Popular Science

Most sharks have five gill slits on either side. But Hexanchus griseus, a giant and mysterious shark species, has an even six gill slits. These fish, appropriately called the sixgill shark, live in both tropical and temperate waters around the world and can reach up to 14-feet-long. They’ve existed since before the dinosaurs, and yet marine biologists still don’t know very much about them. 

One of the problems—for researchers, anyway—is that sixgills usually live in deep oceanic waters, at depths of up to 9,800 feet. It also doesn’t help that they usually favor extremely low-light environments. Among other reasons, these aspects make sixgills difficult to study.

Sixgill sharks (Hexanchus griseus) are older than dinosaurs and are typically found in the deeper parts of the ocean. Image: Seattle Aquarium.

However, these ancient giants have been spotted in Washington State’s Puget Sound year-round, and in water as shallow as 20 feet. Scientists at Seattle Aquarium believe that female sixgills are giving birth in these waters, and new research by the aquarium demonstrates that they have birthing site fidelity. According to the aquarium, they appear to come back to the Salish Sea to give birth numerous times. 

Once the baby sharks—or pups—come into this world, Puget Sound turns into their nursery for some time, though researchers don’t know for how long. The young sixgills spend the summer and fall in more southern locations of the Salish Sea, and migrate more north in the winter and spring. They usually travel less than two miles a day, and frequently come up to shallow waters at dusk before going down into deeper waters at dawn, probably looking for prey. 

“We think these patterns repeat until they eventually depart for the open ocean. This consistency of movement and behavior reinforces the strength of our opportunity to study sixgill sharks in Puget Sound,” according to a statement from Seattle Aquarium. “Through our research, we hope to answer questions about the life history and ecology of sixgill sharks—including migration, growth rates and prey preferences.” 

The aquarium also aims to study previously unexamined physiological aspects of sixgills, and understand human influence. 

The team created a custom “cradle” to safely hold a shark while they work quickly to examine it. Image: Seattle Aquarium.

From May to September, Seattle Aquarium researchers and veterinarians will try to study the elusive species at three different locations in Puget Sound, going to each one once a month. There, the team will lift sharks to the surface, and either bring them onto the boat or keep them at the side of the vessel and flip them upside down. This position triggers a trance-like state in several shark species. Either way, the team will make sure that the sharks can breathe through all of those gills.

Once the sharks are secured, the team will examine them. They should be able to collect measurements, obtain tissue samples, take photos, and deploy wearable tags in only five to 10 minutes. The tags that will then supply information about movement, habitat use, and feeding ecology. The scientists will then return the sharks to the open water. 

“Our goal is to answer as many questions as possible,” Dani Escontrela, a researcher at the Seattle Aquarium, said in the statement. “We’re collaborating with agencies like the Washington Department of Fish & Wildlife, the Big Fish Lab at Oregon State University, Point Defiance Zoo & Aquarium and other researchers to fill gaps in expertise, all while keeping animal health and well-being our top priority.”

The post Mysterious giant sharks that outlived the dinosaurs lurking in Puget Sound appeared first on Popular Science.

Your immune system has one job: to protect you. And most of the time, it does that job like a pro. 

But occasionally it gets a bit overzealous, even paranoid. It mistakes harmless, even wonderful things—flowers, peanuts, cats—for threats, and attacks them (and you—mostly you) with a senseless, chaotic vengeance.

For most allergy sufferers, this might mean giving up a few tasty foods, staying inside during high pollen counts, or rehoming the cat—or, more realistically, the person allergic to the cat. But for a tiny number of people, the immune system decides to take aim at one of the most essential substances on earth: water.

Yes, it is possible to be allergic to water. And the condition is even stranger than it sounds.

“Imagine not being able to go into the pool, or the lake, or the ocean,” says dermatologist Dr. Amir Bajoghli, who has treated a patient with this rare condition. “My patient also has to take much faster showers, as you might imagine. It definitely interferes with quality of life.”

Yes, you can be allergic to water

The medical term for an allergy to water is aquagenic urticaria, a form of hives. The condition is so rare that only an estimated 100 to 150 cases have ever been reported. However, researchers believe many more cases go undiagnosed: When a patient comes in complaining of hives, “it could be water” is probably not the first thing that leaps to mind.

People with this rare condition break out in hives like these when exposed to water. Image: Getty Images / Yuliia Kokosha

“Honestly, a lot of general physicians aren’t even aware of it,” says Bajohgli, an adjunct professor at Georgetown University School of Medicine. “It’s rare, and it’s not on their radar.”

Although scientists don’t fully understand exactly how aquagenic urticaria works, they believe water itself isn’t the culprit. Rather, it appears that certain people’s skin responds differently to water contact, setting off a reaction in the skin’s outermost layer. This triggers the body’s mast cells (immune cells that sound the alarm during allergic reactions), which releases histamine, the troublemaking chemical responsible for allergic responses. 

Within minutes of water touching the skin, a person with aquagenic urticaria will develop raised, intensely itchy welts. The reaction typically lasts anywhere from 30 minutes to an hour, and the longer the exposure, the more severe the symptoms.

You can still drink water, but sweating can be a problem

Interestingly, and luckily, aquagenic urticaria does not interfere with the body’s need for life-sustaining hydration. In other words, drinking water is fine. When water is swallowed and processed by the gut rather than absorbed through the skin, it doesn’t trigger the same immune response, Bajoghli says.

“The gut, just like the skin and the lungs, is one of the first forms of defense,” he says, “but in this case, somehow, it’s not eliciting the response in the gut the way it does in the skin.”

Bajoghli notes that some patients with aquagenic urticaria do react to their own sweat, although his patient does not. Sweat, he explains, involves an entirely different biological process than external water making contact with the skin.

Scientists believe an unidentified substance in the skin may be triggering this reaction, although much remains unknown. 

“It’s still, medically, for us, a mystery,” he says.

How to test if you’re allergic to water

For better or worse (mostly better), water is inescapable. Because of its ubiquity, and also because aquagenic urticaria is something of a medical unicorn, it often takes a while for patients or doctors to connect the dots. 

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Once it occurs to the patient and provider that water could be the culprit, diagnostic testing is fairly straightforward. It typically involves applying water-soaked compresses to the skin and waiting. In most positive cases, symptoms appear within five minutes, although the test can take up to 30.

“We wait 30 minutes before we call it negative,” Bajoghli says.

The importance of very quick showers

So, what is life like for a person whose body treats H₂O as a sworn enemy? For Bajoghli’s patient, an active teenager involved in sports, the condition reshapes even the most basic daily routines. Among other things, this means really fast showers. 

“When he showers for about two minutes, the symptoms are more subdued and milder in nature,” Bajoghli says. “If he takes a longer shower, they’re more severe and they persist longer.”

The good news is that aquagenic urticaria is unlikely to cause a major allergic reaction. It is, however, chronic; patients should not expect it to resolve on its own.

Treatment options do exist, however. Bajoghli’s patient takes an antihistamine called cyproheptadine, which reduces symptoms enough to make that two-minute shower manageable. Timing is important: taking the antihistamine about an hour before water exposure helps maximize its effectiveness.

For patients who need more relief, Bajoghli says a newer drug called omalizumab has shown promise.

For now, the mechanisms behind aquagenic urticaria, including the identity of the substance—or antigen—that triggers it, remain poorly understood, and that knowledge gap makes it difficult to develop more targeted treatments.

“We’re really looking forward to finding out what that antigen is,” Bajoghli says, “and hopefully one day solving this.”

In Ask Us Anything, Popular Science answers your most outlandish, mind-burning questions, from the everyday things you’ve always wondered to the bizarre things you never thought to ask. Have something you’ve always wanted to know? Ask us.

The post Yes, you can be allergic to water appeared first on Popular Science.

Social media is widely considered to be bad for one’s mental health, at least anecdotally. However, it can have some positive impacts, such as videos of animals chewing food very loudly. What could possibly be better than a closeup of an animal’s snout as it crunches on a carrot? 

This week, zoos around the United States have been using social media to highlight one particularly cute muncher—tree kangaroos. Ahead of World Tree Kangaroo Day on May 21, conservation organization AZA SAFE (Saving Animals From Extinction): Tree Kangaroo of Papua New Guinea is inviting organizations working with tree kangaroos to compete in this year’s International Tree Kangaroo Crunch-a-Thon. 

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In the aptly-named competition, participants posted videos on Instagram and/or Facebook of their tree kangaroo eating something. The competition categories are Most Likes, Most Views, and Judges’ Choice, and winners will be announced on May 17, Australian Eastern Standard Time. 

The organizers even provide crunchy food recommendations: bell peppers, celery, romaine hearts, snap peas, green beans, cucumbers, and zucchini—with the caveat that the last two vegetables might not have the best crunch. 

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“In partnership with the AZA Tree Kangaroo SAFE program, we’re participating in the Tree Roo Crunch-a-Thon to help shine a spotlight on this endangered species,” reads a social media post by Roger Williams Park Zoo & Carousel Village featuring three munching, pink-nosed brown and white tree kangaroo. “Our Zoo is home to three Matschie’s tree kangaroos – a species of tree kangaroo native to the cloud forests of Papua New Guinea.”

Tree kangaroos are 14 species in the Dendrolagus genus, the sole arboreal kangaroo group. They are herbivorous marsupials with bushy tails, and usually have long arms and padded back feet. Tree kangaroos live in parts of Australia, Indonesia, and New Guinea’s rainforests. The Golden-mantled tree kangaroo (Dendrolagus pulcherrimus) is among the world’s most endangered mammals and only lives in a small area of Papua New Guinea. 

In the words of the Crunch-a-Thon organizers, “let the crunching begin!” 

The post Watch adorable animals compete for best chewer in 2026 Crunch-a-Thon appeared first on Popular Science.

