There's a long list of everyday things that science hasn't figured out—and there are plenty of more unusual mysteries that have scientists scratching their heads, too, in fields ranging from meteorology to medicine. Here are a few of them, adapted from an episode of The List Show on YouTube.
1. Why Some People Wake Up From a Coma Speaking a Foreign Language
In April 2010, a teenager in Croatia woke up from a mysterious 24-hour coma, much to her family’s relief. But then a strange thing happened: The 13-year-old girl couldn’t speak to her parents in her native Croatian. While she was still able to understand the language, she could only respond in inexplicably fluent German, a language she had only just begun studying in school. She required a translator to be able to communicate with her family, and doctors remained… stumped.
The case of this mysterious Croatian-German language swap isn't the only example of brain injuries leading to unexplainable language phenomena. In 2013 an Australian man woke up from a car crash speaking perfect Mandarin. In 2016, a teenager from Atlanta woke up from a coma speaking fluent Spanish, and had such trouble speaking his native English that he would have a seizure every time he tried.
Doctors and scientists can't fully explain these events. The role of language development in the brain is a dynamic field; scientists generally presume it’s important that all the examples above had some knowledge of their new language, but it’s still unknown why this phenomenon can affect certain people so drastically.
2. What Caused the Tunguska Event
On June 30, 1908, a massive explosion decimated a forest in Siberia near the Podkamennaya Tunguska River. A fireball believed to have been up to 100 meters wide erupted in the sky, flattening some 80 million trees and killing hundreds of reindeer. It was so intense that residents in the nearest town, which was about 35 miles away, felt the heat of the explosion. One eyewitness recounted:
“The sky was split in two, and high above the forest the whole northern part of the sky appeared covered with fire … At that moment there was a band in the sky and a mighty crash … The crash was followed by a noise like stones falling from the sky, or of guns firing.”
All in all, the explosion, which has come to be known as the Tunguska Event, is said to have produced about 185 times more energy than the atomic bomb that was dropped on Hiroshima.
With an event of this size and intensity, you would expect the source to be pretty obvious. But over a hundred years later, scientists still haven’t figured out what caused it. The most common explanation at the time was some sort of meteoroid. But there was no impact crater, and little evidence of any kind of extraterrestrial object in the surrounding area. Some scientists later concluded it was a comet that had entered our atmosphere; comets are largely made of ice and therefore wouldn’t have left behind obvious rock fragments.
A 1958 expedition to the area found some promising globules that pointed toward a meteoritic origin. This might have put the Tunguska mystery to rest, but some scientists still weren’t convinced. A 1973 paper suggested that a black hole had collided with the Earth, which led to the massive explosion. This was quickly disputed. Further studies seem to imply that the event was indeed some kind of meteoric explosion, but a truly definitive conclusion has yet to be found, and theories of UFO crashes or nuclear explosions still persist.
3. How the Patom Crater Formed
The Tunguska Event isn’t the only mysterious thing that has happened in Siberia. There’s another unexplainable thing hidden among the trees in the Irkutsk region: Patom crater, otherwise known as Fire Eagle Nest, is a large rock formation in southeastern Siberia. The crater is about 520 feet in diameter and 130 feet in height, with a ring-shaped crown. It was discovered in 1949 by a geologist named Vadim Kolpakov, but it’s probably about 350 years old.
The region is home to the Yakuts, a Turkic group who have habited the area for generations. According to Yakut legend, the crater is an evil place. Not even deer dare to go near it. When Kolpakov discovered it, he noted, “From a distance it looked like a mine-shaft slagheap, only whitish. I even thought, 'Where are the people?' There were no labor camps in the area. Unless a very, very secret one?”
According to the Tomsk Science Center (with help from Google Translate), he added, “But then I would not have been sent to geo-prospect this area, but, on the contrary, would have been offered to stay away from here. My second thought was an archaeological artifact. But the local Evenks and Yakuts, with my respect for them, are not the ancient Egyptians. They could not build stone pyramids, and didn't have any human resources nor the necessary scientific knowledge."
Not unlike the Tunguska Event, scientists initially tried to explain the craters as the result of some sort of extraterrestrial impact. Some, however, think it might be the result of natural gas bursting through the surface of the earth. There has been so much speculation about the formation in the geologic world that, in 2010, there was an entire conference dedicated to it, appropriately called the Patom Crater Conference. The conference participants reached a consensus: In their estimation, the Patom Crater was not the result of any meteorite. They suggested that it had been created by some sort of geological process, but at this time, that explanation is still just an educated guess.
