In this day and age, it may feel like humans know practically everything there is to know. Yet there are still some facts of life that have had even the smartest minds stumped for centuries: even seemingly simple things such as why we yawn, cry, or laugh. While we experience these phenomena every single day, just why we experience them is a much more complicated — and mysterious — question to answer.
1. A laughing matter
Laughter is such a major part of our lives that most of us probably haven’t stopped much to think about why we do it. Luckily, various boffins have given it more thought than we have! But even they have struggled to find a widely accepted explanation for why we laugh and react to humor and comedy in the way that we do.
What’s clear for scientists is that laughing helps unite humans. Think of all the people at a stand-up comedy show, laughing in unison at the comedian’s jokes, and you get a sense of that. But from an evolutionary standpoint, scientists have suggested that humor comes from something outside a social or physical norm for a human, but not one that is threatening and triggers a fear response. Rather, a lighthearted response helps us to foster bonds with others.
2. An age-old question
Why is it that we age, and can’t just stay young forever? This is something you might have pondered in frustration at seeing a gray hair emerge, or a wrinkle get deeper. Scientists have been on this question for a long time, and there’s big money in the anti-ageing, beauty product industry too. But though they have some knowledge of the process, they haven’t fully figured it out, it’s fair to say.
One substance scientists have pinpointed as being key to aging is free radicals: damaging reactive chemicals that attack the skin’s outer layers. But there are many other factors, and free-radical damage can be limited with protective moisturizers and a healthy diet, for example. Another factor is the shortening of protective caps of DNA known as telomeres on each chromosome in the human body. But still many questions remain. We hope they hurry up and figure it all out so we can go back to being young again!
3. Questions around gravity
You know what gravity is, right? It’s the force by which a planet like Earth draws objects toward its center. It ensures all of the planets orbit around the Sun. It’s the reason an apple falls off a tree onto the ground, as Sir Isaac Newton figured out. But scientists don’t know everything about this complex force.
One of the chief questions about gravity that scientists still have, is why does mass create gravity? Another they are not sure of is how exactly one particular object gravitationally influences another one. Yet another mystery is how weak gravity is when compared to numerous other forces of nature. C’mon scientific community, figure it all out, please!
4. Making purr-fect sense
Hearing your cat purr can be a heartwarming experience, but why do our beloved feline pets produce the endearing, low, rumbling sound? Scientists are not entirely sure of this, or why some species of cats do it and others don’t. For instance, fearsome big cats, such as lions and tigers do not purr, and the latter of those two chuffs instead. But boffins looking into this phenomenon do have a few theories as to why.
One theory is that purring is a soothing mechanism for cats, or a way to express contentment, in the same way a tiger’s chuffs seem to be. But cats also purr when scared or angry, so there’s some doubt on this. Interestingly there has also been an indication from relevant research that cats purr in order to stimulate bone growth, with the frequency at which they do it encouraging tissue regeneration.
5. Gene-packed tomatoes
Would you believe us if we told you that tomatoes have more genes than a human being? Probably not at first, but you’d soon have to come to terms with it being true! Yes, amazingly, it takes more genetic information to create a humble tomato than it does a fully-fledged human being. Around 30,000 genes, in fact, which is roughly 7,000 more than one of us.
Not surprisingly, scientists have been a bit stumped as to how and why this could be the case down the years. They’ve searched for explanations, and developed theories. One suggests that around 70 million years ago, the fruit family of which tomatoes are a part tripled its genome, making three copies of each gene. Some were discarded as time went on, but useful ones remained. This is perhaps one reason why tomatoes have so many genes in them. How did it happen though? Likely through some kind of mutation, and the need for extra genes to survive a tough period on our planet after the dinosaurs became extinct.
6. A crying shame
We all cry at some point in our lives, whether it is due to the death of a loved one, the loss of a valuable relationship, or a tear-jerking movie. But scientists are still unsure as to why we do it. If crying were just to clean the eyes and remove debris from them, then that would make sense. But humans have a unique emotional link with crying, that boffins have yet to fully unpack, or agree on entirely.
Theories abound, though. One is that crying has been developed through evolution as a social mechanism, its purpose being to foster empathy between humans. There is also the idea that crying is a way of communicating sadness, or being submissive to a dominant/stronger human in order to avert violence. All of those make sense to us!