There’s nothing quite like the sound of an airplane toilet flushing. But that incredibly loud sucking sound is actually something of an engineering marvel. These toilets flush, with no water, while zooming along at 500 miles per hour. 

In this episode of Ask Us Anything by Popular Science, we get into all the smelly details of how airplane toilets actually work.

Ask Us Anything answers your most outlandish, mind-burning questions—from the everyday things you’ve always wondered to the bizarre things you never thought to ask. So, yes, there’s a reason we can’t remember being babies and no, not all cats hate water. If you have a question for us, send us a note. Nothing is too outlandish or too ordinary.

This episode is based on the Popular Science article “How do airplane toilets work?”

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Full Episode Transcript

Sarah Durn: You’re six years old, wedged into a middle seat on your very first flight.

Your ears are popping. The engine sounds impossibly loud. Somewhere a baby is crying. And after nervously sipping one too many ginger ales, you realize there’s something else you need to do.

So you make the LONG walk down the NARROW aisle to the airplane bathroom. 

You open the weird sliding door, and this lavatory is tiny. And, after doing your business, you hesitantly hit the flush button.

For one horrifying second, you’re convinced the toilet might actually suck you into the sky.

But what exactly is happening here? How do airplane toilets work?

Turns out, the answer involves physics, pressure differentials, and one surprisingly clever engineering trick. 

Welcome to Ask Us Anything from the editors of Popular Science, where we answer your questions about our weird world, from “why do parrots talk like people” to “what’s the coldest temperature humans can survive?” No question is too ordinary or too outlandish.

I’m Sarah Durn, an editor at PopSci. 

Laura Baisas: And hello, I’m news editor Laura Baisis.

SD: Here at Popular Science, we can’t stop thinking about all the world’s strangest questions, and this week, we’re wondering how the heck airplane toilets actually work, something Laura actually edited a story on. 

So Laura, what’s going on here? What happens when we use the bathroom at 35,000 feet?

LB: First of all, you can relax. The toilet is not strong enough to suck you out of the plane. 

SD: Ah, thank God. Childhood fear officially resolved. 

LB: But that terrifying slurp sound, very real. And it turns out that airplane toilets use a surprisingly clever system that takes advantage of something that planes already have at high altitude, the enormous pressure difference between the cabin and the outside of the plane.

SD: So every time we flush on a plane, physics is essentially doing the dirty work? 

LB: Pretty much. We love physics.

SD: Oh, we do.

LB: And once you learn how the system actually works, from vacuum toilets to something called blue ice, I’m pretty sure you’ll never hear that sound the same way again. 

SD: All right. I’m in. Tell me all the airplane bathroom facts.

LB: I’d be happy to. But before we dive into the science of sky-high plumbing, we want to hear from you. What questions are swirling around your brain? Submit your question by clicking the “Ask Us” link at popsci.com/ask. Again, that’s popsci.com/ask, and click the “Ask Us” link.

SD: We’ll be right back with more about airplane toilets after this quick break.

SD: Welcome back! Okay, Laura, before we get into all the smelly details, I think we need to talk about the history of airplane toilets because early flying was kind of a nightmare.

LB: Oh, absolutely. I mean, that glamorous golden age of air travel, a lot less glamorous if you needed to pee.

SD: Right. So in the very earliest days of aviation, planes just, you know, straight up no bathrooms at all.

LB: Which makes sense if you remember early flights were a lot shorter and planes flew so much closer to the ground.

SD: Yeah, exactly. Pilots were basically flying by sight, and it’s said that early pilots actually peed into their shoes and then would just toss it into the air. 

LB: I still can’t believe that’s real.

SD: Me neither. Or they’d make a hole in the cockpit floor…and just go ahead and, you know, pee through that. 

LB: Correct. This is all so, so bad. So bad. 

SD: But it does get better. I mean, kind of. As passenger air travel became more common in the later 1920s, airlines were like, “Okay, we should probably do something about the bathroom sitch.”

So early passenger planes basically had buckets. Just, you know, a bucket in the back of the plane. 

LB: Ah, truly a luxury travel experience. 

SD: Very chic, very elegant. Then in the late 1930s, the first enclosed plane lavatory debuted on the DC-4 passenger plane. But even those were pretty primitive. The toilet had a removable bowl that crews had to take out and dump after landing.

LB: Yeah, not sure I’d want that job. 

SD: Yeah, same. Eventually planes, though, started using chemical toilets, you know, kind of like a fancy porta potty situation. Waste would sit in these tanks full of bright blue disinfectant liquid.

LB: Ah, yes, we come to the origin of one of aviation’s most disgusting phrases: blue ice.

SD: It doesn’t sound disgusting, which is what throws me. 

LB: It’s kind of a misnomer. 

SD: I know. It sounds like something a superhero would use. But anyways, explain it to us. What is blue ice?

LB: So blue ice forms when waste leaks from a plane at a really high altitude. Since it’s so cold outside, the waste instantly freezes onto the aircraft.

SD: Okay, which is already kinda gross. 

LB: Yeah, and then sometimes, I’m gonna emphasize this, very, very rarely it can break off as the plane descends.

SD: Wait, meaning frozen airplane toilet waste can theoretically fall from the sky? That’s what blue ice is? Frozen human waste raining from above?

LB: Again, gross, but very, very rare, but yes, it can.

SD: Okay. Awful. New fear unlocked. Hate that. Really bad. 

LB: But the good news is that modern airplane toilets are much, much more sophisticated. Most commercial planes today use vacuum toilet systems, which are lighter, cleaner, and honestly kind of ingenious. 

SD: Okay, so let’s get into it. What’s actually happening when we flush while up in the sky?

LB: Okay, so the key thing to understand here is pressure. Airplanes fly at very high altitudes, usually between 31,000 and 42,000 feet up. There, the air pressure outside of the plane is way lower than inside of the cabin.

SD: Because the cabin is pressurized so all of us, you know, can breathe.

LB: Exactly. Breathing equals important. Right. 

SD: Right. 

LB: So engineers realized they could use that pressure difference to their advantage. So when you hit the flush button in an airplane bathroom, a valve opens between the toilet bowl and a waste tank. So because the air pressure is lower on the tank side, everything gets sucked downward incredibly fast.

SD: Which explains the very loud sucking sound.

LB: Exactly. And one reason engineers love this system is because it saves a ton of weight. Traditional toilets need a lot of water, but on airplanes water is heavy and heavier planes burn more fuel.

SD: So instead of gallons and gallons of water, plane toilets mostly use air pressure.

LB: Right, which is why the flush is so dramatic and loud and fast.

SD: Okay, and, you know, silly question, but can you actually get sucked into an airplane toilet?

LB: No. Despite what every child, and honestly some adults, might believe, the vacuum is nowhere near powerful enough to suck a human into the plumbing.

SD: Oh, thank goodness.

LB: Although aviation experts do say that you should close the lid before flushing because the suction can splash some gross things around more than you’d maybe like.

SD: Ooh, yikes. Noted forever.

LB: And that’s… Come on, that’s just good general toilet flushing behavior anywhere. You know, flush with that lid down.

SD: Yeah, I’m a strict lid down girl.

LB: Yep, same. Same. 

And, you know, airplane toilet systems are also designed with a lot of safety features. There are pressure valves, sealed tanks, all kinds of redundancies to make sure the cabin stays pressurized and everything works safely. 

SD: Right, ’cause you don’t wanna mess with the air pressure on a plane. 

LB: Absolutely not.

SD: Okay, so when you flush an airplane toilet, where does everything actually go?

LB: So all the waste gets sucked through pipes into holding tanks elsewhere in the aircraft, and contrary to a very persistent myth, planes do not just simply dump sewage while flying. The waste stays on board until the plane lands.

SD: Unless it’s blue ice.

LB: Unless it’s blue ice. But remember, very rare and not that often anymore. Planes are more sophisticated with their waste.

SD: I’m gonna be so aware of anything falling from the sky. 

LB: I know. 

SD: Watch out. We’re really helping, you know, just assuage a lot of childhood fears on this episode.

LB: You know, we aim to please here.

SD: And okay, so then after the plane lands comes the very misleadingly named honey truck.

LB: The honey truck. Uh, yeah, unfortunately the honey truck is a lot grosser than it sounds. After landing, airport ground crews bring over these specialized service trucks that connect to the aircraft and pump all of that waste out of the holding tanks.

SD: The fact that they’re called honey trucks feels like a crime. Like, who is naming things—blue ice, honey trucks—what the heck is going on?

LB: But, at major airports this happens constantly. Honey trucks are always roving around, pumping waste from planes into their holding tanks for disposal.

Kinda cute, sort of like a poop version of WALL-E happening all along the tarmac without us even knowing. 

SD: Is it cute? Do we think that’s cute? 

LB: I kind… You know what? I kind of do. It’s important. It’s important, so I think it’s cute.

SD: Fair. Yeah, I can’t imagine being the person assigned to the airplane poop truck.

LB: And apparently, as I said, those very important crews also deal with people flushing things they absolutely should not flush. 

SD: Oh, no. 

LB: According to one aircraft engineer, mechanics have found diapers, silverware, soda cans. 

SD: Soda cans? 

LB: Soda cans. And airplane toilet pipes are tiny, so clogs are a huge deal, not to mention they can cause major delays.

SD: Yeah, you do not wanna be the person responsible for grounding a plane because you flushed your ginger ale can.

LB: There are already enough reasons you could get delayed. Do not delay a flight because you decided to flush that can, exactly.

SD: People are crazy.

LB: A clog can even take a plane out of service for days while mechanics fix the plumbing.

SD: It’s honestly incredible that these toilets don’t have more issues. I mean, they’re really clever little pieces of technology. 

LB: And the engineering behind all of this is fascinating. These systems have to work safely, reliably, and hygienically while flying hundreds of people through the sky at 500 miles per hour. It’s amazing.

SD: Airplane toilets are one of those weird engineering marvels most of us never think about unless we’re hearing the very loud slurp sound.

