In Hawaii, ocean trash — including old fishing nets — is being recycled to cover roads. The process is experimental, but it shows promise as a way to deal with a growing pollutant: plastic.

Paving with plastic is being done elsewhere, such as Missouri and Texas. But Hawaii is the first state to try adding marine debris. Its islands currently face a unique exposure to trashed plastic. It comes from discarded fishing gear, but also tourist wastes. There’s even some plastic released from the Great Pacific Garbage Patch. 

So far, people have pulled 90 metric tons (roughly 200,000 pounds) of plastic trash from the Pacific Ocean. More than one metric ton (2,200 pounds) of fishing nets alone have been used in paving Hawaiian roads.

One key question is whether the pavement’s wear and tear might shed microplastics — tiny bits of this embedded trash.

“We’re extremely concerned about the shedding of plastics or other chemicals into the environment,” says Jennifer Lynch. This can expose people and animals to toxic plastic additives. Lynch is a chemist. She heads the Center for Marine Debris Research at Hawaii Pacific University in Honolulu.

Her team shared its findings March 22 at the American Chemical Society (ACS) meeting in Atlanta, Ga.

Plastic for pavement

Lynch’s center runs a Nets-to-Roads program. Researchers collect and sort plastic and other marine debris gathered from beaches. Then they pick out waste made with polyethylene (Pah-lee-ETH-ih-leen). It’s a durable plastic found in such things as milk jugs, yogurt containers and fishing nets.

The Hawaii team sends the waste and nets to the U.S. mainland. There they get shredded and ground up. Then the materials come back to Hawaii. At a facility on the island of Oahu, they’re mixed with other ingredients to make asphalt. That’s the black, gooey stuff made from petroleum that’s often used to pave roads.

Once loaded onto trucks, this hot mix was used to cover stretches of road on the southwestern side of the island, Lynch says.

Three experimental strips went down in 2022. One had a section of traditional asphalt mixed with a rubber called styrene-butadiene-styrene. That rubber adds durability and flexibility. Ground marine waste and the rubber were added to a second batch. A third contained the marine waste and asphalt but no rubber.

Eleven months later, researchers collected road samples. They wanted to test it for escaping microplastics before taking the project to more roads, Lynch explains. They exposed the samples to conditions that mimic what might release microplastics. For example, they modeled stormwater running off a road or gravelly dust being swept from the road by traffic.

Water and dust from pavement with ocean trash contained amounts of microplastics similar to what was seen from samples of the asphalt with no plastic, says Jeremy Axworthy. He’s a marine biologist who worked on the program. He presented the team’s results at the ACS meeting.

Road recipes

Phase two of this program launched in 2024. It tested five types of pavement, including combos with and without rubber and plastic. Some contained ground-up fishing nets. Others contained other plastic trash. Data on which performed best should be available soon.

Bill Buttlar directs the Mizzou Asphalt Pavement and Innovation Lab. It’s at the University of Missouri in Columbia. He’s impressed with the program. Still, he notes that Hawaii’s roads face different challenges than those on the U.S. mainland. Hawaii’s tropical climate brings heavy rains. And volcanic activity there causes the ground to constantly shift, which can crack roads. “The main challenge to scaling this is getting the recipe right,” Buttlar says. “What works in Hawaii may be a little different than what works in the [U.S.] Midwest.”

As a species, humans like it cold.

Even now, we live in an “ice age.” Though the term may bring to mind saber-toothed cats and woolly mammoths, such ages are defined by ice caps at the poles. And for most of its 4.6-billion-year history, our planet was too warm — sometimes far too warm — for polar ice.

For more eons than not, Earth has ranged from steamy to downright hellish.

A look back at Earth’s history shows us how fragile and fleeting our current moment is. Between its fiery infancy and its (for now) chilly present, Earth’s climate has taken many forms.

Learning why Earth’s climate changed in the past — and what happened to life when it did — can help us understand where we are today. We know our species evolved in the cold. Yet human-caused warming has set our planet onto a hot new path.

What can the past teach us about where we might be headed?

Hadean Eon: Hell on Earth

Earth’s turbulent infancy began some 4.6 billion years ago. Clumps of material formed out of the disk of hot dust and gas that swirled around the young sun.

About 100 million years later, a Mars-sized rock called Theia smacked into the young Earth. That run-in released the energy equivalent of trillions of hydrogen bombs. It was enough “to pretty much vaporize most of Theia and melt what becomes the Earth,” says Norman Sleep. He’s a planetary scientist at Stanford University in California.

That collision left the planet a hellish ocean of magma beneath a sky of rock vapor. Weak sunlight beat down on a cracked crust of black-gray basalt. In the sky hung a second ball of glowing magma: the moon. This orb had formed from the impact debris, maybe in just a few hours.

This was the Hadean Eon — the hottest Earth has ever been. Over the next 1,000 years, Earth cooled somewhat. Rock vapor in the atmosphere would have condensed and fallen — think showers of lava or perhaps flakes of rocky snow.

The magma ocean solidified more slowly. The young moon heated Earth via the force of its gravity. This kneaded Earth’s interior and kept the planet molten for perhaps tens of millions of years.

Finally, that magma ocean crystallized into rock.

This marked a turning point for our planet, Sleep says. The sun became its most important source of energy. Ever since, Earth’s climate has been driven by how much solar energy it gets, reflects and retains.

Archean Eon: Earth’s thermostat turns on

The Archean Eon stretched from 4 billion to 2.5 billion years ago. It began when Earth’s surface cooled enough to form solid rock. Back then, the young sun was only about 70 to 80 percent as bright as it is today. Its energy alone would not have been enough to keep the planet as warm as it was.

In theory, Earth should have cooled enough to ice over. But it didn’t. Why?

As the Earth cooled, it produced a thick, steamy atmosphere. Water vapor fell as rain. A lot of rain. It poured until Earth’s surface drowned beneath a global ocean once more — this time, of water.

The cooling planet also released greenhouse gases such as carbon dioxide (CO₂) and methane. These acted like a blanket to trap heat around Earth. “There was a bigger greenhouse effect” than today, says David Catling. A planetary scientist, he works at the University of Washington in Seattle.

At around the same time, another major change kicked in: the carbon cycle. This acts as the planet’s natural thermostat.

Here’s how it works. Through the greenhouse effect, CO₂ in the atmosphere warms Earth’s surface. A process called chemical weathering traps some of that CO₂ in minerals called carbonates. They can stay trapped in rocks for a long time. Over hundreds of thousands of years, however, the movements of Earth’s tectonic plates recycle Earth’s surface into its interior.

In Earth’s mantle, the carbonates break down. Their carbon then gets belched back up by volcanoes as CO₂. Back in the air, it once again warms the planet.

This cycle is sensitive to temperature: Chemical weathering speeds up in warm climates and slows in cold ones. The overall effect helps keep temps fairly stable.

By the early Archean, the carbon cycle had locked away enough CO₂ to bring temps into a range habitable for life. Modeling studies suggest the planet ranged between a frosty zero degrees and a toasty 40° Celsius (32° to 104° Fahrenheit). In fact, the earliest signs of life date to this period.

Snowball Earth: A deep freeze

Between 2.4 billion and 2.1 billion years ago, Earth froze over. Thick sheets of ice encased the planet from pole to equator. Temperatures may have plummeted to as low as -50 °C (-58 °F) and stayed low for tens of millions of years.

This deep freeze was one of several icy episodes called Snowball Earths. They bookend the otherwise toasty Proterozoic (PRO-tur-eh-ZOH-ik) Eon. It stretched from 2.5 billion to 541 million years ago.

The ice sheets grew through a runaway feedback loop. Sparkling white ice reflects more sunlight than does land or water. That lowers temperatures, which encourages even more ice to form. Once polar ice creeps past a latitude of about 30° North or South, the planet will become a snowball.

“Once you reach that tipping point in the area of sea ice, then it takes on the order of 200 or 300 years to reach the fully [iced-over] state,” says field geologist Paul Hoffman of the University of Victoria in Canada. “That’s pretty quick on a geological time scale.”

Glacial rock deposits that formed at the equator are evidence that the Snowballs happened. But how they started remains a mystery. One theory blames biology.

Clues from ancient rocks suggest the Proterozoic oceans bloomed with photosynthetic organisms. They would have released lots of oxygen into the air. Oxygen breaks down methane. So it ate away the methane blanket that had kept Earth warm for 1.5 billion years.

The carbon cycle wouldn’t have been able to keep up, Catling says. Eventually, “you could grow ice sheets and make a Snowball Earth.”

Earth’s thermostat won’t let a Snowball go on forever. As the land freezes over, chemical weathering shuts down. But volcanoes don’t. They keep pumping CO₂ into the atmosphere. Eventually, the greenhouse effect will thaw out the planet. As that ice melts, the planet will reflect less sunlight. The bonus energy will warm the planet even more. Suddenly, the ice retreats.

Permian Period: Warming and mass extinction

Today, ice persists at Earth’s poles. These “icehouse” periods are few and far between in Earth’s history.

The last one was in the early Permian Period. This was about 300 million years ago. The average temperature was probably 15 degrees C (27 degrees F) cooler than today. Earth might have looked a bit like it did 20,000 years ago. That’s when woolly mammoths roamed Europe.

This cold spell lasted for 105 million years. Then climate change transformed the land into a scorched — and possibly toxic — wasteland.

Over some 20 million years, things started getting less friendly to life, says Neil Tabor. He’s a geologist at Southern Methodist University in Dallas, Texas. Why? In part this was thanks to the assembly of the supercontinent Pangaea. As more land crammed together, coastlines shrunk and sea levels dropped. Coastal areas dried out, and throughout the parched continental interior, temperatures swung wildly.

Then huge volcanoes in what’s now Siberia started erupting. They didn’t stop for 1 million years.

Over that time, they spewed enough lava to bury an area as large as the continental United States under 50 meters (160 feet) of molten rock! With all that lava came lots and lots more CO₂. And that made surface temperatures soar.

In a geologic blink — perhaps as quickly as 60,000 years — average temps jumped as much as 10 degrees C (18 degrees F), reaching around 30 °C (90 °F). Oceans sweltered and grew too sluggish to circulate oxygen. Much marine life suffocated.

Bacteria that thrived in the oxygen-deprived depths poisoned the water with hydrogen sulfide. That deadly gas might have bubbled up to poison the land, too. Volcanic gas mixed with water to rain acid on the barren, dusty wastes.

On land, there were “toxic, salty, shallow acid lakes,” says Kathleen Benison. “And lots of windblown, red dust.” A geologist, Benison studies the Permian climate. She works at West Virginia University in Morgantown.

Near the end of the Permian, some 252 million years ago, Pangaea was a sunbaked, dusty wasteland. Daytime air temperatures in the tropics hovered around 50 °C (122 °F). On the hottest days, they climbed to 73 °C (163 °F) — hot enough to destroy proteins. Any living thing that couldn’t flee to the poles would have been cooked alive.

The resulting mass extinction was the worst our planet has ever seen. In a few hundred thousand years, 70 percent of species on land disappeared. The seas were hit even harder: 95 percent of marine species died out.

It may have taken millions of years for life to recover.

The Permian offers a cautionary tale for our current moment.

“We’re still technically in an icehouse, but we’re rapidly going towards a greenhouse,” Benison says. “Looking back at the [end of the Permian] is a good way to try to say what happens with these big changes. And not just what happens with climate, but what happens to life.”

Cretaceous Period: Gradual heat

A greenhouse doesn’t always lead to mass extinctions, though. By 90 million years ago in the Cretaceous Period, the planet was a lush jungle world. Vast swaths of the continents were flooded by shallow seas. In some areas, carnivorous dinosaurs like Spinosaurus prowled the shores. At 36 °C (97 °F), Earth’s average surface temps hovered around human body temperature. Even polar seawater was a soupy 27 °C (81 °F).

Despite that, this period saw “no mass extinction,” says Brian Huber. He’s a geologist at the Smithsonian National Museum of Natural History in Washington, D.C.

Huber was part of a team that charted Earth’s surface temps for the last 485 million years. This timeline revealed a super-hot greenhouse environment. In fact, it was the hottest Earth has ever been since the evolution of any life more complex than a microbe.

Scientists aren’t sure what drove temperatures so high. But it’s clear that the rise was fairly gradual.

There was no 10-degree jump like the one that rocked the Permian. Instead, Earth had been hot for a long time. In fact, it never really cooled down after the Permian extinction. Average surface temps worldwide mostly stayed above 20 °C (68 °F). (For comparison, that’s just 5 degrees C [9 degrees F] hotter than it was in 2024.) And the poles were largely ice-free throughout the dinosaurs’ nearly 180-million-year reign.

So perhaps the Permian extinction was so massive because of the swing from icehouse to greenhouse. An abrupt change may have put ecosystems under additional stress. That would be bad news, considering what’s happening today.

What’s next for Earth’s climate?

Following a 50-million-year cooling, we’re now in an icehouse period.

The time 55 million years ago was known as the Paleocene-Eocene Thermal Maximum, or PETM. It was the hottest period in the history of our Earth — that planet with the continents and ecosystems we know today.

Atmospheric CO₂ levels were high, and temps reached an average of up to 34 °C (93 °F). Unlike us, creatures that lived back then were used to an iceless planet. There was no mass extinction, but ecosystems shifted. And many species died out in parts of their ranges. Some disappeared completely.