4. How The Placebo Effect Works
When scientists want to study a new drug, they'll often test it in comparison to a placebo, such as a sugar pill. At minimum, a drug needs to produce better results than a control such as the placebo to be considered effective. Strangely, though, the placebos themselves can often produce changes in test subjects, even though there's no physiological mechanism to account for the change. The real, measurable impact from what is essentially a "fake" treatment is known as the placebo effect.
The idea of a placebo effect has been around since at least the 18th century, but scientists don’t fully understand it. They know that the brain can perform complex neurobiological reactions just because it’s expecting results, like releasing endorphins or dopamine when it believes it’s receiving an antidepressant. But that doesn’t mean they know why it does that. Researchers at Harvard have been studying the negative and positive effects of the placebo effect, and they consider it a holistic experience. Professor Ted Kaptchuk describes it like this:
"When you look at these studies that compare drugs with placebos, there is the entire environmental and ritual factor at work. You have to go to a clinic at certain times and be examined by medical professionals in white coats. You receive all kinds of exotic pills and undergo strange procedures. All this can have a profound impact on how the body perceives symptoms because you feel you are getting attention and care."
But this still doesn’t explain why the placebo effect doesn’t always work, or why it’s more effective in certain people or situations. For now, it’s just one of the brain’s many unique and confusing traits.
5. How Morning Glory Clouds Form
At this point, it feels like we as a species have a pretty decent understanding of the weather. What causes it, how to predict it, when to talk about it on a failing first date. One weather phenomenon that has escaped our understanding, however, are morning glory clouds. This mesmerizing meteorological occurrence looks like something out of a fantasy novel.
While there have been reports of these wild-looking roll clouds around the world, reliable morning glory clouds are almost solely spotted near Burketown, Australia. Under very specific circumstances, they can take form and stretch up to 600 miles in length. Tourists reportedly flock to Burketown each October to try and spot them, including a fair number of hang gliders who attempt to fly through the unique clouds.
Scientists still don’t really understand morning glory clouds. They have come to a basic understanding of the specific humidity levels, sea breeze patterns, and mesoscale circulations that generally precede morning glory clouds, but why they’re so distinct and nearly unique to this one Australian peninsula is still not understood, very possibly because no one is willing to adequately fund research into what is a visually arresting but not necessarily scientifically important cloud.
6. What Caused Mary Reeser's Death
On July 2, 1951, Mary Reeser’s landlord stopped by her apartment, where she came upon a horrifying scene: Reeser’s charred remains. All that was left intact was part of one foot, still encased in its slipper. Curiously, the room itself was almost completely unburnt.
The FBI investigated and concluded that Mary had taken sleeping pills the previous evening, reporting that she “could have become drowsy or fallen asleep while smoking a cigarette, thus igniting her clothes.” According to their report, her own body fat fed the flames.
For many skeptics, it didn’t seem realistic that a fire so hot could have caused such minimal damage to Reeser’s apartment. Cremation often requires temperatures well above 2000 degrees. For some, spontaneous human combustion seemed a more plausible explanation. These doubts even led to one professor from the University of Pennsylvania theorizing that someone had murdered Mary, incinerated her remains in a crematorium, and then brought them back to her apartment for someone to find. To this day, no one can explain what really happened to her.
7. The Source of the “Upsweep” Sound
In the world of unexplainable phenomena, there’s a whole category of mysterious sounds. Some come from outer space, some from remote parts of the wilderness, and some especially eerie ones from the depths of the ocean. One such sound is the “upsweep” sound.
Upsweep has been around since at least 1991, when the Pacific Marine Environmental Laboratory began recording SOSUS, which had been an underwater Soviet surveillance system with multiple listening stations around the world. The sound “consists of a long train of narrow-band upsweeping sounds of several seconds' duration each,” the lab reports. If that doesn’t give you the proper idea of how it might sound, take a listen for yourself above.
The source of the sound is about halfway between Australia and South America. Curiously, the upsweep sound changes with the seasons. It’s loudest in spring and Autumn, but scientists don’t know why. The leading theory behind this mysterious sound? Volcanic activity.