Understanding the Mysteries of Lightning: Strikes and Science
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Chapter 1: The Myths and Realities of Lightning
It’s a common belief that lightning never strikes the same place twice, but this is a misconception. In fact, the Empire State Building is hit by lightning approximately 23 times each year. To illustrate this, check out this striking video showing the building being hit three times in under a minute:
You might also think that scientists fully understand how lightning works, which is also misleading. Ningyu Liu, a physics professor at the University of New Hampshire's Space Science Center, states, "Despite over 250 years of research, the origins of lightning remain a mystery." This indicates a strong demand for experts in the field.
Liu participated in one of two recent studies that unveiled new insights into lightning, which seems to become even more enigmatic with each discovery. Brian Hare, a postdoctoral researcher at the KVI-CART Institute in the Netherlands, has also made significant contributions. His team recently identified previously unseen structures known as "lightning needles" within thunderstorms. I inquired about the current state of lightning research, and Hare remarked, "We still don’t understand how lightning initiates, travels through clouds, connects to the ground, or why it exhibits its peculiar behaviors."
Section 1.1: A Historical Perspective
To grasp the current understanding of lightning, let’s take a step back. Serious lightning research began over 250 years ago—specifically, in 1752 when Benjamin Franklin’s kite experiment demonstrated a connection between electricity and lightning, although Franklin did not discover electricity itself.
In the late 1800s, advancements in photography allowed scientists to observe lightning more closely. Modern slow-motion video technology has further enriched our understanding of this complex phenomenon.
Current knowledge suggests that lightning originates within turbulent thunderstorm clouds, where strong updrafts and downdrafts interact. The process unfolds as follows:
- Ice particles collide amidst turbulence, stripping away electrons and creating differently charged particles that become separated.
- Smaller particles generally acquire a positive charge, while larger ones tend to gain negative charges. Updrafts elevate lighter particles, fostering a charge difference.
- Once the charge reaches millions of volts, the air’s resistance breaks down, leading to the formation of a conductive plasma.
The process continues with two types of plasma channels, known as leaders, moving in opposite directions based on their charges. Positive leaders grow steadily, whereas negative leaders leap in steps, rapidly searching for an area of opposite charge to connect with, resulting in what we recognize as lightning.
Subsection 1.1.1: Understanding the Breakdowns
However, there are gaps in our understanding. For instance, while we know the air "breaks down," the specifics of how this occurs remain elusive. Hare explains that although the principles of dielectric breakdown are understood on the ground, the mechanisms in the clouds are still unclear. Liu elaborates that measurements of thunderstorm electric fields have consistently shown they fall below the threshold necessary for breakdown, suggesting that more research is needed.
Section 1.2: New Discoveries in Lightning Research
In a groundbreaking study, Liu and his team observed a process they termed "fast negative breakdown," which contradicts previous beliefs that lightning initiation was primarily due to fast positive breakdown. This revelation indicates that lightning formation may be more complex than previously thought.
Eight days later, Hare’s research team made an intriguing discovery of needle-like structures in lightning that might explain why lightning can strike multiple times in quick succession. These structures could be responsible for the phenomenon where a single lightning event produces multiple strikes.
Section 1.3: The Multiple Strikes Phenomenon
The occurrence of multiple strikes during a single lightning event has been documented for years. Research from 1997 revealed that a flash event could produce multiple ground hits, often in close proximity.
Tall structures such as mountains, trees, and buildings are more prone to lightning strikes due to their proximity to storm clouds. Locations abundant in conductive materials, like salt or metal, also attract lightning.
In summary, while we have made strides in understanding lightning, many questions remain. Despite significant advancements in safety measures, lightning-related fatalities have decreased over the decades, illustrating the impact of awareness and education in minimizing risks associated with this powerful natural phenomenon.