10 Scientific Mysteries Marked “Solved”

Although they don’t hang out shingles reading “Consulting Detective” or “Private Eye,” scientists have occasionally solved mysteries associated with crimes. More often, though, they solve puzzles, some of which are centuries old, that are related to their own areas of largely academic expertise: the discovery of the causes of a medical condition, of bacterial locomotion, or of seemingly extraterrestrial radio signals.

Other times, they may figure out the solution to a vexing mathematical theorem, the fate of disappearing molecules, the reason that a computer model can’t seem to account for the apparent contradictions in the persistence of complex ecosystems, or the reason that particular architecture bears unlikely stains.

Other puzzles scientists have contended with—and ultimately solved—posed questions of identity: what the dinosaur with the two huge arms looked like, who painted Madonna of the Veil, and to whom the bones found in some Tennessee woods belonged.

Now that science has marked these mysteries “solved,” they’re even more intriguing than when they’d been only perplexing problems or puzzles.

Related: 10 Forensic Science Tools You Didn’t Know Existed

10 Narcolepsy’s Cause

Before the cause of narcolepsy was discovered, the condition, which is marked by daytime sleepiness, the sudden onset of sleep, a loss of muscle tone, and possible hallucinations, was a mystery that left medical doctors at a loss to treat it effectively. Although narcolepsy is relatively uncommon, affecting approximately only 1 in 2,000 people, the chronic sleep disorder makes life difficult for those who experience it.

Since 1986, Stanford University’s Dr. Emmanuel Mignot, a geneticist, has been attempting to zero in on the gene that causes the condition. In 2022, he finally struck pay dirt, identifying the culprit as a control for a neurotransmitter called orexin, which promotes wakefulness and blocks REM (rapid-eye movement) sleep. His unrelenting, determined hunt for the responsible gene earned Mignot a share of the $3 million Breakthrough Prize, the other part of which has been awarded to Masashi Yanagisawa of Japan’s University of Tsukuba, who, separately, but at the same time as Mignot, discovered orexin.

Further work revealed that narcolepsy is an autoimmune disorder. The neurons that produce orexin are destroyed by the body’s own immune system. Now, when Mignot takes his narcoleptic dog Watson with him to the sleep clinic to help explain the disease to his younger patients, the scientist can deliver the good news that new treatments can be developed to treat the condition. Now, thanks to Mignot, this scientific mystery has been marked “solved!” As a result, before long, those with narcolepsy can, hopefully, look forward to a good night’s sleep and the better daytime functioning that results from such rest.^[1]

9 Bacterial Movement

For half a century, scientists wondered how bacteria got from point A to point B. Light microscopes couldn’t show how bacteria with flagella move at the level of individual atoms, so researchers turned to cryogenic electron microscopy (cryo-EM) and advanced computer modeling in their attempts to depict possibilities. However, as Edward Egelman of the University of Virginia’s Department of Biochemistry and Molecular Genetics points out, the computers’ scenarios were wrong.

Bacteria, it was understood, somehow push themselves ahead by coiling their flagella, their thread-like appendages, into rotating corkscrew-like propellers. How the bacteria accomplish this feat puzzled scientists since the flagella are made up of only protein. Now, this scientific mystery has been solved. It was found that the bacteria’s protein exists in 11 states, and an exact mixture of these states is responsible for the formation of the flagella’s corkscrew shape.^[2]

8 Peryton Origin

No astronomer could solve the puzzling mystery of the origin of the strange radio bursts that appeared to be extraterrestrial in nature. However, Emily Petroff, a doctoral student at the Swinburne University of Technology, solved the mystery. Known as perytons, the bursts resemble deep space signals, which, scientists thought, might have resulted from neutron stars becoming black holes.