LB: And yep, never gonna hear that sound the same way again. 

SD: Yeah, same. 

LB: Or think of blue ice and honey the same way again, if I’m being honest. And with that image in mind, we’ll be right back after this quick break.

SD: Welcome back. Since this episode is all about flying toilets, we have to talk about the fact that while we were making this episode, NASA sent four astronauts into space, headed to the dark side of the Moon for the first time, and then their toilet basically immediately broke.

LB: Immediately. I mean, that poor crew.

SD: I know. Yeah, Artemis II embarks on this historic mission around the Moon, and then just a few hours into the mission, NASA’s like, “Ooh, guys, quick update, the space toilet fan broke.”

LB: Guessing that’s a sentence that probably caused, you know, some stress at Mission Control.

SD: Yeah, just, you know, a little bit, especially because there was only one toilet on board for four astronauts on a 10-day mission.

LB: Yeah, that toilet had a lot riding on it.

SD: Yeah. And unlike airplane toilets, space toilets can’t really rely on gravity because, you know, space.

LB: Space. In microgravity, nothing naturally goes down, which means space toilets use fans to pull waste in the correct direction, and in this case, the fan stopped doing that, which would have meant urine floating around the cabin. Ew.

SD: Yeah. The good news is NASA fixed it pretty quickly. Astronaut Christina Koch worked with Mission Control to get the system back online within a few hours.

LB: And apparently the astronauts had backup emergency urine bags, just in case. 

SD: Which, fun fact, is basically how Apollo astronauts handled this back in the 1960s. No luxury Moon bathroom, just Neil Armstrong peeing and pooping in a bag.

LB: What an image.

SD: I mean …

LB: I know, right? Humanity can build giant rockets, fly hundreds of thousands of miles through space, and still end up improvising bathroom solutions.

SD: Honestly, it all feels very, very human.

LB: It does. And on that note…

SD: May all of your toilets, earthly or cosmic, function correctly.

LB: And that’s it for this episode, but don’t worry, we’ve got more episodes of Ask Us Anything live in our feed right now. Follow or subscribe to Ask Us Anything by Popular Science wherever you enjoy your podcasts, and if you like our show, leave us a rating and review.

SD: Our producer is Alan Haburchak, and this week’s episode was based on an article written for Popular Science by Tom Hawking, with a link in the show notes if you wanna learn more about airplane bathrooms.

LB: Thank you, team. Thank you, toilets, and thanks everyone for listening.

SD: And one more time, if you want something you’ve always wondered about explained on a future episode, go to popsci.com/ask and click the “Ask Us” link. Until next time, keep the questions coming and close those toilet lids.

LB: And watch out for the blue ice…

The post Why airplane toilets are tiny engineering marvels appeared first on Popular Science.

In 1634, English settlers established St. Mary’s City as the first permanent outpost in the colony of Maryland. Many of these early residents were ultimately buried in the town’s Chapel Field cemetery, including 49 colonists between the town’s founding and 1734. Recently, geneticists collaborating between Harvard University, the Smithsonian Institute, and genetics company 23AndMe analyzed these previously unidentified remains as part of a larger genealogical project tracing colonial migration across the United States.

Their findings illustrate how  such a small original population can have vast genetic influences over time. According to the team’s study published in the journal Current Biology, over 1.3 million living descendents can be traced directly to the handful of settlers buried at St. Mary’s City. What’s more, researchers believe that they potentially identified remains belonging to Maryland’s second governor.

The results come after decades of work that began with the excavation of a trio of extremely rare lead coffins from the cemetery’s Brick Chapel in 1986. These were later revealed to contain the bodies of Philip Calvert, his first wife Anne Wolseley Calvert, and an infant son from Calvert’s second wife, Jane Sewell. Calvert served as Maryland’s fifth governor, and came from one of the colony’s most prominent and influential founding families. Later DNA analysis tied the Calverts to three more bodies buried nearby.

“Although additional work is needed to determine exactly how these individuals were related to Philip, this finding is significant given that several members of the extended Calvert family, including Philip’s half-brothers Leonard (1610–1647) and George (1613–1634), died in St. Mary’s during this period,” explained Douglas Owsley, the Smithsonian’s biological anthropology curator.

Further genetic examinations identified relatives among five other families, including one that spanned three generations.

“Because mortality was so high in the early days of the colony, finding a multigenerational family was a surprise,” Owsley said. “It’s a discovery that simply wouldn’t have been possible without genetic study.”

From there, the team was able to move forward through the centuries by comparing the DNA information at St. Mary’s City with more than 11.5 million participants from the 23AndMe genetic database. The results show that there are now around 1.3 million living relatives of Maryland’s first European residents. They were also able to corroborate a major migration that occurred between 1780–1820, when many of the colony’s Catholics fled south to Kentucky due to economic stressors and anti-Catholic sentiments.

One of the study’s more groundbreaking facets involved researchers’ ability to assess unknown remains through a combination of genetic material and multiple family trees that include still-living individuals. First, they identified people in the database who shared the strongest genetic relationships to the three related cemetery bodies. They then examined overlaps in anthropological information and known lineages to narrow down the mystery remains. Based on their findings, the team now believes the remains belong to colonial Maryland’s second governor, Thomas Greene, his first wife, Anne, and their son, Leonard.

“This is the first time that ancient DNA has been used to help identify unknown individuals, without any prior knowledge of who they might have been. And it just so happens that one of those individuals turned out to be one of colonial Maryland’s most prominent figures,” said Éadaoin Harney, a senior scientist at the 23andMe Research Institute.

Study co-author and Harvard Medical School geneticist David Reich added that their latest work showcases how vital ancient DNA analysis can be to expanding our understanding of history. 

“While written records are extraordinarily rich, genetic data can still address gaps in that record and yield surprises,” said Reich.

The post 1.3 million people share DNA with Maryland’s earliest colonists appeared first on Popular Science.

Coral reefs may soon have new swimming visitors observing their life-rich aquatic metropolises. But  that visitor isn’t a fish—or even a human. It’s an autonomous, multi-sensor survey robot. Developed by the Woods Hole Oceanographic Institution (WHOI) Reef Solutions Initiative, this new underwater surveyor uses a combination of hydrophones, high-resolution cameras, and an onboard computer to find signs of marine life hotspots. It then moves in closer for a better look, creating data-rich maps that would likely take many human divers multiple trips to produce.

The system, appropriately called the Curious Underwater Robot for Ecosystem Exploration (CUREE), does all this all by itself. Well, that’s the goal, at least. In actual testing around Joel’s Shoal in the U.S. Virgin Islands, the curious robot was able to home in on the distant crackle of shrimp, and even tailed a barracuda for more than 984 feet. That last barracuda tracking bit required some human intervention to get it back on course, but the majority of the barracuda tracking occurred totally autonomously. The findings were published this week in the journal Science Robotics. 

Keeping tabs on coral reef’s inhabitants 

Coral reefs are like a busy neighborhood or bustling bar in the ocean. Though they account for less than 0.1 percent of physical ocean space, roughly a quarter of all marine species spend some part of their lives there. But overfishing, human development, and warming ocean temperatures are putting those bustling ecosystems at risk. Because of this threat, it’s more important than ever for marine biologists to have an accurate and timely sense of what those environments look like.

Getting a clear sense of what species are where in a reef isn’t simple, though. At any given time, most of a reef is barren, with marine life typically clumping into hotspots distributed throughout the reef. Currently, researchers primarily track those hotspots with  trained human divers, though that approach isn’t perfect. Our pesky lungs and limited oxygen tanks mean human divers run  on a short clock. It’s also costly for research teams to properly train and equip a human diver, which limits the amount of time and frequency with which they can take a plunge.

CUREE (Curious Underwater Robot for Ecosystem Exploration), an autonomous underwater vehicle navigates using information from its cameras and outstretched hydrophones to gather audio and visual information about a coral reef environment. Image: Photo by Austin Greene, © Woods Hole Oceanographic Institution.

An underwater robot could potentially solve both those problems, but it would need the right tools for the job. That’s where CUREE comes in. Engineers outfitted the robot with a variety of sensors that can detect both visual and auditory signals. The system can analyze far-off audio signals in real time to hear distant noises as subtle as fish calling out to each other. It can then triangulate that data using an onboard computer system that moves toward areas it suspects have a high chance of containing marine life. If it spots life once there, it can then use its cameras to provide more precise data about the species and their behavior.

“In some sense, they’re almost a perfect compliment for each other,” WHOI roboticist Seth McCammon said of the multiple sensor method in a statement. “Passive acoustics gives you a broad sense of the environment, while vision is short range, but is this really information-rich data stream.” 

Curious robot stalks a barracuda 

The team put CUREE to the test near Joel’s Shoal, a coral reef located on the coast of St. John in the U.S. Virgin Islands. In one test,  the robot could accurately find and count the number of fish in a region. It was able to detect signs of fish from up to 82 feet away and then use those clues to identify life hotspots.

Woods Hole Oceanographic Institution (WHOI) scientist and WARP Lab lead Yogesh Girdhar tests the CUREE (Curious Underwater Robot for Ecosystem Exploration) autonomous underwater vehicle in the U.S. Virgin Islands in November 2021. Members of the WARP Lab designed CUREE to navigate and sense complex coral reef environments autonomously to identify biodiversity hotspots. Image: Photo by Dan Mele © Woods Hole Oceanographic Institution.

However, the  most interesting result was CUREE’s successful barracuda tracking. Once locked on to its target, CUREE followed the apex predator for a total of nine minutes and 55 seconds, as the fish weaved its way around, looking for lunch. The tracking video in the study shows the barracuda traveling first to a hotspot and then backtracking to another spot where it had previously startled a large reef snapper. And while a human diver had to initiate the robot’s lock on the barracuda,and had to re-lock on the target several times, CUREE did most of the work on its own. The team says eight minutes and 59 seconds of the tracking was done with full autonomy.