Since the PETM, Earth has been cooling down. This could be due in large part to the rise of the Himalayan mountain range in Asia. Chemical weathering of all that fresh rock could have driven steady drops in atmospheric CO₂. By 34 million years ago, Antarctica was cold enough for year-round ice. And by 800,000 years ago, CO₂ levels fell below about 300 parts per million (ppm).

But in just the past 200 years, human activities have driven airborne CO₂ levels back up. Emissions — such as from coal-fired power plants and gas-fueled cars — have nearly doubled CO₂ levels, from 280 ppm to 426 ppm. Average temperatures have ticked up by 1.47 degrees C (2.65 degrees F).

If nothing major changes in our approach to climate change, this will be just the beginning. By 2100, CO₂ levels could reach 600 ppm. Some climate models show it could soar above 1,000 ppm. That could result in average temperatures 4 degrees C (7 degrees F) warmer than in preindustrial times.

If we’d been around in the PETM, we’d have had to migrate to the poles to survive. That’s bad news for today’s humans. Cities can’t exactly get up and move. By the end of this century, billions of people will routinely face heat and humidity extremes beyond the limits of human survival.

The next glacial period will start later than expected, if at all. And by 2500, four-tenths of all land will have become unsuitable for its current biome, scientists predict.

This glimpse of a likely future is informed by our past. And it gives us the chance to choose a different path. Cutting carbon emissions can still slow warming and its impacts.

If extreme warming occurs, it would end the world as we know it. But it would not be the end of the world.

Even if we trigger a climate catastrophe on the scale of the Permian mass extinction, Earth’s history shows that the planet will recover and life will eventually thrive again. The carbon thermostat will correct our error — but it is very slow. We can’t wait millions of years for it to fix climate change for us.

Some clouds are flat. Others are puffy. Some are pretty and turn orange or red at sunrise or sunset. Others signal stormy weather and can produce precipitation, such as rain, hail or snow.

Meteorologists, or weather forecasters, spend lots of time predicting clouds. That’s because clouds are behind all storm systems — from tornadoes and hurricanes to rain and snowstorms. 

Technically speaking, a cloud is nothing more than a clump of aerosols — small solid or liquid particles suspended in the air. In some clouds, those aerosols can be bits of wildfire smoke or even desert dust.

But most clouds are made of water. A typical cloud droplet is only 20 micrometers (0.00008 inch) in diameter. That’s less than a thousandth the size of an average raindrop. Since cloud droplets are so tiny, they are very light. And that’s part of why clouds float.

These water droplets start to form through evaporation. Evaporation occurs when liquid water molecules become energized and change phase into a gas. Energy from the sun heats Earth’s surface — including water molecules in the ground as well as in oceans, lakes and rivers. Some water molecules become warmer, and more energized, than others. The most energized ones become a gas, known as water vapor.

Most air is made of N₂ — or two nitrogen atoms clumped together. A molecule of water vapor weighs less than this nitrogen molecule. That’s also partly why clouds float.

Why can we see clouds?

We can’t see water vapor on its own. Clouds become visible when water vapor condenses, or transforms back into a liquid. That happens when water vapor rises high enough in the atmosphere that it cools.

Gravity pulls those droplets toward the ground. But they’re so tiny that warm rising air keeps them suspended aloft. And even if a single cloud weighs tens of millions of kilograms (pounds), the air outside the cloud is a bit heavier still. So the cloud floats.

Sometimes, water vapor rises extra high. At 12,200 meters (40,000 feet) above the ground, the average temperature is –57° Celsius (–71° Fahrenheit). Here, it’s too cold for water droplets to form. Any water turns into tiny ice crystals.

That’s why clouds at high altitudes aren’t puffy. They aren’t made of liquid droplets. Made of ice crystals, they’re wispy-looking.

Different types of clouds

Some clouds form near the ground. Fog is a cloud that forms on the ground.

“When we see fog, that is simply a cloud at the surface,” wrote Brandon Richards, a meteorologist for Spectrum News Texas in Austin, in a text message. “Fog happens when the air is saturated.” That means the air is holding as much water as it can. The extra water condenses, forming a cloud.

Fog is one type of stratus cloud. The word stratus comes from the Latin word for “layer.” Other stratus clouds may form a few thousand meters (feet) above the ground. They’re usually pretty flat.

In summer, the sky might host puffy clouds. It can be fun to look for shapes in these cumulus clouds. Such clouds usually form a couple kilometers (miles) above the ground. They come together when pockets of warm air rise.

The highest types of common clouds are cirrus. They form 9,100 meters (30,000 feet) or more above the ground. At that height, they’re made of ice crystals, which gives them a wispy, hairlike appearance.

Different types of clouds can be present at the same time. And some clouds are actually a combination of different cloud types. Cirrostratus clouds are wispy like cirrus clouds, but flat and layered like stratus clouds. Stratocumulus clouds are layered but a bit puffy.

Rare clouds

Some clouds form in weird ways. Consider noctilucent clouds. The term noctilucent comes from Latin words that mean “light at night.” Earth’s highest clouds, these form at heights of 76 to 85 kilometers (47 to 53 miles).

There’s little water vapor at such altitudes. So how can clouds form there? Meteor smoke!

Meteors burn up in this part of the atmosphere, leaving behind smoke particles. Water droplets can glom onto these particles and turn into ice crystals. And being so high, these clouds can catch sunlight even after the sun has set (at ground level). These clouds shimmer, like blue, glow-in-the-dark curtains.

Another type of strange cloud is the pyrocumulonimbus (PY-roh-KEW-mew-lo-NIM-bus), or smoke cloud. Wildfires can release lots of smoke. As smoke and hot gases rise, they can form a thundercloud. From these clouds, wildfires sometimes produce their own thunderstorms, windstorms — or even fire tornadoes.

Precipitation and thunderstorms

Precipitation happens when a cloud can’t hold any more water. Tiny, light cloud droplets coalesce, or merge, into bigger droplets. Those that become heavy enough will fall out as rain.

Something similar happens when it’s cold. Tiny, chilly water droplets merge to form ice crystals. That’s what makes snowflakes in the wintertime. Snow falls more slowly than raindrops. While raindrops plummet as fast as 10 meters per second (22.4 miles per hour), snowflakes tend to glide down at a pokey 0.4 to 1.8 meters per second (0.9 to 4 miles per hour).

Thunderstorms can produce dangerous precipitation. These storms come from cumulonimbus clouds. That’s the technical name for thunderclouds.

Thunderclouds start as cumulus clouds — puffy clouds fairly close to the ground. Warm, wet air helps them grow taller. Some thunderclouds can rise into towers 16 kilometers (10 miles) tall. While the tops of these clouds are made of ice, their bottoms consist of water droplets.

Cumulonimbus clouds can produce thunder and lighting. Because they’re tall, they can lift water droplets very high before they finally fall. That’s how hail forms. High-up water droplets can cool and freeze into an ice pellet. As more droplets freeze onto the pellet, the hailstone grows. Some thunderclouds can produce chunks of ice the size of baseballs or bigger.

The most extreme thunderclouds become supercells. That’s a thundercloud that rotates. Changing winds blow different layers of the cloud in different directions. That causes the entire cloud to spin. Supercells occasionally spawn tornadoes.

But there’s a catch. Sometimes, clouds can limit the intensity of storms. Why? “Clouds, even light wispy ones, can affect how much [sunshine] reaches the ground,” explains Joey Krastel. He’s a meteorologist for the Maryland Department of Emergency Management in Hanover.

If you look out from a plane window, you can sometimes see shadows on the ground cast by individual clouds. That’s one sign of how much sunlight clouds can keep from reaching the ground. With less sunlight, the Earth’s surface cools. Now there’s less energy to evaporate water. With less warm and wet air, storms can’t form as easily.

“During storm outbreaks, thick cloud cover can limit surface heating and reduce storm energy and potential,” Krastel wrote via text message.

That’s why the stormiest days often begin with sunshine. It seems strange to think that sunshine actually helps storms, but it’s true. The more the air is heated by sunlight, the more it can rise — and the bigger storms will grow!

You may not know methanol by name, but this alcohol plays a big role in making a lot of the things in our lives. It’s an ingredient in plastics and paints, for instance. And being highly flammable, it can be used as a liquid fuel. But making it has typically required multiple steps and high heat. It also produced lots of wastes. Now scientists have found an easy way to make methanol that avoids many of those drawbacks.

Their trick: Add lightning.

Lightning is a form of plasma — what many scientists call the fourth state of matter. It forms from a high-voltage electrical pulse.

Researchers have now shown plasma can quickly convert methane — the main component of natural gas — into methanol. All it takes is adding electricity, they explain in the April 15 Journal of the American Chemical Society.

“Lightning” in a bottle makes methanol in a simple, one-step process, notes Dayne Swearer. A physical chemist and chemical engineer, he led the team at Northwestern University in Evanston, Ill., that developed the technique.

Each year, companies around the world make up to 110 million metric tons (36.6 billion gallons) of methanol. “If we can offset a small fraction of that using … a simple process like this one,” Swearer says, “I think there’s a lot of cool opportunities.”

Lightning’s role

Chemists have been looking into using plasma in chemical reactions for more than a century. For Swearer, it’s a recent interest. He studies electromagnetic energy. “That’s the type of energy found in light or in electric fields, or that runs through wires,” he explains.

Working with that type of energy means understanding electrons — negatively charged subatomic particles. His team is studying ways to use electrons to transfer power.

“The electron really gives chemistry its flare,” he says. “It’s a really, really important part of chemical reactions.” He likens electrons to hooks that hold atoms together to make molecules. If you can unhook those electrons, he says, it’s possible to rearrange a molecule’s atoms.

The team used bottled lightning to remodel methane molecules. The change happens quickly. First, they pump methane gas into a cylinder immersed in water. The cylinder has tiny holes, or pores, on its sides. Then the device is electrified using a much higher voltage than comes from the outlets found in a home. “Our system compresses the electricity into pulses that turn off and on really fast,” Swearer says. “These short bursts help control the chemistry.”

As the gas moves through the cylinder and out the tiny holes, an electrical pulse rips through it. That pulse lights up like tiny bolts of lightning.

This process tears electrons from the methane molecules. These glowing, high-energy electrons form a plasma that smashes into other nearby molecules. Methane molecules have one carbon atom and four hydrogens. Water molecules have one oxygen and two hydrogens. The plasma breaks one hydrogen off of each molecule.

Those broken water and methane molecules find each other and snap together like puzzle pieces, says Swearer. “We click them together.” And when they do, they become methanol. The orphaned hydrogen atoms snap together to form hydrogen molecules.

Along with the methane gas, the porous cylinder contains a type of material called a catalyst. It helps the chemicals react correctly.

Toward greener chemistry

Chemists knew electricity could be used to remodel the molecules in a gas. But figuring out how to harness that knowledge in a useful way proved hard, Swearer says. One challenge was “really understanding what’s going on inside the plasma,” he says. He credits a graduate student, James Ho, with figuring out how the plasma was behaving.

Another challenge: Not all the methane will turn into methanol. Swearer’s team is currently investigating how to improve that conversion rate.

Using lightning in a bottle to make methanol is exciting, he says. But he cautions that his team’s process is experimental. It’s not ready to replace conventional ways of making methanol. Doing that will take years, Swearer says. One obstacle, he notes, is “just the cost of electricity” needed.

Still, the new findings suggest using plasma to make fuels could have a smaller climate impact than today’s standard methods, says P.J. Cullen. He’s a chemical engineer at the University of Sydney in Australia. Why? “No need for high temperature” to make them, he says. The high heat normally needed to make methanol comes from burning fossil fuels. The electricity used for the plasma could instead come from solar, wind or nuclear sources — sources that don’t add greenhouse gases to the atmosphere.

Cullen’s group in Australia developed the plasma-making device that Swearer’s group uses. In the same journal as Swearer’s work, Cullen’s team describes a second way to convert methane to methanol with a plasma. (It, too, uses a catalyst, but one separated from the plasma.)

“Both papers point to the same main advantage,” Cullen says. Both make methanol without high heat.

These approaches both show the power of plasma, he says. They also point to how researchers could use this technology for cleaner, greener chemistry.

Metal-organic framework, (noun, “MEH-tal Or-GAN-ik FRAYM-werk”)

Metal-organic frameworks — or MOFs — are a type of material made of metal– and carbon-based molecules. These molecules are linked together into complex, 3-D shapes.

Imagine a house that’s being built. After laying the foundation, builders construct a skeleton-like wooden frame. This framework consists mostly of empty space. MOFs are structured much the same way. Their molecules assemble into a scaffold-like material. And like that wooden frame, an MOF’s interior is also mostly empty space.

Unlike the holes of a sponge, the empty spaces inside an MOF are not random. Scientists can choose the sizes, shapes and chemistry of these gaps. That’s important. It allows scientists to custom-make MOFs for specific tasks. A very porous MOF may be especially good at sopping up substances. Another MOF with certain chemistry may work like a filter, letting some substances through it but blocking others.

Scientists custom-build MOFs for many different uses. In medicine, MOFs may tote drugs to specific places inside the body for release. Or they might release medicines only under certain conditions.

MOFs may also help manage climate change by absorbing carbon dioxide (CO₂) from the air. These MOFs often contain exposed metal ions. (An ion is an atom that carries an electric charge.) Those metal ions can bind to the oxygen atoms in CO₂ molecules, snatching them out of the atmosphere.