The actual cause of the signals was much more mundane: Microwave ovens used by astronomers to heat up their pot noodles. The oven’s door had been opened before the timer ended, causing the appliance’s magnetrons to emit very brief bursts at the 1.4Hz frequency. These emissions are typical of fast extragalactic radio bursts, but they were not coming from beyond the Milky Way.^[3]

7 Fermat’s Last Theorem

Seventeenth-century mathematician Pierre de Fermat’s Last Theorem remained a mystery for three centuries. Presented in the form of a seemingly straightforward equation, the theorem states there are no whole number solutions to the equation xn + yn = zn when n is greater than 2. Intrigued by the mystery since his boyhood, Andrew Wiles studied intensely during the seven years he attended Princeton University before the answer came to him. It happened thanks to a method involving “modular forms, elliptical curves, and Galois representations.” The fact that such pursuits are likely to be unfamiliar to us isn’t surprising, as they mean nothing to the layman but everything to brainiacs trying to solve this problem.

For his troubles, the Oxford University professor was awarded the 2016 Abel Prize and $700,000 cash. He also achieved fame. As a representative of the Norwegian Academy of Science and Letters said, “Wiles is one of very few mathematicians—if not the only one—whose proof of a theorem has made international headline news.”^[4]

6 Disappearing Molecules

During ultracold chemistry research, Kang-Keun Ni, the Morris Kahn associate professor of chemistry and chemical biology and of physics at Harvard University, and her team lowered the temperature of two potassium-rubidium molecules to almost absolute zero. As a result, they prolonged the duration of the existence of the intermediate, the space where reactants transform into products, a million times longer than they live in higher-temperature regions. They extended it to about 360 nanoseconds, allowing them not only to observe the reactants’ transformation into a product but also to manipulate it using lasers. In the process, the team learned why ultracold molecules disappear when forced to react.

When trapped together in the laser light, the gas molecules bumped against each other as expected, but some simply disappeared—or seemed to. In reality, the disappearing molecules are believed to have transformed into new species when they collided. So rather than simply heading off in different directions because of the light that the team used during their experiments, the molecules deflected off their typical reaction path and into a new one.^[5]

5 Persistent Complex Ecosystems

Scientists use computer models for much the same reasons that filmmakers use special effects: either it is impossible or too dangerous to chart or shoot the real deal. A case in point: scientists struggle to identify ecosystem responses to environmental change. Sometimes, such models themselves introduce unexpected mysteries. One such enigma is the co-existence of divergent complex systems, such as jungles, deserts, and coral reefs, in which species coexist and interact with one another. The math says that the persistence of such systems is impossible; nature shows that it is not.

How to reconcile the math with the reality was a puzzle that stymied scientists until recently. According to the U.S. National Science Foundation, Stefano Allesina and Si Tang, both from the University of Chicago, solved that vexing modeling mystery by introducing a real-world variable that the modelmakers had omitted. Namely, it was the fact that, whether in the rainforest, the desert, the coral reef, or elsewhere, some species interaction takes the form of the eat-or-be-eaten relationships between predators and prey. The model designed by Oxford University’s Robert M. May omitted such behavior. Allesina and Tang added predation to the mix.

The results of this additional variable showed that the stability properties of complex ecological systems were determined by the type of interaction among species (predation, competition, mutualism) and the strength of those interactions. The researchers did so without using the supercomputers or other high-tech instruments that are so frequently at the core of current biological discoveries, employing nothing more than pen and paper. Their breakthrough came after finding a 1988 article on quantum physics that gave them the key to cracking the problem.^[6]

4 Deinocheirus Mirificus’s Appearance

It’s difficult, even for scientists, to solve a mystery when they have only a couple of the pieces of a puzzle, and that’s all paleontologists had of a dinosaur’s fossilized skeleton. All the bones but two—a pair of massive arms—were missing. Scientists tried to guess the appearance of the rest of the Deinocheirus mirificus. It was thought it might have resembled a T. rex-type predator. On the other hand, it might have looked more like a giant sloth-like climber that used its arms to dangle from trees. After a complete skeleton of the mystery beast was finally discovered in 2014, lead researcher Yuong-Nam Lee of South Korea’s Institute of Geoscience and Mineral Resources said it was found to have been “weird beyond our imagination.”