Though this isn’t the first underwater robot, its use of multiple sensor types makes it unique because it’s eventually a jack of all trades. Researchers can, in theory at least, drop the robot in a broad area of water and let it get to work surveying. 

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Only around 600 of the nearly 4,000 known snake species are venomous. The recently discovered Guangxi reed snake (Calamaria incredibilis) in China is not one of those species, but its alternative defense mechanism is strange enough to keep most predators at bay. According to a study recently published in the journal Zoosystematics and Evolution by biologists at the Natural History Museum of Guangxi, C. incredibilis wields its wide, stubby tail like a second head to scare away potential threats.

Researchers first spotted the Guangxi reed snake during a biodiversity study in China’s Huaping National Nature Reserve near the nation’s southern border with Vietnam. The mostly nocturnal, non-venomous serpent grows to about eight-inches-long, and is identifiable by its small brown scales and seven darker stripes. Largely docile, it prefers to hide away between rocks and underneath leaves, and prefers a diet of insect larvae and earthworms.

Although largely timid, the Guangxi reed snake has evolved a strategy to bluff its way out of dangerous situations. Whenever it feels threatened, the reptile raises its tail off the ground and begins waving it like an additional head. The tail even features similar markings to those seen on the snake’s head, which adds to the overall realism. 

As People recently noted, the reed snake is far from the first new snake species discovered in 2026. Earlier this year, researchers identified both a vibrantly turquoise pit viper and a flying snake in a Cambodian cave alongside previously unknown geckos, millipedes, and microsnails.

The study’s authors explained the Guangxi reed snake “highlights the underestimated diversity” in the reptile’s larger family, as well as underscores the region’s role as an “ important hotspot” of unique animals.

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Death Valley National Park’s ephemeral spring superblooms get most of the attention, but another national park in California has its own impressive floral show this year. Redwood National Park in northern California is awash in a purple riverbank lupine (Lupinus rivularis) superbloom. It was first spotted earlier in May and is expected to last through the end of the month. 

The park six hours north of San Francisco is home to over 30 species of plants, including to the state’s famous redwood trees—the tallest trees in the world. The landscape features open prairies, oak woodlands, wild rivers, and untamed coastline. 

Purple riverbank lupines help attract important pollinators. Image: NPS photos / O. Seweryn.

This year’s purple riverbank lupines are blooming at the Lyons Ranch Trailhead and covered the Bald Hills with purple flowers. Riverbank lupine is a fast-growing and multi-stemmed member of the pea family (Fabaceae) that can grow up to five-feet tall. Its seeds provide food for birds, while its dense patches give rabbits, birds, and other small animals cover. Bees are also attracted to its pollen and nectar, and the plants possibly host two species of butterflies—the orange sulphur (Colias eurytheme) and the western tailed blue (Cupido amyntula).

This year’s lupine super bloom is more than just pretty purple flowers coloring the landscape. Lupine also demonstrates how prescribed burns play an important supporting role in prairie ecosystems.

“The prairies of the Bald Hills have been managed using fire since time immemorial, revealing a fascinating trend in the relationship between fire and flowers,” park rangers wrote in a Facebook post. 

These flowers consistently bloom “in abundance” two years after a prescribed fire. The fire likely helps the hard-coated seeds germinate, leading to a super bloom. 

Purple riverbank lupine superblooms typically occur two years after a prescribed burn. Image: NPS photos / O. Seweryn.

According to SF Gate, a prescribed fire was set two years ago to burn off flammable materials and help prevent wildfires. 

“We are returning fire to this landscape, and we’re realizing that one year after a fire, we end up with a lot of vegetative lupines,” an unnamed botanist told SF Gate. “But two years post-burn, just like the burn that they did in this drainage two years ago, we end up with a lupine superbloom.”

When visiting any national park or superbloom, it is critical to “take only photographs, leave only footprints.” Visitors should stick to designated trails to keep the delicate flowers safe for pollinators and try to disturb the plants and wildlife as little as possible. While lupines are beautiful, these wildflowers are not there for picking. Viral social media posts of previous superblooms in Death Valley and other parks have led to serious damage to the flowers that influencers claim to love.

Photography news site Fstoppers offers several tips on how to photograph superblooms without disrupting them, including using telephoto lenses and shooting from low angles. 

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Every week, without fail, the three-toed sloth takes a breathtaking, almost suicidal risk—all for the sake of a bowel movement. Or, to put it in terms familiar to anyone who has sat through a long Zoom meeting, a “bio-break.”

With fast-moving predators lying in wait, being on or near the ground is the number one cause of mortality in sloths. And because sloths have among the slowest metabolisms ever recorded in animals, the climb down the tree and back up represents one of the biggest energy expenditures of their entire week.

“It’s like if I had to go on a 5K run down the middle of an interstate, just to use the bathroom,” University of Wisconsin-Madison wildlife ecologist Dr. Jonathan Pauli tells Popular Science. “It’s really costly, and it’s really risky.”

Which begs the question: Why do three-toed sloths take such risks for a poo? Why not just do the sensible thing and poop from the trees?

The answer involves mutualism—a relationship where all parties benefit—between sloths, moths, and that precious pile of dung sloths risk their lives to leave behind. 

Sloths are home to flightless moths

The key to this whole system turns out to be a much smaller and less glamorous creature: sloth moths (Cryptoses choloepi). These moths spend their entire adult lives in sloth fur—yes, entire. The moment a moth finds and colonizes its slow-moving host, it loses the ability to fly. Permanently.

That’s OK, because sloth moths don’t need to fly once they find their sloth homes. Instead, the moths hitch a ride with the sloth to the base of the tree for its weekly poop session. 

Some sloths do a little wiggle or dance when they’re trying to poop. Video: Have you ever seen a Sloth POOP Dance?, The Sloth Conservation Foundation

After the sloth has deposited its dung on the forest floor, pregnant female moths jump off the sloth into the dung pile (because they can’t fly, they literally hop), lay their eggs, and that’s pretty much the end of the moth. 

Meanwhile, a new generation of sloth moths is dreaming big dreams. After hatching within the dung, the newborn larvae quickly commence chowing down on the dung that spawned them. 

“Larvae will feed off the sloth dung. They actually chew a chamber into the sloth dung,” Pauli says. “The larvae then pupate and emerge as moths.”

And then, for one fleeting moment, sloth moths can fly. The newly emerged moths drift up into the canopy of the tree, find and inhabit a sloth host, and the cycle begins again. The moths are permanently grounded. Until, one day, their offspring will make that brief, one-way flight all over again. 

Algae creates a sloth’s green camo coat

Enter the third player in this strange triumvirate: algae.

Because the moths are flightless, many of them live out their entire lives in the sloth’s fur and die there. As they decompose, they release nitrogen and phosphorus directly into the sloth’s coat. 

Pauli describes the sloth’s peculiar water-absorbing hair as “almost like a hydroponic growth area” for algae. 

More moths means more fertilizer, and more fertilizer means more algae, specifically Trichophilus, or “hair-loving algae,” a species found nowhere on earth except sloth fur. Pauli likens the effect to a ghillie suit (the head-to-toe camouflage gear snipers wear to vanish into foliage). The algae turns the sloth’s fur green enough to disappear into the forest canopy.

The algae living on sloths gives their fur a green hue, helping the slow-moving animals blend into the forest canopy. Image: Getty Images / zen rial

But that algae also serves another purpose beyond being cool living camo. It’s also a potential food source for these slow-moving mammals.

Do sloths farm algae on their bodies? Maybe.

To find out whether sloths were actually eating this nutrient-rich algae, Pauli and his colleagues did something that sounds alarming but is apparently just a normal Tuesday in wildlife ecology: They pumped the stomachs of roughly a dozen three-toed sloths. 

What they found wasn’t all that surprising: lots of Cecropia leaves, a staple of sloths’ diet. But they also found Trichophilus algae. And since Trichophilus exists nowhere on earth except sloth fur, there was only one way it could have gotten there: The sloth ate its fur. Testing the algae, Pauli and his team found it to be digestible and lipid-rich—a potentially valuable supplement to a diet of nutritionally poor leaves.

What the team of researchers don’t know is whether it matters. Is the sloth cultivating, munching on, and extracting nutrition from its own self-grown snack?  

“It could be totally trivial and unimportant,” Pauli says. “It could be that they incidentally get a little bit in their stomach, it’s all by accident. It would be like the equivalent of me eating a Snickers bar too quickly and accidentally eating part of the wrapper.”

Or it could be that sloths are deliberately consuming it, extracting real nutrition from the algae growing on their own bodies. Whatever is driving it, Pauli is fairly certain of one thing: The sloth isn’t doing it on purpose.

“It’s not conscious—I don’t think the sloth is ever thinking ‘Time to re-up my algae.’ I think it’s more that individuals that have these behaviors, that fortify these relationships with these other species, see fitness benefits. That’s why we see these behaviors persist.”

In other words, this whole system—from flightless sloth moths to algae to sloth diets—may be helping sloths survive. 

Which brings us back to that suicidal weekly commute. It turns out the sloth’s trip to the forest floor may be doing a lot more than answering nature’s call. In fact, it may be the key to maintaining the entire system. No ground trip, no moth-to-dung delivery. No moth delivery, no fertilizer. No fertilizer, no algae. And no algae means no camouflage, and possibly no nutritional supplement for an animal that can barely afford to lose either. Not bad for a bathroom break. 

In Ask Us Anything, Popular Science answers your most outlandish, mind-burning questions, from the everyday things you’ve always wondered to the bizarre things you never thought to ask. Have something you’ve always wanted to know? Ask us.

