15 Seemingly Simple Questions We Don't Know the Answer To

By: Jack Sackman
Man thinking with his hand under is jaw. Also question marks and exclamation marks around him
Science, mathematics, and technology have answered so many thoughts and questions. But it may sound weird to tell you that some of the simplest questions have not been answered by science. triloks / Getty Images

The fields of sciences and mathematics are capable of some amazing things and answering some of the biggest and most puzzling questions on the planet. But what may shock you is that some of the most mundane and seemingly simple questions have no real confirmed answers from scientists.

From how a bike works to how many planets are actually in the solar system, these are 15 seemingly simple questions that we don’t know the real answer to.


15. What Causes Static Electricity?

The traditional explanation states that when two objects come in contact, friction knocks the electrons off the atoms in one of the objects and transfers them to the other object. This leaves the first object with an excess of positively charged atoms and the second with an excess of negative electrons. Both objects can then be said to be statically charged. But why do electrons flow from one object to the other, instead of moving in both directions?

As Northwestern University researcher Bartosz Grzybowski detailed last year in the journal Science, patches of both excess positive and excess negative charge exist on statically charged objects. In addition, he found that entire molecules, not just electrons, seemed to migrate between objects as they are rubbed together. Therefore, it would seem the forces involved in generating this patchwork of particle migration are still a little bit mysterious.


14. Why Do Lightning Strikes Happen?

This is a subject of great theoretical debate. One theory holds that when ice particles within a cloud collide, they break into smaller particles with positive charge, and larger particles with negative charge. Gravity then pulls the negatively charged particles downward, while updrafts lift the positively charged particles skyward resulting in an imbalance. However, after examining the electric fields in thunderclouds scientists didn’t obtain the measurements they would have expected from such a process. This prompted the development of a theory involving cosmic rays from space shooting down through the clouds and stripping off negatively charged electrons, but, as things stand, there’s not enough evidence for it to be widely adopted.


13. How Does the Brazil Nut Effect Work?

The “Brazil Nut Effect” is a phenomenon seen in a many-body system, such as a bowl of mixed nuts, where the largest objects tend to rise to the top of a random distribution.

This sounds counter-intuitive as you’d think that the heavier object would sink to the bottom. But you also have to consider that the smaller pieces might just be falling through the cracks and trickling to the bottom. Some have noted that it is similar to the way a convection current works or that it might be attempting to move from a high-energy state to a low-energy state. While all these theories might be plausible, we just can’t seem to figure with certainty why it occurs and, thus far, no computer algorithm or mathematical formula has been able to reproduce the effect. So you could say this problem has turned out to be a real tough nut to crack.


12. Why Do We Like Music?

In Twelfth Night, Shakespeare’s words propose that music is the food of love. This evokes the idea that music evolved as a sort of human mating display in much the same way that birds of paradise evolved to have elaborate plumage. However, while this reasoning goes a long way in explaining why even the grungiest of garage bands can still manage to get a devout following of groupies, it fails to account for a number of aspects. For example, most people can probably listen to Susan Boyle’s moving rendition of Wild Horses without getting too hot in the pants. There just has to be some other reason as to why humans, and perhaps other animals with highly evolved brains, seem to have a universal appreciation of music. We just have no idea what it is.


11. Why is Ice Slippery?

Until recently, it was thought that the reason ice is slippery is because the pressure created by stepping on it causes the top layer to melt. But experiments have now shown that the average human body doesn’t exert nearly enough pressure on ice to change it into liquid. The force of friction has also been ruled out since when you stand still on ice, it still remains slippery. So with pressure and friction out of the picture scientists have had to get pretty creative with their explanations for what makes ice slippery. Currently, their best guess is that the layer that forms on top of ice is not a liquid, but a “supersolid skin” that allows for the bonds between water molecules to stretch without actually breaking. These elongated bonds are thought to be responsible for generating an electrostatic field that makes the slippery effect by effectively levitating you ever so slightly off the surface. Not all scientists agree on this point but what they do agree on is that this interpretation sounds far too complicated than it should be.


10. How Long is the U.S. Coastline, or Any Coastline for That Matter?

Of all the simple questions here, this might be the simplest, as the mountains, rivers and continents aren’t going anywhere, at least not fast. But the truth is, estimates vary wildly as numerous different studies have come up with very different answers to the question. This whole phenomenon is known as the “Coastline Paradox.” The Coastline Paradox is the idea that the coastline of any land mass doesn’t have a distinct and well-defined length. Essentially, the length of the coastline depends on the method used to measure it. Since a landmass has features and portions at all sizes, from hundreds of feet high to tiny fractions of an inch and below. Also, there is no obvious size of the smallest feature that should be measured around, and therefore there is no single well-defined perimeter to the landmass.