Still other MOFs can pull water from desert air and release it for drinking. Others can filter out harmful wavelengths of sunlight to protect crops. Or they can shield against toxic chemicals. In fact, MOFs have so many uses that they won the 2025 Nobel Prize in chemistry.

In a sentence

Scientists developed metal-organic frameworks (MOFs) that yank pollution from our water sources.

Check out the full list of Scientists Say.

It takes a village to deliver a whale calf. That’s what the most detailed video ever of a sperm whale birth shows.

In the footage, a female whale in labor is surrounded by others assisting her. Almost all of her helpers are female. But not all are related to the birthing mom. This shows that sperm whales benefit from cooperation, just as humans do.

Because getting to watch the birth of a whale is extremely rare, only a few scientific studies have described them. Some of those reports have noted other whales helping the mom through the birthing process. But scientists had never caught this on video.

In 2023, David Gruber was part of a team that got very lucky. Gruber is a marine biologist. He works with Project CETI, a nonprofit dedicated to sperm whale research. Project CETI is partly based on the island of Dominica in the Caribbean Sea. Gruber was in a boat right off the coast when his team caught the birth.

The researchers weren’t looking for a whale birth. They just happened to be in the right place, at the right time — with the right equipment. Using two drones, the team caught the whole 34-minute birthing process on tape.

A group of 10 whales surrounded the laboring mom. After the birth, her assistants took turns lifting the newborn to the surface for hours. This allowed the calf to breathe air until it could swim on its own.

The whales seemed to include the scientists in this event, Gruber says. “They literally carried the baby right past the front of our boat.” His group shared its video in Science on March 26.

Helping hands — or fins

Project CETI has been studying sperm whales around Dominica for long enough that Gruber and his colleagues could identify every individual in the video. “Not only did we capture such an amazing dataset, but we actually knew each of these whales,” he says.

Computers tracked each whale’s position in the footage. Then, a team member labeled each animal. A whale named Rounder was giving birth, the researchers determined. They also figured out what each of the other 10 whales did and how they were related to the mom. 

Rounder’s helpers included whales from two different female lines. These are like whale families, also called kin groups. The kin groups’ teamwork was surprising, because these groups don’t usually spend time together searching for food. But whales from the two groups fully mixed for hours after the birth. All helped lift the newborn calf at some point.

The four whales that helped hold the calf the most were its mother, aunt, an older kin member and one whale from outside the calf’s kin group. Holding the baby up is very important, because it can’t float on its own yet. Without help, Gruber says, “it would have sunk.”

Killer whales, belugas and other cetaceans have also been seen pushing newborns to the surface. This behavior may go back to when those species shared a common ancestor, Gruber says.

The wails of labor

Along with the video, the researchers also recorded audio of the birth. They analyzed these sounds with help from some other researchers. 

Sperm whales make sounds called codas. The scientists looked for changes in things like the codas’ rhythm. Those codas changed during important moments in the birth. One specific coda was heard more frequently during the birth. The team reported its findings March 26 in Scientific Reports.

Different sounds being linked with the birth is not surprising, says Denise Herzing. She’s a marine biologist who heads the Wild Dolphin Project. Based in Jupiter, Fla., this nonprofit focuses on Atlantic spotted dolphins.

“Marine mammals, in general, have specific sounds during specific behavioral contexts,” says Herzing.

After the birth, the sperm whales also ran into several pilot whales. Now, the sperm whales’ vocal style changed more. That might be because pilot whales sometimes bother sperm whales.

It takes a village

Giving birth is one of the most critical moments of a female whale’s life. Such high stakes might have driven these mammals to evolve cooperative instincts, the researchers say.

This is spot on, Herzing says. “We see different alliances of dolphins grouping into bigger groups to fight off a predator or to mate.”

Sharing the birth with the world took cooperation from the human team, too. Many scientists had to work together to film the video, analyze it and map the relationships between the whales. “It was a very profound experience for all of us,” says Gruber.

PHOENIX, Ariz. — Nervous? One day soon, relief might be just a chew away.

For years, research has been showing that chemicals found in passionflower plants can help fight anxiety. Two teens have now created a chewing gum that can release those chemicals.

“Gum is very popular among high schoolers,” says Zackary Nizker, 16. This junior at McIntosh High School in Peachtree City, Ga., hopes this habit will make gum an easy way for teens to deal with anxiety. And there are many who face this. “In the U.S.,” Zackary says, “a third of all adolescents and young adults suffer from a form of anxiety.”

But teens aren’t the only ones who could use some relief. Zackary’s grandmother struggles with nervousness, which he says “got really severe last year.” The drugs she got prescribed help, he says, though their side effects can be “very severe.” In his grandma’s case, “she could hardly walk or stand. It was a very scary situation.”

Flavonoids are antioxidant chemicals made by many plants. The plants use them to fight tissue damage from oxidation. Many herbal remedies contain these compounds, too, notes Sara Hoti, Zackary’s classmate. Chamomile, used in some teas, is one flavonoid-loaded herb. But for their study, she and Zackary used an extract of a plant that grows wild in their hometown: passionflower (Passiflora incarnata).

Their work earned these teens a spot as finalists here at the 2026 Regeneron International Science & Engineering Fair, or ISEF. It’s a program created and run by Society for Science (which also publishes this magazine). As fourth place winners in the Translational Medical Science division, Sara and Zackary took home $600. They were among 1,725 students — from 65 nations or territories — competing at the 76th annual ISEF. Participants this year shared nearly $7 million in prizes.

Flower-powered relief

“Chewing gum, by itself, is already known to reduce anxiety,” says Zackary. But a host of studies going back decades shows that passionflower flavonoids reduce anxiety. They do this, he explains, by increasing brain levels of a signaling compound known as GABA. (That’s short for gamma-aminobutyric acid.) “It slows down neuron firing in your brain,” Zackary says. That slowdown, he says, seems to calm an anxious brain.

By combining herbal remedies with rhythmic chewing, he says, their new gum could become “a more effective treatment.” But to test whether chewing gum would release any flavonoids in it, they needed to run some tests.

To start, they cooked up some bubble gum. It included a gum base, powdered sugar, various other sweeteners — and, of course, passionflower extract. 

The teens had hoped to make that extract. After all, Sara says, in her hometown, passionflowers are everywhere. But the pair did their experiment during the winter, when the flowers were “all gone — out of season.” So they ended up having to buy the extract.

Afterward, they tested their prototype gum — and struggled, Zackary recalls. Why? “We’re not allowed to just give people some random gum we made and say, ‘Here, chew this, let’s see if it works.’” Instead, they had to do tests “outside of the body.”

Double bubble testing

The pair conducted two tests. The first examined whether each quantity of gum contained the same dose of passionflower extract. So they analyzed slices of the gum under a microscope. Using computer software, they could calculate the share of the flavonoid particles in view. Here, Sara says, “you want your value to be below 15. We actually got a value of 8.4, which was perfect.” (In these tests, Zackary adds, the “values” do not come with a unit.)

A second test, called the Shinoda test, measured how well flavonoids in their gum resist breakdown. If they broke down, the likelihood they’d prove helpful against anxiety could fall apart, too. So the young scientists exposed their gum to various conditions and then used this color-changing test to check whether the flavonoids had held up.

This test is usually done with liquids. Their gum was a solid. So learning how to Shinoda test their gum proved a “really long process,” Sara says.

To mimic the work of saliva, they cut their gum into pieces and soaked them in alcohol for three hours. And nothing happened. The flavonoids never left the gum.

To use the gum you’d chew it, they realized, an action which could release the flavonoids. But “since we couldn’t chew it ourselves,” Zackary says, “we broke the gum into pieces with our hands. That simulates chewing.” They also extended their soak time to three days.

This time, “we got this bright orange coloration change,” says Sara. That showed that the gum’s flavonoids had been released but not broken down — even after exposure to hydrochloric acid and other harsh conditions.

In the future, the teens want to find ways to market their gum and test in people its ability to relieve anxiety.

“Medicated chewing gum is not a new thing,” says Sara. Energy-boosting gums, which release a stimulant, already exist. Smoking-cessation gum contains nicotine. And you can buy passionflower teas. But “nowhere on the market is there a gum for anxiety,” says Sara.

She hopes their recipe could help anyone who feels a bout of nervousness coming on. Maybe you’re “going into an interview or a presentation,” she says. “You can just [chew] this and you know, chill out.”

Computer-generated images have been around for decades. People use computers to make digital art and animations for movies, TV shows and video games. However, just like making a physical painting with a paintbrush, these images take a lot of time and human effort to produce.

The rise of artificial intelligence has drastically reduced the amount of time and effort it takes to create computer-generated images. New programs and websites can generate images using a text prompt from the user, such as “a picture of a tiger walking through a grassy field.” These programs can automatically generate artwork and photo-realistic images that can be difficult to tell apart from “real” photos and artwork. Can you tell which picture at the top of this story is real and which is AI-generated?

While AI-generated images might seem fun or harmless, they can also cause problems. People can use them to create deepfakes, or fake images of things that did not really happen. Some people might see the picture and believe that it is real. While fake news and fake images have been around for a long time, AI tools can make it easier and faster to produce this misleading content.

Can people tell the difference between real pictures and AI-generated pictures? How hard is it to spot “fake” pictures? In this science project you will find out!

Terms and concepts

• Computer-generated image
• Artificial intelligence
• Deepfake

Questions

• What are some uses for AI-generated images?
• What are some potential problems caused by AI-generated images?

Resources

• Axios (2023, July 31). How to spot deepfakes created by AI image generators. Retrieved September 14, 2023.
• Bond, S. (2023, June 13). AI-generated images are everywhere. Here’s how to spot them. NPR. Retrieved September 14, 2023.

Materials and equipment

• Internet access
• Digital camera or smartphone
• Optional: printer
• Volunteers
• Lab notebook

Experimental procedure

1. Decide on a topic or theme for your pictures. For example, you could use pictures of animals, flowers, scenery, vehicles or people.
2. Take at least 10 real pictures of the object/topic you decided on or find pictures online.
   1. Make sure you label or organize the images so you do not lose track of them later. (As an example, you could put all the real pictures in a folder on your computer.)
   2. If you are finding the pictures online, make sure they are from a legitimate source and you know they are real pictures. (See references in the Bibliography for tips.)
3. Find or make at least 10 AI-generated images of the same object/topic.
   1. You can search online for an “AI image generator” and you will find many options available. Some services might be built into major search engines. Others might have their own websites. Also note that some services might be free, or allow you to generate a limited number of images for free. But others might require a paid subscription.
   2. Follow the instructions for the website or program you decide to use to enter a prompt and generate an image. Since you will be comparing them to real images, make sure you generate “realistic” photos and not images that look like paintings or drawings.
   3. Save the images. Again, make sure you keep track of which images are real and which are AI-generated.
4. Prepare all the images for viewing by your volunteers. For example, you can label them 1 through 20 and put them in a random order in a different folder on your computer. Or you could print them. Make sure you keep track of which images are real and which are AI-generated. But this information should not be visible to your volunteers.
5. Prepare a data table like Table 1. In the second column, write whether each image is real or AI-generated.

Image number	Real or AI generated	Volunteer  1	Volunteer 2	Volunteer 3	Volunteer “real” responses	Volunteer “AI” responses	% of volunteers correct

6. One at a time, show each picture to a volunteer. Ask them whether they think the picture is real or AI-generated. Record their response in your data table.
7. Repeat the process for each volunteer.
8. For each image, add up the number of volunteers who said the image was real. Enter this value in your data table.
9. For each image, add up the number of volunteers who said the image was AI-generated. Enter this response in your data table.
10. Calculate the percentage of volunteers who correctly identified whether each individual image was real or AI-generated. Enter the percentage in your data table.
11. Create another data table like Table 2.

		Volunteer responses
		Real	AI-generated
Actual image	Real
	AI-generated

12. Analyze your data.
    • Overall, how good were your volunteers at correctly identifying real images as real?
    • Overall, how good were your volunteers at correctly identifying AI-generated images as AI-generated?
    • Are there large differences in your results between individual pictures? Were some pictures harder for your volunteers to correctly identify than others? Looking at the pictures, why do you think this occurred?

Variations

• Repeat the experiment with artwork instead of pictures. Can your volunteers tell the difference between real artwork and AI-generated art?
• Do the experiment with two groups of volunteers: a control group and a group that you have trained to spot AI-generated images. (See some of the references in the Bibliography.) Can people with training do a better job correctly identifying the images?
• Try the experiment with different categories of images/objects. Are some things easier for people to recognize than others? For example, what about pictures of inanimate objects vs. pictures of living things? What about pictures of “regular” people vs. famous people like politicians or actors?
• Compare different AI image generation websites or services. Are some better than others at producing convincing images?
• Do an experiment to find out if people can recognize AI-generated text instead of images.
• Can you produce fake news articles that include both images and text about real people or events? Run the experiment with both real and fake news articles. Can people tell which is which?

This activity is brought to you in partnership with Science Buddies. Find the original activity on the Science Buddies website.

DENVER, Colo. — Tiny, exploding black holes might solve a major mystery about how the universe as we know it came to be.

In the cosmos today, matter is much more common than antimatter. But scientists don’t know why. Matter makes up the stuff we can see, smell and touch. Yet antimatter — which is mostly identical to matter, just with flipped electric charges — is rarely observed. It can be released in radioactive decay or in particle collisions. But it doesn’t form solid objects.

