The probability of being struck by lightning is less than one in a million, but that probability has decreased significantly this month, with more than 4.2 million lightning strikes recorded in every Australian state and territory over the weekend of 12-13 November. That’s a huge amount of electricity when you consider that each lightning bolt is traveling at over 200,000 miles per hour.
Have you ever wondered about lightning? For the past 50 years, scientists around the world have debated why lightning zigzags and how it relates to a storm cloud. No definitive explanation has been given so far, as a plasma physicist at the University of South Australia has published a landmark paper that solves both mysteries.
Dr John Locke, a former CSIRO scientist and now an assistant research fellow at UniSA, says the physics of lightning has puzzled top scientists for decades.
“There are several textbooks on lightning, but none explain how zigzags (called steps) form, why the conductive column connecting the steps to the cloud remains dark, and how lightning can travel for miles.” – Dr. locke . says
Answer? Singlet-delta metastable oxygen molecules.
Basically, lightning occurs when electrons strike oxygen molecules with enough energy to form high-energy single delta oxygen molecules. After colliding with the molecules, the “separated” electrons form a highly conductive step, bright at first, which redistributes the electric field, causing successive steps.
The conductive column connecting the cascade to the cloud remains dark as the electrons bind to neutral oxygen molecules, then the electrons are immediately separated by single delta molecules.
Why is this important?
“To better protect buildings, airplanes, skyscrapers, precious churches and people, we need to understand how lightning starts,” says Dr.Loucke.
Although people are rarely struck by lightning, buildings, especially tall and isolated buildings (the Empire State Building is struck by lightning about 25 times a year), do happen many times. The solution for protecting structures from lightning strikes has remained unchanged for hundreds of years.
Invented by Benjamin Franklin in 1752, the lightning rod is essentially a thick fence wire that attaches to the roof of a building and attaches to the ground. It is designed to attract lightning and protect the building from damage by grounding the electrical charge.
Dr. “These Franklin rods are necessary for all buildings and churches today, but the unclear factor is how many are needed for each structure,” Locke says.
Hundreds of structures, often made of galvanized iron and supported by wooden posts, are also currently unprotected, including sheds in parks. This could change with new Australian lightning protection standards that recommend grounding roofs. Dr Locke was a member of the Australian Standards Committee that recommended this change.
“Improving lightning protection is now crucial because of more extreme weather events caused by climate change. Also, as the development of environmentally friendly composite materials in aircraft improves fuel efficiency, these materials significantly increase the risk of lightning damage, so we need to review additional protection measures.
“The more we know about how lightning occurs, the more knowledgeable we will be in designing our anthropogenic environment,” says Dr.Loucke. Source
Source: Port Altele