7. Turbulent search for the truth
If you’ve even been on a plane when it suddenly starts shaking violently, then you’ll be acutely aware of at least one type of turbulence. But this phenomenon is something that scientists are yet to fully get their heads round. There has been a lot of research into it, as it is imperative from an engineering perspective to learn how it really works. Turbulence covers not just rocking airplanes, but how far golf balls can travel and how internal combustion engines function.
Such is the complexity of turbulence that frustrated physicists mark it as one of the largest remaining gaps in knowledge in their field. As of today, no physicist has been able to present a perfect model of turbulent flow. One of the problems in doing so is the abnormality, randomness, and pure chaos of turbulent flows. Doesn’t seem like we’ll have an answer any time soon, then!
8. Migration mystery
The migration of birds is a wonderful thing to witness, should you be lucky enough to catch it. Other animals migrate too, such as Antarctic fur seals, who amazingly can locate the site of their birth with unerring precision. But scientists are stumped as to why some birds migrate large distances, while others don’t, and precisely how animals such as fur seals can return to such specific spots to mate.
The reasons for migration seem pretty clear: warmer climes and more abundant food sources. It takes a lot of energy to save energy though, with that initial long-distance migration, and many don’t make it. And the question of why some migrate and others don’t remains unanswered. Fortunately, tracking devices are now allowing scientists to learn more about bird’s migration behavior, so maybe a more definitive answer is on the way. Meanwhile, fur seals are thought to navigate back to the spots of their birth via an amazing reading of the planet’s geomagnetic field, but this has not been conclusively proved beyond doubt.
9. Inconclusive urge to itch
Itching is not a pleasant sensation, and more often than not it leads to an urge to scratch the itchy area of the body. But why do we feel the urge to scratch, and more often than not proceed with it, when it likely makes the problem worse? Scientists have grappled with this question for many years now and still don’t have a conclusive answer.
One theory they do have, though, is that of the “mechanical itch.” This is the type that is triggered when the body’s fine hairs are bothered. It’s thought that this may be an evolutionary development to alert the itchy human being to the presence of parasites or biting insects on the skin, that could be removed by scratching away. But the histamine chemical itch that arises after a bite still pushes us to scratch and likely make things worse, so go figure.
10. Blood-type brainteaser
Why human beings have different blood types is a really curious thing. How is that our blood is different to many others of the same species, with contrasting ability to fight infections and ward off serious diseases? It appears to be some kind of natural selection process, but why we have evolved in this way is not something scientists have been readily able to understand.
It doesn’t appear that there are any major theories as to why, beyond the natural selection advantage gained by having certain blood-types. Dr. Mohammad Mobayed of ProMedica Hematology/Oncology Associates told website thehealthy.com that there are “no definitive theories [that explain] why blood types differ among humans.” Well, better get to work on forming some then, doc, as we want to know. Chop chop!
11. Secrets behind sleep
Humans and animals need sleep. Sleeping is no doubt essential to a human’s functioning, and even high achievers need it; continual sleep deprivation will eventually lead to death. But scientists are still unsure as to exactly why we sleep. One reason for such interest in this is the disadvantage sleep provides to both humans and particularly animals, leaving them open to being snaffled by predators.
Theories abound as to what happens when we sleep. Scientists remain unsure about the mechanisms that the body utilizes in order to put us in an NREM or REM state, and why some humans can function well with just a few hours, while others cannot. A working theory on the need for sleep has come out of research that suggested that the brain runs vital maintenance during periods of shut-eye, including forging connections with itself. Researchers have also learnt that waste chemicals are cleared out the body whilst we sleep.
12. Mysterious glass
Drinking liquid out of a glass is surely just a case of it being solid, right? Erm, no is the simple answer. Whilst glass may feel completely solid in your hand, it is actually a non-crystalline, or amorphous solid. This means it doesn’t possess a well-ordered molecular structure symptomatic of other solids, but at the same time it is not unequal enough to be a liquid. As such, scientists have been a bit baffled as to how this is the case.
