Popular Science

The entire field of archaeology hinges on what can withstand the test of time. This typically means that most excavations center on hard evidence including structural remains, pottery, weapons, or metalwork. Occasionally, researchers discover something softer that’s been preserved for thousands of years despite the odds. In Switzerland, archaeologists recently identified what may be an especially rare find. While clearing the grounds of an upcoming residential development about 20 miles northeast of Zurich, specialists at the Aargau Cantonal Archaeology service found what they believe is a chunk of charred, 2000-year-old Roman bread.

The “alleged pastry” described in an online post from the Aargau Cantonal Department of Education is approximately four inches wide and 1.2 inches thick and likely a type of flatbread. Researchers spotted the burnt morsel in August 2025 while combing through a 43,000-square-foot area near the Roman site of Vindonissa. Known for its strategic position along major river routes, Vindonissa began as an outpost for Roman legion soldiers in what was once the empire’s northern frontier.

Archaeologists needed to carefully excavate the bread within surrounding earth before transporting it to a lab. Credit: Canton of Aargau KAA 6

However, archaeologists have questioned the settlement’s origins for decades. Until the latest excavations, it was unclear when Vindonissa expanded from a temporary encampment into a full-fledged and permanent military fortification. Based on the latest findings, it seems Rome’s presence in the area solidified earlier than previously believed. An exact date remains unclear, but military legions certainly operated a well-stocked and furnished hub well before the first century CE.

Rarities like this preserved bread are exceptionally unique artifacts. Food and other organic materials generally decays extremely quickly, unless they are preserved under intense circumstances. The most common examples occur thanks to sudden carbonization—a process that only happens in disastrous situations like the volcanic destruction of Pompeii in 79 CE. Until they conduct a laboratory analysis, archaeologists won’t be able to provide a confident theory of how the Roman flatbread has survived for thousands of years. That said, its charred condition certainly suggests some kind of kitchen mishap.

Regardless, the new information gleaned from Vindonissa will help experts better understand more than simply when Rome extended its reach into present-day Switzerland. Rare finds like the ancient bread also contextualize and humanize history—while reminding us that humans have always loved our bread.

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For humans, humidity often makes us cranky, sweaty, and downright uncomfortable. For sweat bees, humidity changes their already vibrant colors. According to research recently published in the journal Biology Letters, moisture in the air makes the bees go from blue to green. 

“When people think of bees, they often picture drab, brown honey bees,” Dr. Madeleine Ostwald, a study co-author and behavioral ecologist at Queen Mary University of London, said in a statement. “In reality, bees are incredibly diverse and colourful—and we’re only just starting to understand how their appearance reflects the climate they live in.”

A sweat bee in the wild. Image: Photo ©Jeremiah Bender.

Insects use color to help control their body temperature, communicate, camouflage, and more. However, it’s still unknown how color shifts affect their behavior or ability to survive in the wild.  There are nearly 4,500 known sweat bee species. These largely harmless bees are native to North America, but can be found on every continent except Antarctica. The name “sweat bee” comes from their supposed attraction to human sweat. As far as appearances, sweat bees are known for their bright, metallic green and blue hues that anecdotal evidence suggests change color from time to time. This study provides the first experimental proof of their chameleon-esque capabilities. 

For this study, the team looked at the fine-striped sweat bee (Agapostemon subtilior), a species found in North America. They placed the bees in dry air, where they appeared a deep blue color. When the humidity increased, they changed into a more copper-green. Once the air dried out again, they returned to their original blue.

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In most animals, color comes from pigments. Instead of pigments, sweat bees get their color from microscopic structures on their bodies that scatter and reflect light at particular wavelengths. This same wavelength warping effect creates the iridescent feathers of hummingbirds and cuttlefish’s shifting scales.

These tiny structures also swell slightly when exposed to moisture in some animals. The swelling makes them reflect more red colors. A similar process may be happening in bees—even if they are not turning red—but more work is needed to fully understand what’s going on behind the scenes. 

The team also compared the color changes in the lab with those in the wild. They analyzed hundreds of photos posted to iNaturalist, comparing the sweat bee’s color with local humidity levels. The bees in drier areas tended to appear more blue, matching what they observed in the lab. 

