Learn about why you might feel stronger after just one workout; why the Earth’s core doesn’t melt, even though it’s so hot; and prosopagnosia, the surprising neurological condition of face blindness.
Learn about why you might feel stronger after just one workout; why the Earth’s core doesn’t melt, even though it’s so hot; and prosopagnosia, the surprising neurological condition of face blindness.
Feeling stronger after one workout? It's not your muscles, it's your nervous system by Grant Currin
If The Earth's Core Is So Hot, Why Doesn't It Melt? by Ashley Hamer
What do you do when you can’t recognize faces? by Cameron Duke
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/why-some-people-cant-recognize-faces-weight-lifting-strengthens-your-nerves-too-and-why-earths-core-doesnt-melt
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about why you might feel stronger after just one workout; why the Earth’s core doesn’t melt, even though it’s so hot; and the surprising neurological condition of face blindness.
CODY: Let’s satisfy some curiosity.
Getting stronger means growing bigger muscles, right? Well, not necessarily. A flurry of studies published over the last few years has revealed something surprising about gettin’ those gainz: it turns out the nervous system plays a huge role in getting stronger, at least when you first start working out.
Stay with me here. Imagine you start going to a gym — or doing some socially distant bodyweight exercises at home. You steadily increase the number of push-ups and pull-ups you can do over the first week, but when you look in the mirror, it doesn’t seem like your muscles are any bigger. And they’re not: it takes several weeks of exercise for muscles to grow. But judging by the number of reps you can do, you’re definitely stronger. So where are those gains coming from?
They’re happening in your nerves. In order to lift a weight, whether it’s a barbell or your own body, your brain has to send a signal from the motor cortex to your spinal tract to the motor neurons in the muscle that make it contract. As you exercise, those signals get stronger.
Consider this recent study in the Journal of Neuroscience, which involved a couple of incredibly strong monkeys. Researchers attached electrodes to bundles of nerves in two female macaques. Then they enticed them to work out five days a week for nearly three months. By the end of the regimen, the primates were able to perform the monkey equivalent of fifty one-armed pullups.
That’s fifty. One-armed. Pullups. They should sign up for a Spartan race or something.
Anyway, after analyzing the data from the electrodes, the researchers did indeed find that nerves along the spinal tract were relaying stronger, more urgent messages from the motor cortex to the muscles that had been trained.
This could explain a lot of weird things that happen during strength training. Like, did you know that if you only work out one arm, the other arm will get stronger anyway? That’s called cross-education, and scientists think it might happen because that nerve signal isn’t picky: it gets stronger in both the trained and the untrained arm. It could also explain why even though lifting light weights and heavy weights leads to the same increase in muscle mass, the heavy weight leads to greater gains in strength. It comes down to a stronger nerve signal!
So if you’re feeling stronger after a few workouts? Don’t thank your muscles. Thank your nervous system.
At the very center of our planet, inside a liquid outer core, there’s a Pluto-sized orb of solid iron. That's right, solid — even though it's nearly the same temperature as the surface of the sun. You’d think it would melt, right? I mean… that’s PRETTY hot. Well you’re not alone: scientists wondered the same thing for years. But in 2017, a team of Swedish researchers figured it out.
So, the atoms in a solid block of iron are arranged in a crystal structure. At the normal temperatures and atmospheric pressures we know, iron takes on a classic cube shape, with eight corner points and a center point. At extremely high pressures, though, iron's structure morphs into what's called a hexagonal close-packed (HCP) phase, with each point surrounded by twelve other points. Since the pressure at the Earth’s core is extremely high, most scientists believed that the iron there takes on that hexagonal formation. If it didn’t, it wouldn’t stay solid. At least, that’s what they thought.
Scientists at KTH Royal Institute of Technology in Sweden simulated the conditions in the Earth’s core on a supercomputer, and they got a big surprise. The simulations showed that the core is actually in a cube structure — and it’s thanks to the very extremes that scientists thought made it impossible. See, at normal temperatures, that cube structure is unstable, and its atomic "planes" easily slide out of the structure into a liquid state. But in the extreme temperatures of the core, atoms are moving so quickly, so close together, that they don't have anywhere to go. They’re like passengers on a packed subway car — they might switch positions, but the crowd maintains its original shape.
This explains more than why Earth's core is solid. It also explains why seismic waves, the kind that cause earthquakes, travel faster between the earth's poles than through the equator. The way that atoms move among this cubic structure adds "texture" to the iron the way wood has a grain, giving it a "preferred" direction. And this understanding of our planet’s structure can help us make important predictions for what might happen to it in the future.
Being able to recognize faces is something that seems natural to most of us. But what if you couldn’t? There’s a neurological condition that makes it almost impossible to recognize faces. It’s called prosopagnosia, or face blindness, and it’s much more common than you probably think.
Prosopagnosia comes in two forms. Acquired prosopagnosia is the rarer kind, and happens due to brain damage. Developmental prosopagnosia is the more common form. It’s a neurodevelopmental condition similar to dyslexia. Just like people with dyslexia have difficulty recognizing words, people with prosopagnosia have problems recognizing faces.
Otherwise, people with prosopagnosia are completely normal in terms of attention span, memory, and general intelligence. Famous prosopagnosics, as they’re called, include Brad Pitt, Apple co-founder Steve Wozniak, and primate researcher Jane Goodall. But this list could be much longer. Researchers estimate that as many as 1 in 50 might experience varying degrees of prosopagnosia.
It’s difficult to know for sure, because many prosopagnosics aren’t aware there’s a problem. They become so accustomed to their condition that they often don’t realize that they’re mostly recognizing people based on non-facial cues like voice, posture, or social context. Often, prosopagnosics won’t be able to recognize a friend that changes their hairstyle or appears in an unexpected place, like a doctor’s office. This can even extend to family members.
Understandably, face blindness often comes with social anxiety, and this starts at an early age. Face blind children struggle to form friendships and social connections. Adults will often avoid social events like conferences and parties and might come off to others as being rude.
This condition often runs in families — in fact, every face-blind participant in a 2006 study was found to have at least one first-degree relative with the condition. Although scientists don’t understand the exact genetic mechanisms, they think the condition is caused by a single dominant gene variant.
This variant seems to cause specific regions of the brain in something called the fusiform face area to develop improperly. These are little marble-sized areas that sit just behind the ears, and they’re crucial in a person’s intrinsic ability to recognize faces.
Unfortunately, prosopagnosia isn’t curable. Still, recent research suggests that it may be possible to train face-blind people to recognize faces based on other details, like the spacing of facial features. But if you don’t count yourself among the faceblind, just remember: if someone you’ve met doesn’t recognize you, have some understanding. There may be more going on than you think.
ASHLEY: Let’s do a quick recap of what we learned today
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CODY: Today’s stories were written by Grant Currin, Ashley Hamer, and Cameron Duke, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Scriptwriting was by Cody Gough and Sonja Hodgen. Curiosity Daily is produced and edited by Cody Gough.
CODY: Join us again tomorrow to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!