5 Everyday Science Facts (Nearly Everybody Gets Wrong)
We all love science, sure. It's what makes things explode when we want them to, and keeps things from exploding the rest of the time. But science is hard, and there's lots of stuff we can't get our heads around. And we're not just talking about super complicated topics, we're talking about everyday stuff all around us, like ...
"You Are What You Eat"
Not long after humans became self-aware and also realized we like eating, we figured out we're made out of the same stuff as those yummy bits of food. We eat, we break food down, and we build those food components into our body. Eat a lot, and you get big; eat nothing, and you wither and die. If you skip on eating some specific nutrient, you can't build that into your body, and you get sick. And if you eat a lot of a nutrient, you build a whole lot of it into your body. Right?
That sounds reasonable enough. But that very last observation is kind of only true with fat, which is something your body likes to store away (and even fat storage is more complicated than that). With other stuff, you have to eat it, but if you eat extra, your body just kind of discards it.
Take cholesterol. Doctors have long known that when patients have lots of cholesterol in their blood, that's bad for their heart, so doctors advised such patients to strike all cholesterol from their menus. These patients dutifully gave up eggs and quit Sausage McMuffins, and if their cholesterol stayed high, well, doctors assumed they were cheating on their new diets. But it turns out that there's no relationship between how much cholesterol you eat and how much cholesterol's in your blood.
That's because you make your own cholesterol (which is a necessary compound, part of every cell) in your liver. Eat less cholesterol, and your liver makes more; eat more, and your liver produces less. There are substances you eat that raise your cholesterol, true, but these substances aren't cholesterol themselves—they raise your cholesterol by breaking how your body works, not by pumping more cholesterol into your system. Eating cholesterol no more leads to cholesterol in your blood than eating oil leads to oil on your face … which is another myth, by the way.
Something similar goes on with good nutrients. Like calcium. Calcium's essential. Miss out on calcium (or on the vitamin that lets you use calcium), and you develop rickets, which gives you bendy bones and a sickly British accent. "That means," reasoned parents for decades, "if we give kids lots of calcium, their bones will be extra strong!" So they gave kids a big ol' glass of milk with every meal.
But it turns out your kid's body will deposit some amount of calcium into their bones today, yet if they drink extra calcium beyond that, that doesn't help at all. Studies lasting decades have failed to find any benefit on people's bone health from drinking extra milk. There's even some evidence that drinking extra milk makes your bones lose calcium. The science on that last part is uncertain (it has to do with blood chemistry and how the body deals with acidity), but it's possible, because biology's more complicated than "I eat, therefore I am."
Or take iron. Iron's another essential mineral, and if you don't eat enough, you get anemia, which means thin blood and another sickly British accent. So, what happens if you eat extra amounts of iron? Are you going to get a bunch of extra red blood cells, and also the ability to run marathons? Uh, no. You just kind of take in the iron without using it.
For a long time, people believed spinach was a great source of iron—this was why Popeye got his powers from spinach. Hilariously, this was a myth based on a typo that accidentally multiplied the amount of iron in spinach by 10. But what's possibly even more hilarious is that even if spinach did have 10 times the amount of iron it really has, that wouldn't do you any good. It would not coat your entire body in iron armor. Assuming you aren't starving and aren't bleeding out, you almost certainly don't have an iron deficiency, so the extra iron wouldn't make any difference whatever. (Unless you really do eat a ridiculously high amount. Then you get iron poisoning.)
"Save The Rain Forest, It's The Earth's Lungs"
Speaking of essential elements, oxygen is pretty important, and if you don't believe us, just try holding your breath a couple minutes and see how much you like it. Good thing then that we have trees gently farting that sweet stuff into the air. Maybe you've heard the following wistful quote about how we underappreciate this contribution from trees:
In particular, when people talk about fires in the Amazon, you'll hear about how important that rain forest is in providing a fifth of all our oxygen.
