8 Simple Questions You Won't Believe Science Can't Answer

8 Why We Sleep

As far as we know, virtually every creature on earth enjoys a good night's rest as much as people do (though the hours we choose to sleep varies greatly). So obviously sleep must serve a key purpose for all living things, right? Well, it turns out science doesn't have a clue.

What we have is a handful of proposed explanations for sleep that not many scientists can agree on. There's the theory that it's helping the brain clean house after a long day of learning. You see, your brain is constantly generating new pathways thanks to all the stuff that you see and do all day, so sleeping is when all the useless info gets tossed out.

Or maybe, instead of ditching the stuff that's not necessary, the brain might be reinforcing the stuff you do need. Scientists have seen that, when rats were asleep, the same neurons fired as when they had run mazes earlier that day. That means that the rats are essentially reliving their day and "practicing" the maze. This has led Harvard sleep researchers to assert that sleep is crucial for humans to form memories and to learn.

But there's a problem with both of these theories. Plants and microorganisms, otherwise known as "things without brains," have dormant states that are very similar to sleep, which kind of puts doubt on the whole "sleep is good for the brain" theory. Then there's the fact that scientists have found certain humans who can go without sleep with no ill effects. There's even one dude who claims he hasn't slept a wink in 33 years.

In fact, all of these theories kind of went out the window when researchers discovered a gene mutation that allows people to sleep two to four hours a night without any adverse effects at all. So, is sleep useless, then? Is it just God's way of making us take a break between masturbation sessions? Your guess is as good as science's.

7 How Many Planets Are in Our Solar System

Since Pluto was surprisingly kicked out of the solar system treehouse, we've known that the membership of the Planets Club is subject to change at science's whim. What you may not have realized is that the current inventory of eight planets and one sun is pretty much just science's best guess for the time being.

It sounds bizarre, considering you all saw the same model of the solar system in elementary school. And every time you hear anything about space in the news, it's always badass telescope this, or new photograph of faraway galaxy that. We're mapping the edge of the freaking known universe over here. There's no way anything in our own cosmic backyard is escaping our notice, right?

But despite what Big Space wants you to believe, the vast majority of our solar system is still uncharted and unknown. 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 theasteroid belt by the hundreds of thousands. Oh yeah, and some of astronomers think there might be a second sun. Seriously.

You see, not even our best telescope technology can see things that are far behind Pluto, where sunlight doesn't illuminate things all that well and where we're essentially blind. So astronomers have to combine vague clues and guesswork to figure out what's going on out there, kind of like space CSI.

First off, the fact that there's a huge gap in asteroids after a certain distance behind Pluto tells scientists that there's very likely a planet between the size of Earth and Mars that gobbled up all the space rock out there, so yeah, our solar system is probably back up to nine planets again. They're getting really tired of rewriting those middle school textbooks. And speaking of Pluto, astronomers have also discovered an object named Sedna orbiting the sun, and although no one's a hundred percent certain of its size, they're pretty sure it's carrying at least Pluto's heft.

But wait, that's not all, folks. Another little anomaly that astronomers have noticed is that comets' orbits aren't exactly going along as predicted. The explanation? There must be another planet out there that's affecting the icy rocks' orbits. And according to their hypothesis, this mother of a planet is huge -- like, "four times the size of Jupiter" huge. Named Tyche, this giant gas ball is way too far away for sunlight to reach it, but still, scientists are pretty confident that evidence gathered from a NASA telescope will prove its existence very soon. Who knows, in a few years, naming all the planets may be as hard as naming all 50 states.

6 Why Ice Is Slippery

Saying that ice is slippery is like saying that water is wet -- it's something we've known for as long as we can be said to have known anything. Presumably, humans as a species knew ice was slippery before we knew fire was hot, or that it existed. But ask anyone why, and they won't be able to give you any better explanation than one of those cave people would have.

We just don't know why it is that you can ski on ice but not on boulders. Although at this point, most of you are probably screaming "It's water, stupid!" -- and that's more or less the answer that scientists have always concluded. Even in some modern textbooks you can still read the popular explanation: Unlike most substances, ice expands when it freezes. So when you walk on it, you're actually compacting it back into slippery old water. Sounds simple, right? Too bad then that it's bullshit. Experiments have shown that your puny body doesn't exert nearly enough pressure on ice to squeeze even a tiny bit of it into liquid.

There are some competing theories, though none of them are better than the others. One popular theory is that the surface of ice remains liquid because there's nothing but open air on one side to put pressure on it. And some tests have confirmed that -- although they also confirm that the liquid layer is probably too thin to have any effect on friction.