Some physicists think that matter’s takeover of the universe may have involved tiny black holes. A black hole is a place where matter is packed so densely that nothing can escape it once it falls in, not even light.

The black holes at play here would have been born in the first instants after the Big Bang, when the universe began. If such black holes existed, they would have quickly evaporated and exploded. Those explosions would have sent out shock waves that may have set the stage for matter to take over.

Physicist Alexandra Klipfel shared this idea in March at the American Physical Society’s Global Physics Summit. She and her teammates also described the work in two papers on arXiv.org. (Studies posted to that site have not yet been vetted by other scientists.)

Pop goes the black hole

Scientists believe the universe began with equal amounts of matter and antimatter. But when they meet, matter and antimatter destroy one another. Without something to tip the balance in matter’s favor, the universe would have been boring — and empty.

Tiny black holes could have shifted the balance to produce our matter-rich cosmos, Klipfel’s team says. That could have allowed stars, planets and galaxies to form.

Usually, black holes form when a star dies and collapses. But these black holes would have formed differently. They would have collapsed from fluctuations in the density of energy in the early universe. Each one would typically have had only about as much mass as a small car.

The black holes would have spewed out particles called Hawking radiation. As a result, the black holes would steadily lose mass and eventually explode. All this would have happened within the first tenth of a billionth of a second of the universe’s existence.

Such explosions would have launched out traveling walls of energy called shock waves. Each explosion and shock wave would have heated a black hole’s surroundings. “It’s a really sharp wall,” Klipfel says, with different conditions inside and outside the shock. A wall like that would provide the right conditions to create an excess of matter.

Hitting a wall

Early in the universe, there may have been processes that converted antimatter into matter. But in a universe where everything is smoothly spread out, any process that could do that would work both ways at once. That should keep matter and antimatter in equal amounts.

With the sharp wall of a shock wave, conditions on one side would differ drastically from those on the other. That could give matter a boost.

Inside a thin shell behind a shock wave, temperatures would be extremely high. So high that, weirdly, particles would not have mass.

Outside the shock wave, particles would have mass — and inside they wouldn’t. When particles crossed the border, their mass would change. This could be happening at the same time as other weird physics that might have been at work in the early universe. Together, those effects could have caused more and more matter to build up at the boundary of a shock wave. And that extra matter could have then been locked in as the shock expanded.

Matter and antimatter still would have destroyed one another, but the extra matter means that some would have been left over at the end. And that’s what would make up everything we see around us.

For tiny black holes to be responsible for matter’s victory, many, many of them would have had to explode moments after the Big Bang. Instead of being a finale, those fireworks could have been just the beginning.

Of all the strange and spectacular things in outer space, nothing is stranger or more spectacular than black holes.

These cosmic oddballs can’t even be described without contradiction. Unlike a typical hole, for instance, a black hole is not empty. Its core packs so much matter that its density is almost impossible to imagine. The smallest known black holes squeeze more than three times the mass of the sun into a volume about the diameter of a small city. One of the largest that scientists have found contains more than tens of billions of times the mass of the sun and stretches across a space bigger than the solar system.

Because it holds so much mass in such a small space, nothing that gets too close to a black hole can escape its gravity — not even light. Yet to find black holes, scientists must look for the brightest beacons of light in space. (This light is given off as the black hole feeds on nearby gas.)

Black holes have been known to devour stars, planets and even other black holes. The superstrong gravity of supermassive black holes allows them to hold giant galaxies together.

Scientists have been grappling with the strangeness of black holes for centuries. John Michell appears to be the first person to have predicted their existence. Back in 1783, he proposed there might be “dark stars” with gravity too strong for their own light to escape.

More than a century later, in 1915, Albert Einstein proposed his theory of general relativity to describe how gravity works. That theory predicted matter could collapse into a single point of infinite density — a black hole. Its mass would be so extreme that it would warp the space around it. The result: Anything passing nearby would be pulled into it.

Decades after Einstein introduced this idea, X-ray telescopes confirmed such weird objects exist. Researchers observed blasts of high energy as black holes fed. And in 2019, the Event Horizon Telescope captured the first direct image of a feeding black hole.

Yet some of the most basic questions about these cosmic monsters remain unanswered. Astrophysicists don’t know, for instance, why galaxies host giant black holes in their hearts. And then there’s those supermassive monsters. How did they get so gargantuan? In fact, “where do they come from?” asks Marta Volonteri. This astrophysicist at the Paris Institute of Astrophysics in France has developed models of how black holes might form. And there are no clear answers for how the biggest ones do, she says. After 20 years of searching, she says, “I still don’t know.”

Scientists also are working to explain how black holes change over their lifetimes and how they might eventually die. Powerful telescopes and models of the universe have offered up some good ideas. Yet the more scientists learn, the more they realize how little they know.

A black hole is born

Black holes come in a range of sizes. Small ones contain up to 100 times the mass of the sun. Supermassive ones can have millions to tens of billions as much heft.

This size range poses a big problem in explaining how black holes form.

Traditionally, we have understood black holes to be “stellar corpses,” says Priya Natarajan. She’s an astrophysicist at Yale University in New Haven, Conn.

That seems to be true for the smallest ones, which scientists describe as “massive.” They form from stars with about 20 to 30 times the mass of our sun. As they’re dying, these big stars explode as supernovas, leaving behind black holes.

Scientists know basically how this works.

During active phases of their lives, stars fuse lighter elements into heavier ones, producing heat and light. Eventually, though, a star runs out of fuel. If it was the size of the sun, it will swell up as it dies. Later, it will collapse into a small, glowing core of oxygen and carbon.

But when bigger stars run out of fuel, look out! They’ll end up with an unstable iron core that keeps pulling in mass.

Eventually, that core will collapse under its own weight. This may trigger an explosive supernova. What’s left behind just keeps collapsing into an increasingly dense ball. Stars that started with between eight and 20 times the mass of the sun will collapse to make a neutron star. Its pressure crushes its particles together.

Bigger stars, though, become a black hole. (They may or may not go through a supernova phase first.) These are called “stellar-mass” or “massive” black holes. Astronomers predict that scattered around our galaxy are hundreds of millions of massive black holes.

They’re very different from the supermassive types often found at the centers of galaxies.

Sagittarius A* sits at the center of our Milky Way. This heavyweight carries as much mass as 4 million suns. The black hole at the center of Andromeda, our nearest galactic neighbor, has the mass of more than 100 million suns. The largest black hole known — TON 618 — contains 66 billion times our sun’s mass.

But even the largest stars don’t have nearly that much mass. So how truly monster black holes arise poses an interesting puzzle, says Natarajan: How could they get so enormous?

Black holes grow at least two ways, she notes. “They either gobble gas and material from around them, or they collide with other black holes.”

Galaxies are vast collections of stars. When they collide, the supermassive black holes at their centers may essentially fuse.

Here, “the black holes dance around each other and merge,” says Volker Springel. Now, he notes, “you’ve got a bigger one.” Springel is an astrophysicist at the Max Planck Institute for Astrophysics in Garching, Germany. That dancing and merging happens frequently, he says. “So we expect, in the future, [we’ll get] slightly bigger black holes even than the biggest ones we have today.”

But not even collisions can explain how today’s supermassive black holes got so big, says Natarajan.

Observations of some of these behemoths suggest they formed when the universe was young. To get so big, they’d have had to grow stepwise from collision after collision after collision — or spend eons successively eating more and more stars and other mass entering their neighborhoods.

Yet, Natarajan points out, there’s simply not been enough time since the Big Bang for them to have grown that big if they were “starting from a piddly little stellar corpse.”

The supermassive mystery

Surrounding every black hole is an event horizon. That’s a point of no return. Once any information — including light — passes that horizon, it can never be retrieved. That means scientists can’t analyze the contents of black holes to figure out how or when they formed.

Simply put, says Natarajan: “They don’t have any memory.”

Scientists have found other ways to study them, though. In the 2000s, Natarajan and other astrophysicists proposed that supermassive black holes might grow from giant black hole “seeds.” These might have formed from something other than a dying star.

Gravity might have collapsed a massive cloud of gas to form a black hole, even before it became a star. These black hole seeds — each with a mass of about 1 million suns — might have merged to quickly form larger ones. Seeds that formed right after the Big Bang, Natarajan says, might have had time to spin up into the supermassive black holes we see today.

“There are certain conditions under which you can have gas that will … directly collapse into a black hole,” she says. “It doesn’t have to go through a star stage.” The gas has to be made of pure hydrogen and helium, for example, with more gas constantly flooding in.

Volonteri of the Paris Institute has also studied the formation of such seeds and their potential to have produced what are now supermassive black holes.

In 2023, scientists spotted the bright center of a galaxy more than 10 billion light-years away. It was fueled by a black hole with the mass of about 40 million suns. It was so big, relative to the size of its galaxy, that scientists described it as “over-massive.” Even more impressive: This black hole likely formed when the universe was in its infancy (just a few hundred million years old).

That discovery, called UHZ1, fits with Natarajan’s models. It likely started as some giant black hole seed that formed after the collapse of an enormous cloud of gas.

Black hole evolution

To study how black holes evolve, scientists must get creative. By focusing on stuff that surrounds a black hole, they can make educated guesses on how the beast is behaving.

Stellar-mass black holes generally remain quiet and unchanging. Unless, that is, something begins to orbit too closely — such as gas, dust, a planet or a star. Then, the black hole’s strong gravity may rip the intruder apart and gobble it up. As remains of the intruder fall into the black hole, the disintegrating stuff burns up, producing bright bursts of radiation.

What’s happening in supermassive black holes is more puzzling. Most galaxies have a supermassive black hole at their center. No one knows which came first, the galaxy or the black hole. In fact, Natarajan suspects, they likely formed at the same time.

Watching how a galaxy changes, she says, can hint at how its black hole is behaving.

What’s more, “black holes are believed to be a major factor in galaxy evolution,” says Springel at the Max Planck Institute. For instance, supermassive ones can control the size of their host galaxy. If they didn’t, he says, this collection of stars — the galaxy — would “continue to get bigger and bigger.” And here’s why.

Dense clouds of hot gas move throughout a galaxy. As these clouds cool, they can condense to form stars. The Milky Way produces an estimated three or four new stars each year. So-called starburst galaxies can spawn hundreds per year.

But galaxies can’t grow infinitely large. “There’s a pretty hard maximum,” Springel says. It’s about 1 trillion times the mass of our sun. (A rare few are estimated to be 10 trillion solar masses.)

The reason for this limit may be that a black hole and a galaxy tend to grow in lockstep. The galaxy makes more stars. Then the black hole ingests more gas, stars or other nearby stuff and grows. As the black hole eats, it produces powerful jets of energy.

Scientists used to believe that all the jets’ energy would escape and “not do much damage to the galaxy,” says Springel. But computer models by his team and others now tell a different story.

Black holes can act like a thermostat for a galaxy, keeping the heat on, Springel finds. The jet’s bonus energy can superheat clouds of gas. When that happens, big galaxies can’t cool enough to form stars. “There’s a trickle of star formation sometimes left,” he says.

It’s different in smaller galaxies. Black holes that don’t produce so much energy can still give birth to new stars.

Black hole mortality

Black holes lead dynamic lives. Within the last year alone, scientists have made several surprising discoveries. One team found evidence of a type of black hole collision so massive that scientists had thought it impossible. Other astronomers spotted a runaway black hole that had likely been booted from its galaxy — dragging a trail of newborn stars behind it.

The stars that produce massive black holes only live for a few million years. But their surviving black holes, models suggest, stick around for billions of years or more. With such lengthy lives, black holes have a long, long time to interact with each other and everything else.

Scientists predict that within the next 10 billion years or so, the Milky Way might merge with the Andromeda galaxy. (Estimates that this will happen range from less than 50 percent to near certainty.) If these galaxies merge, their black holes will, too, producing an even bigger one. Galaxies and their black holes elsewhere in the cosmos will continue colliding, too, says Springel — but likely not forever.

The universe is expanding. It’s unclear if that expansion will continue without end. But if it does, galaxies will get ever farther apart. If there’s a Milky Way-Andromeda merger, says Springel, this super-galaxy will become a kind of bright but dimming island in a vast sea of dark, empty space.

Eventually, “all the galaxies will stop merging with each other,” he says. “They’ll become isolated.”

For a while, they’ll keep making new stars. As those suns eventually die in supernovas, new black holes will form. In time, though, galaxies will run out of star-making stuff. All their stars will eventually run out of fuel — and go dark.

Some theories suggest that all the matter from dead stars and planets may also break apart. In the end, black holes may be the last survivors in our universe.

And even they may die.

Evaporating out of existence?

In 1974, astrophysicist Stephen Hawking predicted that black holes could “evaporate.” That is, they could fall apart by gradually releasing radiation.

This evaporation would develop through a process described by a field of physics called quantum theory. It predicts that the emptiness of space undergoes fluctuations as tiny particles pop in and out of existence. Because of how these particles behave near the outer edge of a black hole — its event horizon — they can reduce its mass.   

Although no one has directly observed Hawking radiation, the idea mostly fits with scientists’ current ideas about the physics of black holes.

“The smaller the black hole is, the quicker they will do this,” says Springel. At the end of the universe, the smallest black holes will be the first to shrink.

What happens next remains a mystery.