Now, the next time someone with a clipboard stops you in the street with this line and tries to get you to donate to Greenpeace, there's a very simple well actually response you can give: Most oxygen doesn't come from trees at all. It comes from algae in the ocean. And you don't get many trendy charities for looking after algae, because no one had fun climbing algae as a kid.
But we shouldn't really be quibbling over whether some particular rain forest provides 20 percent of our oxygen or 2 percent of it. Because overall, the rain forest doesn't produce oxygen at all. It consumes it. The forest consists of trees but also all the animals who live there (when fires or industry destroy the forest, we mourn the animals too). Tally up trees and beasts, and the forest takes in more oxygen than it produces, and destroying the forest reduces oxygen consumption. We're not talking about how tree loss has recently made the area overall worse at capturing carbon—we're talking about untouched parts of the forest, thanks to the sum total of everything living there.
Trees aren't that great at producing oxygen, you see (or at absorbing carbon dioxide, which is the other side of the same equation). A tree produces oxygen as it splits CO₂ apart to make biomass, but nearly all that biomass will eventually be consumed—partly by the plant itself—or will rot, which turns oxygen right back into carbon dioxide again. So when you hear businesses talking about searching for new carbon capture tech, don't snicker because we already have the perfect tech in the tree. We're looking to make something vastly more efficient than that.
Okay, we seem to have digressed a little from trees producing oxygen to trees absorbing carbon dioxide. There's a reason for that. Because what if we tell you that, despite what we said a little while ago about oxygen being important, it's not actually at all important how much oxygen plants create? The reason: We have so much oxygen right now that it makes no difference.
The atmosphere is about 22 percent oxygen, and we have a lot of atmosphere. For the last couple decades, we've been burning off eons' worth of captured carbon, and that raised the level of carbon dioxide in the atmosphere (and reduced the level of oxygen) by just 0.005 percentage points ... which is a staggering amount when we're talking carbon dioxide, which we measure in parts per million, but it's nothing when we're talking oxygen. All of our oxygen consumption involves organisms breaking down organic matter, and even if all organic matter on Earth were instantly burned, that would only use up 1% of the reserve oxygen supply. Even if all oxygen production worldwide stopped today, we'd be perfectly fine (fine oxygen-wise; factors other than an oxygen shortage will wipe us out). We have enough oxygen to last for millions of years.
Praising trees for giving the atmosphere oxygen is a bit like praising bacteria for giving the atmosphere nitrogen. Nitrogen is also an element that cycles through living creatures, and if the air ever ran short of nitrogen, we'd all die. But the fact is, the air won't run out of nitrogen, or oxygen. There's just so much of both. It would take the passing of new whole geological ages for the composition of either to change much.
Trees are still great for what they do for climate, biodiversity, water regulation, lumberjack roleplay, etc. But something about our psyche makes them feel most valuable when we falsely picture them as little factories constantly pumping out a gas we all need. Maybe because we're all industrialists at heart, or maybe it's because we play too many resource management video games. Both of which might also explain our next misconception:
"Let's Keep Squeezing Solar Panels Everywhere!"
Having conceded that trees are great, though not in the way some people think, let's also reassure you that we think solar power is great. The tech works, it's advanced enormously recently, and we should build a bunch of new solar arrays. But many people seem to take this to mean that we need a solar panel, like, right there, right where they’re staring right now. As though the big problem with solar power is that there's not enough room for all the panels, and the solution to that problem is the blank space right over there, that one.
It's what leads people to, say, support coating the nation's roads with solar panels. "We have 25,000 square miles of roads," says this argument. "If we cover that with solar panels, that would be more than enough to provide electricity for everyone!" True, but the problem with laying down 25,000 square miles of solar panels was never that we couldn’t figure out where to put them.