Another theory that scientists have put forward is that ice is not actually slippery at all. Though this sounds like something that science, exasperated, would proclaim while waving a gun in your face to make you stop asking stupid questions, a guy named Dr. Salmeron thinks that the roughness on the surface of ice is actually so high that, ironically, it becomes slippery when you flash-melt it due to the sheer friction you're applying to it. Of course, in the same breath, Dr. Salmeron admits he may be talking out of his ass.

5 How a Bicycle Works

Bicycles have been around since the early 19th century, and its basic design has actually changed relatively little for almost 200 years. You always had two wheels, a frame to connect them and a handlebar for steering, and you required a person completely devoid of shame to ride on it.

At the very least, you'd think that the guy who invented the damn thing knew what he was doing, but after more than a century of research, science has been forced to conclude that he was probably some kind of sorcerer. The first bicycles were invented, not through any kind of scientific procedure, but by dumb old trial and error. Even modern bike design schools admit that it's not engineering or computer knowledge that make a good bike designer, but instead "intuition and experience."

So, what happens when you ask scientists exactly what makes a bicycle stable? Or what keeps it going? Or how people ride them? Well, odds are they'll either nervously tell you that they have cookies in the oven and run out on you, or if they're honest, they'll give you a pretty big shrug. In fact, top bike researchers admit that, even though some people have come up with equations on how to ride a bike or how they think bikes work, those equations are pretty much fancy icing on top of a cake of cluelessness. One Cornell researcher even says that absolutely nobody has ever come to an intuitive understanding of what makes a bicycle do its thing.

For ages, scientists assumed that the gyroscopic effect (the force that keeps a spinning top from falling over) was the key for a bike's balance. But nope! In the '70s, a scientist disproved that theory.

So then, scientists thought that the principal factor for a bike's stability was something called the caster effect, or trail (something to do with the front wheel's angle away from the frame). But just this year, top bikeologists from Cornell and other universities formed an angry scientific mob, then torched and pitchforked that theory as well. They did this by building a goofy-looking bike that has no gyroscopic effect and no trail, but manages to stay upright nonetheless.

So scientists are essentially back at square one, as things such as steering geometry and the physics of stability are all going back to the drawing board. At least you can be secure in the knowledge that the humiliation you feel when you ride a bike is akin to the humiliation science feels when it's asked how a bike stays up.

4 How to Beat Solitaire

Odds are pretty high that you're reading this article while you're at work. And once you're done wasting time with Cracked, odds are you'll continue to waste time with something else. And conveniently at your fingertips is one of the most played and addictive games of all time, one that you don't even need a partner for: solitaire.

More specifically, Klondike solitaire, which is as familiar to career procrastinators as Minesweeper. All of us at some point, usually around our 10th consecutive loss, have buckled down and tried to figure out the secret. After all, if Rain Man can break Vegas, surely you can beat a goddamn Windows game.

Wrong!

Maybe it has something to do with the fact that scientists get distracted when "studying" solitaire, or the fact that solitaire may have evolved from freaking black magic, but pretty much every damn thing about the game has remained a mystery since the 1800s. In fact, big-time mathematicians openly admit that it's one of the "embarrassments of applied mathematics" that almost nothing about the standard Klondike solitaire game is currently known.

For example, when the math geeks tried to find the odds of winning, they ran into a problem. They couldn't even get a fixed idea of how many winning hands are possible. The mathematicians came up with an approximate percentage of how many hands are winnable that was somewhere around 80 or 90 percent. But think about it -- when you play solitaire, do you win at least eight out of every 10 hands? Either you have the lamest X-Men superpower ever, or you're lying.

Now, there's some wild-ass guesses out there as to what the actual odds of winning Klondike are, but you'll never get an exact answer, even if many computer people agree that you don't have a good chance of winning at the game.

You might think that it's just because scientists are too busy breaking apart neutrons and quarks to bother trying to hack a card game. But consider that science has already cracked the secrets to the seemingly much more complicated game of Monopoly. But solitaire? It's simply beyond our powers of understanding. Then again, if we actually did know how to beat solitaire, we'd have to go back to work faster.

3 How Many Species of Animal Exist

In the 21st century, the days of Marco Polo and Columbus are long behind us. Nobody is exploring new lands and finding exotic new creatures like the platypus for the rest of the world to call bullshit on. So surely, having stomped across every nook and cranny of this blue earth, we should by now have some kind of ballpark figure about how many species we have left to kill, right?