What scientists — and glassmakers, of course — do know is that when glass is in its molten form, it is possible to shape it into many different contours before it reaches its cool, solid state. Those free-moving molecules slow down when out of liquid form, but not in a regular pattern, hence those beautiful wine or beer glasses you have at home, or pick up in a bar. But as to why this happens, scientists are currently none the wiser.
Anesthesia is the loss of sensation caused by an anesthetic, and it is of course a vital part of any major surgery in a hospital. An anesthetic literally numbs any localized pain you would have felt from having surgery without it, or knocks you out to sleep whilst an operation is being done. But scientists don’t really know how and why anesthesia works, and though there are theories out there, no scientific consensus has been yet reached.
One theory developed from research centers around anesthesia interrupting the neural activity in the fatty parts of the brain. Researchers also noted that certain receptors found in our gray matter link themselves to the anesthetic, which culminates in a loss of sensation or consciousness, depending on the dose and how it is applied. There may be more to it than this, though, so assorted clever people are still working to figure out more.
14. Why only some thunderstorms produce tornadoes
Thunderstorms are among the Earth’s most spectacular natural phenomena, and they vary greatly in power and severity. For instance, only a small number of thunderstorms lead to the development of tornadoes, and these almost always happen in specific areas of the planet, for example along Tornado Alley in the central area of the United States. But why is this?
Whilst scientists don’t really know why only some thunderstorms produce tornadoes, they are aware that they often form when cold, dry air mixes with its warmer, more humid counterpart; Tornado Alley is so prone to tornadoes because of the cold Arctic air emerging from the Southwest meeting with the warm air emanating from the Gulf of Mexico. Scientists have also pinpointed air-temperature changes flowing downward around mesocyclones leading to the formation of tornadoes, but again, they can also form without this, so there is still a considerable gap in knowledge on the subject: not least on how they subside.
15. Ice-skating intrigue
Ice skating is a fun outdoor winter pastime, and a telltale sign that the holidays are here or on the way! You’ve probably not given it much thought as you glide around the ice, but why is it that you can skate on top of ice in the fun way you can? Scientists are surprisingly stumped about why this is the case, but have some theories as to why at least.
Boffins used to believe that you can glide across the rink due to the pressure of the skate lifting the temperature of the ice, so that it slightly melted and left a skin of water for the movement to work. That has been largely debunked now, and scientists are more interested in theories that the water molecules at the ice’s surface aren’t bound as tightly together, or that flaws in the structure of it enable it to reach a liquid state more readily.
16. Theories on blushing
We’ve all blushed at some point in our lives, whether it was in the company of our first crush or when we were involved in a humiliating incident. And while scientists aren’t sure about quite why our cheeks go red with embarrassment, there are a few theories that have been conjured up.
Firstly, some scientists have suggested that blushing might be a developed evolutionary response, in order to show deference to group leaders. Then again, other boffins have hypothesized that blushing is a way of winning people over: studies have suggested regular blushers are often seen as more likable and tend to render other people more willing to overlook their past indiscretions.
17. Right-handed regularity
The majority of people on planet Earth are predominantly right-handed. But why is this, and what is the significance of it? It’s not the case in apes and monkeys, for instance, where there is a roughly 50/50 split you might also expect to see in humans. Unfortunately, scientists don’t really know for sure. But they do have a few theories about why this curious trend may be the case.
Some scientists have claimed the reason for most humans having a preferred hand is down to evolution: there was some advantage to be had from using complex tools using one hand in particular. But this doesn’t explain the predominance of right-handers: an estimated 90 percent of us, compared to just 10 percent who favor our left hand. Some research has shown those with genetic diseases like Down’s syndrome are more frequently left-handed, and there is often unusual brain development in lefties; perhaps there is some disadvantage to being left-handed?
18. Yawning gap in knowledge
Yawning is something that humans and animals alike do, and on a very regular basis. It most often happens when we are tired, and for some reason it appears to be contagious to other people, as you may have noticed when you’ve yawned at a late get-together with a friend! But why do boffins know so little about yawning, and what are the theories as to why we do it?
The main reason we yawn, scientists suggest, is as a method to push more oxygen-rich blood into the brain, where it is needed to keep us alert and awake. Another theory is that we do it to jolt our bodies, as our heart rates increase and eye muscles become more tense. We might yawn to regulate the temperature of our brains too. The contagious nature of yawning could be down to social mirroring of animals and humans, but who really knows?