If we were to build that many solar panels (at a cost of around $65 trillion just for the panels, not even going into the cost of transporting, installing, and wiring them), we wouldn't need to put them on roads. We could put them anywhere other than roads. Even alongside highways would be better than on the highways themselves, because they'd be better off without trucks rolling over them, but best would be constructing a proper array in the desert, where the panels can tilt to always grab the sunlight, generating much more power than solar roadways ever could.
On a more personal level, there's current research going into creating transparent solar panels we can put on mobile phone screens. That's a very dumb place for a solar panel. Your phone doesn't see much direct sun, and it needs a ton of power for an object to small. Maybe people will get tricked into buying these phones, but it'll just be a gimmick. Much like solar-powered calculators, which were only possible because calculators use much less power than a phone (and also, it turns out that a bunch of solar panels on calculators are actually fake).
We Have No Way Of Picturing Extreme Probabilities
Thoroughly shuffle a deck of playing cards. How many different sequences of cards do you think you could come up with? The answer is 52 factorial, or around 8 times 10 to the 67th power, a number so big none of us can understand it. Here it is written out:
Except it isn't. The number of sequences is actually a million times the one we wrote out above. Sorry, no, we lied. It's a million million times that. Haha, we lied again. It's a million million million million times that. Which is obviously vastly more, but it all sounds the same when we hit numbers that big.
"No! No it isn't!"
Now, here's how someone online summed up that surprising stat:
To do so, they state that's it's 99.7% likely that your shuffle will be unique. And thousands of readers were impressed by this. But that hugely underestimates the actual probability. It looks like that random internet poster grabbed the number "99.7" out of their ass just because it sounds kind of big. The actual probability of any given two shuffles being different is 100-(1/52!), (the exclamation mark represents factorial) or 99.9999999999999999999999999999999999999999999999999999999999999999987602%. To get the probability of a given shuffle having never come up before, you have to multiply the (1/52!) in that equation by the total shuffles ever done–which is so tiny compared to 52 factorial that it won't make the slightest dent.
Now, here's the awkward part. Suppose we straight-up tell you that a thoroughly shuffled deck will produce a sequence that no one has ever come up with before. What would you say?
We don't know for sure because we don't know you. But we suspect you'd argue that, no, it's not certain. Likely, but not certain. Very likely, just as 99.7% is very likely, but it's not certain. In reality, the chance of that shuffle having come up before in playing cards' 3,000-year history, during which only 110 billion people have lived, is impossibly, infinitesimally small, so small that most calculators and spreadsheets just show the probability of a fresh shuffle as "100%" rather than the figure we printed above. And yet instinct makes you stubbornly insist there's a chance the shuffle came up before.
You'd probably fiercely resist even rounding the probability to 100%, thinking it fairer to call it 99.99%—even though the probability is closer to 100 than 99.99, by a factor of several trillion quadrillion. That's because people can only interpret probability as "quite certain," like 99.99 or 99.7% certain or whatever, and have no way of really understanding anything more than that.
Let's try to illustrate the difference between 99.99% and the actual probability here for you. Let's say there's a 99.99% chance you won't catch COVID today. Sounds good! But if all 7 billion people in the world have that chance, then we can expect 700,000 people to get COVID today, which isn't very good (and with a 99.7% of escaping COVID, 21 million would catch it today, which isn't very good at all). On the other hand, if everyone has a 100-(1/52!) percent chance of eluding COVID today, we can expect no one to get COVID today, and no one to get it in a million billion trillion years.
"What? No, this is a fantasy scenario, are you f---ing listening at all?!"
That was our attempt at expressing that probability, anyway. But it wasn't a very good one. Because like we mentioned earlier in the article, "a million years" is too long a time to be a relatable point of comparison for any of us, and "a million billion trillion years," which is an actual figure we calculated, just sounds like nonsense babytalk.
Here's another attempt. Did you see the Avengers movies? Doctor Strange looks at 14,000,605 possible futures and spots only one in which good triumphs. So, many viewers left Endgame saying, "Nitpick that fight all you want, but that was the only possible way they could have won." And yet, a 1-in-14 million chance isn't that low, compared with just how low probabilities can get. It's far more unlikely that, say, Doctor Strange should happen upon the one exact future that comes to pass, after looking through only 14 million realities out of infinite possibilities.