9. How Do Bicycles Work?

We’ve been riding them for decades, all the while expecting that some genius out there knows how and why they work. The bikes can stand up on their own as long as they remain moving forward, and this was long believed to result from a law of physics called the conservation of angular momentum. But recently, a group of engineers went against this theory of bicycle locomotion. Their investigation showed that this law wasn’t needed for the bike to work. To prove it, the engineers built a custom bicycle which couldn’t take advantage of the effect. And yet, the bike worked. Scientists are baffled at how something so simple to most of the world can evade detection and reason for so long.


8. How Many Planets are Actually in Our Solar System?

We all know about how Pluto was famously kicked out of the solar system treehouse a few years back, but what you might not know is that the current count of eight planets and one sun is basically just science’s best guess for the time being. This sounds crazy because we’ve all seen the same model of the solar system since elementary school. But despite what you might believe, the vast majority of our solar system is still uncharted and unknown by science. In fact, the area between Mercury and the sun is too bright to see, and the area beyond Uranus is too dark. Scientists are still finding new objects in the asteroid belt by the hundreds of thousands, so there could be numerous other planets that we have never discovered.


7. Why are Moths Drawn to Light?

If you’ve ever been out camping or at the cabin and have a porch light on at night, chances are that you have seen a number of moths that seem to mindlessly flock to light and run into it. But surprisingly, the reason for these insects’ suicidal nosedives remains a total scientific mystery and the best guesses why aren’t even very good. Some entomologists believe moths zoom toward artificial light sources because the lights throw off their internal navigation systems. But this theory runs into major stumbling blocks. One major stumbling block is that campfires have been around for about 400,000 years. Wouldn’t natural selection have killed off moths altogether as their instinct tells them to go kamikaze every time they feel blinded by the light?


6. Why are There “Righties” and “Lefties”?

One tenth of the population have better motor dexterity with their left hands than their rights, and no one really knows why lefties exist. But for that matter, no one really knows why righties exist either. Wouldn’t it make more sense if everyone was equally proficient with both hands? One theory claims that handedness results from having more intricate wiring on the side of the brain involved in speech (which also requires fine motor skills similar to using our hands). Because the speech center usually sits in the brain’s left hemisphere, which is wired to the right side of the body, the right hand ends up dominant in most people. However, the theory about the speech center controlling handedness gets a big blow from the fact that not all right-handed people control speech in the left hemisphere, while only half of lefties do. So, what explains those lefties whose speech centers reside in the left sides of their brains?

5. Why Do We Sleep?

As far as we know, nearly every creature and animal on earth enjoys sleep just like humans do, but the hours of sleep vary greatly. This means that sleep obviously must serve a key purpose for all living things, right? Well, it turns out science doesn’t really have a concrete answer. What we do have is a number of proposed explanations for why we sleep, but scientists can’t really agree on them. There is the theory that the brain is “recharging” when we sleep, there is a theory that claims we are reinforcing things in our brain that we need in day-to-day activity, and another claims we toss out a bunch of useless information in our brain when we sleep. It seems as if sleep is necessary for us to survive, but we don’t really know why.

4. How Does Gravity Work?

At its simplest, gravity is one of the most basic things of all time. You throw something up, it comes back down. But in reality, gravity makes very little sense at all. It is crazy how gravity can be so incredibly weak and incredibly strong at the same time. Gravity holds the entire universe together, and no matter how far out you travel, it never completely disappears. And yet, it is the weakest force in existence. For example, you know when you bring two magnets near each other and they snap together? That force is actually 10^36 times stronger than gravity. But the biggest gravity mystery out there is that once you get down to the level of atoms and molecules and even smaller stuff, gravity just plain stops working. It is without a doubt one of the true mysteries of science.

3. Why Do Cats Purr?

Whether it’s a big cat or a small house cat, all felines seem to purr. They seem to purr in a bunch of different situations such as: when they are pet by humans, when they nurse their kittens and even when they are stressed. This means it seems that cats purr both when they’re happy and when they’re upset, which makes it hard to know the true origins of it. One possibility is that it promotes bone growth. Purring contains sound frequencies within the 25- to 150-Hertz range, and sounds in this range have been shown to improve bone density and promote healing. Because cats conserve energy by sleeping for long periods, purring may be a low-energy way to keep muscles and bones healthy without actually using them. However, this type of theory doesn’t explain why cats purr in the few situations they do.

2. Why Do We Yawn?

Yawning, it’s something that you do throughout life when you are bored or tired. But the truth is, nobody really knows why we yawn. We know that yawns are contagious and why they are (that is because of deep roots of empathy and social bonding), but we still don’t have a concrete reason why we exhibit yawns. In fact, embryos are thought to do it to sculpt the hinge of their jaws, but the reasoning why it continues throughout life and seems to transition to something we do when tired, is unknown.

1. What is Time?

And coming in as the simplest question we don’t know the answer to is: what is time? Now this isn’t simple in a sense of answering the question, but the concept of time is one of the easiest things to learn that almost everybody understands, but why does it exist and where did it come from? Time is often referred to as the fourth dimension and is normally seen as a measure in which events can be ordered from the past through the present and into the future, but the true meaning of it is a question that has eluded scientists forever. A great website to visit if you want to learn more is www.timephysics.com.