19. Upright bicycles puzzle
Bicycles are a common form of transportation and exercise for humans. Indeed, bikes are so common — particularly in the Dutch capital city of Amsterdam — that it is easy to forget what a wonderful invention they are, and how they work. But you might be shocked to discover that scientists are rather baffled as to how they stay upright when moving.
Yes, whilst boffins know how a bike works — the foot pedal turning the gear which in turn moves the wheel — they have so far not understood why a bike can continue upright on its own whilst moving, before collapsing in a heap when it stops. One theory put forward is that the spinning of the wheel gives the bicycle the necessary stability, but why though, is it balanced? Another idea was that the wheel acts like a caster on a shopping cart, but this has largely been abandoned. Amazingly, the bike-mad Dutch have created an entire center to try and figure out this question.
20. Why we have hiccups and how to stop them
Having hiccups is a strange and often horrible experience. Some people endure them only for a few minutes or hours, whilst more unfortunate types can experience them for years. But despite their regularity, scientists have never quite figured out what causes them, or what they are for, let alone how to cure them.
Scientific theories on why humans develop hiccups have been developed over the years. One such idea is that hiccups are a relic response from an earlier stage of human evolution: one that is not needed now and which arises relatively rarely. Another theory is that hiccups are an attempt to expel unwanted gas, most often in babies. But boffins have done relatively few studies on the questions surrounding hiccups, and haven’t come up with many ideas about how to get rid of them, either.
21. Appendix ambiguity
The appendix: an organ in the human body that is about as much use as a chocolate teapot. Yes, this thin pouch affixed to the large intestine doesn’t appear to have any role in the body. Still, when it gets infected it can cause a lot of pain, and has to be removed quickly; a burst appendix can lead to peritonitis and can even prove fatal.
Scientists, though, aren’t exactly sure or in full agreement what the appendix is for. The most common theory — one that goes back to Charles Darwin — was that the organ is effectively an evolutionary leftover, a tool for aiding digestion of greenery, back from when our ancestors ate mostly plants. This idea has been countered more recently by another, which hypothesizes that the appendix actually stores and protects some good bacteria needed by the body. The jury is still out on this, though.
22. Dreaming debate
Dreaming is one of the more unusual things that humans do. We’ve all awoken from a vivid dream one night, likely either disappointed that it isn’t true, or relieved and sweating profusely at the sheer horror of it. But why we dream — about both good and scary things — is something scientists and other boffins don’t fully understand.
Indeed, some professed experts in sleep believe that dreaming serves no meaningful purpose, but is just a way for the brain to explore during sleep. But others think that it does, and one theory is that dreaming is a sort of evolutionary response to danger or prospective situations. So, that scary dream where you are being chased could be a way of preparing you for just such a threatening situation in the future, should it arise in real life.
23. The mystery of viruses
Viruses are nasty bacteria that only live in our bodies when we are ill, right? Incorrect, actually, the answer to that question is emphatically no. Biologists now know that there are a range of viruses that live within our bodies at all times. But they don’t fully know why this is the case.
Yes, why we have viruses inside our bodies even when we are not ill is something that biologists are working on. They estimate that there are a whopping 380 trillion viruses in your body now, in what is called the human virome. In 2010 scientists didn’t really know such a thing existed. They are trying to figure out more, and this discovery made them realize humans are superorganisms of cohabitating cells, fungi, bacteria, and viruses. Maybe someday soon they will figure out the answer to this question.
Fingerprints are an interesting aspect of the human body. They almost act as an evolutionary identity, given that they are completely unique to us and no set of them is the same, not even among identical twins. But why we have these personal patterns on our fingers is a question with which scientists have been wrestling for a long time, but are still scratching their heads about today.
Initially, it was suggested that fingerprints were developed to help humans grip things. But an investigation into this theory discovered this was baloney, as having smooth, fingertip-less fingers would enhance our grip. So, perhaps it is that they protect our digits in some way, or that they enhance touch sensitivity? C’mon boffins, figure it out for us!
