Today you’ll learn about what it means for the planet now that we’ve reached a global population of 8 billion people, how leprosy might be able to repair damaged livers, and some information about an asteroid that’s been dubbed a, “Planet-killer.”
Today you’ll learn about what it means for the planet now that we’ve reached a global population of 8 billion people, how leprosy might be able to repair damaged livers, and some information about an asteroid that’s been dubbed a, “Planet-killer.”
World Population Reaches 8 Billion
Leprosy
Planet-Killer
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Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/world-population-reaches-8-billion-leprosy-planet-killer
NATE: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from Discovery. Time flies when you’re learnin’ super cool stuff. I’m Nate.
CALLI: And I’m Calli. If you’re dropping in for the first time, welcome to Curiosity, where we aim to blow your mind by helping you to grow your mind. If you’re a loyal listener, welcome back!
NATE: Today you’ll learn about what it means for the planet now that we’ve reached a global population of 8 billion people, how leprosy might be able to repair damaged livers, and some information about an asteroid that’s been dubbed a “planet-killer.”
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: WHOOSH]
CALLI: You might already know that leprosy is a contagious disease that negatively affects the skin. And in especially severe cases, can even cause permanent deformities. But what if I told you that the bacteria responsible for leprosy may actually be holding the secret to repairing the body?
NATE: To me, it sounds like those two sentences are a bit at war with each other. And it might be time for you to be calling a cease fire. How can leprosy be responsible for damaging a body and for repairing it?
CALLI: Okay, I totally understand your skepticism here. This study actually began with a bit of a paradox. The bacterium that causes leprosy is called mycobacterium leprae, and when it gets into a human's nerves, skin or eyes, it can cause irreversible disability, but it can also convert one type of bodily tissue into another. For example, an earlier experiment on mice showed the leprosy bug infected nerve cells, and for a few weeks the bacteria began to morph the nerves into stem cells. For lack of a better word. They called this biological alchemy.
NATE: Because in alchemy, you're attempting to turn base metals into gold, right? So to expand on that metaphor, what kind of gold are these scientists hoping to mine?
CALLI: Well, one of the first places the leprosy bug attacks in an animal is the liver. The researchers had a theory that if you introduced the bug to the liver and found a way to prevent it spread to other areas of the body, then the bug would actually repair and the liver damage. They knew this would work with mice, but the experiment wasn't ready for human testing yet, so they turned to one of the only other creatures that can catch leprosy, armadillos.
NATE: Armadillos? Why? Why them can't? Chimps and red squirrels and some other primates also catch leprosy? Why not them?
CALLI: Because the armadillo is the only animal we can reliably isolate the leprosy bug in. Remember when I said finding a way to prevent the spread? With armadillo testing we don't need to do that. And so when scientists introduced mycobacterium leprae to the armadillos liver, they got to see firsthand what would happen without having to worry about a further spread. The bad news is that the liver nearly doubled in size in one day.
NATE: I thought you said this experiment repaired the body.
CALLI: And the good news is that it grew because it's completely repaired the armadillos liver to a healthy, functional level with no negative effects on its blood vessels or bile ducts.
NATE: Okay. Wow. Oh, how does leprosy do that? How did the leprosy bug fix that?
CALLI: Well, okay. Even the researchers were a bit thrown off, calling the findings, “Mind blowing.” They concluded that the leprosy bug might be rewinding the developmental clock in the liver. To put it simply, the bacteria are reversing. The liver's aging to the point that the armadillos cell DNA are now closer to that of a much younger animal, sometimes even as close as a fetus.
NATE: That sounds amazing, but you're still not telling me how it's doing this.
CALLI: Okay, so let me put it this way. I don't know. Nobody actually knows. I read an article about this that said it's possible to forcibly turn a body's clock all the way back to the point where cells regain the ability to become another type of cell in the body. But this could risk turning them cancerous. What we're seeing with the leprosy bug is an alternative and much safer way to change the body's aging process. But it's still super mysterious.
NATE: That's all very bizarre. So, all right. What's the next move for this research? I mean, are you telling me this is some kind of medical fountain of youth?