Walt Disney Pictures
If their chance at success really was 1-in-14 million, we could have got the following conversation:
Strange: "I went forward in time to view alternate futures. To see all the possible outcomes of the coming conflict."
Quill: "How many did you see?"
Strange: "52 factorial."
Tony: "How many did we win?"
Strange: "Six million billion trillion quadrillion quintillion. More wins than atoms in the Earth, or stars in the galaxy, or indeed atoms in the galaxy."
Tony: "I like those odds. And how many futures in which I shuffle the same sequence of cards twice in a row?"
Walt Disney Pictures
"Hey guys. Just shuffled cards the same way twice. No big deal."
People tend to call numbers this big "astronomical," and sometimes pull out comparisons involving the universe or the galaxy or the distance from the Earth to the Moon. But that too is rarely helpful because ...
None Of Us Can Picture Distances In Space
There's a Douglas Adams quote about how big space is, something about how it's considerably more than even the distance from here to CVS. The joke there isn't just that space is very large indeed but that every familiar point of reference means nothing against those inconceivable distances. Take our closest celestial neighbor, the humble Moon. This distance to there is somewhere around 385,000 kilometers, or some 230,000 miles (coincidentally, pretty close to the distance light travels in one second). Here's a diagram we pulled off a science website depicting the distance:
That looks about right, doesn't it, if a little simplified? And that scale seems to be backed up by the following GIF -- which, cartoonish as it looks, is an animation made from actual NASA photographs.
But as dating apps prove, even an actual photograph can fail pretty hard at depicting sizes and distances (we have some personal photos that suggest the moon is the same size as our thumb, and just inches away). The next photo we'll share with you was also taken by NASA, by the OSIRIS-Rex spacecraft that landed on an asteroid last year. This photo was taken from nearly a million miles away from Earth:
Yes, that is the actual distance from Earth to the Moon. Earth is the bright circle in the top left, while the Moon is the dot in the opposite corner. Damn, getting to the Moon really was a big deal! Not that people tend to understate how big a deal getting to the Moon was—"they put a man on the Moon" is shorthand for something amazing we managed to do—but still, we rarely picture the journey as looking like that exactly. That photo looks more like we might picture the distance between the Sun and Pluto … which is almost appropriate, because depending on where the Moon is in its orbit, it's actually possible to fit every planet in the solar system end-to-end between the Moon and the Earth.
But let's talk some more about the planets then. Kids are taught to make models using fruit to teach them how the solar system looks. This is worse than useless and teaches them nothing, just as building baking soda volcanos teaches them nothing about how volcanos work (and not much about how baking soda and vinegar work, for that matter). Below is a more accurate scale diagram of the solar system.
Sorry, we lied again. While maybe more accurate than using a grapefruit for the Sun and an apple for Earth, the above illustration is just another inaccurate one that serves only to remind us how difficult it is to picture what the solar system is really like. The below picture, however, is a scale image of the solar system, just as far as Earth:
The circle on the left is the Sun of course. And the planets? They're in there, you just can't see them in any illustration that shows the Sun and also all the planets, because of the distances and sizes involved. Viewing the full-resolution image and zooming in will give you a slightly better idea than looking at a featureless black strip. The Sun is 99.8% of the mass of the entire solar system—nothing else is significant next to it. Seeing the solar system like that might also help you understand why there could easily be a ninth planet in our system (a legit planet, not Pluto-like), and there in fact most likely is, but we just haven't been able to spot it yet.
We could extend this exploration further to show you how big the Milky Way is compared to our tiny solar system and then some hint of how big the rest of the universe is. But Douglas Adams had some thoughts on that too, and apparently that level of perspective instantly drives anyone insane, so let's leave that for another day.