25. The secret of soft sand
Beach bums among us will likely have fond feelings from the sheer mention of soft sand on a beach. Indeed, for these types walking barefoot across a warm, sandy beach is literally Heaven on Earth. The soft sand that you find on many popular beaches worldwide seems to ooze a sense of calm to those who walk across it. But scientists are unsure about how this sand feels so soft.
Indeed, boffins who study these kinds of things are stumped by the unique tactile quality of soft sand, but at least have some theories as to why it is like it is. One key one is that a smaller grain of sand most often means it’ll feel softer, because it is able to move more easily between your feet as you stride along it barefoot. Still, if it’s too small, there’s a chance it will be clumpy and sticky due to moisture. Of course, the top layer of sand hasn’t been compressed down like the lower ones, so that is another reason why it feels softer on top.
26. Contagious chuckling curiosity
We all have that friend who has an infectious belly laugh which sets us all off cackling ourselves. They make us laugh even if we don’t find whatever they were laughing about in the first instance that funny. This is an example of contagious laughter, a weird phenomenon if ever there was one. But whilst it seems pretty clear then that laughter is contagious, for some reason or another, scientists are yet to find out why.
Scientists have presented several theories and undertaken numerous studies on the question of why laughter can be so catchy. One centers around the fact that humans are social creatures, and laughter is something that occurs through humans being empathetic and group-oriented. Another suggests that laughing is good for our health as it releases endorphins from the brain, so we are prone to doing it whenever we can.
27. How static cling works
When you were a child, you might well remember rubbing a balloon on clothing and holding it over your hair in science class to pull at strands and demonstrate a static charge. It’s a neat little trick, but how does it work? Well, unfortunately we aren’t entirely sure. Not just laymen like us, though. Scientists don’t know either, despite having investigated the phenomenon.
Yes, scientists are remarkably still unclear about the mechanisms involved in creating a static charge from a balloon, indeed or why it happens in the manner that it does. Theories have been developed, though. One suggests that the static charge occurs due to the interaction of two different materials which carry a different number of electrons. This has since been debunked, as static charges can arise from two objects made out of the same material. So, the favorite nowadays among scientists is that there are other molecules that are swapped during the contact between hair and balloon, for example.
28. Cureless common cold
We reckon every single reader of this article will have suffered from a cold at some point. But how is it that something that is so common — and downright annoying — has yet to be figured out by the brightest scientific minds on the planet?
Indeed, scientists have failed to find a cure for this most common of ailments, but there is a fairly good reason why this is the case. You see, colds arise from seven distinct families of viruses, and those families all have sub-viruses within them. Scientists have so far not been able to create a “catch-all” cure for all cold viruses, because of mutations, and the fact there are over 200 of them!
29. How lightning strikes
Lightning is one of the most thrilling and scary natural phenomena on the planet, though which of those attributes comes to the fore probably depends on how close you get to a strike! There are around 100 lightning strikes around the globe every second, but weirdly scientists are still at a loss as to exactly what causes them.
Yes, boffins are divided on precisely how lightning strikes come about. They know all about what the cumulonimbus clouds contain, but can’t pinpoint exactly why the charged elements in the clouds that generate lightning separate in quite the manner they do. One theory suggests that cosmic rays are responsible, and that when they hit the Earth’s atmosphere they alter the electrical composition of clouds. But this theory is unproven, and the fact that air does not conduct electricity well is another head-scratcher for scientists trying to figure out this phenomenon.
Tylenol is a regular over-the-counter medicine that we use in our lives when in a bit of pain. Scientists and doctors must surely know how it works then, given it is FDA approved and so widely in use? Erm, well, no actually. In fact, as crazy as it sounds, scientists are a bit unsure about Tylenol, namely its generic form acetaminophen, and how exactly it works to nullify pain.
How do we know this? Well, look on the side of the bottle next time you buy Tylenol, and you’ll see a physician’s note that lays this shocking fact bare. Scientists don’t know why it works or the processes it follows. Theories have arisen from research though. One is that Tylenol works by blocking an enzyme that is linked with the feeling of pain. Another suggests that the medicine engages with the endocannabinoid system that is linked to pain, and yet another points to the potential of it adjusting serotonin signals. Maybe all three of these theories are true, or perhaps none. Who knows?