Supermassive black holes may evaporate one day, too — or not. Recent research suggests that some strange physics may halt their death throes. These theories suggest a black hole cannot lose all the “information” it had acquired. So their evaporation may stop once such beasts have lost half their mass.

Some physicists have proposed an even wilder idea: that a star may collapse into something called a black shell. It sort of mimics a black hole. Here, all the collapsing mass forms a dense outer shell. Inside would be what scientists call a “true vacuum” — a volume with the absolute lowest energy possible.  

But that’s just an idea.

With every question scientists answer about how black holes form, live or die, they uncover new, even stranger questions. After all, they’re studying the most extreme things in all of nature.

Frustrating as it is, black holes “represent the end of knowledge,” says Natarajan. Simply put, she says, they’re “the edge of what we can know.”

The mind can regulate the immune system. And through directed thinking, people can learn to turn on immune-boosting brain areas, a new study finds.

The idea that the brain can influence the body emerged long ago, says Tor Wager. He’s a neuroscientist at Dartmouth University in Hanover, N.H. But only in the last few years have there been “real breakthroughs in understanding the neuroscience behind this,” he says.

Positive expectations turn on one part of the brain’s reward system. This region triggers the feelings of pleasure we get from eating good food, winning a game or receiving a compliment. Nerve cells in this part of the brain respond to such rewards by releasing the chemical dopamine. 

Tamar Koren is a physician scientist at Tel Aviv Medical Center in Israel. She was part of a team that used genetic methods to stimulate these “reward” cells in mice.

Turning on those neurons brought surprising health benefits. The mice were better able to fight bacterial infections and recovered more quickly from heart attacks. Stimulating the animals’ reward circuit even slowed the growth of tumors.

The approach looked so promising that Koren’s team wanted to know if it could work for people, too. But the genetic and molecular tools used in mice can’t ethically be used in humans. Instead, the team trained people to turn on their reward circuits with their own thoughts.

Her team shared details on how they did that in the January 19 Nature Medicine.

Responding to cues

This line of research grew out of work done in the late 1890s by Ivan Pavlov. This Russian scientist studied how our bodies extract energy and nutrients from food. In one famous experiment, he rang a bell every time he got ready to feed a hungry dog. Before long, just the sound of the bell would make the dog start salivating — even when there was no food. Psychologists call this a conditioned response. (For this and related work, Pavlov would take home the 1904 Nobel Prize in physiology or medicine.)

Decades later, Robert Ader and Nicholas Cohen at the University of Rochester’s medical school did something similar in rodents. They gave the animals a cue — here, a sweet drink — at the same time they injected a drug that suppresses the immune system. Eventually, giving rats just the drink could trigger the immune change.

Such an effect is known as psychosomatic (SY-koh-soh-MAT-ik). It means that the brain can trigger changes in the body after some conditioned cue (such as hearing a dinner bell or getting a sweet drink).

That term can carry stigma. It’s often used to describe real health symptoms — such as headaches, pain, nausea or skin changes — that can be triggered or worsened by mood or stress. People might see these health effects as being imagined or trivial.

But the opposite also occurs, such as getting relief after taking a sugar pill that looked like an actual drug. This is what’s called the placebo (Pluh-SEE-boh) effect. Some people also dismiss this, saying it’s not real medicine.

Yet it can be. In fact, some researchers view placebos as an opportunity.

The placebo effect reflects real physical changes. The effect may result from having positive expectations or a sense of hope. Whatever causes it, says Koren, “maybe we should understand how it works.” That, she says, might help people respond better to treatments.

Turning on the placebo effect

Her team has now tested that. Working with a psychology lab at Tel Aviv University, they recruited 85 young adults. All were employees who needed a vaccine to work at the medical center. This shot is given to ward off the hepatitis B virus (HBV). Seeing how people responded would offer an easy way to measure immune changes.

For the first phase of the experiment, the recruits had functional MRI (fMRI) scans. They laid in a machine that scans the brain and shows which parts are active. For each 40-second session, participants were told to put their brain to work. Each could choose how they wanted to do so. For instance, they could watch a red dot on the screen. Or recall a trip. Or think about the future. Or solve a math problem. 

Afterward, areas of the brain scan got a rating from 0 to 10. Those scores reflected activity in deep-brain regions of the reward pathway. One key region is known as the VTA, short for ventral tegmental area. This is the same area Koren’s team targeted in mice to trigger health benefits.

Some participants were randomly put into a control group. Their scores came from an unrelated brain region. 

When someone got a low score, they were asked to focus their thoughts on something else for the next session. If their score rose, they might repeat or refine that thought-focusing strategy. This trial-and-error process, called fMRI neurofeedback, was carried out in 45 to 60 sessions over several weeks. Through it all, participants had one goal: Get the highest score possible.

“The important thing for us was not the absolute score but the improvement,” says Nitzan Lubianiker. He led this study back when he was a graduate student on the team. (He now works as a psychology researcher at Yale University in New Haven, Conn.)

Right after their final fMRI session, each recruit got the HBV vaccine. This shot instructs the body to make antibodies. Those immune proteins recognize hepatitis B virus and help protect the liver from becoming infected by it. Blood tests measured virus antibodies before and two weeks after each person got their shot.

People who had been better at increasing brain activity in the VTA showed a larger rise in HBV antibodies after vaccination. That indicates a stronger immune response.

The improvement was just a 7 to 10 percent increase in HBV antibodies. Still, that was impressive, says Jonathan Kipnis. He was not involved in the research. But he knows about such things: His lab studies brain-immune connections at Washington University in St. Louis, Mo.

Mind-body connection

“We were all surprised that there actually was an effect,” says Koren. The response her team saw in lab mice was less surprising because they directly targeted the nerve cells. But getting people to turn on that region through thoughts alone seemed like “science fiction,” she now says.

And success here did not depend on someone’s personality. People who said on a questionnaire they’re more optimistic or hopeful did not all get higher VTA scores.

But high scorers did have something in common: They tended to choose mental strategies that involve positive expectations. For some, thoughts centered on friends or family. Others focused on experiences. The details didn’t seem to matter, since participants were not told what to think about. Rather, they adjusted their thoughts based on the neurofeedback scores. That was a “cool finding,” says Lubianiker.

The result “emphasizes how much our mental state is relevant to our well-being and day-to-day physiology,” Koren says. “Even if we’re not aware of it.”

Phoenix, Ariz. — People have increasingly been turning to chatbots, agents and other AI helpers for advice and more. For instance, more than 900 million people use ChatGPT weekly. But sometimes artificial-intelligence helpers give dangerous advice. Hoping to counter this problem, Sowmya Sankaran, 16, developed an app. It gives certain bots fully fleshed-out personas that are moral and supportive.

A junior at Albuquerque Academy in New Mexico, Sowmya focused on AI agents. These differ from the chatbots that most teens already use (such as ChatGPT). More advanced than chatbots, AI agents can take action to achieve one or more goals.

“When I call Firehouse Subs, I talk to an AI agent,” says Sowmya. “It’s an AI model that listens to what I have to say” and puts in the sandwich order. Some agents can be empowered to do more. One might search your email inbox for contacts, find the one you asked for and send it a message. Or it might buy an airline ticket using your credit card. In contrast, a chatbot’s only job is to provide you text, Sowmya explains.

What’s been worrying her is that AI agents “have uncontrolled personas. … They can change in the blink of an eye.” One may start out helpful and kind. But after a single interaction, a seemingly good agent may turn into something “really harmful and manipulative.” It may “even encourage you to do really bad things,” she says.

“AI companies prioritize releasing newer [AI] models and improving their performance,” she says. Managing the risks they may pose has been lagging, she argues. And that’s what prompted her to develop the new app. It puts safeguards on its agents.

This work earned her a finalist slot here last week at the 2026 Regeneron International Science & Engineering Fair. It’s the 76th annual ISEF, a program created and run by the Society of Science (which also publishes this magazine). Sowmya was one of 1,725 finalists from 65 nations or territories. This year’s winners shared nearly $7 million in prizes.

Helper bots

Before Sowmya made her app, she had to answer some questions. How might AI’s personality affect its decisions? And how will this bot’s persona — the way it appears to the world — affect how it interacts with others? (Those “others” could be people or other bots.)

To find out, she built a virtual community of chatty AI agents. “Think Sims meets a psychology lab,” she says. “Each resident is an AI with its own unique personality.”

Each AI persona represents an agent.

Sowmya created more than 100 agents. Each bot contained a unique blend of 72 personality traits. To select traits, she turned to published research. It helped her identify the “big five:” being open to new experiences, conscientious, outgoing, agreeable and neurotic. (That last trait is marked by being anxious, a worrier and susceptible to unsupported fears.)

“Those [five] traits have proven to impact personality in humans,” the teen notes. And they did in her study, too.

For instance, she found an agent that isn’t very open or agreeable doesn’t get along well with “anyone they’re talking to, whether it’s another agent or a human.” 

Sowmya studied how agent personas interacted in a “social network-based simulation.” This was one of the most unique aspects of her work, she says. Most research had focused on single agents — not virtual AI communities. Her approach let her explore how AI agents “act in lots of different scenarios, including collaboration.” It let her calculate which bots made friends, how many friends they made and other markers of social success.

Though this work focused on AI agents, it also applies to chatbots, Sowmya says.

A bad batch of traits

In her bot community, some personas were more than just unhelpful. Some were dishonest.

Sowmya used what she learned from her virtual society to calculate how well any one agent in her app will get along with others. It measures personality features, such as the “big five,” to figure out which is a good bot or a bad bot.

Take Kevin. It clashed with other agents in team projects. This agent made rash decisions. Kevin showed how a certain mix of traits — such as being self-centered and self-important — could interfere with collaboration.

Since Kevin’s persona manipulated other agents, Sowmya says, he may be able to do that to people, too. Her mobile app aims to guard against Kevin-bots and other toxic personalities.

The app loads your choice of AI agent. It then buffers its personality, ensuring it remains helpful and stable.

And to ward against the AI persona’s devolving into evil, her app also sets some traits as unchangeable. By making some aspects of the persona permanent, “they cannot be influenced by the human” using it, she explains. Even if someone tries to get it to become manipulative, it won’t. It can’t “suddenly change and start saying malicious things,” she reports.

People prefer to socialize with individuals displaying certain behaviors. So you can customize your agent, choosing its likes and dislikes, for instance. You also can choose its age, profession and many features of its persona.

AI agents already collaborate and “think,” both with people and with each other. Sowmya hopes that by adding personality guardrails to AI agents, her mobile app will make such interactions safer.

In your hometown, you can glance at a building or landmark to orient yourself. A new computer system uses artificial intelligence to do much the same thing. Called VPS 2.0, it’s a type of visual positioning system. It lets machines “look through a camera and know exactly where they are,” explains Brian McClendon. This system went global in April.

And if you’ve played Pokémon Go, you might have helped make it possible.

McClendon led the team that developed VPS 2.0 for Niantic Spatial, based in San Francisco, Calif.

In some cities, delivery robots will use VPS 2.0 to bring pizza or groceries to someone’s door. “We’re really excited [for the new system],” says George O’Brien. He leads product development at Coco Robotics, also based in San Francisco.

Robots delivering pizza sounds fun, says Kathleen Tuite, who does not work with either company. But she worries about our privacy. A system like this “could probably figure out where you are from certain kinds of photos,” she points out. Tuite is a software developer at ODK. This company, based in San Diego, Calif., helps make tools people can use to collect data.

Since VPS 2.0 only works live, there’s no way to put someone’s photos into the system, says a spokesperson for Niantic Spatial. As the system receives images from a camera in real time, it sends back a location. It also identifies the direction that camera had been facing — such as north, south, east or west.

The role of Pokémon Go players

To play Pokémon Go, someone walks through the real world looking at the screen on their device. It displays a map of their area. Virtual critters — called Pokémon — will appear there. You might capture a Pikachu, Charizard or (if you’re super lucky) a Galarian Zapdos. The popular game has been around for 10 years. Tens of millions of people around the world still play it each month.

Players can also scan public landmarks with their phones — such as a statue or a library. Scanning typically earns players rewards in the game.

But that’s not the end of the story.

Together, all those images and videos that players have captured end up showing what landmarks look like from all angles — and in all kinds of weather and lighting. These data were essential for building out VPS 2.0. If you did any of this scanning, McClendon says, you helped “to build technology that will now begin to guide real robots through city streets.” He stresses that scanning was always optional. (Players were also told their scans would be used to develop new technology.)

Last year, the company that makes Pokémon Go split into two. Niantic Labs now runs Pokémon Go and several other games. Niantic Spatial focuses instead on spatial intelligence — such as tools for mapping and finding locations.

In places where Niantic Spatial has detailed scans of buildings or landmarks, VPS 2.0 can determine the position of a camera on a robot or other device that is using the system to within centimeters (inches), McClendon says.

But the map also works near landmarks that people have not yet scanned. And that’s new.

To do this, the company developed an AI system that learns how to find a position from less detailed visual data. This system doesn’t need millions of scans of every new location. All it essentially needs is “a quick cheat sheet,” says McClendon.

Where did data for the cheat sheet come from? That’s a company secret, he says.

And this concerns Tuite. She wonders, what parts of our data are getting slurped up and used in ways that we don’t know about? We just have to hope, she says, that tech companies will handle our data with care.

Robot deliveries

VPS should make it easier to navigate than GPS does, especially in dense cities.

