Today, you’ll learn about a potential obstacle to human flight to Mars, a discovery in a Laotian cave that is sending archaeologists back to the drawing board, and how new technology could keep us cool in a warming world without adding to the problem of climate change.
Today, you’ll learn about a potential obstacle to human flight to Mars, a discovery in a Laotian cave that is sending archaeologists back to the drawing board, and how new technology could keep us cool in a warming world without adding to the problem of climate change.
Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/space-swells-brain-cavity-cave-fossils-keeping-cool
Space Swells Brain Cavity
Cave Fossils
Keeping Cool
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[SFX: INTRO MUSIC/WHOOSH]
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 a potential obstacle to human flight to Mars, a discovery in a Laotian cave that is sending archaeologists back to the drawing board, and how new technology could keep us cool in a warming world without adding to the problem of climate change.
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: WHOOSH]
CALLI: Have you ever got space brain?
NATE: No. I’ve heard it exists. But I’m perfect. My brain is a perfect…uh…what’s that word?
CALLI: Specimen?
NATE: Okay. So it’s possible I space out from time to time. Who doesn’t? It’s fine.
CALLI: Well…a new study has found that astronauts who spend months in space can get a literal form of space brain that can take years to resolve.
NATE: Oh boy. We could file this story under “More reasons it’s going to be really hard to go to Mars,” right?
CALLI: It’s a whole genre of Curiosity Daily stories, isn’t it? Well…it might not be the biggest problem, but it definitely needs some focus. This study found that the fluid-filled chambers in the brains of astronauts tend to expand in microgravity. And it turns out that it can take three years for these structures to shrink back to normal.
NATE: Geez. You said it might not be the biggest problem, but that doesn’t sound great, if we’re being honest. Fluid-filled brains?!
CALLI: Let’s talk about the brain for a sec. There are these spaces inside the brain called ventricles. There are four of them, and they are already full of fluid. They basically give the brain a little bit of cushion and also help clear out waste.
NATE: So they’re like self-cleaning airbags? Except…instead of air they’re full of fluid?
CALLI: That’s one way to look at it. In Earth gravity, the ventricles keep their shape and size just fine. But in space, with no gravity to manage the fluid, it tends to accumulate in the head. And the ventricles adapt by taking in more fluid and expanding.
NATE: That makes sense.
CALLI: The study also found that the longer the mission, the more the ventricles seemed to expand. So a two-week outer space vacation is no big deal. But a six- or 12-month mission led to more significant enlargement.
NATE: Like…how significant? I’m imagining those cartoons where someone’s head blows up like a balloon…
CALLI: Not quite. Only three of the ventricles showed signs of expansion, and the expansion in the fourth was too small to see any changes at all, if there were any.
NATE: That’s why you said it’s no big deal.
CALLI: I said it might not be a big deal. But it could be. The study also found that time between missions seemed to make a difference. Astronauts who had flown before and then waited three to nine years for their next mission had more enlarged ventricles than those who had waited less than three years.
NATE: Okay - lemme see if I get this right. The astronauts who didn’t wait three years - their brains didn’t expand because…they hadn’t yet returned to normal size?
CALLI: Exactly.
NATE: Gotcha. So…what happens when our ventricles get enlarged? Like…how bad is this, is this a health emergency?
CALLI: That’s the thing - they’re just not totally sure. But it's one of the bajillion little factors that NASA is going to have to take into account as they plan future missions, especially long-duration missions to Mars.
NATE: Yeah, I can imagine that a two-year trip to Mars would be pretty hard on the brain.
CALLI: And this study shows that there could still be a ton of effects we haven’t even uncovered yet. The good news is that NASA is doing research to try to mitigate the effects of spaceflight on the brain. And they're also developing new technologies that could help astronauts stay healthy on long-duration missions.
NATE: Everyone talks a lot about the challenges in engineering and thrust and rocketry we have to overcome to get to Mars. But those things seem pretty minor when compared to figuring out how to make a mammal, who has evolved for millions of years in Earth gravity and atmosphere, make the leap through space and stay healthy.
