We all know thunder and lightning go together, but, even for scientists who have made it their mission to study these things, it's not entirely clear how.

"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," Dr. Maher A. Dayeh, a research scientist in the Southwest Research Institute (SwRI) Space Science and Engineering Division, said in a press release. "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."

Dayeh and a team from SwRI set out to visually capture the sound waves created by thunder. Of course, lightning is a visual representation of the same complex process of electrostatic charges that cause thunder—or conversely, thunder is the audible representation of lightning—but by imaging the acoustics, researchers hope to gain a better understanding of exactly where the thunder originates.

To do so, they had to figure out a way to harness thunder and lightning. This was accomplished by sending a small rocket that had a copper wire attached to it into a storm. The copper served to attract lightning to a specific spot so that the scientists knew where to focus their instruments—specifically, 15 microphones, spaced one meter apart, lined up 95 meters away from where the triggered lightning would strike.

The resulting images appeared to be total nonsense at first, but when Dayeh viewed them at a higher frequency, they revealed a distinct thunder footprint.

Here, you can see how the rocket trailing copper attracts the lightning bolt to the predetermined location:

Below, on the left, you can see a long exposure of the copper wire as it is repeatedly struck by lightning. On the right, you can see acoustic data for the nine different lightning strIkes and their distinct signatures:

Image Courtesy of University of Florida, Florida Institute of Technology, and Southwest Research Institute

You can see a similar phenomenon in the images below. Those white lines in the top two photos are long exposure shots of lightning bolts. In the bottom two, you can see how the shape of the acoustic renderings matches the lightning above:

Image Courtesy of University of Florida, Florida Institute of Technology, and Southwest Research Institute

[h/t Science Daily]