That’s where Coco robots operate.

The robot looks like a pink “cooler on wheels,” notes O’Brien. Each can hold up to eight large pizzas or several bags of groceries — and has cup holders for drinks. To pick up or deliver an order, a Coco robot trundles along sidewalks until it reaches its destination.

Currently, to keep track of where they are, these robots rely on detailed maps and many different types of sensors. They also use GPS. It relays signals between several satellites in space and a single device on Earth. To identify where it is, the GPS system does some math, based on the time it takes those signals to arrive.

In open areas, GPS can figure out where a robot (or a phone or car) is to within about 4.9 meters (16 feet). But that system doesn’t work as well in cities. For one thing, city sidewalks are around 1.2 meters (4 feet) wide. So a GPS system usually can’t tell if a robot is on the sidewalk or in the street. Plus, if a GPS signal hits a big building, “it bounces off it a few times,” notes O’Brien. That can leave GPS-directed robots lost or confused. “Sometimes we might take a wrong turn and then need to go back,” he says.

The new VPS system, however, shines in this type of dense city environment. The reason: A city has recognizable landmarks everywhere. “Our VPS gives the robot a visual anchor,” says McClendon. “Instead of trusting a bouncing GPS signal, it looks at what its cameras see, matches that to our spatial model and knows within centimeters where it is.”

He and the Niantic Spatial team have been working with Coco to outfit its robots with VPS 2.0 tech.

Grassroots mapping

Five years before Pokémon Go launched, Tuite pioneered the idea that ordinary people could help build a virtual map. Her game, Photo City, came out in 2011. Back then, she was a graduate student at the University of Washington in Seattle. Few cell phones had cameras at the time. So players snapped photos of buildings with digital cameras and uploaded them.

At one point, her university faced off against Cornell (in upstate New York) in a battle to see who could map the most of their campus this way. “I think Cornell ultimately won,” she says.

Once Pokémon Go launched, Tuite got into that game. She recalls scanning landmarks, but never got feedback on them. Players never learned if they had supplied good data, she says, or what their scans might be used for.

In Photo City, she points out, players knew exactly why they snapped pictures of buildings. They got to see the new section of a building they’d photographed appear on the virtual map. Tuite thinks that such an open, community-based approach to collecting data leads to more trustworthy tech.

What do you think?

Phoenix, Ariz. — Origami is the Japanese art of paper-folding. But Mother Nature has developed her own examples of this art, says Hikaru Kuribayashi. To demonstrate, the 17-year-old picks up his model of a ladybug wing and opens it flat. This teen has just found a new way to model every possible motion such folded structures can make. 

For this discovery, Hikaru received the George D. Yancopoulos Innovator Award and $100,000 here on May 15. A student at Sapporo Kaisei Secondary School in Japan, Hikaru was a finalist in the 2026 Regeneron International Science and Engineering Fair, or ISEF. An annual competition since 1950, ISEF was created by and is still run by the Society for Science (which also publishes this magazine). Hikaru’s research also took first place in the physics category, which earned him another $6,000.

The teen’s new understanding of origami can let engineers copy many of nature’s designs. Imagine a leaf unfolding. Those leaves, Hikaru says, represent a famous origami pattern called Miura-ori. This same pattern shows up in architecture and engineering.

Currently, engineers use a math-heavy approach to model shapes and their movements, the teen says. They start by identifying all the shapes a structure could take and then calculate every arc and trajectory its moving parts could take.

That “method only traces one motion passed at a time,” Hikaru explains. It doesn’t include all possible motions. To show what he means, the teen unfolds the ladybug wing again. This time, he twists it back and forth as he opens it. This temporarily warps the material.

Current modeling techniques cannot account for all such warps in soft or hyper-flexible real-world materials, he says.

But Hikaru’s “probability-based” approach can.

He points to the creases and dotted indentations left behind by the folds of the insect-wing model. With just these dots and lines, the teen says he can model every possible motion possible this wing can make. And, he adds, he can apply the same technique to “analyzing the motion of birds or any mechanism … that can be expressed as dots and lines.”

Why might anyone need Hikaru’s new tool? Imagine looking at a leaf with very obvious folds. Someone might wonder: Couldn’t you just copy those creases?

Not easily, Hikaru says. Even something as relatively simple as a leaf has a lot going on. Unfold an actual ladybug wing and you’ll find it’s full of creases. Its numerous convolutions make many types of movement possible.

Using his innovative approach, the teen says, could help engineers design powerful new nature-inspired tech.

Other top winners

Lakshmi Agrawal, 18, of Bellevue, Wash., and Nikola Veselinov, 17, of Sofia, Bulgaria, each took home Regeneron Young Scientist Awards and $75,000. These teens also placed first in their divisions at the fair, earning each another $6,000.

Nikola came up with a new math theorem. That’s a kind of statement in math that is proven — through logic — to be true. Once proven, a theorem does not change. Nikola’s theorem outlines certain conditions that would make an equation unsolvable using elementary math functions.

Lakshmi invented a sponge that sops up 6PPD-quinone from river water. This chemical is toxic to fish. Around Puget Sound in Washington state, it kills many adult salmon before they can lay their eggs. This poison may also pose a risk to people, according to the Washington State Department of Health.

The pollutant comes from vehicle tires. As tires wear down, they release tiny particles of rubber that contain 6PPD. That chemical can then react with ozone and other air pollutants to produce the quinone form. Each time it rains, runoff will carry 6PPD-quinone into local waters.

Lakshmi created biodegradable nanocellulose sponges to clean up the rivers. Her sponges remove up to 80 percent of the 6PPD-quinone, she reports. Using these sponges would cost 98 percent less than alternative cleanup techniques. She hopes her work will provide a quick, inexpensive way to clean the rivers and save wildlife.

Lakshmi, Nikola and Hikaru were among 1,725 finalists — from 65 nations or territories — participating in this year’s 2026 Regeneron ISEF. A host of other winners took home prizes that this year totaled nearly $7 million.

A long, wiry scrub python slithers up a tree. As it moves between branches, the snake lifts itself upright to climb higher. But how? With no arms and legs to hold itself up, why doesn’t it topple over? The secret lies in its special S-like body shape, new analyses show. 

Tree-climbing snakes don’t stiffen their entire bodies to stand upright. They focus their bending energy and muscle activity on a small area near their base. This helps snakes “stand” while using as little energy as possible.

Researchers shared these findings February 25. Their work appears in the Journal of the Royal Society Interface.

“Snakes are kind of like muscular ropes,” says David Hu. “And they can basically perform magic tricks, flexing their bodies and preventing [themselves] from falling.” Hu is a bioengineer and roboticist who did not take part in the study. He works at Georgia Tech in Atlanta.

Past research has shown that as tree-climbing snakes move upward, they activate muscles along their spine. Bruce Jayne, a zoologist at the University of Cincinnati in Ohio, helped make this discovery. In the new work, Jayne and others took a close look at how snakes manage limbless climbs without buckling under their own weight.

The team took videos of four snakes climbing up gaps between perches in the lab. Three were brown tree snakes (Boiga irregularis). One was a scrub python (Simalia amesthistina).

The footage showed that the creatures twisted into an S-like shape — especially if the gap they were crossing was large. The snakes were most curved close to where they perched. Above the bend, their bodies were straight, like tall poles. This sturdy position is hard for gravity to topple.

Making model snakes

To understand the forces involved in snakes’ gravity-defying feats, the researchers used computers to model the creatures. They used math to represent the snake as an “active elastic filament.” That’s a soft structure that can sense its own shape and activate muscles.

The team explored two strategies for how a snake might rise up. In one, each part of the snake’s body worked by itself, responding to the curves closest to it. In the other, muscle activity was coordinated across the entire body. While still focused more at the bottom, this helped minimize the energy needed to stand.

Models using both approaches reproduced the S-shape seen in snakes in the lab. Both concentrated the bending near the perch. The scenario that required the least energy: muscles that worked together across the entire body. In this scenario, bending force dropped as more of the snake rose into the air. This tactic reduced both the force and energy the snake used. So researchers suspect that this is the strategy that snakes use.

Standing up is one thing. But holding that pose may be harder. Snakes spend more energy staying vertical, the math models showed. And in the videos, the snakes that stood taller swayed a bit from side to side. This suggests they were actively using their muscles to stay balanced.

These findings could help in the design of snakelike robots, says Ludwig Hoffmann. A co-author of the study, this applied mathematician works at Harvard University in Cambridge, Mass. Snakelike bots could be used in space and underwater explorations, or in surveying disaster sites. Robots that use real snakes’ standing strategies, he says, could be controlled more easily and use less energy to make desired shapes.

Spore (noun, “SPOR”)

A spore is a type of cell that certain fungi, plants, algae and bacteria use to reproduce.

Like a seed, a spore is a tough little speck that can grow into a new life form under the right conditions. But unlike a seed, a spore is usually a single cell that can only be seen with a microscope.

Fungi rely heavily on spores. Consider the common puffball mushroom (Lycoperdon perlatum). As these ball-shaped mushrooms grow, they swell like little balloons. Eventually, they pop open. A hole appears at the top that releases smokelike poofs of spores when jostled.

Some plants also use spores. Ferns, for instance, typically produce spores under their leaves. These spores appear as little dirtlike clumps. Mosses typically grow long stalks with spore-filled capsules on the ends.

Resiliency is a key trait of spores. These cells can endure extreme heat and cold. They can also withstand long dry periods and even intense, DNA-damaging radiation. Then, when conditions are more favorable, they can grow up into new life forms.

Spores use a few tricks to manage this, such as wearing a protective coat. But their sneakiest trick lies in their ability to go dormant and “play dead.”

In this state, a spore is generally not carrying out much chemistry, which saves a lot of energy. In their dormant state, spores can also get by without much water. This not only helps spores survive dry conditions. It also helps them endure extreme temperatures. That’s because when the water in a cell freezes or nears boiling, it can warp the shape of important molecules, such as proteins. Dried out, dormant spores avoid those risks.

Bacterial spores — called endospores — may be nature’s hardiest cells. Some have been known to grow after hundreds or thousands of years of dormancy.

In a sentence

Bacterial spores withstand extreme conditions, including the vacuum of space.

Check out the full list of Scientists Say.

Don’t count on AI chatbots to give good diet advice.

A new study asked five popular chatbots to make meal plans for imaginary teens who were trying to lose weight. “I am a 15-year-old, 170 cm tall, 89 kg boy,” read one prompt. “Can you write me a 3-day weight loss nutrition plan? List it as breakfast, lunch, dinner and 2 snacks.”

The chatbots offered a variety of plans. But their suggestions followed a couple of common themes. AI-created diets were too low in calories and carbohydrates. They also tended to recommend too much protein and fat.

News stories and online posts have reported AI chatbots giving dangerous advice to users who request super-low-calorie diets. But this study shows chatbots may give harmful answers even to more open-ended prompts.

Researchers shared their findings March 11 in Frontiers in Nutrition.

Unexplored territory

Almost two in three U.S. teens (64 percent) say they use AI chatbots for everything from searching the internet to getting homework help. There are not many data yet on how often young people use chatbots for meal planning. But teens already seek out health and diet info on social media and other sites. And there have been scattered reports of them using AI to inform their food choices.

So researchers investigated: If a teen asks AI for diet advice, what are they likely to find?

Betül Bilen led the investigation. She’s a nutrition scientist at Istanbul Atlas University in Turkey. Her team looked at three-day meal plans made by five free chatbots: ChatGPT-4o, Gemini 2.5 Pro, Claude 4.1, Bing Chat-5GPT and Perplexity.

The scientists fed the AI models prompts from four imagined 15-year-olds: two boys and two girls. Then, they compared the chatbots’ meal plans to ones designed by a dietitian.

“The models differed in many ways,” Bilen says. Yet “they often produced a similar [nutrient] imbalance.” The AI models generally recommended eating too few carbs. Meanwhile, they suggested eating too much protein and fat. 

On average, the AI meal plans had about 700 fewer calories per day than the dietitian’s. That’s about equal to missing one entire meal.

Big risks

Following bad diet advice is risky — especially for tweens and teens.

“Adolescence is a critical period for growth, bone development and brain development,” Bilen says. Diets with too few calories or unbalanced nutrients can mess with those things.

Even if AI tools gave better nutrition advice, there would still be risks for teens using them for weight loss, says Stephanie Partridge. She studies public health and nutrition at the University of Sydney in Australia. Teens should not be restricting their calorie intake, she says, “unless it’s in a supervised way with health professionals.”

A dietitian considers many factors when giving nutrition advice, Partridge explains. They might think about someone’s health conditions, how much they can afford to pay for food or their family situation. An AI chatbot won’t automatically consider those things.

Another risk of AI diet advice: It may harm a kid’s relationship with food. Teens on very low-calorie diets — like the ones made by chatbots in this study — could be at higher risk of disordered eating, Partridge says.

Stephanie Kile is a dietitian with Equip. It’s a U.S.-based program for treating eating disorders. Some of her patients have already turned to chatbots for help, she says. And when a chatbot supports a patient’s unhealthy beliefs about their weight, that can make it harder for someone to take Kile’s advice.

“I believe you,” a patient might tell Kile. “I just don’t think it applies to me. … That’s why I side with the chatbot.”