A single museum specimen (about 1 centimeter long) from the experiment,changing color as it goes from blue in dry air (left) to green in humid air (right). Most of the change happened in the first 24 hours. Image: Photograph by Leslie Cervantes Rivera.

Surprisingly, the older museum specimens they also analyzed showed the strongest color changes. This could be because the bees’ outer shells slowly degrade over time, allowing moisture to get in more easily.

According to the team, these findings suggest that color changing may be common among bees. The insects already display a wide range of shimmering colours and live in environments ranging from dry deserts to moist rainforests.

“Most people associate colour‑change with animals like chameleons that actively control it. These bees aren’t choosing to change colour—it’s happening passively, simply in response to the humidity around them,” said Ostwald. “That adds a whole new layer of mystery to why these colours evolved in the first place.”

The post Humidity makes these bees go from blue to green appeared first on Popular Science.

Yellowstone National Park doesn’t just sit on a volcano—it is a volcano. Underneath the park, red-hot magma reservoirs flow, superheating hot springs and geysers like Old Faithful. This vast volcanic system is known as the Yellowstone Caldera, and with one blast it could plunge the world into chaos. 

About two million years ago, as sabertooth tigers and mastodons roamed the future United States, Yellowstone was a powder keg. Large amounts of hot magma accumulated beneath the Earth’s crust, building pressure and volcanic gases that triggered a major eruption. It was among the largest volcanic eruptions in our planet’s history, blanketing large parts of North America with ash. 

Since then, Yellowstone has seen two more major volcanic eruptions and many smaller ones—earning the name “supervolcano.” The three “super” explosions carved out giant craters (or calderas), which contain much of the park and give the Yellowstone Caldera its name. 

Though Yellowstone hasn’t had a supereruption in millennia, it’s impossible not to wonder: Will Yellowstone’s so-called supervolcano ever explode again? 

Yellowstone’s supervolcano isn’t erupting anytime soon—we think

Experts studying the Yellowstone volcano say it probably will erupt again—it’s just a matter of time, a lot of time. A major Yellowstone eruption likely won’t happen for thousands, and potentially millions, of years.  

Scientists say that the magma underneath Yellowstone is mostly solid and not eruptible. One study that identified magma hotspots underneath the Yellowstone Caldera suggests the magma is more concentrated underneath the northeast section, and that magma is shifting in that direction. 

It’s possible that Yellowstone’s magma, as it draws heat from Earth’s mantle and potentially concentrates in the northeast, may one day become liquid enough to erupt. But Poland says the shifting magma could also lose heat and stall as it hits thick, continental rock within the Earth’s crust. 

“We know there’s a magma chamber beneath Yellowstone,” Michael Poland, the scientist-in-charge of the Yellowstone Volcano Observatory, tells Popular Science. “But we know that it’s mostly solid, so it’s not really capable of feeding a large eruption. It’s like the odds of being struck by lightning are one in a million, but if you’re standing in a field, not a cloud in the sky, the odds you’re going to be struck in the next five minutes are basically zero.”

Yellowstone might see other volcanic activity sooner

The next volcanic incident in the Yellowstone Caldera likely won’t be a volcanic explosion. A powerful hydrothermal eruption from a geyser, activity that can create impressive craters but has limited impact outside the park, is more likely. 

Named in 1870, Old Faithful is one of the most famous geysers in Yellowstone National Park due to its frequent and consistent hydrothermal explosions. Image: Photography by Deb Snelson / Getty Images Deb Snelson

Another possibility is a lava flow, which occurs when slow-moving, thick lava erupts and forms rock piles that creep across the landscape over months or years.  

The Caldera has already caused a massive bulge in the ground the size of 279 football fields, but Poland says that change isn’t surprising due to the magma flowing beneath the park. 

The term supervolcano can be misleading

Poland isn’t a big fan of the term “supervolcano,” which refers to volcanic systems that have experienced eruptions emitting more than 1,000 cubic kilometers of magma, ash, and other volcanic deposits. 

Poland says using the term “supervolcano” for Yellowstone can be misleading, because it implies the system experiences only supereruptions, when lava flow eruptions are far more common. Still, the last lava flow incident was about 70,000 years ago.

These days, Poland worries more about hazards from hydrothermal eruptions or earthquakes, many unrelated to volcanic activity, in the park. 

