Debunked science

Before science got it right: 10 wild misconceptions that misled everyone

Image: Philippe BONTEMPS

Before modern science lifted the veil on some of nature’s most baffling phenomena, people relied on what they knew—and when that failed, they invented explanations that now seem spectacularly bizarre. But even if these early ideas now seem strange or even foolish, they helped pave the way for modern science. Each flawed theory pushed curious minds to investigate further and refine how we understand the world. From spontaneous generation to the theory of miasma, here are 10 examples of what people believed not so long ago.

Image: Glenn Carstens-Peters

For centuries, people believed the Earth was a flat disc floating on water. Ancient maps depicted oceans surrounding a flat plane, and falling objects supposedly plummeted straight down to the abyss.

While Aristotle was among the first to argue for Earth’s true shape—observing ships vanishing hull-first over the horizon and the round shadow cast during lunar eclipses—and Eratosthenes later refined these intuitions to calculate the planet’s circumference with remarkable accuracy, the flat-Earth concept still persisted well into the Middle Ages.

Image: Adrian Lange

During the Middle Ages, and for long before, it was believed that maggots, mice, and other creatures could arise spontaneously from mud, rotting meat, or grain.

It wasn’t until the 17th century that Francesco Redi’s experiments disproved this idea: maggots appeared only when flies had access to lay their eggs. Later, Pasteur confirmed that microbes also do not arise spontaneously.

Image: Ganapathy Kumar

Early natural philosophers suspected the tides followed the Moon’s cycle, but without a concept of gravity, they proposed more imaginative mechanisms. One widely repeated idea described the Moon as "breathing" or exhaling a kind of pneumatic force that pulled the seas upward, much like winds or vapors moving through the air.

It wasn’t until Newton’s work in the 17th century that a clear physical explanation emerged, showing that the tides are driven by the gravitational pull of the Moon and Sun acting on Earth’s oceans.

Image: Karl Callwood

Some early natural philosophers suggested earthquakes were caused by giant underground worms or serpent-like creatures shifting through the Earth. The analogy came from observing how smaller burrowing animals disturbed soil and assuming larger unseen versions could shake the ground itself.

As geological science progressed, however, these notions gave way to evidence showing that earthquakes result from the movement and fracturing of Earth’s crust along fault lines.

Image: Lightscape

Early explanations for the northern lights often described them as fires or glowing vapors igniting high in the atmosphere. Some natural philosophers proposed that luminous gases rose from Earth’s surface and caught fire in the upper air, while others compared the lights to reflections from vast, distant flames.

With improved observations, scientists showed that auroras are caused by charged particles from the solar wind interacting with Earth’s magnetic field and energizing atmospheric gases.

Image: Javier Miranda

Some early astronomers—including Jesuit priest Christoph Scheiner—argued that sunspots were actually small planets or satellites orbiting the Sun, preserving the idea of a "perfect" Sun untouched by blemishes.

Galileo, however, tracked their shapes and motions and noticed they transformed and changed irregularly, which meant they were on or very close to the Sun’s surface—so they couldn’t be planets.

Image: Ruvim Noga

People once believed diseases like cholera, plague, and malaria spread through "miasma," or poisonous bad air rising from decaying matter. The theory shaped public health for centuries and even informed major sanitation reforms in the 19th century.

It wasn’t until the work of Snow, Pasteur, and Koch that germ theory replaced miasma, showing that infectious diseases are caused by specific microorganisms—not foul-smelling air.

Image: Kubo Mičuch

Early hydrologists often believed springs were fed by vast underground rivers flowing through hollow channels in the Earth. The idea came from observing surface rivers disappearing into caves and reappearing elsewhere, leading to the assumption that similar large waterways existed everywhere below ground.

Modern hydrogeology shows that most groundwater doesn’t travel in rivers but moves slowly through porous soil and rock, driven by pressure and permeability rather than hidden subterranean channels.

