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9 Strange Sounds No One Can Explain

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Everyone has a favorite Wikipedia rabbit hole. Mine is “List of Unexplained Sounds.” I can’t remember how I first made my way to the page, but its array of sonic mysteries has shown me that while space is incredible, our planet is its own frontier of intrigue and unexplainable phenomena.

1. Upsweep

Upsweep is an unidentified sound that’s existed at least since the Pacific Marine Environmental Laboratory began recording SOSUS—an underwater sound surveillance system with listening stations around the world—in 1991. The sound “consists of a long train of narrow-band upsweeping sounds of several seconds duration each.” The source location is difficult to identify, but it's in the Pacific, around the halfway point between Australia and South America. Upsweep changes with the seasons, becoming loudest in spring and autumn, though it isn’t clear why. The leading theory is that it’s related to volcanic activity. 

2. The Whistle

The Whistle was recorded on July 7, 1997, and only one hydrophone—the underwater microphones used by the National Oceanic and Atmospheric Administration (NOAA)—picked it up. The location is unknown and limited information has made it difficult to speculate on the source. 

3. Bloop

Bloop is the big kahuna in unexplained sounds. In 1997 (a big year for auditory ocean mysteries), an extremely powerful, ultra-low-frequency sound was detected at various listening stations thousands of miles apart and traced to somewhere west of the southern tip of South America. The sound only lasted about a minute and and was heard repeatedly over the summer, but not since. Bloop is generally believed to be the sound of a massive icequake, but scientists haven’t totally ruled out the possibility that the sound originated from something “organic.” 

That’s where things get eerie. If an animal was the source of Bloop, it would have to be larger than a blue whale. The most fanciful of all theories stems from the fact that Bloop’s location is somewhat close to author H.P. Lovecraft’s fictional sunken city of R’lyeh, where the creature known as Cthulhu lies “dead but dreaming.” Cthulhu can best be described as part man, dragon, and octopus, which seems as likely a source as any for the ocean’s greatest aural anomaly. 

4. Julia

Julia was recorded on March 1, 1999, lasted for roughly 15 seconds, and was loud enough to be heard by the entire Equatorial Pacific Ocean hydrophone array. An Antarctic iceberg run aground is the leading suspect for its source. 

5. Slow Down

Slow Down was first recorded on May 19, 1997 and is also credited to an iceberg running aground, though some people insist it might be a giant squid. The sound, lasting about 7 minutes, gradually decreases in frequency, hence the name “slow down.” Like Upsweep, the sound has been heard periodically since it was initially detected. 

6. The Hum

The Hum has been recorded on several occasions, mostly during the last 50 years or so. In these cases, there have been reports of a relentless and troubling low-frequency humming noise that can only heard by a certain portion of the population. It’s difficult to pinpoint when instances of the Hum began, but it’s been well-documented since the 1970s, and since then, cases have popped up all over the world—from Ontario, Canada to Taos, New Mexico to Bristol, England to Largs, Scotland and Auckland, New Zealand.

In most instances, the affected group only makes up around two percent of the population, but for those individuals, the Hum is largely inescapable and impossible to track. Those affected report never having heard noises before, and say the Hum is generally heard indoors and becomes louder at night. It’s also most common in rural and suburban areas and among people between age 55 and 70. 

Scientists have long investigated the cause of the drone, occasionally tracing it to industrial equipment emitting particular frequencies. For the most part, though, the sound has left the world completely puzzled. The list of other possible culprits is long and wide-ranging—wireless communication devices, power or gas lines, electromagnetic radiation, radio waves, or earth tremors are all suspects. Because the Hum appears and disappears and because the cause may vary from case to case, the phenomenon still baffles researchers. At this point, a few things are clear: The Hum is real and likely a byproduct of 21st-century living. 

7. Skyquakes

Skyquakes, or unexplained sonic booms, have been heard around the world for the last 200 years or so, usually near bodies of water. These headscratchers have been reported on the Ganges in India, the East Coast and inland Finger Lakes of the U.S., near the North Sea, as well as in Australia, Japan, and Italy. The sound—which has been described as mimicking massive thunder or cannon fire—has been chalked up to everything from meteors entering the atmosphere to gas escaping from vents in the Earth's surface (or the gas exploding after being trapped underwater as a result of biological decay) to earthquakes, military aircraft, underwater caves collapsing, and even a possible byproduct of solar and/or earth magnetic activity. 

8. UVB-76

UVB-76, also known as "The Buzzer,” has been showing up on shortwave radios for decades. It broadcasts at 4625 kHz and after repeated buzzing noises, a voice occasionally reads numbers and names in Russian. The source and purpose has never been determined.

9. 52-Hertz whale

This animal, also known as the loneliest whale in the world, calls at a highly unusual 52-hertz, well above the normal frequency. Scientists have been listening to 52-Hertz for decades, and recently, filmmakers raised $400,000 on Kickstarter to seek the mammal out. It should be noted that the fundraiser reached its goal through the help of Leonardo DiCaprio, another mysterious beast.

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What Causes Sinkholes?
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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.

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DNA Analysis of Loch Ness Could Reveal the Lake's Hidden Creatures
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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]

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