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At the Yellowstone Volcano Observatory, a consortium of scientists from the U.S. Geological Survey, the National Park Service, and several universities constantly monitor the Yellowstone volcanic system. They tap into a network of seismic stations, which measure earthquake activity, and steam gauging stations, which monitor volcanic heat release.

If Yellowstone’s volcano were to erupt, scientists at the observatory would likely know weeks to months beforehand. As of now, it looks like we’re safe—though experts like Poland are keeping a close watch. 

But what if Yellowstone’s supervolcano did erupt?

Poland says the chances of a major eruption in the Yellowstone Caldera within the human timeline are as close to zero as it gets. But what if Yellowstone did erupt while billions of humans still walked this planet?

Yellowstone National Park covers nearly 3,500 square miles, mostly in Wyoming. Every year, the national park welcomes roughly 5 million visitors. 

If the supervolcano erupted tomorrow, it would happen like this: hot magma would have already accumulated in the Earth’s mantle, building more and more pressure—until cracks formed in the Earth’s crust. Then, magma would finally burst forth in a massive explosion. 

Upon eruption, the immediate radius, including parts of Montana, Wyoming, and Idaho, would be swept clean—as huge eruption columns, pillars of superheated volcanic ash and gas, collapse under their own weight and incinerate the land. 

These avalanches of ash, gas, and rock, known as pyroclastic flows, would wipe out trees, homes, and infrastructure in their path. Any remaining ash would settle over the landscape. 

Using models, scientists at the Yellowstone Volcano Observatory predict that a supereruption would drop thousands of feet of ash within the park radius, and coat communities stretching from Missoula, Montana, to Albuquerque, New Mexico. 

In April 1815, Mount Tambora erupted on Sumbawa Island in present-day Indonesia. The event was the largest volcanic eruption in human history, and plunged the world into a prolonged period of frigid temperatures. Image: mikroman6 / Getty Images mikroman6 The explosion heard around the world

Poland says that a Yellowstone supereruption would drop at least a few millimeters of ash over much of the U.S. and parts of Canada, devastating agriculture, water supplies, and electrical grids. Huge amounts of ash and gas launched into the stratosphere would act as aerosols, blocking sunlight and plunging the Earth into a long period of cold and dark. 

A common example cited by volcanologists modeling the global impact of large volcanic eruptions is the 1815 Mount Tambora eruption in present-day Indonesia. Widely considered the largest eruption in recorded human history, this catastrophic explosion claimed tens of thousands of lives and plunged Earth into the “Year Without Summer”—a prolonged period of low temperatures that ravaged crops and caused widespread famine and disease epidemics around the world.

Based on evidence from past volcanic eruptions and climate models, Poland says scientists believe the effects of a supereruption like Yellowstone could last five to 10 years—though he is confident that Earth would recover. 

“A lot of people would die, but it would not wipe out humanity,” Poland says. “No explosive volcanic eruption has ever been associated with a mass extinction on Earth. We’d make it, but it definitely wouldn’t be fun.”

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 What would happen if Yellowstone’s ‘supervolcano’ erupted today? appeared first on Popular Science.

The fashion industry is ecologically tacky, to put it mildly. Textile manufacturers guzzle around 200 million liters of water every year, while animal leather generates its own immense environmental burdens. But out of everything we wear on any given day, shoes are some of the most unsustainable accessories. As much as 95 percent of all footwear ends up in landfills, where all that rubber, plastic, and foam takes generations to decompose.

While there is no easy recipe for crafting a greener shoe, researchers at Belgium’s Vrije Universiteit Brussel (VUB) hope to find a solution in fungi. Together with La Monnaie/De Munt opera house’s head shoemaker, Marie De Ryck, the team unveiled a new experiment ahead of Milan Design Week: the world’s first boot crafted entirely from mycelium.

Fungi is most recognizable above ground in the form of spongy mushrooms, but they’re only a fraction of the organisms’ larger story. Below the soil, fungi are frequently connected by miles of fibrous webs of mycelium. These networks transport vital environmental information between fungi on precipitation, soil health, sunlight access, and more. The communications are so detailed that many mycologists consider these webs a form of intelligence.

Fungi and their mycelial networks are now being applied in some exciting spaces, including organic computing and even mushroom-powered toilets. But according to VUB microbiologists, those fungal roots can also be engineered to form every necessary component in a shoe. This goes beyond previous experiments that utilized mushrooms only for surface materials or leather substitutes.