The creature was huge, with a beak, a humped back, and giant, hoofed feet. It was 36 feet (11 meters) long and weighed six tons with an elongated head, a duck-like beak, a large humped sail on its back, short and stumpy legs, and big hooved feet. It moved slowly and inhabited boggy wetlands, dining on plants and fish. It possibly used its long forearms and giant claws to dig and gather herbaceous plants in freshwater habitats. Professor John Hutchinson, a paleontologist with the UK’s Royal Veterinary College, said, “It really is shocking to see how many weird features it has. It changes our view of what kind of forms dinosaurs can take.”^[7]

3 Botticelli Painting Authenticity

To collectors and museums, authenticity means big bucks in the art world. However, forgery is more prevalent than may be thought. One of the questions of authenticity in the twentieth century involved Madonna of the Veil, allegedly painted by the Italian master Sandro Botticelli.

Around the time of World War II, art experts began to harbor suspicions about the painting. Electron-beaming EDX analysis on the painting revealed it contained opaque chromium oxide green, a pigment that didn’t become widely available until 1862, some 350 years after Botticelli died. The painting’s frame must have been old, though, since its wood bore wormholes. The holes, however, turned out to be the work of a drill rather than of wood-hungry beetle larvae. Ultimately, the supposed masterpiece was exposed as the work of Umberto Giunti, an Italian forger at work during the 1920s. Science had solved the mystery of the bogus Botticelli.^[8]

9 Cold Case

Years of uncertainty about what happened to a missing person is frustrating, to say the least. It is also quite an ordeal for those without a clue about their loved one’s fate. The distress of those who knew fifteen-year-old Tracy Sue Walker, who disappeared in Lafayette, Indiana, in 1978, did not come to an end until years after she went missing. This happened when, four hundred miles from Lafayette, some of her bones, including her skull and teeth, were found in the woods of Campbell County, Tennessee, along with a necklace. However, the forensics of the day weren’t able to positively identify the remains as Tracy’s. It wasn’t until 2022 that the Tennessee Bureau of Investigation was able to ID the remains of the missing female.

Thanks to new techniques that allowed the creation of a DNA profile from the scantest remaining material, despite long-term environmental contamination, digital information could be uploaded to genealogical databases. As a result, a potential relative was located in Indiana, as were possible family members in Lafayette who confirmed that Tracy had disappeared from the area. The University of North Texas Center for Human Identification in Fort Worth was able to confirm that the remains that had been found in the Tennessee woods were, in fact, those of Walker. At last, her family now knows where, if not how, their missing loved one died.^[9]

1 Alhambra’s Purple Stains

The “purplish smudges” on the “gilded plasterwork” of the Alhambra, the Islamic fortress-palace monument in Granada, Spain, mystified experts. Specifically, they wondered what had caused them. Scientists knew what they were not. They weren’t effects of added pigment. A bit of library research turned up a possible culprit: gold particles. Examining the purple stains under an electron microscope verified the researchers’ hypothesis. Now all that remained of the mystery was how the gold particles had been produced.

The centuries-old age of the Alhambra made it difficult to pinpoint the exact process by which the gold particles were created, but the location in which they were discovered offered a clue. The purple stains of the Alhambra are not everywhere, only in some of the gilded portions of the monument that are outdoors or exposed to humidity and salt from the spray of the Mediterranean Sea, which is only 31 MILES (50 kilometers) away. These facts led researchers to finally solve the mystery of Alhambra’s purple stains. They are due to a mixture of elements: the tin sheets behind the gold leaf, the humidity of the environment, and the aerosols that the wind brings from the Mediterranean, which dissolved the gold in the sheets. Experts marked another scientific mystery “solved!”^[10]