Image: Forsaken Films

For centuries, comets were thought to be atmospheric phenomena—fiery vapors or clouds igniting high in the sky. Even Aristotle’s model placed them in the upper atmosphere, and this view persisted well into the Renaissance.

Until Tycho Brahe’s observations in the 1570s showed that comets had no measurable parallax, it hadn’t been realized that they were actually far beyond the Moon. This helped establish comets as true celestial bodies orbiting the Sun.

Image: Chris Nagahama

Early explanations for magnetism often invoked a "living force" within lodestones, suggesting they possessed a kind of spirit or soul that allowed them to attract iron. Others claimed magnets emitted invisible _effluvia_—mysterious vapors that pulled metals toward them.

William Gilbert’s De Magnete (1600) replaced these ideas with a physical model, showing that magnetism was a natural property of matter and that Earth itself acted like a giant magnet.

Decoding

Being a "treasured guest" is not a compliment. This is the hidden meaning

Have you ever heard "Code Adam" while shopping for groceries at Walmart? Or maybe you’ve heard how "Dr. Firestone" was being paged during a routine hospital visit. They sound like harmless announcements. But behind these ordinary words are secret codes staff use to signal emergencies without causing panic. From hospitals and supermarkets to airports and Disney Parks, these phrases quietly warn employees that something is happening. You hope you never hear them, but if you do, it helps to know exactly what they mean.

We all love getting special attention at airports or hotel desks, but if you hear the clerk call you a "treasured guest," don’t feel so flattered. You may not be as VIP as one could think.

In the hospitality industry, "treasured guest" has become a humorous bit of industry folklore to describe someone causing trouble. Maybe a customer yelling at staff over expired coupons, demanding impossible accommodations, or throwing a full-blown tantrum at the front desk. Whatever it is, the phrase has become the staff’s secret way to warn co-workers without escalating the situation in front of the customers. Most guests don’t realize the meaning, but once you know it, you may start hearing it more often. We just hope it’s not about you.

Imagine you’re pushing a shopping cart through Walmart when suddenly the overhead speaker announces, "Code Adam." You can easily assume it’s some kind of employee meeting or cleanup request. But when you see them start locking the exits and moving around, you know something’s wrong.

This code was created in 1994 by Walmart in collaboration with the National Center for Missing & Exploited Children (NCMEC), in memory of the tragic case of 6-year-old Adam Walsh. Adam was abducted from a Sears department store in 1981 while shopping with his mother. His father, John Walsh, later became famous for hosting the TV program America’s Most Wanted and advocating for missing children. Even if Adam’s story ended in tragedy, Walmart created the emergency system in Adam’s memory, and other retailers soon adopted it nationwide, intending to have a quick response to missing or abducted children.

You’re sitting in a hospital waiting room during a routine check-up when you suddenly hear "Code Blue, Room 214." Most people immediately know it sounds serious, even if they are not entirely sure why.

The phrase "Code Blue" is used at hospitals to draw the necessary staff and equipment to perform a resuscitation. It was created in the early 1960s at Beathany Medical Center by Dr. Hughes Day. Before then, hospital resuscitations were often chaotic and poorly coordinated. In 1961, Dr. Day received a grant to build one of America’s first cardiac care centers, and he developed both the Code Blue alert system and the modern crash cart to improve survival rates during cardiac emergencies. Today, the system is used in hospitals across the country, sometimes with specialized versions like "Code Blue Pediatric" or "Code Blue Neonate."

Imagine visiting a loved one in the hospital when the intercom calmly announces, "Paging Dr. Firectone to the third floor." Your head surely goes, "Dr. Firestone’s probably having a busy day up there." He is, but it’s not what you think.

The phrase is actually a discreet fire alert used to warn staff about smoke, flames, or overheating equipment without frightening patients and visitors. Hospitals adopted these coded announcements after realizing that openly yelling "fire" over loudspeakers could create panic, especially among patients who aren’t able to move quickly. "Code Red" is an alternative used by many health centers today, but it also hints at the situation while keeping hallways calm.