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Astronaut food has come a long way from the freeze dried packets aboard the Apollo missions. During their historic lunar fly-by in April, the Artemis II crew dined on beef brisket, mac and cheese, quiche, and a lot of tortillas. The same can be said for the hungry inhabitants of the International Space Station (ISS). With regularly scheduled restocks, the astronauts don’t have to worry as much about issues like shelf life. That means that even when nearly 250 miles above Earth, ISS residents can still snack on fresh fruit and vegetables.

NASA highlighted one such astronaut grocery delivery in a photo released on May 14. Taken on April 19, astronauts Jack Hathaway, Jessica Meir, Chris Williams, and Sophie Adenot are seen in microgravity alongside what are presumably upcoming snacks like oranges, apples, peppers, and one conspicuous onion.

Food wasn’t the only precious cargo on the Cygnus XL spacecraft visit that month, however. In addition to the colorful produce, the ISS also received over 2,300 pounds of research hardware and science equipment. These materials encompass the tools the crew needs for their research on blood stem cells for cancer treatments and ways to strengthen astronaut gut health. The ISS is now also home to a new exercise machine, courtesy of the European Space Agency, as well as replacement nitrogen and oxygen tanks for spacesuits.

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The Mary Rose is a remarkable remnant of maritime history. One of England’s largest Tudor Era vessels, the four-masted carrack sailed with a crew of around 450 sailors during the 16th century French and Italian Wars armed with anywhere between 78 and 91 guns. Those weren’t the only tools at the Mary Rose’s disposal. Thanks to primary sources and an extensive analysis following its recovery in 1982, the ship included some truly gnarly handheld weapons.

Some of the most intense—and mysterious—of these were giant incendiary darts. However, there is very little historical information tied to them. Although reminiscent of flaming arrows, these much larger variants were simply far too large to be launched from bows. Historians aren’t even sure exactly how they were wielded or crafted, so medieval weapons specialist and replica crafter Tod Todeschini decided to investigate for himself. The result is a two-part video series that documents his research into the fire darts, as well as the construction of his very own set.

Based on the remnants of the three surviving original examples, Todeschini’s weapon combines an incendiary mixture wrapped in flammable cloth that is then encased in pitch. Wooden fuses inserted into the casing provide a delayed ignition, allowing the wielder enough time to aim and launch the wooden spear at their enemy.

But how were they used in combat? While there is no definitive answer, Todeschini’s experiments alongside Mary Rose Museum research director Alex Hildred led to some likely possibilities. He quickly realized that his initial instinct to hurl it one-handed like an oversized dart was basically impossible—and incredibly dangerous. Once the javelin was lit, you want to be as far away from the melting pitch and flames as possible. Knowing this, he then learned that he could effectively launch the weapon by gripping it near the shaft’s middle while using his other hand to support the end. Subsequent throws easily carried the flaming spear upwards of 60 feet away. That may not be very far compared to a bow-and-arrow’s distance, but it’s more than enough for someone standing in a crow’s nest aboard the Mary Rose to reach an enemy ship that has drawn up to the vessel during close combat.

It’s also plausible that sailors fired their darts from specialized cannons. A standard amount of gunpowder would destroy the supersized arrow before it hit its target, but a soft charge producing less force is a feasible alternative. Todeschini also tested this version by launching a scale model of the dart from a tube using compressed gas.

From there, it was time to see what kind of destruction these weapons rained on unfortunate sailors’ heads. In short, you would not want to encounter one of these things. Aside from virtually inextinguishable flames fueled by molten pitch, the payloads likely included toxic ingredients like camphor and arsenic. The ensuing clouds of smoke would not only blind anyone nearby, but choke them, too. To illustrate their efficacy, Todeschini demonstrated what happens when one of the darts lands in an enclosed environment like those below deck on a ship. After firing one into a shipping container, it only took a matter of seconds before the entire area was enveloped in noxious fumes.

While the weapons weren’t useful in every situation, it’s easy to see how a few well aimed launches could turn the tide during naval combat. That said, they weren’t a guarantee for success—the Mary Rose ultimately sank during battle in 1545, after all.

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Japan’s bear problem continues, and the country is running out of the robot wolves that help keep them at bay. First released in 2016 by the manufacturer Ohta, Monster Wolf was originally designed to ward off the agricultural foes like boars, deer, and the island nation’s Asian black bear (Ursus thibetanus) and brown bear (Ursus arctos) populations. The creative solution quickly went viral for its red LED eyes and menacing fangs—as well as its admittedly odd, furry pipe frame.

Starting at around $4,000, each bespoke Monster Wolf is now equipped with battery power, solar panels, and detection sensors. Its speakers are programmed with over 50 audio clips including human voices and sirens audible over half a mile away. These aren’t assembly line products, however. Each Monster Wolf is custom made, and Ohta simply can’t keep up with the current demand.

“We make them by hand. We cannot make them fast enough now. We are asking our customers to wait two to three months,” company president Yuji Ohta recently told the AFP.

Bear encounters in Japan have steadily risen, as urban development continues to encroach on their habitats and limit their food sources. The country’s rapidly aging population is also making them particularly susceptible to attacks, especially in more rural regions. Since the beginning of 2025, the government has reported at least 200 injuries and 13 fatalities—over twice the previous mortality record. Official data also recorded over 50,000 bear sightings across the country during the same time period. 

Last year, Japan even deployed its own military to help cull bear numbers. More than 14,600 animals were captured and euthanized in 2025, an all-time high and almost triple the previous year’s tally.

Ohta told the AFP that amid the ongoing crisis, there has been “growing recognition” that Monster Wolf is “effective in dealing with bears.” The main customer base remains farmers, but orders are also coming from golf courses and rural workers. Upgraded versions will soon include wheels to actually chase animals and patrol preset routes. There are also plans to release a handheld version for outdoor enthusiasts and schoolchildren.

Until Ohta catches up with its orders, residents and visitors are encouraged to review the Japanese government’s own bear safety tips.

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A pair of rare silver coins discovered by metal detectorists in Denmark were meant to offer 11th century Christians a bit of protection against Viking raiders.. According to the National Museum of Denmark, only 30 of these silver coins laden with Christian imagery have ever been found. 

The coins were uncovered in northern and southern parts of Denmark’s Jutland peninsula. England minted the  coin in 1099 during the reign of King Æthelred II,also known as “Æthelred the Unready” after the Anglo-Saxon king did not adequately prepare his country for Viking attacks. The nickname “unready” is also a bit of wordplay from the 12th century. According to History Extra, people pronounced the word Aethelred as Av-el-raid, meaning “noble council” or “good council.” By tweaking it with the Old and Middle English term “unræd,” which means “ill-counselled,” the nickname became a way for people to mock him.

Since Viking attacks and raids continued in England, King Æthelred II called for public fasting and acts of penance while commissioning a coin with strong Christian imagery. 

On the front, the “Lamb of God” or “Agnus Dei” coins depict a lamb pierced by a cross, representing Christ’s crucifixion. A tablet with the Greek letters alpha and omega are beneath the lamb. These letters represent symbols of God as the beginning (alpha) and the end (omega). The reverse side features a rising dove to symbolize the Holy Spirit. By comparison, the other English coins at this time featured the king’s portrait on one side, with a cross on the reverse.

However, these coins did not really work in protecting England from Vikings. The attacks continued and Vikings took many of these coins as tribute payments. Instead of immediately rejecting them, they may have used them in jewelry. 

“What fascinates me most is how from such a small coin you can unfold a story about the English kings and Christianity in England, which draws threads to the Danish Viking kings, the Danish monetary system and even the establishment of the Danish state,” Gitte Tarnow Ingvardson, an archaeologist at  the National Museum of Denmark, said in a translated statement. “Because it concerns the entire Viking community. Imagine that such a small coin holds so much history!”

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Five new mules at Olympic National Park in Washington State are ready for the busy tourist season. Murl, Cutti, Pip, Checkers, and Gopher join the park’s large working mule herd. Mules have helped maintain the trails in national parks since the early 1900s, and they continue to help monitor Olympic’s one million acres, 600 miles of trails, and 64 trailheads.

Murl, Cutti, Pip, Checkers, and Gopher were named by the park staff and are a nod to the different native plants and animals found at the national park. The mules help trail crews in more wild areas of the park.

Olympic National Park’s mule herd works from April through October and then spends the winter in a large pasture. Image: Olympic National Park.

Mules are the result of interbreeding between a male donkey (Equus asinus) and a female horse (Equus caballus). Thanks to their strength, agility, and endurance, they are the perfect pack animal, according to Washington’s National Park Fund. The park’s over two dozen mules each weigh about 1,000 pounds and can haul roughly 20 percent of their body weight. They carry everything from trail maintenance gear to construction materials and research equipment during their working season—April through October. They will even support the park’s search and rescue teams, safely evacuating any injured hikers out of the wilderness.  

When a new mule arrives at the park, they spend time next to older and more experienced mules to learn the ropes. They are housed in a corral in the Elwha River valley during their working season and head out to their winter pasture in Sequim for a five-month break.

To help introduce the mule team to the greater public, Olympic National Park featured a Mule of the Month last year. Previous winners include a spirited and quick “sports-model” mule named RainCloud and Daisy, who is dubbed a “magnificent matriarch.” 

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Nearly half of all known objects currently orbiting Earth technically classify as space junk, but the true amount may be even higher. Not only that, the debris continues amassing faster than it’s being removed.

The latest red alert report comes from the engineering components company, Accu, and is based on information compiled from the U.S. Space Surveillance Network and its Space-Track database. According to their assessment, there are at least 12,550 tracked orbital debris fragments circling the planet “with no control or purpose.” That’s around 47 percent of the 33,269 known objects, which includes almost 17,690 satellites. But with many of those satellites now inactive along with nearly 2,400 jettisoned rocket bodies, the total space junk is likely worse than the current numbers suggest.

Countries are racing to establish a long-term human presence in space and on the moon, but there are a lot of little problems to consider. More specifically, these issues range from the size of screws and paint chips to dead satellites. All that space junk orbits the planet at roughly 17,400 miles per hour, meaning even a tiny collision could derail an entire mission. In 2016, for example, debris no bigger than a few thousandths of a millimeter smacked into one of the International Space Station’s quadruple-glazed Cupola windows and left behind a quarter-inch-wide crater.