CALLI: Not. Not exactly. The researchers hope this will end up being a reliable way to repair the livers of anybody waiting for a transplant or possibly even reverse some of the damage caused by aging. So not exactly a cure all fountain of youth, but a way to reverse a lot of damage we previously thought was irreversible. The next step is figuring out a way to isolate the leprosy bug in a human's liver.
[SFX: WHOOSH]
NATE: All right. It is official. As of November 15th, 2022, there are now over 8 billion people on Earth. It was enough of a reason to celebrate that November 15th has now been deemed the day of 8 billion by the United Nations. But what if that number isn't a reason to celebrate, but actually a reason to be concerned?
CALLI: Okay. No, you're not about to hit me with a study about the woes of overpopulation, are you? Because that's eugenics. And I have to remind you that eugenics is a bad.
NATE: No, no, no. The problem in this case is actually under population. You see, 8 billion is a lot of people and with a lot of people comes a lot of problems relating to social and economic development, environmental sustainability and so on. But any development is usually related to how fast people are being born, not how fast people are dying. All of that is to say we reached 8 billion people slower than expected because certain parts of the world are seeing more deaths than births.
CALLI: Huh. Okay. I don't actually know what to say about that. What does that mean for us?
NATE: It could mean a number of things. Some of the poorest countries are still more concerned with meeting the needs of a larger population. But many of the richest are worried about how they can promote fertility. They're afraid of the population aging and declining, resulting in labor shortages as well as a weaker military power. Now, whether these worries are justified or exaggerated, these demographic changes would have huge implications on any sustainable development.
CALLI: So just how bad is this problem? I mean, this feels a little bit abstract to me because I can't really wrap my head around 8 billion people. That's a lot of people.
NATE: Yeah, absolutely. So the United Nations previously predicted that the world would reach 11.2 billion by the year 2100, but at the current rate, they're predicting the population in 2100 to be just over 10 billion instead. It doesn't sound like a huge difference until you realize it's because a whopping 61 countries are expected to have their populations actually shrink between 2022 and 2050.
CALLI: That's a lot more grim than it sounded at first. What's driving that decline?
NATE: Economic inequality, lack of food accessibility or clean water and in some cases, governmental restrictions. Like how in China there used to be a one child policy that limited families to only giving birth once. This was reversed in 2015, but it resulted in a sort of baby boom so intense that China is now being touted as a peak population.
CALLI: I am not familiar with that term. What's a peak population?
NATE: As in, there's probably not going to be any more growth. More people are dying than being born in China, a country with over one and a half billion people alone. That's almost 20% of the entire global population. Wow.
CALLI: All right. So where do we go from here?
NATE: Well, there are a lot of blind spots for countries experiencing humanitarian crises like Somalia, Yemen and Syria. The U.N. believes that if we can get more accurate numbers out of those places, we'll learn whether the population being in decline is a problem or an exaggeration. Demographers are most curious about how fertility rates are going to change, though, because these factors help us figure out what will happen to the global population in the future. For the time being, whether a slowing population is a problem or not. The best we can try to do is make the world a safer place for everybody being born into it.
[SFX: WHOOSH]
NATE: I just heard about an asteroid so big that it is called a planet killer. So start your day off right.
CALLI: Nate? We've had a lot of beginnings to a lot of stories now, and this is the least comforting one so far.
NATE: All right, a little more. A little more info. Might calm things down a little bit. This is an asteroid named 2022 AP7. Rolls off the tongue name. This is classified as a near-Earth asteroid or NEA for short. And it was discovered alongside a few other NEAs by a research laboratory in Chile by accident.
CALLI: How do you accidentally find something like this? A planet killer asteroid accidentally found.
NATE: I mean, it was hiding behind the glare of the sun. And so to look behind the sun, you have to wait for the right twilight hour time of day. But what the researchers found there were actually they found three asteroids. There was a kilometer long asteroid named 2021 LJ4, another kilometer long asteroid called 2021, PH27 and PH27 is currently the closest known asteroid to the sun. And it's close enough that the surface of the asteroid is so hot it can melt lead. But neither of these asteroids have a chance of hitting Earth for that. You got to you got to look back to AP7.