You’re standing at a checkout counter when the cashier picks up the phone and quietly says, "I need a Code 10 authorization." If you think that’s just another way to get a supervisor’s approval or technical issue, think again. In reality, the cashier may suspect the credit card is stolen or fraudulent.

Code 10 was developed through a cooperative effort between major credit card companies like Visa and Mastercard, along with international standard organizations. As credit cards became more common in the 1960s and 1970s, stores needed a discreet way to alert banks about suspicious activity without directly accusing customers and potentially putting employees at danger. When a cashier requests a Code 10, the bank’s operator begins asking yes-or-no questions to assess the situation and guide the employee on what to do next.

You’ve probably experienced those long airport security lines. The wait is usually uneventful. But sometimes, you can hear "Code Bravo" over the speakers. Maybe it’s a delay, or maybe it’s an issue with luggage. Within seconds, people stop moving, the security line freezes, and exits may even close. It’s something bigger.

Code Bravo is the emergency phrase used by airport security and the Transportation Security Administration to signal a serious security threat, such as an unattended bag, a breach at a checkpoint, or someone slipping into a restricted area. The term comes from the international phonetic alphabet used in aviation and military communications, where "Bravo" represents the letter B. When this is called, security staff immediately lock down affected areas, stop screening lines, and search for the source of the threat. To passengers, it’s sudden and confusing, but to security, it’s a carefully rehearsed response.

You are heading back to your cabin on a cruise ship when the speakers announce, "Code Alpha, Deck 7." You may think Alpha is related to the captain, but that’s not the case. It means someone on board is suffering a medical emergency.

The phrase comes from the NATO phonetic alphabet, where "Alpha" represents the letter A. In maritime emergency jargon, it became shorthand for a Priority A medical situation requiring immediate response. Cruise lines such as Royal Caribbean and Disney Cruise Line commonly use the term, though some ships use variations like repeating "Alpha" three times. Once the code is announced, onboard medical teams rush toward the specified deck or cabin. If necessary, stretcher crews are mobilized, and in severe cases, the ship may even divert course toward the nearest port for emergency evacuation. Passengers are enjoying the views, but the staff is running to save a life.

Anyone who remembers the CB radio craze of the 1970s probably smiles when they hear "10-4." Movies, truckers, and radio fans turned those number codes into a part of American culture. So if you overhear "10-33" on a police scanner, you might assume it’s just another routine message. But it’s not as simple as it sounds.

The 10-code system was first created in 1937 by Illinois State Police communications director Charles Hopper and later standardized by the Association of Public Safety Communications Officials, better known as APCO. Officers needed short phrases they could understand clearly over crackling radio signals. The 10-33 code commonly means an officer needs emergency assistance. In some departments, it also signals radio silence so dispatchers can focus on the crisis unfolding in real time.

Disney World is amazing, the parks offer something for everyone, and there are things to see wherever you look. But that’s exactly the kind of place where a child can easily disappear into a sea of strollers, balloons, characters, and crowds. For that reason, Disney has developed the "Signal 70," which alerts cast members and security that a child has become separated from their family.

The number comes from older police and emergency radio systems, where "70" was commonly associated with missing persons. Disney adopted the phrase because it allows employees to communicate discreetly without frightening or alarming nearby guests. If a member finds the child, they gently -and magically- escort them to Baby Care Center, where they coordinate the reunion.

Cruises are great to relax, enjoying a good book under the sun with a nice drink by the side. Until you hear "Echo, echo, echo" on the speakers. If you do, something is happening somewhere else on the ship.

The code is used among cruise employees to signal that dangerous winds or a navigational hazard are affecting the ship. It comes from the international maritime phonetic alphabet, where "Echo" stands for the letter E. In maritime signalling, the letter traditionally means "I am altering my course to starboard." And, in time, the phrase became associated with urgent ship maneuvers and weather-related warnings. However urgent, the repetition of the word by three doesn’t represent life-threatening situations. It alerts the crew of a certain hazard to prepare while avoiding panic among passengers.