Crunching the numbers further, Accu calculated that there are seven debris objects for every 10 satellites orbiting Earth. The responsibility almost entirely falls on three contributors—China has generated 34 percent of the junk, while the United States and the Russian-aligned Commonwealth of Independent States (CIS) have both provided about 31 percent of the debris.

Most abandoned objects revolving around Earth follow a decaying orbit due to the planet’s gravity and will burn up during atmospheric re-entry. But that often takes years to occur, and as Accu points out, it doesn’t always erase the issue. Material like aluminum, copper, and lithium may vaporize before they hit the ground, but their particulates remain in the upper atmosphere. More research is needed to understand the full impact, but evidence already suggests harmful effects on the ozone.

So what’s being done to address the issue? Not much, unfortunately. Accu notes there are no major projects in development to remove space junk, although there is growing investments in at least maintaining or reducing the overall problem. The European Space Agency (ESA) is leading the charge with programs like ClearSpace-1, the first active debris collection mission. Meanwhile, a number of private companies are also beginning to implement their own endeavors. Technology like robotic arms, drag sails, and even harpoons are all being researched as potential ways to help address the problem.

The bottom line is that the roughly 15,550 tons of space junk currently above everyone’s heads is literally not going anywhere anytime soon. That’s about the same weight as 40 jumbo jets, and it’s only increasing. Accu’s report isn’t meant to offer concrete solutions, so much as highlight that this is a very real problem that requires international coordination and efforts to control. Without that, humanity is going to have a much more difficult time exploring the cosmos.

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A few years’ back, a viral trend overtook social media that nobody saw coming: ShantyTok. Seemingly overnight, TikTok and Instagram were inundated with posts celebrating the niche world of maritime sea shanties. The fad ostensibly began with the spread of Scottish singer Nathan Evans’ version of “Wellerman,” a New Zealand whaling shanty with historical roots stretching back well over a century.

As newcomers dove into a vast backcatalog of songs, many quickly highlighted just how catchy these tunes really are. But while early sea shanty composers didn’t envision ever reaching the top of the charts, they certainly wrote them to be earworms. The sea shanty is only one variant of a work song—rhythmic melodies designed to help laborers keep pace with one another during repetitive, often backbreaking jobs. Other types of work songs developed over generations among Appalachian coal miners, prison chain gangs, and British textile workers, just to name a few examples.

While there are extensive anthropological studies on the folk tradition’s influence and importance of work songs, there isn’t as much empirical research into its efficacy during actual work. At Austria’s Central European University, a team of cognitive scientists recently delved into how songs like shanties may affect the laborers’ performance. Their findings, published in the Proceedings of the Royal Society B, provides strong evidence that work songs not only maintain collective timing among team members—the shared tempo prevents individuals from accidentally quickening the pace.

Groups often unintentionally speed up shared tasks, so much so that there is even a term for it: joint rushing. Don’t feel bad if you’re a victim of it, however. You’re not alone.

“This can happen even when they try to keep a steady tempo, and even among trained musicians,” cognitive researcher and study co-author Thomas Wolf told Phys.org on May 12.

Wolf, like many other listeners, became curious about work song traditions amid the #ShantyTok era. While reading Ted Gioia’s seminal book, Work Songs, he noted how the tunes were frequently described as “keeping the pace.” One prominent example was the Scottish tradition of oyster dredging, whose workers often sang to keep the right tempo while rowing.

Wolf and his colleagues decided to examine work songs under controlled laboratory conditions. They paid particular attention to two frequent aspects that they believed helped keep tempo—solo vocalization and metric subdivision.

“Many work songs are sung either by a lead singer or in call-and-response patterns, meaning that at least part of the vocalization is produced by only one person,” he explained, adding that the songs also regularly include “musical events between the instrumental actions.”

For instance, a work song for a task requiring an action like pulling a rope or swinging a hammer may include additional notes or syllables that coincide with the task itself. These musical subdivisions lower the chance of varied timing, which is known to cause joint rushing.

To test their theories, Wolf’s team asked pairs of volunteers to tap along to a metronome’s tempo, then continue to keep time once the device was turned off. They then compared their performances to those undertaken during a “work song condition” in which one person counted off “one, two, one, two,” (and so on) with the metronome. Taps needed to match the one, while the “two occupied the space between taps. Although their past research showed joint rushing is difficult to control even among groups of trained musicians, the results were completely different in the latest experiments.

“What was striking in this study was that, just by having one person count in a specific way, joint rushing was not only reduced, but statistically speaking, it was completely eliminated,” said Wolf.

Their findings indicate even simple vocalizations can strongly influence group coordination. According to the study’s authors, this means that work songs are not only popular because they keep people aligned. They also prevent the speedier ones from throwing everyone else off their groove. Although interesting from a historical standpoint, this research could help inform solutions to coordination problems that many people deal with today in sports, occupational safety, high-stress situations, and physical rehabilitation. So while sea shanties and other work songs helped laborers during a bygone era, the psychology behind them can still help people for generationst to come.

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New satellite images are helping scientists understand a major tsunami that changed the landscape of a popular tourist destination in Alaska forever. 

On August 10, 2025, a tsunami larger than the Eiffel Tower ripped through Tracy Arm fjord in southeast Alaska. The rapid retreat of the South Sawyer Glacier triggered a landslide that swept huge rocks down the picturesque waterway visited by millions aboard Alaskan cruises every summer. At least 64 million cubic meters of rock slid down the slope of the glacier. The rocks created an enormous tsunami that stripped trees and other vegetation from the opposing fjord wall up to 1,578 feet above sea level. 

The NASA-USGS Landsat satellite images show the dramatic changes to the landscape. In one photo taken on July 26, 2025, the fjord is surrounded by green vegetation. 

The shores of Tracy Arm on July 26, 2025. Image: NASA Earth Observatory images by Michala Garrison, using Landsat data from the U.S. Geological Survey.

In the second image, taken nine days after the landslide on August 19, the fjord is dominated by a gray scar made by the cascading rock. 

The shores of Tracy Arm on August 19, 2025. This image was taken after the tsunami and landslide. Image: NASA Earth Observatory images by Michala Garrison, using Landsat data from the U.S. Geological Survey.Image: NASA Earth Observatory images by Michala Garrison, using Landsat data from the U.S. Geological Survey.

“The bright landslide scar on the north side of the fjord is striking, as is the ‘bathtub’ ring around the fjord showing the areas where the forest was leveled by the tsunami,” said Dan Shugar, a geomorphologist at the University of Calgary.

Sawyer Island, located about 6 miles away from the landslide, also turned from green to brown. Only a few trees still stood at the island’s higher elevations.

Over the past several months, Shugar and his colleagues combined satellite, airborne, and ground-based observations with eyewitness accounts and simulations to build a complete story with how this historic event transformed. Their analysis was published May 6 in the journal Science.

Their analysis found that water continued to slosh around the fjord for more than one day. Geologists call this water-sloshing phenomenon a seiche. Both the landslide and resulting seiche produced seismic signals that were detected around the world and equivalent to a magnitude 5.4 earthquake.

The landslide scar and the zone where vegetation was stripped by the resulting tsunami are both visible in this aerial photo of Tracy Arm and South Sawyer Glacier, captured on August 13, 2025. Image: U.S. Geological Survey/John Lyons

The Landsat images also show that the South Sawyer Glacier retreated significantly in less than a month. Typically, glacial retreat takes much longer. 

“Part of that occurred between the date of the first image and the date of the landslide,” Shugar said. “But part of it is from the landslide itself, which broke off a big chunk of the terminus of South Sawyer Glacier, resulting in a slurry of icebergs in the fjord.”

Fortunately, no one was injured in the event, largely because it occurred around 5:30 a.m. local time. The wave did sweep away some gear from a group of kayakers camping on Harbor Island near the fjord’s mouth. Passengers aboard a small cruise ship in neighboring Endicott Arm also reported swings in water levels and a strong current associated with the tsunami. 

In response to the event, at least six cruise lines have eliminated the Tracy Arm fjord from their itineraries for 2026 due to the hazards. The United States Geological Survey also warns that steep, mountainous landslide areas are “inherently unstable” and that the Tracy Arm fjord tsunami will likely continue to change the landscape.

The post NASA satellite images show how a massive tsunami in Alaska changed the landscape forever appeared first on Popular Science.

This article was originally featured on The Conversation.

Exactly how did birds evolve from dinosaurs? It’s a mystery that has been with us for more than 150 years, and palaeontologists are still hunting for pieces of the puzzle today.

Among them is the University of Edinburgh’s Professor Steve Brusatte, whose latest book, The Story of Birds, tells the whole fascinating story. We caught up with him recently to find out more.

Of all the great dinosaur subjects, why this story?

I’ve always been fascinated by birds. They are all around us and there’s such a stunning diversity and variety. As a palaeontologist I specialised early in the theropod (two-legged) dinosaurs. This is the group that includes T.rex and Velociraptor – and gave rise to birds.

The more I studied theropods, the more I became more curious about the modern-day animals that descended from them. Back in the early 2010s my PhD was about the origin of birds. Its core involved building a big new family tree of theropod dinosaurs to understand where birds slot in, how they evolved from dinosaurs, and how their body features came together.

I wrote about the dinosaur bird connection in my first book, The Rise and Fall of the Dinosaurs (2018), but that was just one chapter. It made me think it would be really fun to do an entire book on the subject. That was how my new book, The Story of Birds, came together.

Is there still any debate about birds evolving from dinosaurs?

I think people have generally heard that birds descended from dinosaurs. In the newer Jurassic World films you even see feathers on some of them. And yet it hasn’t really broken through to the public consciousness that today’s birds really are dinosaurs. They are part of the dinosaur family tree. They just happen to be a peculiar group of dinosaurs that got small and evolved wings, took to the skies and have survived until today.