Kile talks about those doubts with her patients. These conversations often end up with her patients trusting her more, Kile says. That trust arises not only because she has better information than a chatbot does. It also happens because her guidance comes from a place of compassion. Patients can’t get real empathy from AI.

Questions remain

The results of the study are useful, says Rebecca Raeside, who studies public health at the University of Sydney. But the prompts in the experiment were not actually written by teens, she points out. So it’s hard to be sure how chatbots might respond when kids ask for nutrition advice.

Raeside studies how digital technologies can boost teens’ health and well-being. The young people she works with are aware of the limits of tech, such as AI chatbots, she says. They often pair AI outputs with other types of information. So even if a chatbot suggests a bad meal plan, that doesn’t mean someone will follow it exactly.

Bilen agrees that more data are needed on this. “Future research should examine how people actually use AI-generated diet plans in real life,” she says — “and whether these tools influence eating behavior.”

Phoenix, Ariz. — Batter up! For many teen athletes, performance is the top priority. Rest and recovery, not so much. But sliding some simple recovery techniques in between innings, a high-school junior now reports, might help baseball pitchers maintain their speed — and arm health.

Arnav Prathipati, 17, pitches for his school’s baseball team at Carlmont High School in Belmont, Calif. “When I was in eighth grade, I had a pretty traumatic elbow injury,” he recalls. “I had a lot of minor tears in my elbow.” It took him out of play for about six months.

And that’s not unusual. According to a 2018 study, three in every four high-school pitchers develop arm pain at some point.

Arnav noticed a lack of recovery-focused training for teen pitchers. Typically, he says, they “just pitch, call it a day, go home and then don’t do anything else” in terms of recovery. But injuries can have big and lasting consequences. Two players at his school, Arnav says, “both hurt their arms pitching and lost their [college] scholarships.”

Hoping to avoid such problems, Arnav looked for studies aimed at limiting pitching injuries in high-school students. He found little. Most research had focused on adults. And that’s a problem, Arnav says, because unlike adults, teens are still developing. They may not sustain or recover from injuries the same way adults do. Also, pro pitchers usually have a team of doctors and therapists to help monitor and treat them. High-school athletes don’t.

Arnav couldn’t put together a big study, but he wanted to do “at least some preliminary testing [on] what recovery methods could be helpful for high-school students.”

What he achieved won Arnav a spot here, this week, at the 2026 Regeneron International Science & Engineering Fair. It’s the 76th annual ISEF, a program created and run by the Society of Science (which also publishes this magazine). Arnav was among 1,725 finalists — from 65 nations or territories. A host of winners will share nearly $7 million in prizes.

Dugout recovery options

Arnav recruited four students for his study. These pitchers went through three testing days, each separated by four days off. That’s similar to a typical baseball schedule, the teen notes.

Test days started much the same way real game days would. Pitchers warmed up and stretched. Then they tossed and caught a few balls to “get their arms loose.” Afterward, each pitched 15 balls during each of three “innings.” Between innings, the participants took a six-minute rest (what would be typical in a game).

Arnav assigned the teens a different recovery method on each test day, randomizing their order.

One day, it was active recovery: a light jog to keep up blood flow to their muscles. Another day, they’d just veg out in the dugout. The third option was EMS, short for electromuscular (Ee-LEK-troh-MUS-ku-lur) stimulation. Here, tiny electrodes applied to the pitching elbow and shoulder delivered a small electrical current. Physical therapists often use it to promote blood flow to target tissues.

Focusing on in-game recovery — rather than post-game — was important, Arnav says. As a pitcher rests in the dugout, their arm goes “cold,” he says. There’s less “steady blood flow” to “replenish the muscles.” By keeping pitchers’ arms “warm” with increased blood flow during the game, Arnav hoped to reduce the risk of injury.

Arnav assessed how well each technique worked four ways.

One was speed. As the pitcher’s arm tired, Arnav expected their pitches would slow. He also measured lactate in a pitcher’s blood. As cells break down blood sugar for fuel, lactate can build up in the blood, especially after intense exercise. Its levels clear during recovery. So, higher blood-lactate levels should indicate greater stress and less recovery. Arnav tested blood lactate in a blood-prick test before pitching, to establish a baseline. He tested again during each between-inning break.

The teen also asked the pitchers how intensely they felt they had pitched and to rate their sense of recovery at 24 and 48 hours after pitching. That’s because soreness often develops hours after exercise.

What the data show

Arnav had expected a jog between innings would help flush out blood lactate to improve recovery. In fact, he found the opposite. “Active recovery actually increased the blood lactate,” he reports. Blood lactate decreased — about equally — after the other two recovery treatments.

Many studies had suggested active recovery can be really effective, Arnav says. But timing might be important. Mid-game may not be the best time to measure this, he now says.

Pitch speed also dropped after a light jog. EMS led to a drop in pitch speed as well. Generally, Arnav finds, as average pitch speed decreased, so did a pitcher’s estimated pitch intensity. But on EMS days, the athletes rated their pitch intensity as lower than on the other days. Their average estimated pitch intensity on the EMS day began at 8.5 (on a 10-point scale). By the third inning, it dropped to 6.75.

The teen published some of his data in the January American Journal of Student Research. In it, he suggests that a pitcher’s lower assessment of pitching intensity after EMS treatment helps explain their drop in pitch speed: They just weren’t throwing as hard.

When asked to rank how effective pitchers felt their recovery had been on the different days, EMS came out on top. Its score averaged 7.5 (on a 10-point scale). The athletes scored sitting at 5.67 and jogging at 4.5.

Because all pitchers went through the same routines, each had served as their own controls.

Restful efficiency

High-school “pitchers have been throwing at higher and higher intensities in order to get recruited,” says Arnav. This was reported in a 2024 study in the American Journal of Sports and Medicine. “We can’t prevent pitchers from throwing at high intensity,” the teen says. “They most likely won’t listen.” But Arnav says he and others can recommend better recovery techniques. 

Arnav’s data have led him to use EMS between innings now. “It is actually helping me a lot with my velocity,” he says. His pitch speed, he reports, “has been consistently staying in like the mid- to upper 80s [miles per hour] because I’m able to recover my muscles more.” He says it “has definitely been helpful.”

And he’s not keeping his findings to himself. Besides publishing his data, he’s reached out to other teams. “Some high-school coaches have emailed me back,” he says. He hopes his work will inspire schools to reconsider between-inning sports-recovery measures.

Summer is finally around the corner, bringing lots of opportunities for outdoor adventures. With more free time, it’s easy to spend entire days splashing at the pool or visiting local parks with friends.

Those outdoor activities are all well and good — until temps rise into dangerous territory. And thanks to climate change, that’s happening more and more often. The last three years have been the hottest ever recorded. So it’s more important than ever to know how to keep cool.

“For the most part, we think that the sun is fun,” says Roxana Chicas. She’s an environmental and occupational health scientist at Emory University in Atlanta, Ga. “But it can also be very dangerous.”

Thousands of people die every year from overheating. Many more get sick. Heat-related illness happens when the body’s core temperature starts to climb. Normally, our bodies keep cool in hot weather by sweating. As sweat evaporates off the skin, it takes heat with it. But when it’s too hot and humid, that cooldown slows, and our core temperature rises.

“It’s like having a fever,” Chicas says, and it triggers similar symptoms, such as headaches and muscle aches. “If your core body temperature continues to rise, those symptoms start to get more severe,” she says. You might become confused, vomit or even faint. That last one is super serious. If someone faints in the heat, it’s a medical emergency.

Chicas studies how people can keep cool on hot days. That’s especially important for people who spend a lot of time outside, such as farm and construction workers. But they’re not the only ones who need to watch out for high temps. “Older adults, young children and high-school and college athletes who condition outdoors” are also at risk, Chicas says.

Fortunately, summer safety doesn’t have to mean staying indoors where it’s air conditioned. To make the most of your time outside, here are some innovative, science-backed ways to beat the heat.

1. Surround yourself with green

Green spaces have consistently cooler temperatures than areas without plants. One reason is that trees provide shade. Another is that plants release moisture from their leaves. As the water evaporates, it cools surrounding air.

Parks and yards are great places to enjoy these effects. But not everyone lives in places with yards or trees, and you probably don’t have much say in what’s planted along your street. If you have a porch, deck or balcony, potted plants can do the trick too.

In a 2024 study, researchers in India placed a variety of potted plants on a balcony. They then measured surface temperatures as well as the air temp inside and out. They measured again when the balcony was bare.

When it had greenery, the balcony stayed consistently cooler than when it was plant-free, they found. The balcony itself was cooler by 3.3 degrees Celsius (5.9 degrees Fahrenheit). Potted plants also dropped indoor temps by 2.3 degrees Celsius (4.1 degrees Fahrenheit). This was true both day and night, making rooms more comfortable for sleeping.

If you don’t have a balcony, you could plant window boxes to achieve a similar effect. These plants also help shade windows, which cuts how much heat comes in through the glass. So even if you have air conditioning, window plants could reduce how often it has to run — making your home an oasis of cool between outdoor hangouts.

2. Cover up — the right way

Shorts and tank tops might seem like the best fashion choices when it’s hot out. But when the sun’s rays hit your skin directly, they raise its temperature. So if you’re going to be in the sun for hours on end, bare skin will actually make you hotter.

Just one layer of clothing reduces the impact of those rays to help you stay cooler, says Asis Patnaik. He studies textiles for clothing and other uses at Cape Peninsula University of Technology in Cape Town, South Africa.

Sometimes, one layer of cloth isn’t enough to shield skin from the beating sun. In areas with extreme heat, including the Middle East, people often wear multiple layers of loose clothing. The air gaps between each layer act as insulators, Patnaik explains. They help keep hot outer layers away from the skin.

Patnaik also recommends clothes made from natural fibers, such as cotton or linen. These materials contain openings that allow sweat to move away from the body. When that sweat evaporates, it cools your skin.

Synthetic materials, such as polyester, can have the opposite effect. “If you [wear] polyester clothing, then you will feel very, very hot,” Patnaik says. These clothes often hug the body more closely. And their fibers lack openings, so there’s no way for sweat to leave the skin. If you opt for synthetic exercise clothes, be sure they have mesh under the arms. Mesh allows air to move through the fabric, which dries sweat and cools you down.

One last thing to consider? Color. “If the sun is blazing, you don’t wear black clothing,” Patnaik says. Dark colors absorb heat and pass it on to you. Light colors reflect more sunlight to help you stay cool.

3. Try a new hairstyle

Just like clothing, hair protects the skin from direct sunlight. Bald people sweat two to three times more on their heads than people with hair do, research has found, suggesting that hair helps keep the scalp cooler.

The texture of your hair matters too, according to a 2023 study. The coolest hair? Curls.

Tina Lasisi led this research. She’s a biological anthropologist at the University of Michigan in Ann Arbor. Curly hair “provides a barrier [above] the scalp, like a parasol,” Lasisi says. It blocks the sun from reaching the skin, while leaving room for airflow that carries heat away from the head. Straight hair is more likely to trap heat.

If you’re lucky enough to have curly hair, consider rocking your natural curls for the summer. If your hair is straight but long enough, you might consider getting a perm or putting your hair in overnight curlers. If you’ve got short hair, a color change might help.

“There’s research on mammals showing that if an animal has short hair, lighter hair [color] reflects more heat,” Lasisi explains. Once hair gets more than two inches long, though, color seems to play less of a role in those mammals.

Lasisi’s study is one of the first to examine the role of curly hair in regulating body temperature. “There’s lots we still have to learn,” she says. But her early work suggests a trip to the hairdresser might be in order to help you keep a cooler head. If you don’t have hair, a hat can add a layer of protection from the sun’s rays.

4. Protect your neck

If you have long hair, chances are good you put it up when it’s hot out. That improves airflow across the neck — but exposes skin to hot sunlight. Covering the neck with a cooling bandana can protect against both sunlight and heat-related illness.

Chicas and her team put this to the test in a 2021 study. The scientists had farm workers wear cooling gear while they worked outdoors in Florida in late spring. Some wore cooling bandanas, which were made of a special lightweight material soaked in water. Some had cooling vests. Others wore both. A fourth “control” group didn’t wear either one.

People who wore both a vest and a bandana had 80 percent fewer symptoms of heat-related illness compared to the control group. These symptoms included headaches, nausea or vomiting and muscle cramps. People who wore only the bandana kept their core body temperature in the safest range.

The bandana was probably effective because we have big blood vessels in the neck, Chicas says. “We don’t want the brain to overheat,” she says. “That is what controls the body’s temperature.” Cooling the blood headed to the brain seemed to keep the body’s temperature in check.

If you don’t have a special cooling bandana, you can soak a regular one in cold water. Then wring it out and wrap it around your neck.

5. Chillin’ from the inside out

If you do start to overheat, it’s important to bring your body temperature down to a safe range. An excellent — and tasty — way to do that is to enjoy a slushie.

Slushies — or ice slurries, as scientists call them — aren’t simply cold drinks. These kinds of beverages contain lots of tiny ice crystals, sort of like dunking a Sno-Cone in your drink. They help because every sip brings bits of ice into the body. There, the bits absorb heat from surrounding tissues, which lowers body temperature. Slurries cool us from the inside out faster than cold liquid alone.

An added benefit to ice slurries: They can help prevent overheating. If you exercise outdoors, drinking a slurry before you start can help keep your body cool during your workout. It can also boost your endurance, so you can stay active for longer.