CALLI: That observation is out of this world. You’re welcome.
[SFX: WHOOSH]
NATE: We’ve talked a lot on Curiosity Daily about ancient remains and ancient cave art that can paint a picture of how early humans lived. But a recent finding in a cave in Laos is sending archeologists back to the history-of-human-migration drawing board.
CALLI: That’s a pretty big claim. What’s the deal?
NATE: So most genetic and archaeological evidence suggests that humans - that is, homo sapiens - left Africa around 60,000 years ago, and made quick work of settling out across Southeast Asia and into Australia. But archeologists have discovered human fossils in this cave in northern Laos. The thing is…these bones are up to 86,000 years old.
CALLI: 86,000 years is hard to get your head around.
NATE: I’ll say. That makes them the oldest modern human fossils ever found in Southeast Asia, and they suggest that our species arrived in the region much earlier than we thought.
CALLI: So if these fossils are 86,000 years old - that means scientists missed the mark by 26,000 years?! That’s kind of a huge swing and a miss, isn’t it?
NATE: Okay…maybe. But it might be more complicated than that. The cave is called Tam Pa Ling - which translates to Cave of the Monkeys - and is known for its rich archaeological deposits. Tons of stuff has been discovered there in recent years, including parts of a skull that dated back at least 46,000 years.
CALLI: So if I’m hearing this right - some folks wandered out of Africa way earlier than we ever thought, made their way to The Cave of the Monkeys in northern Laos, and then lived there alone for thousands upon thousands of years until they were joined by their long-lost pals from Africa?
NATE: That’s where this gets really interesting. It just means that at some point, a group of humans wandered out of Africa into what is now northern Laos and - at least one of them - died in that cave. And the fossils from the older humans are smaller than the younger humans. They are what are called ‘gracile” homo sapiens - basically slender humans.
CALLI: I suppose people change a lot over the course of 40,000 years, though, right?
NATE: Could be. But scientists actually think the older fossils represent what they call a failed migration. Like you said, a group of folks wandered out of Africa as far back as 86,000 years, made their way to the Cave of the Monkeys. But instead of hanging out and waiting thousands of years for their pals to arrive…
CALLI: …they all died?
NATE: Yep - that population died out. Which also means that - most likely - none of the older remains in that cave sent their genes into the future.
CALLI: Whoa. So that would mean that we were trying and maybe failing to leave Africa for thousands of years before human migration finally took.
NATE: And one other cool thing to note - this cave is about 300 kilometers from the coast. Archeologists tend to think that most early migration happened along the coastlines, especially rapid migration. But this suggests that we were also walking inland.
CALLI: Do you ever think about how crazy it is that the further we go into the future, the further back in the past we’re able to study?
NATE: That…just blew my mind a little bit. But you’re totally right. And it’s discoveries like this one in northern Laos that remind us there’s still so much to learn about our ancient history. In other words, stay curious!
CALLI: I see what you did there.
[SFX: WHOOSH]
CALLI: Are you ready for a hot topic?
NATE: If this is about crypto, I’ve got news for you. Not so hot at the moment.
CALLI: I mean it’s a hot topic, literally - keeping cool in a warming world.
NATE: Ahh. Gotcha. That’s definitely something that’s been simmering in the news lately, especially as this year could be the hottest year on record.
CALLI: Yep. Several days this year have already broken heat records. Scientists think they could have been the hottest days in a hundred-thousand years.
NATE: Yikes.
CALLI: That heat can cause all kinds of problems, as anyone who’s been out on a 120 degree day knows. So we need to figure out how to create more spaces that offer people a break from the heat. But here’s the thing: air conditioning actually makes climate change worse.
NATE: Right. I would guess putting millions of new ACs online is going to ramp up electricity usage.
CALLI: In a big way. They already send almost 2 billion metric tons of CO2 into the atmosphere. Not only that, but ACs use refrigerants that use hydrofluorocarbons to keep us cool.