It was Charles Darwin’s great disciple, Thomas Henry Huxley, in the 1860s who first noted similarities between the skeletons of some dinosaurs starting to be found in Europe and those of modern birds. This was back before anybody knew what DNA was, for instance.

Huxley’s idea did enter the public consciousness, at least in Victorian Britain. Darwin added it to the later editions of On the Origin of Species. But then it went out of favour. This was the great era of exploration, especially in the US and Canada. The frontier was being pushed westwards, and all these new dinosaurs were being found – Stegosaurus, Brontosaurus and later Brachiosaurus and T.rex.

None look anything like birds. I think dinosaurs obtained this stereotype as giant reptilian monsters, and this still largely dominates the public consciousness today.

Yet there were also a lot of smaller dinosaurs. Many had feathers and wings, and many were very bird-like. It’s really only in the past few decades that the idea that birds evolved from dinosaurs has become scientific consensus. The discovery of feathers on dinosaurs in the 1990s really sealed the deal on that.

What mysteries remain?

There are of course still things we don’t know, like how dinosaurs started to fly. How did they start to move their wings in a way that generated enough lift and thrust to get them airborne? Did they run on the ground and use their wings to defy gravity? Did they do it from the trees down, using these wings as a way to manipulate gravity? That’s one of the biggest mysteries.

Another area of uncertainty is which dinosaurs were the closest relatives of birds. The more fossils we find, especially feathered dinosaurs in China and other places, the more it’s clear there was a whole bunch of small dinosaurs with feathers. A lot had wings, some had wings only on arms, some on arms and legs. Some had wings of feathers. Some had wings of skin like a bat.

There was a huge diversity of them right around that point in the family tree where proper modern-style birds evolved with big arm wings that they flap to keep airborne. Each new fossil gives us more information but also another layer of complexity. It makes it just a little trickier to untangle the knot of exactly which dinosaurs were the closest rivals of birds. You still see new discoveries being made every year.

You say in the book that wings evolved not to fly?

The fossils tell us clearly that feathers evolved long before any of these animals were flying. Many dinosaurs had simple feathers; they looked like little strands of hair. In fact most dinosaurs probably had them – they just don’t normally preserve because they decay away so quickly. It’s in spectacular fossil sites where lots of dinosaurs were buried quickly, usually by volcanic eruptions, where you see a lot of these feathers (Liaoning province in north-eastern China is a good example).

But these feathers were not used for flying. There’s clear evidence from the fossil record that feathers evolved in a simpler form for other reasons. Our best hypothesis is they evolved for insulation, to help them stay warm – just like hair in mammals.

Later on, these feathers evolved on some dinosaurs into quills that made up wings. But the fossil record shows that the first wings that show up in dinosaurs between the sizes of sheep and horses. Those wings were only about the size of laptop screens, and by the laws of physics, those could not keep an animal of that size in the air.

That hints that wings probably also evolved for another reason and were only later co-opted for flying. We can tell a lot of these feathers had flamboyant colours and patterns, so one leading idea is that wings first evolved for display, to attract mates; to intimidate rivals. This is still true today, of course.

You can imagine if those wings got bigger over time, more flamboyant, more ornate, at some point the laws of physics would take over and they would generate some of those aerodynamic forces. It’s not like we have fossils of the exact dinosaurs that were the first to flap their wings, but that is at least what the fossil record is telling us.

Did dinosaurs have to get smaller for flying birds to evolve?

This is a big part of the story. Some dinosaurs, such as T.rexes, got bigger over time, but the dinosaurs that evolved into birds had been getting smaller for tens of millions of years. We don’t know why exactly, but there’s all kinds ecological niches where it pays to be small: it’s easier to hide, you can grow more quickly, and so on.

So it seems you had this group, that their bodies were getting smaller, and their wings were getting bigger. At some point you had a wing that was big enough to keep a body that was small enough in the air. At that point, natural selection could take over and start refining these dinosaurs into ever better flyers.

Is it an accident of evolution that flying creatures the size of elephants don’t exist?

Animals that need to flap wings to fly can’t be that big. The biggest flapping flyers today are wandering albatrosses, and their maximum wingspan is about 3.5 metres. We have fossils of birds that were bigger: the Pelagornithids were giant soaring birds that went extinct right before the ice age. They had wingspans that were something like 7 metres long. But beyond that, I think it would be very hard to flap wings to fly.

It makes total sense to me that it was probably a crow-sized to lapdog-sized raptor dinosaur that first started to flap as opposed to some dinosaur the size of an albatross. It’s just that the stereotype of dinosaurs being huge makes it harder to envision some small dinosaurs flapping and flying.

How did birds survive the asteroid?

That was a big mystery for a long time. There were proper birds at least 150 million years ago, which means they lived alongside their dinosaur cousins for some 80 million years. Then the asteroid comes down around 66 million years ago and all the dinosaurs die except the birds – why is that?

The reality is that lots of birds went extinct at the same time as the other dinosaurs. Many birds were still quite primitive and would have looked a lot like their dinosaur cousins. The only ones to survive were very modern-style birds. They had beaks instead of teeth, big wings and large chest muscles, and could grow really quickly like birds today.

A lot of recent research has clarified why they survived. What it comes down to is: the asteroid was a shot out of the darkness of outer space, a six-mile wide rock that smashed into the Earth one day. It changed everything instantaneously. There were earthquakes and tsunamis and wildfires. There was dust blocking out the sun, giving rise to a nuclear-style winter that lasted several years. Natural selection can’t work on that timeframe, so when the asteroid hit, all the animals had to confront the situation with the features they already had.

Most of the dinosaurs were big, and nothing bigger than a husky dog survived on land. With all these fires and acid rain and storms, simply being outside and exposed to the elements would have been bad. If you were smaller you could hide away more easily.

Also, modern-style birds had a bunch of features that turned out to be beneficial. They grew to adult within year, so it didn’t take too long for them to nurture the next generation. They could fly away from danger. But crucially they also had beaks, which could have allowed them to eat seeds.

When the Earth went cold for many years, ecosystems collapsed. Plants did not have sunlight to photosynthesise. So plant-eaters died, which meant meat-eaters died. Seeds were probably the last foods that survived. If you could eat them, it could probably have got you through those lean years.

We have gut content of birds from the Cretaceous period (145 to 66 million years ago) and we can tell a lot of them did eat seeds. So the modern-style birds had a good hand of cards just as the world became this fickle casino and survival was a matter of the odds.

Which bird species appeared after the asteroid?

Bird fossils from the Cretaceous (meaning before the asteroid) are limited because it’s hard to fossilise birds. They’re small and their bones are really delicate. But we do know there’s birds like Vegavis and Asteriornis that lived in that period and were respectively members of the modern groups of ducks and chickens.

It doesn’t mean other modern species like owls or falcons weren’t there, but certainly they were not a major component of the ecosystems at the time. Then the asteroid hit and we start to see in the Paleocene (66 to 55 million years ago) fossils of things like penguins, mouse birds and multiple other modern groups.

Yet the really strong evidence about what happened is from the DNA of modern birds. Researchers are using whole genomes now. They can compare the similarities and back-calculate to predict when two groups would have diverged. When you do this, it predicts there was a big bang of bird evolution right around that time – including species like owls, parakeets, falcons and hawks.

It makes sense that if you have a mass extinction that kills 75% of species, there would have been abundant opportunity for whatever survived. But we’re still waiting for fossils to confirm this directly. It’s a real target for people doing fieldwork to confirm this story by finding the fossils of birds up to 5 to 6 million years after the asteroid.

You write that great birds have come and gone – talk us through some of those

There are more than 10,000 species of birds today, basically double the number of mammal species, so in that sense we’re still in a dinosaur world. But there are even more incredible extinct birds, some of which went extinct quite recently because of us, as we’ve spread around the world and changed the environment very quickly.

A lot of these fantastic birds got their start in the ecological vacuum after the asteroid. There were birds that became basically born-again T.rex and Triceratops – filling the top predator/top plant-eater role in a lot of ecosystems.

In South America were the “terror birds” (Phorusrhacidae). They stood taller than a person, had a head the size of a horse head and a massive hooked gnarly beak. They were the top predators there for tens of millions of years. South America was an island for lot of that time; only later did jaguars and big dogs arrive.

South America’s terror bird, once the apex predator on the continent. Harper Collins, CC BY-SA

In many places, birds were the biggest plant-eaters. Australia had birds called demon ducks (Dromornithidae) that lived for tens of millions of years. Think of the modern duck and super-size it by 100. Some were heavier than cows.

Elsewhere there was New Zealand’s moa and Madagascar’s elephant bird. Elephant birds were maybe the heaviest birds of all time. They laid eggs the size of watermelons. Many of these birds couldn’t fly. They gave up that ability as a trade-off to allow them to become really big.

The Pelagornithids also really fascinate me – the birds that were double the wingspan of an albatross. They lived for tens of millions of years, sailing the world’s thermals like giant kites. They would have been utterly spectacular animals.

Pelagornithids had twice the wingspan of the modern wandering albatross. Harper Collins, CC BY-SA

We only know about most of these birds because of fossils – except for some like the moas and elephant birds and demon ducks, which did meet humans but didn’t last long, unfortunately.

Is it surprising birds never became as intelligent as humans?

When I was growing up in the late 1980s and through the 1990s, it was an insult to say “you’re a bird brain”. It’s such an unfair biological slur, because birds are very smart.

It’s just that they have small brains – I don’t know how many hummingbirds could fit into the head of an elephant. But when it comes to the size of the brain relative to the size of the body, which is largely what matters for cognition, problem-solving and so on, birds are right up there with mammals.

Song birds learn intricate songs. Similar to a human language, they learn them from tutors, they babble when they’re young and make mistakes, then master their avian language later on.

