Everyone has seen. lightningYou were amazed at its power. But despite its frequency – about 8.6 million lightning strikes occur worldwide every day – why lightning proceeds in a series of steps from the thundercloud to the earth below has remained a mystery.
There are many textbooks on lightning. However, they don’t explain how these “zigzags” or steps form, nor how lightning can travel more than kilometers.
My New researchThis is an explanation.
Thunderclouds are intensely electrical and excite electrons so that they have enough energy to make what are known “singlet-delta oxygen molecules”.
These molecules and electrons combine to create a brief, highly conducting step. This light-up intensely for a millisecond.
There is a pause at the end of each step as the buildup continues. Then, another bright, flashing jump follows. It is repeated repeatedly.
Lightning protection is becoming more important because of the increasing frequency of extreme weather events. Understanding how lightning strikes occur allows us to plan how to protect buildings, planes, and people.
Additionally, the use of environmentally-friendly composite materials in aircraft improves fuel efficiency. Lightning damage can increase your riskWe need additional protection.
What is the secret to a lightning bolt?
Lightning strikes occur when thunderclouds that have an electric potential of millions upon millions of volts are connected with the earth. The ground and the sky are heated by a current of thousands if amps.
Lightning photographs reveal details that are not visible to the naked eye. Usually, you will see four to five faint “leaders,” coming from the cloud. These leaders are branches and zigzags that follow an irregular path to the earth.
The lightning strike begins when the first leader reaches the earth. The lightning strike ends with the extinguishment of all other leaders.
High-speed photography made it possible to capture even more complex scenes fifty years ago. In “steps” of approximately 50 meters (164 feet), the leaders descend from the cloud. Each step is bright for one millionth of a second. After that, it’s almost dark.
Another step is formed after 50 millionths more of a second, at the conclusion of the preceding one, but the steps before it remain dark.
Why are these steps necessary? What’s happening between the steps? How can steps be electrically connected with the cloud, but there is no visible connection between them?
These questions can be answered by understanding how an energetic electron interacts with an oxygen molecule.
If the electron has enough energy it can stimulate the molecule into singlet delta. This is a “metastable” state, which means it is not perfectly stable – but it usually doesn’t fall into a lower energy state for 45 minutes or so.
In this singlet state, oxygen is able to detach electrons (required for electricity flow) from the negative ions. These ions can be replaced by electrons which attach to oxygen molecules almost immediately.
The air can conduct electricity if it contains more than 1 percent oxygen.
The lightning steps are formed when enough metastable states can be created to separate a substantial number of electrons. The density of electrons as well as metastable state is increasing during the dark phase of a step.
After 50 millionths of a second, the step can conduct electricity – and the electrical potential at the tip of the step increases to approximately that of the cloud, and produces a further step.
The column formed by the excited molecules in the previous steps leads to the cloud. The entire column becomes electrically conducting without the need for an electric field or emission of light.
Protection of people and property
Understanding lightning formation is essential for designing protection for buildings, people, and aircraft.
Although it is Lightning rarely strikes people., buildings are hit many times – especially tall and isolated ones.
Lightning strikes a tree and causes sap to boil, resulting in steam that creates pressure, causing the trunk to split open.
The same thing happens when lightning strikes a corner of the building. Water from rain seeps into the concrete and boils. The building’s corner is blasted by the pressure, posing a danger of collapse.
Benjamin Franklin invented the lightning rod in 1752. It is essentially a thick fence wire that is attached to the top and ground. It attracts lightning and ground the electric charge. It prevents the building being damaged by directing the flow of electricity through the wire.
These Franklin rods will be required for tall buildings or churches. The only problem is how many of them are required.
Hundreds of structures, including shelter sheds, are not protected. These structures are usually made of highly conductive galvanized steel, which attracts lightning and is supported by wooden posts.
Standards Australia recommends that such shelters be grounded in the new version for lightning protection.
John LowkeAdjunct Professor of Physics. University of South Australia
This article has been republished from The ConversationUnder a Creative Commons License Learn more Original article.