CALLI: Yeah. So about AP7. You've said the other ones have no chance of hitting Earth. Can you please say the same thing about AP7, too? I I'd appreciate it.
NATE: It is headed for Earth. Kinda.
CALLI: Kinda?! Kinda? Nate, hair is kind of red and I am kind of hungry right now. This is not the word that we used to describe a planet killer asteroid.
NATE: All right, so here's what it is. So there is a bit of uncertainty about whether or not this asteroid could hit Earth sometime within five years, 2022 AP7 is going to finish its rotation around the sun and then it will head on a trajectory into Earth's orbit. The good news is that scientists all agree that it does not now or any time in the future have a trajectory that will have it collide with the earth.
CALLI: So this sort of seems fine, kind of.
NATE: Well, that leads me to the bad news, which is like all other orbiting objects. 2022 AP Seven's trajectory will slowly change because of gravitational forces influencing it, such as planets, and it's next to impossible to know how its trajectory will be modified.
CALLI: So we actually have no idea if this thing is going to sling its way directly towards us, doing we?
NATE: I mean, we don't know for sure. It's pretty unlikely, though. All right. No need to be so grim because even after AP7 circles the Sun, it's still going to be several million kilometers away. There's next to no risk, really, because AP7 will more than likely fly right past us into the abyss.
CALLI: What if it doesn't? Nate, like I really need to know now what happen if this thing hit us.
NATE: So let's just say that AP7 does hit Earth. It's about one and a half kilometers wide, so just under a mile and something like that hitting Earth would instantly wipe out a massive portion of the population before launching dust into the air. That would create a bit of a cooling event, similar or maybe worse than the prehistoric ice age. And researchers involved say that this would be an extinction event like hasn't been seen on Earth in millions of years. So in short, I would say it would be really devastating.
CALLI: Yeah. So, you know that gif of that dog sitting in a room that's on fire and it just says, this is fine. Yeah, that's about how I feel right now.
NATE: Okay, listen, I know it's scary, but even if something like that were to happen, the asteroid's path changing to be headed toward us. I've saved the best news for last. NASA has figured out a way to prevent something like that from actually occurring. If a planet killer were on course to hit Earth, Nasser would send unmanned spacecraft into the asteroid, changing its trajectory away from Earth. And they actually tested this back in September of 2022, and it was successful.
CALLI: I actually remember us doing a story on that. So that makes me feel a little bit better. But at the same time, this sounds wild, like this sounds like the movie Armageddon.
NATE: This is a I said an unmanned spacecraft. So it's different. But either way, you know, I'm not going to knock NASA for wherever they get their ideas. All I'm saying is that if planet killing asteroids exists and they could head toward Earth at any time, I'm glad that we will know way ahead of time and that we have some tried and true methods to stop them. So rest assured, Calli, Armageddon could be a true story someday.
CALLI: Not comforting, Nate.
[SFX: WHOOSH]
NATE: Let’s recap what we learned today to wrap up.
NATE: Congratulations, Earth - you now have 8 billion humans sitting on top of you! Although the threat of “overpopulation” is wildly exaggerated, the bigger issue seems to be under-reported - the population growth is actually SLOWER than originally predicted! We might not see any differences in our lifetimes, but the shift of a slower growing population could actually spell disaster for the world in a few generations!
CALLI: Pop quiz: can leprosy destroy or restore the human body? Trick question: new research out of Edinburgh suggests the answer is BOTH. It turns out that by introducing the leprosy bug into a developed armadillo’s liver, the bug can “rewrite” the liver’s DNA, repairing damage we once thought was irreversible. No word yet on if this will work on humans, but if it does - cirrhosis might just become a thing of the past!
NATE: In a development ripped out of a Michael Bay action movie, a mile-wide asteroid is headed toward Earth! Kinda. Scientists aren’t convinced 2022 AP7 actually poses any danger to Earth, but should its path lead it into Earth’s orbit, NASA has developed a way to crash an unmanned spacecraft into an asteroid to change its trajectory. Even though “planet-killer” asteroids are big and scary, we can all sleep easy knowing that science is here to the rescue!