Parrots can mimic human speech. And whereas plenty of animals use tools in a rudimentary way, some crows can make their own tools. It’s really only crows and humans and maybe some close primate relatives that do that. Crows take sticks and branches and twist and turn them. They make hooks out of them and use them to probe for food.

Since the asteroid, there were probably long stretches where it was actually birds that were the cognitive superstars. It was maybe only a few million years ago when some primates eclipsed birds in having the biggest brain relative to body size.

When did birds start singing?

Sound doesn’t fossilise, of course. But we can look at the family tree of modern birds. We can look at the songbird group and use DNA to predict when they would have originated. We can then look at the fossil record of the skeletons of birds, and see if they more or less match up with what the DNA suggests.

This tells us that song birds go back in Australia as long as 50 million years ago. Songbird evolution then probably went into overdrive about 27 million years ago. This was probably triggered by tectonic events such as little microplates, and islands moving around and forming new corridors and environments in South East Asia.

It’s only in the past 20 million years or so where you’ve had songbirds moving around the world. Nowadays, more than half of birds are song birds.

Anything else that is a priority?

The very first birds in the fossil record – proper flapping flight birds like Archaeopteryx – are from about 150 million years ago. Archaeopteryx had big feathered wings that could flap, but also teeth in its jaws, as well as big claws and a long tail. It’s the quintessential evolutionary link in transitional species, and has been known since the 1860s, when Huxley and Darwin wrote about them. Archaeopteryx was integral to their idea that birds evolved from dinosaurs.

We still haven’t discovered anything much older. We have some new fossils from China that are about the same age. Yet these birds must have had ancestors that were a bit more primitive, that could only fly in more of a rudimentary way. That’s one thing we’re waiting for, maybe from the Late Jurassic (162 to 143 million years ago) or even Middle Jurassic (174 to 162 million years). Those fossils would give us proper insight into how flapping flight really originated.

The Story of Birds US edition publishes on April 28, while the UK edition publishes on June 11 and is available for pre-order.

This article features references to books that have been included for editorial reasons, and may contain links to bookshop.org. If you click on one of the links and go on to buy something from bookshop.org The Conversation UK may earn a commission.

To read an extract from the book, click here.

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Fifteen-year-old Evan Budz was on a camping trip when he saw a snapping turtle that would become the impetus for an award-winning invention. As someone who loves hiking, canoeing, and just being outside, the Canadian high school student from Burlington, Ontario, had actively been looking for ways that he could go out and help the planet. 

“My parents brought me up with the sort of principle that every place that I visit, I should leave it a bit better than I found it,” he says. So when Budz noticed the turtle swimming in some nearby waters, he knew that he’d found his next passion project: a bionic robot turtle that could help protect underwater environments. 

How a turtle inspired an award-winning science project

“When I saw the snapping turtle, it was so graceful, fluidic, and generally non-disruptive” to its surroundings, says Budz. “I thought it’d be really interesting to go and try and replicate its natural swimming kinematics [basically the study of how things move]” in a robot.

Along with mimicking the fluid motions of a wild green sea turtle in the water, his autonomous device uses AI to monitor underwater ecosystems for ecological threats, such as invasive species and coral bleaching. 

“Most current underwater technologies can produce things like noise from their propellers or very high-pressure water streams,” which can erode environments, he says. 

However, by mimicking the motions of a sea turtle, Budz’s robot can move through the water innocuously, gathering vital data in a way that doesn’t stress marine life or damage delicate habitats. “I don’t want to harm the various places that I’m hoping to protect.”

High school student Evan Budz works on the flippers for his bionic turtle. Image: Evan Budz How to build a robot turtle

To create his bionic turtle, Budz got to work studying the reptile’s locomotion. He watched videos of sea turtles swimming and talked with experts at his local aquarium, learning how the reptiles use their front flippers to propel themselves forward and their hind limbs for steering. He then used his 3D design and electronics know-how to plan a prototype in SolidWorks, a 3D Computer-Aided Design (CAD) and engineering software. From there, the high school student started creating his robot turtle’s 3D parts. 

The robot has four flippers in total—with the larger front flippers providing its main propulsion and its smaller rear flippers used mainly for stability and changing direction, just like a real turtle. It also has a main acrylic tube “body” for housing its electronic components, which include a Raspberry Pi microcomputer. This runs AI models to detect environmental threats and records and transmits data. In addition, the bionic turtle navigates the water using various sensors. These include a GPS module for position tracking, allowing the robot to follow a predefined grid pattern. 

Budz’s robot also has a front camera for “seeing” its surroundings, along with additional sensors on its exterior to help guide the autonomous reptile, offer depth control, and check for ecological hazards like microplastics and bleached coral. 

Meet the Bionic Underwater Robotic Turtle, aka BURT

While not an official name, Budz has been calling his invention “BURT,” an acronym for “Bionic Underwater Robotic Turtle.” BURT maintains the same body-to-flipper-size proportions as a real-life sea turtle but is smaller overall, which allows it to move easily in different environments. It weighs about 11 pounds, though much of the robot’s weight is just added metal that allows it to sink down. This gives BURT an opportunity to monitor depths well below the water’s surface. 

“To achieve neutral buoyancy in the water,” says Budz, “I needed the turtle to basically be heavier than the force of buoyancy that’s pushing it up.” 

Budz did much of BURT’s testing in his grandparents’ backyard pool. Image: Evan Budz

BURT can swim for up to eight hours per charge on a lithium battery, though it also has a solar panel that can keep it going for even longer periods. Right now, Budz has BURT set up to swim at the typical speed of turtles (approximately 0.5 miles per hour). “If I do want it to swim faster, I can just change the flipper oscillation frequency,” meaning the rate of its flipper strokes. 

Most of BURT’s testing has taken place in Budz’s grandparents’ backyard pool, which has a depth of just over eight feet. 

“I basically went out and created a simulated coral reef setup using 3D models,” he says, programming the turtle to understand what coral bleaching and invasive species actually look like. “And the turtle then swims around them to simulate what it would do in a real-world environment.” 

BURT is also set up to follow a predetermined search pattern, “so there’s no need for any sort of tether like you might find on a traditional underwater drone.” The bionic turtle scans its surrounding waters through its front-mounted camera, with all of the recorded data then feeding back into its Raspberry Pi microcomputer. According to the Budz’s testing, BURT has been able to detect replicated coral bleaching with 96 percent accuracy.

Budz tested BURT in Lake Ontario. Image: Evan Budz BURT, the robot turtle, keeps getting smarter

Budz’s next step is to bring BURT into different environments to see how deep the robot can actually go. To deal with especially murky waters, he has installed lights on the front of the robot and added an ultrasonic transducer, which utilizes high-frequency sound waves to detect potential obstacles. 

This year he’s even developed a new holographic imaging device, which he’s using to record the structural characteristics and shapes of tiny particles in waterways. He then uses a custom-trained neural network, which processes data in a way that’s similar to a human brain, to classify if each particle is a microplastic. 

Although Budz built his robot as a labor of love, it’s since won some major awards, including first prize at the European Union Contest for Young Scientists, held in Latvia in 2025, and the Canada-Wide Science Fair, an annual science fair in which finalists qualify from approximately 25,000 competitors. 

Budz’s goal is to have a fleet of these sea turtles that can be set out to detect ecological threats. “I’ve already looked at coral bleaching, invasive species, and microplastics,” he says, “but there are so many different places where this can be used.”

In The Workshop, Popular Science highlights the ingenious, delightful, and often surprising projects people build in their spare time. If you or someone you know is working on a hobbyist project that fits the bill, we’d love to hear about it—fill out this form to tell us more.

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A life-long car lover recreated the Griswold’s famous station wagon

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Regular coffee drinkers know there is a big difference between a brew’s aroma and its taste. A cup may smell warm and full-bodied only to leave you with a lingering bitterness behind the first sip. Researchers have long known a coffee’s potentially acrid flavor profile is dictated at a molecular level thanks to your tongue’s taste receptors, but how that occurs has remained a mystery. Now, a team at the University of North Carolina at Chapel Hill has the answer thanks to precise imaging technology—and their findings may have much wider ramifications beyond the coffee pot.

The details were published in the journal Nature Structure & Molecular Biology, and focuses on TAS2R43, one of our 26 different bitter taste receptors. These mechanisms are expressed throughout the human body, and likely evolved to guard the species against toxic substances as well as helping regulate our metabolisms.

“Bitter taste receptors are thought to be important for detecting toxins, pathogens, and harmful bacteria in the airways, gut, skin, and organs, initiating immune responses, clearing pathogens, regulating immune cells, influencing hormone secretion, and aiding digestion,” explained study co-author and molecular biologist Bryan Roth.

Scientists first determined the microscopic structure of TAS2R43 a few years ago, but until Roth’s team, no one had analyzed how it responds to bitter compounds. To accomplish this, researchers relied on a technique called cryogenic electron microscopy (cryo-EM). This method involves flash-freezing biological molecules, then employing electrons to generate highly detailed 3D images of their overall shape. Roth and his colleagues recorded how TAS2R43 receptors responded to coffee’s bitter elements including caffeine and mozambioside, then compared those to the reaction of other receptors.

“In this work, we solved the structures of TAS2R43 bound to bitter compounds and showed, in molecular detail, how this receptor detects bitter molecules,” said molecular biologist and study co-author Yoojoong Kim.

Researchers now have a molecular framework for creating future compounds that intentionally control how someone experiences bitterness in drugs or foods. Aside from finally understanding how taste receptors like TAS2R43 physically respond to bitter molecules, the discoveries could also help develop new medical treatments. 

“In the long term, this could help guide the development of new therapeutic strategies for diseases involving airway defense, gut function, inflammation, or host responses to microbes,” Kim added.

The post Why coffee tastes bitter, according to molecular biology appeared first on Popular Science.