Scientists discover what thunder looks like
Thor’s got nothing on the Southwest Research Institute. A group of geophysicists from the Institute have come up with a way to capture what thunder looks like. It is the first time on record that the audio phenomenon has been visually recorded.
“Lightning strikes the Earth more than 4 million times a day, yet the physics behind this violent process remain poorly understood,” Maher Dayeh, a research scientist at the institute, said, according to Tech Radar.
The sound of thunder is created when air is superheated by lightning. We know the temperature reaches about three times hotter than the surface of the sun, and we know the general mechanics of how thunder is created as a result. Scientists aren’t all that clear on why we hear thunder differently based on location though.
“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,” Dayeh said.
When lightning strikes, those at a distance hear a low, rumbling sound. Those near the lighting, however, hear a sharp cracking sound.
“The farther you go, it gets more complex as propagation effects get more into play,” he said. “That said, this is a topic to be investigated.”
To study this, the geophysicists launched a small rocket into the predicted path of a lightning storm. The rocket remained attached to the ground using a copper wire, which conducted the lighting in a controlled manner.
To record the thunder, the researchers placed 15 microphones, each about a meter apart, starting at 95 meters from the launch pad. Initially, the scientists thought the experiment had failed. The results yielded an interesting image, but not a useful one.
Things changed when the researchers reexamined the image at a higher frequency.
“The red indicates the highest acoustic pressure associated with the shock wave arrival at the array’s ‘ear,’” Dayeh said. “The surrounding green and blue are from ground reflections and background noise.”
The result for the team is a new understanding of how lightning and the corresponding thunder interact. For the rest of us, we get to see thunder. Bet you didn’t think you’d see that any time soon.