CLOSE
iStock
iStock

This Is What Thunder Looks Like

iStock
iStock

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]

nextArticle.image_alt|e
Mark Ralston/AFP/Getty Images
arrow
Big Questions
What Causes Sinkholes?
Mark Ralston/AFP/Getty Images
Mark Ralston/AFP/Getty Images

This week, a sinkhole opened up on the White House lawn—likely the result of excess rainfall on the "legitimate swamp" surrounding the storied building, a geologist told The New York Times. While the event had some suggesting we call for Buffy's help, sinkholes are pretty common. In the past few days alone, cavernous maws in the earth have appeared in Maryland, North Carolina, Tennessee, and of course Florida, home to more sinkholes than any other state.

Sinkholes have gulped down suburban homes, cars, and entire fields in the past. How does the ground just open up like that?

Sinkholes are a simple matter of cause and effect. Urban sinkholes may be directly traced to underground water main breaks or collapsed sewer pipelines, into which city sidewalks crumple in the absence of any structural support. In more rural areas, such catastrophes might be attributed to abandoned mine shafts or salt caverns that can't take the weight anymore. These types of sinkholes are heavily influenced by human action, but most sinkholes are unpredictable, inevitable natural occurrences.

Florida is so prone to sinkholes because it has the misfortune of being built upon a foundation of limestone—solid rock, but the kind that is easily dissolved by acidic rain or groundwater. The karst process, in which the mildly acidic water wears away at fractures in the limestone, leaves empty space where there used to be stone, and even the residue is washed away. Any loose soil, grass, or—for example—luxury condominiums perched atop the hole in the ground aren't left with much support. Just as a house built on a weak foundation is more likely to collapse, the same is true of the ground itself. Gravity eventually takes its toll, aided by natural erosion, and so the hole begins to sink.

About 10 percent of the world's landscape is composed of karst regions. Despite being common, sinkholes' unforeseeable nature serves as proof that the ground beneath our feet may not be as solid as we think.

A version of this story originally ran in 2014.

nextArticle.image_alt|e
iStock
arrow
science
DNA Analysis of Loch Ness Could Reveal the Lake's Hidden Creatures
iStock
iStock

Stakeouts, sonar studies, and a 24-hour video feed have all been set up in an effort to confirm the existence of the legendary Loch Ness Monster. Now, the Associated Press reports that an international team of scientists will use DNA analysis to learn what's really hiding in the depths of Scotland's most mysterious landmark.

The team, led by Neil Gemmell, who researches evolutionary genetics at the University of Otago in New Zealand, will collect 300 water samples from various locations and depths around the lake. The waters are filled with microscopic DNA fragments animals leave behind as they swim, mate, eat, poop, and die in the waters, and if Nessie is a resident, she's sure to leave bits of herself floating around as well.

After extracting the DNA from the organic material found in the water samples, the scientists plan to sequence it. The results will then be compared to the DNA profiles of known species. If there's evidence of an animal that's not normally found in the lake, or an entirely new species, the researchers will hopefully spot it.

Gemmell is a Nessie skeptic, and he says the point of the project isn't necessarily to discover new species. Rather, he wants to create a genetic profile of the lake while generating some buzz around the science behind it.

If the study goes according to plan, the database of Loch Ness's inhabitants should be complete by 2019. And though the results likely won't include a long-extinct plesiosaur, they may offer insights about other invasive species that now call the lake home.

[h/t AP]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios