Science helps us make sense of the world, but not everything we hear in school or on TV is accurate. In fact, some of the most popular “facts” we’ve accepted as scientific truth are actually just myths. These misconceptions often spread through word of mouth, pop culture, or outdated textbooks. And despite how widely they’re believed, they just don’t hold up under scrutiny.
In this article, we’re debunking 10 common science myths that many people still believe—so you can separate real science from science fiction once and for all.
1. We only use 10% of our brains
This myth has been recycled in movies, self-help books, and motivational speeches for decades. The idea that humans use only 10% of their brains—and could unlock hidden abilities by tapping into the rest—is simply false.
Modern neuroscience shows that we use virtually every part of our brain. Brain imaging scans like fMRI clearly reveal activity across the entire brain, even while performing simple tasks like reading or talking. While it’s true we don’t use all parts of the brain at once, no region is permanently dormant. Every part has a function.
This myth likely gained traction because the brain is incredibly complex, and we’re still learning about how it works. But rest assured, your brain is already firing on all cylinders.
2. You can see the Great Wall of China from space
Many schoolchildren grow up hearing that the Great Wall of China is the only man-made structure visible from space. It sounds impressive—but it’s just not true.
From low Earth orbit, astronauts can see many human-made structures, including highways, airports, and cities. The Great Wall, on the other hand, is relatively narrow and blends into the natural landscape. Most astronauts report that it’s difficult or even impossible to see with the naked eye.
The myth dates back to long before humans actually traveled to space. It’s a powerful image, but scientifically inaccurate.
3. Lightning never strikes the same place twice
Lightning is unpredictable, but the idea that it won’t strike the same place twice is a dangerous myth. In fact, lightning often strikes the same place multiple times—especially tall, isolated structures like skyscrapers, towers, and trees.
The Empire State Building in New York City gets struck by lightning around 20 to 25 times a year. That’s because lightning seeks the path of least resistance to the ground, and tall conductive objects are perfect targets.
Believing this myth can lead people to let their guard down during storms. Remember: if you’re in a lightning-prone area, safety is more important than superstitions.
4. Bulls hate the color red
You’ve probably seen bullfighters waving a red cape to provoke a charging bull. But here’s the twist: bulls are colorblind to red.
What actually enrages the bull is the movement of the cape, not its color. Bulls, like most cattle, are dichromatic, meaning they can only see a limited range of colors—reds and greens just appear as shades of gray to them.
The red color is more for the audience than the animal. It’s dramatic and eye-catching, which helps enhance the visual spectacle. So next time someone says bulls hate red, you’ll know better.
5. Cracking your knuckles causes arthritis
This one has been repeated so often it feels like common knowledge—but science says otherwise.
Cracking your knuckles might be annoying to others, but it doesn’t cause arthritis. The popping sound comes from gas bubbles rapidly forming and collapsing in the synovial fluid of your joints. It’s not damaging the bones or cartilage.
Several studies, including one published in the journal Arthritis and Rheumatology, have found no correlation between habitual knuckle cracking and arthritis development. So while excessive cracking might cause temporary discomfort or reduce grip strength in some cases, it won’t wreck your joints in the long run.
6. Goldfish have a three-second memory
Poor goldfish get a bad rap for being forgetful—but in reality, their memory is much better than we think.
Studies have shown that goldfish can remember things for weeks, even months. They can be trained to recognize sounds, navigate mazes, and associate certain cues with food. In behavioral experiments, goldfish have demonstrated learning abilities and long-term memory similar to many other fish species.
The myth probably came from a misunderstanding of animal intelligence. Just because goldfish live in a bowl doesn’t mean they’re not smart in their own way.
7. The seasons are caused by how close Earth is to the Sun
It might seem logical to assume that we have summer when Earth is closer to the Sun and winter when it’s farther away. But the real reason for the seasons is the tilt of Earth’s axis, not its distance from the Sun.
Earth’s orbit is slightly elliptical, but this has very little effect on temperatures. What actually causes seasonal changes is how sunlight hits different parts of the planet. During summer in the Northern Hemisphere, the North Pole is tilted toward the Sun, resulting in longer days and more direct sunlight. Six months later, the Southern Hemisphere gets that same benefit.
In fact, Earth is closest to the Sun in early January—right in the middle of winter for many countries in the Northern Hemisphere. So, distance has nothing to do with it.
8. Hair and fingernails keep growing after death
This myth is especially common in horror stories and mystery novels. The idea that hair and nails continue to grow after someone dies creates a creepy image—but it’s not accurate.
What really happens is dehydration. After death, the body loses moisture, causing the skin to shrink. This shrinkage makes nails and hair appear longer, but they aren’t actually growing. Growth requires active cell division, which stops shortly after death due to lack of oxygen and nutrients.
It’s a case of illusion over biology—nothing supernatural going on here.
9. Humans have only five senses
Sight, hearing, touch, taste, and smell are the five traditional senses we all learn about in school. But science has long since identified more than just five.
In fact, humans have at least 9 to 20 senses, depending on how you define them. These include balance (equilibrioception), body awareness (proprioception), temperature perception (thermoception), pain (nociception), and even the sense of time.
The “five senses” idea comes from ancient Greek philosophy, particularly Aristotle. While it’s a simple teaching model, it doesn’t reflect the full complexity of human sensory perception.
10. Vaccines cause autism
This is not only a myth—it’s one of the most dangerous and harmful pieces of misinformation in modern history.
The idea that vaccines cause autism originated from a now-discredited 1998 study by Andrew Wakefield. The study was later retracted due to serious flaws and ethical violations. Countless follow-up studies involving millions of children have found no link between vaccines and autism.
Vaccines are among the safest and most effective public health tools we have. They prevent deadly diseases like measles, polio, and whooping cough. The persistence of this myth has caused unnecessary fear and led to declining vaccination rates, putting communities at risk.
If you’re ever unsure about vaccines, consult peer-reviewed studies or talk to a licensed medical professional. Don’t rely on internet rumors.
Bottom line
Science myths are surprisingly sticky. Once they enter the public consciousness, they tend to linger—regardless of what the facts say. But the more we learn about how science really works, the better equipped we are to think critically, challenge false assumptions, and share accurate information with others.
Whether it’s the belief that lightning avoids repeat targets or that goldfish are memory-challenged, these myths show how science fiction can sometimes overtake science fact. The good news is that debunking them isn’t just fun—it also helps foster a more scientifically literate world.