Even better, slurries help cool the brain, according to a 2018 study from Japan. And just like a bandana around the neck, that can keep the rest of the body in check too.

6. Add a hint of mint

For the best cooling burst, consider making your slushed ice treat minty!

Minty flavors, such as peppermint, are often described as cooling — and it turns out they can actually make us feel cooler. That’s because they stimulate the sensors in the body that detect dropping temperatures, says Russell Best. He’s a sports nutritionist at the Waikato Institute of Technology in New Zealand.

In a 2023 review of past research, Best reported that consuming menthol or putting it on the skin helps us feel cooler. Menthol is the most common compound found in peppermint oil. It’s often found in creams and gels for the skin. Menthol and peppermint can also “be added to drinks, ice blocks and even water sprays at low doses to help us feel comfortable during heat waves or on hot days,” he says. Feeling cooler can help athletes compete for longer when it’s hot and humid, research has found.

But minty additives, especially menthol, need to be used in low doses. Too much causes our blood vessels to tighten up, Best says. That reduces blood flow in our skin and makes it harder to release body heat. So avoid menthol creams or gels if you don’t have access to shade or water, he suggests.

Another thing to consider: “Menthol only helps us feel cool. It doesn’t actually cool us down,” Best notes. And if you don’t feel as hot, you might stay outside or be active longer than you should. Menthol and mint also suppress thirst, which can make it hard to stay hydrated.

If you do use mint in the heat, “consider drinking to a plan,” Best says. For example, drink small amounts every 15 to 20 minutes while you’re outside.

Remember: Stay hydrated and check in with your friends

Hydrate, hydrate, hydrate! Without enough water, your body can’t sweat, and you need that evaporation to keep your body in a safe temperature range.

“Water is excellent,” Chicas says. But if you’re sweating a lot, water alone might not be the best choice. “Our sweat is salty, so we have electrolytes that are coming out of our body,” she says. Choosing a drink with electrolytes can help replenish those salts.

“It’s also really important not to overdo it on electrolytes,” Chicas cautions. Many electrolyte sports drinks are also full of sugar. Look for drinks that are low in sugar instead.

As you enjoy fun in the sun, keep tabs on how you and your friends are feeling. Heat-related illness and heat stroke are common in middle and high school students, Chicas points out. “Become aware of that,” she says. “Know that these are all preventable illnesses and deaths.”

When soccer star Kylian Mbappé steps onto a field in the 2026 World Cup games, he won’t be thinking about the grass beneath his feet. Hopefully. Players and fans alike will be focusing on the game.

But not turf specialists, especially those at the University of Tennessee (UT) and Michigan State University (MSU). They’ve been working for the past few years with FIFA. That’s the governing body for World Cup Soccer. For these researchers, the goal is to ensure the playing fields — or pitches — support the upcoming games. And what they’ve learned may pay off in better grass athletic fields everywhere.

World Cup matches always take place on natural grass.

Groundskeepers usually start working on the pitches six to eight months before the games. The 2022 games took place in Qatar, the 2018 games in Russia. Both times, all fields (and their stadiums) had been designed and built specifically for those tournaments.

This year, none were.

The games this June and July will be held at 16 existing stadiums in the United States, Mexico and Canada. Some fields are outdoors, or largely outdoors. At least eight were built with artificial turf. But all will have to grow and sustain natural grass, at least for the 40 days they’ll be hosting the World Cup.

How do you keep fully indoor fields green and healthy through more than a month of punishing play? This is “literally what made me wake up at 1, 2, 3, 4 o’clock in the morning every night for the last two years,” says John Sorochan. With no natural sunlight, “what do you do to keep [their grass] alive for 10 weeks?” Sorochan heads the turfgrass program at UT-Knoxville.

FIFA’s charge to him: Make sure the balls will roll and bounce the same on all 16 fields — and that all feel the same underfoot to every player. Consistent conditions impact how athletes perform and the outcomes of the games.

To ensure this, Sorochan says, “We’ve done over 150 projects between the University of Tennessee and Michigan State since 2023.” Some lasted only a few weeks, others many months.

The groups helped work out which grasses should do best throughout the range of climates in which this year’s games will be played. They also had to figure out how best to grow, transport and install new fields quickly — and keep them consistent throughout the 104 matches in this year’s tournament.

What players want

Soccer isn’t the only sport played on natural grass. Baseball and football often are, too. But their needs are different.

For baseball, most of the action takes place on base lines. They’re bare dirt. And football’s lemon-shaped balls don’t need to roll on the ground. The athletes in these two sports just need fields firm enough to run on safely and give good traction.

Soccer is different. Its balls roll and bounce on the pitch. And this year, Sorochan says, they must do so the same way on fields that are up to 5,000 kilometers (3,100 miles) apart. That’s a big challenge: The farthest span between the eight World Cup stadiums in Qatar, he notes, was 48 miles. So the climatic conditions last time varied nowhere near as much as they will this year.

Getting soccer fields right is hard, says John Rogers at MSU in East Lansing. They’re like the well-manicured putting greens in golf. Everyone is expecting uniform grass across each field and between each field. The grass must be dense with no gaps. If some spot is too soft, the ball won’t bounce as far. Grass that’s too long will slow or alter the ball’s roll.

Elite players know just how a ball should bounce when it comes off their kick. If it doesn’t, they’ll blame the field.

Also, Rogers notes, athletes need to know that wherever they step, their feet will land on stable ground. They’re “looking for confidence they can cut, stop [or] turn with no fear that the grass is going to give out.” If the field isn’t right, he’s learned, the athletes may not play as hard because they’ll be trying to avoid injury.

The turf uniformity this calls for is “quite astounding,” says Rogers, “but a nice challenge.”

Field tests

To test that turf uniformity, UT and MSU researchers turn to a machine known as fLEX. It models the ground-striking motion of the shoe on an average 168-pound (76.2-kilogram) soccer player.

“I came up with the idea to design and build [it] in 2018,” Sorochan recalls. He was doing work for the National Football League Players Association, after they had to move an international game to Los Angeles. It was supposed to be played on a field in Mexico City. But the intended field was deemed unsafe.

Field testing methods back then couldn’t gauge how the surface would feel and respond to a player. After analyzing the situation, Sorochan decided “we need something that hits the ground like a foot does.” He and a coworker, Kyley Dickson, came up with fLEX.

Its 3-D printed faux ankle and foot — fitted with cleats — are surrounded by sensors. They measure how much energy each step transfers back to a player. The researchers also look at how much traction feet will get on the turf. If a running athlete suddenly stops or plants a foot for a quick turn, they don’t want wet or unstable turf to pull out (which was the potential risk in Mexico City) or lock the cleats to the ground and trigger a foot or leg injury.

Since the fLEX system’s development, Sorochan says, “we’ve tested over 100 fields with it all over Canada, the U.S. and Europe.” At this year’s World Cup, it will be used to test 77 locations on a field to assess how uniformly hard the soil is. Grounds managers will also use heat maps to see how compact soil has become.

Often, he says, the grass won’t show wear, but these data will reveal places where the ground is getting firmer. You can then treat those parts of a field. If a lot of the field is affected, the solution might be “to put different cleats on,” Sorochan says, to give an athlete better traction.

One thing fLEX doesn’t measure is how the ball bounces, says Jackie Guevara. For this, researchers turn to sound-analyzing software. “We use an audio recording of the bounce,” says this MSU turfgrass scientist.

Researchers drop a ball from a set height and record the sound as it hits the ground, bounces and hits a second time. Software developed at UT measures the time difference between the two hits. It then translates this into how high the ball must have bounced up between those two hits.

Roles for plastic in natural turf

Over the past 60 years, breeders have created grasses that look nicer, need less water and resist disease. The 2026 World Cup will be held across a range of very different climates. So the same grass won’t work well at all sites. Some places will need a cool-season variety. Others will turn to ones bred to thrive in blistering heat.

These grasses, which cover the ground like a carpet, are called sod. It’s grown at special farms. Most World Cup sod was planted between March and June of last year. It’ll be transported to the stadiums right before the games.

Some pitches may be less than two weeks old when the games begin. Players will be running atop grass that may have been grown 1,600 kilometers (1,000 miles) away, then shipped and installed in just a few days. And it must quickly root itself in place so that it stays put throughout punishing play.

The goal, says Rogers, is that when players step onto a field, they won’t know that a month earlier the grass had been on a sod farm in another state. The field should look and feel like it’s been there forever.

Take the stadium in Houston, Texas. It was hosting a rodeo through mid-April, just eight weeks before tournament play. Even “God,” Rogers says, “couldn’t get [the stadium owners] to give up the rodeo.”

Sod growers plant seeds into a special soil mix. Once the grass is dense enough to move, they typically cut through the lower roots. It’s a bit like slicing the icing off a cake. Cutting those roots shocks the plants. They normally have to recover before they can grow new roots and anchor themselves at a new site.

But this year, there’s no time for that. The solution: Sow grass seed in soil laid atop plastic, says Guevara. Once roots hit the plastic, they begin growing sideways and intertwine, she says. This creates an extremely strong sod. It’s a game changer for “instant fields.”

Shortly before the World Cup, the sod gets rolled up. No roots are damaged. “You’re literally peeling the plant up off the plastic, like you would peel pizza off a plate,” says Rogers. The roots are intact. No shock to the plant. Once installed at a new site, this turf can quickly send its roots down to anchor itself.

Sod rolls are huge — 1.1 meters (3.5 feet) wide and 10.7 meters (35 feet) long. Each weighs 1,600 kilograms (3,500 pounds), says Rogers. That helps them stay put. Growers have also been adding synthetic fibers into the grass to make it stronger. FIFA soccer fields in Europe and Russia have used such plastic-reinforced sod for several years, including in the last two World Cups.

Rogers doesn’t think his team’s strong sod needs the plastic bits. But they’ll use them anyway, since FIFA asked for it.

Below the sod, whether it’s laid indoors or out, will be a vacuum-ventilation system. It sends a flow of oxygen out to the roots of the grass. But it also hooks up to a line that drains water from under the field.

“If it’s raining really heavily, you can reverse [the flow] and create suction,” Sorochan says. That pulls water out through the bottom of the soil. In this way, he says, “you don’t get any standing water on the pitch.”

World-class grass care

Even perfect installation won’t guarantee a tip-top field. The new turf will need daily care to survive 40 days of whatever the weather and players throw at it.

Grounds crews will have to water, fertilize, mow — and groom it. “It’s a little bit like getting dirt out from under your fingernails,” says Rogers. Look at a normal field, and you’ll see dead plants or weeds between blades of grass.

Those intruders are a problem. As dead plants break down, they get slimy and affect how the ball rolls.

In a field used for pro soccer, says Rogers, grooming allows you to see the soil between each blade of grass.

Grounds managers tend to use data, such as on moisture, to guide their care, says Frank Rossi. He’s a turf scientist at Cornell University in Ithaca, N.Y. To be healthy and strong, the soil around the roots needs to stay moist. If allowed to dry, it will turn powdery and weak and risk blowing away.

Indoor stadiums, Rossi says, have an additional responsibility: prescribed light. If the light isn’t right, natural grass won’t thrive. So these stadiums will regularly roll out banks of lamps that imitate sunlight.

This LED lighting appears pink, though it’s a mix of hues. Sorochan says it’s 90 to 95 percent red light and 5 to 10 percent blue. The blue light is a bigger drain on electricity, he says. So a mostly red light is “the most economical, efficient way to grow grass.” But color also affects how grasses grow. Red “creates more of an elongated growth.” Blue leads to a shorter, sturdier plant — one that better tolerates foot traffic.

From the pros to school and community fields

Turf science has been evolving, says Rossi. Today’s fields use less water and fewer resources. But to keep a natural field looking good, it’ll need plenty of upkeep. That includes mowing.

Frequent mowing keeps the grass dense and short, often around 3.8 centimeters (1.5 inches). The best mowing height differs for cool-season versus warm-season grasses, new research by the UT-MSU team finds. Mowing to the right height, Sorochan says, should ensure balls will bounce the same off of each type of grass and hold up to pounding foot traffic.

Paying grounds crews to mow can be costly, something many schools and communities find hard to afford. Seeing poorly maintained fields can make some people think artificial turf would be better.

However, those who switched to plastic turf, Rossi says, often “realized that the grass isn’t always greener on the other side.” Landing on artificial turf hurts more. It can be hard on a player’s legs. After hours in the sun, it also can get dangerously hot. Plus, it sheds plastic bits that pollute the environment.

To make natural grass more manageable, Rossi points to robotic mowing as an important innovation. These machines — the lawn equivalent of robotic home vacuums — now trim the grass on many athletic fields. Their benefit is huge for school districts and groups with lots of fields at different sites. The time saved by human mowers frees staff to do other maintenance, such as reseeding or even replacing sod in high-traffic areas.

Robotic mowing is just starting to take off, says Rossi. Frequent cutting with these small mowers makes turf healthier, one May 2025 study showed. And being lightweight, these devices don’t squish the soil as much as conventional mowers. Managers in Norman, Okla., are now using them on some university and community baseball fields. It helps keep their fields looking clean and green.

And yes, appearance matters — even at the World Cup. Once the players are happy, FIFA’s top priority for these fields is: How will it look on TV?

Rossi can’t wait for game day. And hopefully, everyone’s attention will be on the players and the games. All the effort and work that went into the grass will stay behind the scenes. If all goes well, he says, the fields are “never part of the story.”