We still don’t know

An immortal jellyfish? 10 spooky and unanswered questions about the sea

Some people are scared of the ocean. Can you blame them? Though waters cover 70% of our planet, scientists are still scratching their heads about certain unanswered questions. How long can blue whales actually live? What substance makes some waters glow eerily white at night? And what’s with the self-rejuvenating, immortal jellyfish? These are some of the mysteries we’ll explore in this article!

Found abandoned in 1872 with sails set, cargo intact, and dinner still on the table, the Mary Celeste is the poster child for maritime enigmas. The whole crew vanished without a trace and was never heard of again.

Mutiny? Rogue wave? Alcohol fumes? Giant squid? No theory fully fits. It's a fascinating tale that has been the subject of documentaries, theatre plays, novels, and movies.

For centuries, sailors have reported seeing entire portions of the ocean surface glowing white at night, like a ghostly reflection.

An explanation could be massive blooms of bioluminescent bacteria, but no one knows how they coordinate light across such huge distances or why the phenomenon lasts for hours. Even with satellite detections, it remains one of the ocean’s eeriest light shows.

Tales of a giant squid have been alive for centuries, but it was only in 2004 that humanity was able to photograph this fabled creature. In that year, a Japanese team captured a live one on camera in its natural habitat and finally proved that the creature behind centuries of sea-monster legends was very real.

And yet, we still know shockingly little about its life cycle, breeding habits, or how something that big stays so well hidden.

You’d think the largest creature ever to exist would be the easiest to study. Nope. We still struggle to track migration patterns, understand their communication system, or explain the full recovery timeline after they were nearly hunted to extinction.

Turritopsis dohrnii cheats death by reverting its adult cells back to a juvenile state when stressed. It’s like if a human under pressure suddenly turned back into a toddler.

This regeneration process is wildly complex and not fully understood, and scientists hope that cracking its secret might reveal insights into aging itself.

The stretch between Florida, Bermuda, and Puerto Rico has inspired endless theories. Unexplained disappearances, bizarre compass behavior, and strange weather patterns have contributed to building the legend.

Scientific explanations abound, from methane hydrates to violent storms, but the Triangle’s mythic aura refuses to die.

The Challenger Deep, the trench’s lowest point, plunges almost 7 miles. Only a handful of people have ever explored its bottom, including filmmaker James Cameron in 2012.

What lives down there? What geological processes unfold under such pressure? Every new expedition reveals creatures that look like they belong in fever dreams.

Off the coast of Japan lies a submerged stone structure with terraces, pillars, and sharp geometries that seem carved… Unless they were shaped by strange phenomena of nature.

Some believe it’s the remains of an ancient city, sunken after an earthquake; others argue it’s purely geological. Today, it’s a riddle lying quietly under turquoise waters.

In 1918, a massive US Navy collier vanished without a distress call while crossing the Caribbean. More than 300 people disappeared with it, the single largest non-combat loss of life in U.S. Navy history.

No wreckage has ever been found. Storm? Structural failure? Something stranger? The sea has kept its mouth shut.

This line gets repeated a lot because it’s shockingly true. With sonar mapping still incomplete and most of the ocean floor left untouched by human eyes, researchers say we’ve charted only about a quarter of it in detail.

Mars, by contrast, has been mapped in full thanks to satellites. The ultimate plot twist is that we might understand another planet better than our own.

Secret uses

There’s a hidden microphone in your phone, and here’s where it is

You’ve probably twisted a bread bag closed, filled up your car, or pulled a sheet of aluminum foil from the box thousands of times without giving it a second thought. But many of the everyday objects we’ve used for decades have clever features that most people never notice. From the tiny pocket on blue jeans to the little arrow next to your gas gauge, these hidden designs have practical stories behind them, and once you know them, you’ll never look at these familiar items the same way again.

If you own an iPhone, you’ve probably noticed the tiny black dot next to the rear camera. It’s small, so people tend to assume it’s another camera sensor or even part of the phone’s design. The small hole found near the camera bump on every iPhone is actually a rear microphone.

It captures clearer audio when you’re recording videos and helps reduce background noise during FaceTime and regular phone calls. If you own an iPhone Pro model from the iPhone 12 Pro onward, you'll also see a larger dark circle. That’s the LiDAR scanner, which sends out invisible infrared light to create a 3D map of your surroundings. It helps the camera focus faster in low light, powers Apple’s Measure app, and makes augmented reality features much more accurate.

Whether it's a holiday dinner, an anniversary, or simply a nice meal with friends, you’ve probably held a wine bottle and noticed the deep indentation in the bottom. Many people tend to think the deeper the indent, the fancier the bottle.