There is a reason such a project hasn’t succeeded in the past—mycelium simply isn’t easy to utilize. It took over two years of trial-and-error to find a balance between natural growth and resilience. Ultimately, the biggest issue was figuring out a way to take mycelia grown as flat sheets and transform them into a three-dimensional, supportive sole of a shoe. In the end, designers settled on two types of fungi—one to supply the foamlike, malleable sole, and another for the shoe’s leathery upper section.

“This is a conceptual object intended to frame what is currently possible with the material,” VUB designer Lars Dittrich explained in a statement. “It reflects…addressing how we grow and craft this material, made from a microorganism, into a functional three-dimensional form.”

“While the initial material samples posed a real challenge and did not immediately meet the technical requirements of a complex shoe construction, the progress we have made is truly inspiring,” added De Ryck.

While the early prototype may not exactly be ready for a haute couture runway show, it’s a certainly promising step forward towards truly sustainable footwear.

The post This shoe is made entirely from mushroom ‘brains’ appeared first on Popular Science.

In the latest episode of old museum collections revealing new discoveries, two researchers in Australia have solved a paleontological mystery with an Ice Age fossil first discovered over  100 years ago.

The fossil was found in  the underground Foul Air Cave in Buchan, Victoria, Australia. It’s the partial skull of an Owen’s giant echidna (Megalibgwilia owenii), a now-extinct giant echidna that weighed 33.1 pounds and grew up to 3.3 feet-long. The genus name, Megalibgwilia, consists of “mega” (great or mighty in Ancient Greek) and “libgwil” (the Wemba Wemba word for echidna). 

“The apparent absence of the extinct large-bodied Owen’s Giant Echidna Megalibgwilia owenii from Victoria is unusual in light of its wide distribution across the continent’s southeast including Tasmania,” the researchers write in a paper recently published in the journal Alcheringa: An Australasian Journal of Palaeontology. “It is the first example of Megalibgwilia identified from Victoria, and reconciles the taxon’s otherwise disjunct southern distribution across mainland Australia.”

Though the fossil was retrieved from a cave in Buchan, researchers identified it in Museums Victoria’s Palaeontology Collection. Tim Ziegler—collection manager of vertebrate palaeontology at Museums Victoria Research Institute—initially spotted it in 2021, and found it came from a 1907 expedition by Frank Spry, a naturalist and museum officer. 

The Megalibgwilia owenii fossil. Image: Museums Victoria

“Museum collections preserve the link between science, heritage and people,” Ziegler, lead author of the study, said in a statement. “Over a century ago, Spry along with scientists and locals investigated Buchan’s caves with little more than ropes and kerosene lamps, and they inspired us to carry on their work.”

Ziegler and his co-author Jeremy Lockett, a Deakin University vertebrate palaeontology student, investigated modern and fossil echidnas in other Australian museum collections, presumably comparing them to the one from the Museums Victoria. Its characteristic straight-beaked snout, with which it would have crushed big insects and dug into Ice Age Australian soils, verified it to be an Owen’s giant echidna.

“Previous research by Museums Victoria has shown the Buchan Caves preserve an exceptional record of Australia’s unique megafauna,” Ziegler said. “The next amazing discovery could come from inside the museum, from continued fieldwork, or the keen eyes of a citizen scientist.”

Today, echidnas are egg-laying, spiky-looking, long-nosed mammals that live in places including Australia and Indonesia. They grow 14 to 30 inches long, weigh 5.5 to 22 pounds, and are endangered. And sometimes, these hedgehog-like creatures end up in shark vomit. 

The post New megafauna looked like spiky, 30-pound hamster appeared first on Popular Science.

Who doesn’t love a brownie? It’s the ultimate comfort food—beloved around the world and even beyond it. Astronauts aboard the International Space Station have brownies on their menu too.

But what makes a perfect brownie? That depends on who you ask. Some like a light, cake-like crumb. Others want a dense, fudgy center or a chewy bite. 

To tailor your brownies to your taste, you need to understand the science behind them. “Each ingredient has a specific role, and the ratios between them determine whether the brownie turns out fudgy, cakey, or chewy,” explains Dr. Lesa Tran, a chemistry professor at Rice University. 