Actually, not even close. When you ask taxonomists (scientists specially tasked with finding and cataloging animals), they'll tell you they haven't even scratched the surface in their attempts to find all the creatures that live on the planet. However, despite working on this mission for almost 250 years, along with discovering over 15,000 new living beings each year, taxonomists don't even have the faintest idea of how many species live on Earth.

In fact, although scientists have identified almost 2 million of the species we've got, estimates for the amount of species that are actually on the planet range from a measly 5 million up to a daunting 100 million. The reason for this supernova-sized room for error is that, no matter what method the scientists use to make their estimates, there's always some amount of guesswork involved.

One of the early estimates from 19th century taxonomists said that there were about 400,000 species on Earth, and seeing as how we've already discovered five times that many, it's only logical to conclude there was some faulty sciencing involved there. In fact, the most recent estimate, which claims that that there's less than 10 million species, is being heavily criticized by scientists. Hell, even the people who put out this estimate admitted publicly that they might be way off.

There are a few good reasons why the birds, bees, and bacteria remain woefully uncounted. First off, the research on species takes place mostly in the northern hemisphere, which remains more technologically advanced than the southern, so it's very likely that places like Australia have yet to show us the complete horror of their fauna.

But the biggest reason that science is still shrugging its shoulders and making sad trumpet noises is that 99 percent of all living space is under the ocean, and humans have explored less than 10 percent of it (experts say we have better maps of the surface of Mars than of our own oceans). We discover new and horrible types of life there all the time!

2 The Length of the U.S. Coastline (Or Any Coastline, For That Matter)

Of all the subjects we learned in high school, the one with the least amount of mystery was probably geography. The continents, rivers and mountains aren't going anywhere. At least not very fast, they're not. Sure, the fine points can get more complicated. Maybe the tallest mountain isn't the one you think, and maybe the largest desert will surprise you, but even then, it's all just a matter of committing definitions to memory and spewing them back to your teacher. It's all freaking measurements! Surely the length of the United States coast isn't something "up for debate."

Yet estimates vary wildly. The Central Intelligence Agency, for example, officially lists the length of the U.S. coast as around 12,380 miles. But another study came up with 29,093 miles. Then this study from the National Oceanic and Atmospheric Administration (a U.S. government agency) came up with 95,471.

What the hell?

You see, measuring coasts isn't simple and indisputable, like measuring a straight line on a piece of paper. It's complex and prone to wild exaggeration, like measuring your dong in the bathroom. The reason is that, depending on how much detail of a coast you want to measure, you'll always get a different final outcome from someone who chose to take into account a different amount of detail. If you want to just take the rough outline of a coast, you can get a measurement like the CIA has. But when you get into the fine details of every little inlet and estuary, suddenly the numbers get much bigger as you calculate in all of these twists and turns.

And the thing about all those numbers is that they can all be adopted as "official" measurements by government agencies, and nobody would bat an eye. In fact, the disparity between coastline measurements is accepted and is a pretty well-known problem in geography dubbed the "coastline paradox." This coastal conundrum comes from the fact that, no matter how much detail you choose to take into account in your measurement of a coastline, no matter how many of the zigs and zags you measure, there is always more detail to get. This paradoxically makes every single coastline of every single country infinitely long.

1 How Gravity Works

Come on, it's gravity. Is there any concept in the universe quite so basic? You throw shit up, it comes down again. Despite his textbook reputation, Newton didn't discover gravity. It was discovered by the first fish ancestor who crawled onto land and found it had lost the ability to swim upward. What's to understand?

Turns out there are four basic forces that hold the universe together, and out of these four, gravity is the only one that doesn't make any sense. Specifically, how it 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. To illustrate, you know when you bring two magnets near each other and they snap together? That force is actually 10^36 times stronger than gravity. Yeah, the technical term for that is "a big-ass order of magnitude" stronger.

To add to the confusion, because all these other forces are controlled by their own particles, it stands to reason that gravity should have its own particles, too. But this hypothetical critter -- the graviton -- is basically the only one we haven't found yet, unlike the particles that mediate a lot of the other important forces in nature, which have been altogether more cooperative.

But the mother of all baffling gravity mysteries is that, once you get down to the level of atoms and molecules and even smaller stuff, gravity just plain stops working. In fact, gravity is one of the biggest reasons why quantum physicists and real-world physicists have nothing to say to each other. We know more about what's inside an atom than we do about why a ball comes back down when we throw it in the air. For all science knows, it's because of ghosts.

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For more questions that do have answers, check out 5 Mind-Blowing Scientific Answers to Life's 'Big Questions' and 7 Hotly Debated Movie Questions That Totally Have Answers.

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