That indentation is called a punt, and it’s been a part of the bottle-making for centuries. Originally, it helped strengthen hand-blown glass bottles, making them less likely to crack under pressure. Today, it still adds structural stability, particularly for sparkling wines, while also giving servers a comfortable place to rest their thumb when pouring, though some say it helps collect the sediment as wines age. In any case, a deeper pun doesn’t automatically mean a better or more expensive bottle.

Almost every driver has experienced that awkward moment at the gas station. You pull up to the pump, step out of the car, and suddenly realize the fuel door is on the opposite side.

To help prevent exactly that situation, many modern vehicles include a small arrow next to the gas pump symbol on the dashboard’s fuel gauge. The arrow points towards the side of the vehicle where the fuel filler door is located. It’s a small detail on the dashboard, yet once you notice it, you’ll never have to circle the pump again.

All elevators look pretty much the same. Bigger or smaller, they all look similar, a gray box with a mirror and buttons. But if you pay close attention, you may notice there’s a small round opening near the top of the door.

That opening is a keyhole used by trained maintenance technicians and emergency responders. With a special elevator key, they can manually unlock the landing doors when repairs are needed or if passengers become trapped inside. The system allows professionals to reach the elevator safely without damaging the doors or relying solely on electrical controls. Hopefully, most of us will never need to see it in action. But in an emergency, that tiny opening becomes one of the most important parts of the system.

If you’ve ever stood in the bread aisle comparing loaves, you’ve probably noticed the colorful plastic clips or twist ties holding the bags shut. Contrary to what many think, they’re not simply a part of the packaging.

For many bakeries and grocery stores, the colors indicate the day a loaf was delivered or baked. While the exact color schedule can vary between bakeries and regions, employees use the system to quickly spot older inventory and rotate fresher bread to the back of the shelf. That way, customers are more likely to pick up the freshest loaf available.

Whether you wear jeans every day or only pull them out for yard work, you’ve probably noticed the tiny extra pocket tucked inside one of the front pockets. It’s too small for a phone and not very useful for loose change, but there’s a reason for it.

Back in the 1800s, when Levi Strauss & Co. created rugged denim pants for miners, ranchers, and cowboys working across the American West, pocket watches were commonplace. Workers needed a safe place to carry their watches while riding horses, so that little pocket was designed specifically to protect the watch from damage. Pocket watches disappeared, but the tiny pocket became such an iconic part of blue jeans that manufacturers have continued including it for well over a century.

Almost everyone has had the same frustrating experience. You pull on a sheet of aluminum foil, and suddenly the entire roll slides out of the box and lands on the kitchen counter.

That’s exactly why major manufacturers such as Reynolds introduced the small side tabs, known as end locks, in the mid-1990s. By pressing the tabs inward, they hold the cardboard roll in place like built-in axles. This keeps the roll from sliding out of the box, makes it much more stable as you pull, and helps the serrated edge cut a cleaner, straighter sheet. It also reduces waste by preventing the foil from bunching up or tearing unevenly. It’s a simple design, yet useful as it can get.

Every household has pens lying around for all kinds of purposes. And most of them have a common feature, a hole in the cap, which isn’t simply part of the design.

BIC and other pen manufacturers included the opening as a safety feature. If someone, especially a child, accidentally swallows a pen cap, the hole can allow a small amount of air to pass through, reducing the risk of complete airway blockage while emergency help is on the way. The design became part of border efforts to improve consumer product safety after choking incidents drew attention to the danger of small plastic objects.

If you grew up sewing or watching somebody do it, you probably remember the classic tomato-shaped pincushion sitting beside the sewing basket. Hanging from it was a tiny red strawberry that looked like nothing more than a cute finishing touch.

In reality, that little strawberry has its own job. Instead of soft stuffing, it’s filled with emery, a gritty material made from crushed abrasive minerals. Running pins and needles through it helps polish away tiny spots of rust, smooth rough edges, and keep the points sharp enough to glide through fabric more easily.

Think back to the first time you learned to type. Maybe it was at work, or on a family computer. Wherever it was, someone probably told you to keep your fingers on the "home row." That’s exactly why the F and J keys have tiny raised ridges.

The bumps let your index fingers find the correct starting position by touch alone, allowing you to type without constantly looking down at the keyboard. The technique, known as "touch typing," is widely credited to American court stenographer Frank Edward McGurrin, who demonstrated it in 1888. As typewriters became more common, manufacturers experimented with different ways to help typists orient their hands, and by the mid-20th century, companies such as IBM standardized the subtly raised plastic bars that remain on nearly every keyboard today.