What each ingredient really does Flour

Flour is the backbone of your brownie. When mixed with water, its proteins (gliadin and glutenin) link up to form gluten, a network that gives structure, explains Tran.

The more flour you add—and the more you mix it—the stronger that network becomes. The result? A lighter, more cake-like texture. Use less flour and mix minimally, and you’ll keep your brownies dense and fudgy.

Sugar

Sugar does far more than sweeten.

In the oven, it breaks down (or “caramelizes”) and reacts with proteins, a process known as the Maillard reaction. These processes create deep, complex flavors and aromas, says Tran. 

Sugar also locks in moisture by binding to water, keeping brownies soft.

And that shiny, crackly crust? That’s sugar too. In the oven, sugar dissolved in the brownie mixture rises to the surface and re-forms into crystals, which create that signature crust, explains Tran.

If you use less flour in your brownie batter, you’ll end up with fudgier brownies. Image: Getty Images / Mint Images

For chewier brownies, use more brown than white sugar, Tran suggests. This adds more chew because it has more molasses (thick, dark brown syrup obtained from sugar beet and sugar cane plants).

If you want to cut back on sugar without sacrificing taste and texture, try using a finer sugar like caster sugar instead of granulated sugar. Scientists studied the effect of different sugar particle sizes on chocolate brownies and found that brownies made with smaller sugar particles tasted sweeter, and were also softer and moister than those made with larger sugar crystals. So if you want a fudgy brownie with less sugar, go for caster sugar.

Fat

Should you use butter or oil? Science has the answer.

A study comparing butter to nut oils (like almond, pistachio, or walnut oil) found that, compared to butter-based brownies, oil-based versions are softer, more elastic, and moister—and often preferred in taste tests. They’re also higher in heart-healthy unsaturated fats, and lower in unhealthy, saturated fat.

Whether you use butter or oil, more fat means a richer, fudgier brownie, says Tran.

Eggs

Eggs pull double duty, adding structure and richness. Like flour, they contain proteins that set when heated, giving structure to the brownie, explains Tran. 

Egg yolks also contribute fat, making brownies richer and fudgier.

“Adding more egg whites provides more proteins to create a lighter, cakier texture,” says Tran, “while more egg yolks provide more fat to give a richer, denser result.”

Chocolate

What’s best: melted chocolate or cocoa powder? It depends on what texture you’re after. 

Melted chocolate contains cocoa butter, which solidifies as it cools—giving brownies a dense, fudgy bite. Cocoa powder, with less fat, produces a lighter, drier crumb.

If you use cocoa powder, choose wisely: natural cocoa is more acidic and sharp in flavor, while Dutch-processed cocoa, which is chemically treated to reduce its acidity, is smoother and mellower, says Tran.

Some people like to add chocolate chips to their brownies. The chips’ fat-crystal structure helps them hold their shape somewhat so you get little melty pockets inside the brownie, similar to what happens in chocolate chip cookies.

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Salt

A pinch of salt doesn’t make brownies salty—it actually makes them taste sweeter by helping your taste receptors detect sugar more effectively.

Leavening agent

Baking soda or powder introduces air into the brownie batter, creating lift and a cakier texture, says Tran. Skip them entirely if you want dense, fudgy brownies. 

Science-backed baking tips

The kind of baking pan you use matters. Metal pans heat quickly, resulting in faster bake times and firmer brownie edges, says Tran. Glass and ceramic conduct heat more slowly and retain heat longer, which can lead to uneven baking.

How long you leave the brownies in the oven also affects the end result. Brownies continue to cook when removed from the oven—a phenomenon known as carry-over cooking—because of the heat held within the food itself. 

“For a fudgy center, remove them when a toothpick inserted into the center of the brownie comes out with a few moist crumbs,” says Tran. “For a cakier center, remove them when a toothpick comes out clean.”

The bottom line

To create your perfect brownies, follow one of these formulas: 

• Fudgy: less flour, more fat, more egg yolks, use melted chocolate, no leavening agents. Mix lightly and slightly underbake.
• Cakey: more flour, less fat, more egg whites, use cocoa powder, plus a leavening agent. Bake until fully set.
• Chewy: don’t skimp on sugar (brown not white!) and fat.

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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