NATE: Don’t tell me - hydrofluorocarbons cause warming?
CALLI: They can capture anywhere from 150 to 5,000 times the energy of the sun than carbon dioxide.
NATE: Oh good. So as the world gets hotter, we need more air conditioning, which will actually make the world even hotter? So…what do we do?
CALLI: We need new ways to cool the air around us that use less energy. And mechanical engineer Eric Kozubal and his team think they might have one.
NATE: Is it a giant fan in Antarctica that blows icy wind up north?
CALLI: That would be cool. But…no. It’s a system that uses salt water to cool you off.
NATE: Saltwater? That sounds…uh…confusing.
CALLI: So most air conditioners do something called evaporative cooling.
NATE: That’s where the moisture evaporating off your body actually cools you off, right?
CALLI: Exactly. Evaporating moisture actually carries the heat away from you. Think about when you get out of a pool - even on a hot day, you feel the cooling effects of evaporation. So traditional ACs use those hydrofluorocarbons for evaporative cooling. But Kozubal’s team has figured out a way to get salt water to do the trick.
NATE: How does it work?
CALLI: Their system uses salts like lithium chloride or potassium acetate to absorb humidity from the air, which makes the evaporation process more effective. If the air around you is dry, the water evaporates better. That means cooler air using only a fraction of the electricity that traditional air conditioners require - and none of the old hydrofluorocarbons.
NATE: So it’s more efficient?
CALLI: It uses about a sixth as much electricity as old units.
NATE: Wow…that’s really…cool.
CALLI: Oh my gosh.
NATE: So where can I pick up one of these saltwater units.
CALLI: The bad news is that it’s not yet on the market, but they’re working on it. But they aren’t the only ones trying to innovate here. Another group has developed a cooling system that uses water instead of greenhouse gas fluids. It sprays water onto porous ceramic tunnels, which absorb the heat and cool the air passing through. It's energy-efficient and doesn't harm the environment.
NATE: That’s all great. But here’s a dumb question: so many Americans and others in developed countries already have AC. What about places where electricity is scarce or unreliable?
CALLI: Great question, especially because these are the regions where power outages are common - and that will likely need the most new systems in the coming years.
NATE: Seems like a perfect storm.
CALLI: There’s good news. There are passive cooling techniques that don't require any electricity. Like window coatings that block infrared and ultraviolet light while radiating heat away. They help keep indoor spaces cool without any extra power consumption.
NATE: Ahh. That’s great. I love simple solutions to problems like these. But what about the cost? Are these new technologies affordable? They’re kinda worthless if no one can afford them, right?
CALLI: Affordability is huge. Luckily, experts are optimistic and everyone is taking cost into account when designing their systems. Most believe they can create devices that are cost-competitive with standard air conditioners.
NATE: I think the thing I love most about this story is that it shows that we can take concrete steps to knock out so many of our climate change problems.
CALLI: Exactly. It can be disheartening to hear about the crazy heat waves and feel helpless about the changing climate. So it’s important to see people actually doing things that could help solve these massive problems.
NATE: We can do anything we set our minds to - at least that’s my hot take.
CALLI: See, why are you allowed to make puns and I’m not?
NATE: Because mine are so much better.
CALLI: Rude.
[SFX: WHOOSH]
NATE: Let’s recap what we learned today to wrap up.
CALLI: Scientists have found that the brains of astronauts show signs of minor swelling, especially after being in space for long periods, and that it can take up to three years for the swelling to return to normal. It’s just another challenge they’ll have to address in order to send humans to Mars.
NATE: Archaeologists discovered human fossils in a cave in Laos that are thought to be up to 86,000 years old, which would make them the oldest homosapien remains ever found in South-East Asia, and could mean that humans left Africa thousands of years earlier than we thought.
CALLI: In a world of extreme heat, engineers have begun developing air conditioning systems that are cost-effective, efficient, and don’t add to our already out-of-control carbon dioxide emissions.