Using the University of Florida’s ECE Lightning Research Laboratory, scientists from the Southwest Research Institute artificially induced Thor’s lightning strikes to capture the first ever image of thunder.
Thunder and lightning, the basics
The sights and sounds of lightning and thunder have captivated the attention of us starry-eyed earthlings for centuries. A series of flashes followed by deep rumbles and snapping crackles sends loved ones into each others’ arms and little children under the covers. Awe. But this is science, damn you, and the discovery of truth their quest!
Lightning is what you see, and is the result of electrical charges moving vertically between clouds and the surface of the Earth or horizontally between clouds. As these electrical chargers rip through the skies, the surrounding air heats up which eventually releases a sudden burst of energy in the form of sound that we know as the grumblings of thunder.
Since thunder can’t be seen to the naked eye, scientists created an acoustic map of thunder.
Acoustic imaging of thunder explained
To create this acoustic map of thunder, Dr. Maher A. Dayeh and his team positioned fifteen microphones, each a meter apart, around an area from which they fired a rocket with a copper wire trailing behind into a storm cloud. As the lighting bolts traveled down the wire, Dayeh and his team used a variety of techniques to record higher sound frequencies, which eventually led them to identify the specific sound signature of thunder. They then processed these sound waves to provide the first ever visual image of thunder.
Other than its obvious coolness factor, scientists are also excited about this discovery because more studies like this will provide greater insight into the nature of thunder and lightning, which are expected to increase in the near future due to global warming.
Lightning strikes the Earth more than 4 million times a day, yet the physics behind this violent process remain poorly understood. While we understand the general mechanics of thunder generation, it’s not particularly clear which physical processes of the lightning discharge contribute to the thunder we hear. A listener perceives thunder largely based upon the distance from lightning. From nearby, thunder has a sharp, cracking sound. From farther away, it has a longer-lasting, rumbling nature. MAHER A. DAYEH
The following video shows how a rocket trailing copper wire generates lightning when fired into a storm cloud:
Putting the importance of this technique succinctly, Joseph Dwyer, an atmospheric physicist at the University of New Hampshire in Durham who was not involved in the research, says, “Whenever we can come up with a new tool for studying lightning or seeing it in a new way, that’s a good thing. That’s what this new acoustic imaging does”