.

In culture

The first known photograph of lightning was taken in 1847 by Thomas Martin Easterly, and the first surviving photograph was taken in 1882 by William Nicholson Jennings. Many cultures see lightning as a sign of gods or powerful forces. For example, Zeus in Greek mythology, Thor in Norse mythology, and Indra in Hindu mythology are all linked to lightning.

In popular culture, people often think lightning never strikes the same place twice, but this isn’t true—lightning can and does strike the same spot many times. For example, the Empire State Building in New York City is struck about 23 times each year. Lightning is used as a symbol of power and speed in flags, logos, and military symbols.