In 2021, Volkswagen AG approached the global law firm Freshfields with a problem. The German carmaker’s technology unit was preparing to release new software features and wanted to make sure that they would be compliant in the more than 100 countries where Volkswagens are sold. Ordinarily, Freshfields said, it would bring in lawyers from each jurisdiction to vet the updates, budgeting thousands of euros per country — a process that would need to be repeated if any components changed in the futur

"I actually started crying."

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This weekend, Earth will be treated to a nice blue moon. Our planet’s only natural satellite won’t put on a pleasant azure hue (indeed, blue moons have nothing to do with color). Instead, it will be the second full moon for the month of May, following the full Flower Moon on May 1. The blue moon will reach peak illumination at 4:46 a.m. EDT on Sunday May 31. 

Seasonal vs. calendrical

According to the Farmer’s Almanac, there are two definitions of a blue moon—a seasonal blue moon and a calendrical blue moon.

A seasonal blue moon is one extra full moon within an astronomical season, or the dates between solstices and equinoxes. A typical astronomical season has three full moons within it. If it has four full moons instead, then the third may be called a blue moon. 

A calendrical (or monthly) blue moon is the one most of us are familiar with. It is the second full moon to fall in one calendar month—like in May 2026. It takes the moon roughly 29.5 days to complete one cycle of phases (new moon to new moon). So if a full moon falls on the first of the month on the calendar, there will be a second full moon at the end of the month. The only month in which a calendrical blue moon cannot fall is February. 

How rare are blue moons?

Blue moons are not quite as rare as the phrase “once in a blue moon” makes it sound. Calendrical blue moons happen every 2.5 years (or 30 months) on average, and seasonal blue moons fall about once every two to three years. 

The last calendrical blue moon was on August 31, 2023 and the next calendrical blue moon will rise just in time to ring in the new year on December 31, 2028. 

Two blue moons can also occur in one year. In 2018, January and March both had two full moons, with no full moon in February. The next time two blue moons will fall in one calendar year won’t be until 2037.

Why is it a micromoon?

May’s blue moon will also be a micromoon and the smallest micromoon of the year. Micromoons have nothing to do with size and everything to do with distance. Typically, the moon is about 238,855 miles away from Earth. Micromoons are further away, and this month’s micromoon will be 252,360 miles away. With the further distance, a micromoon may appear a bit smaller and dimmer than usual. 

On the opposite end of the spectrum are supermoons, which are closer to Earth at only 225,130 miles away.

How to watch and photograph a blue moon

If you want to see the blue moon rise over a historic city, the Virtual Telescope Project will broadcast the event live from Italy. 

NASA has also put together a handy lunar photography guide if you want to snap that perfect moon pic. If using a smartphone, NASA recommends stabilizing the device, turning off the flash, and tapping the moon on screen to focus the camera directly on it instead of the sky. Your brightness also needs to come down and taking pictures at twilight or as the moon clears the horizon will give the sensor less contrast. 

The post Look up for a blue moon on May 31 appeared first on Popular Science.

Sunburn and mosquito bites go together in the summer like a hot dog and ketchup. To keep from becoming a mosquito buffet, most of us turn to bug sprays with DEET.  An acronym built from its scientific identification (diethyltoluamide), DEET was developed for the United States Army in 1946 and entered civilian use in 1957. It is generally considered safe when used as directed. 

However, mosquitoes can learn to associate the repellant with food. They may even become attracted to it. The findings are detailed in a study published today in the Journal of Experimental Biology.

“If someone applies DEET and the concentration fades over time, but a mosquito still manages to feed, the insect may begin associating that smell with a reward,” Clément Vinauger, a study co-author and biochemist at Virginia Tech, said in a statement. “That’s a possibility we should take seriously when we think about how repellents are used in the real world.”

Ace processors

Like it or not, Earth’s over 3,500 known mosquito species are pretty smart and an evolutionary wonder. They use sensory information to find hosts and can adapt to changing environments.

In previous studies, Vinauger’s team has shown that the insects remember and avoid hosts who swat them away, can combine smell and vision to precisely track humans, and even gravitate toward and away from the smell of certain soaps.

“Mosquitoes are remarkable at processing information about their environment,” Vinauger said. “What we are trying to understand is not only how they detect us, but how their brains interpret those cues and turn them into behavior.”

A DEET-covered dinner bell?

In this new study, the team focused on the yellow fever mosquito (Aedes aegypti). This species spreads several diseases to tens of millions of people each year, including dengue fever, Zika, yellow fever, and chikungunya.

The team trained mosquitoes using a form of Pavlovian conditioning. Often called “Pavlov’s dogs,” this training method developed by neurologist and physiologist Ivan Pavlov in the early 20th century was used to teach dogs to associate the sound of a bell ringing with food. 

The mosquitoes were restrained behind a piece of fabric mesh. They then offered the mosquitoes a bag of warm blood (yum) that was just out of the insects’ reach to see how enthusiastically the insects stabbed at it with their proboscises. As expected, the mosquitoes were interested in the blood, particularly when the team rewarded them by lowering the bag within reach. Things changed a bit once DEET entered the experiment. When the team offered the insects blood when surrounded by the scent of DEET, they initially stayed away from the potential feast.  

To see if they could be trained to associate that smell with the dinner bell, the team fed the mosquitoes warm blood for 20 seconds, squirting the scent of DEET into the enclosure in the final 10 seconds of dining. They repeated the procedure three more times before noting how the mosquitoes responded to only the scent of DEET. In this trial, over 60 percent of mosquitoes tried to bite when they smelled DEET.  

To examine further, the mosquitoes were given a choice between two human hands. The hand belonged to study co-author Ayelén Nally of the University of Buenos Aires. One of Nally’s hands was coated with DEET at normal concentrations and the other was bare. The untrained mosquitoes avoided the DEET-treated hand, while the trained mosquitoes were drawn to it.

Interestingly, the mosquitoes could form that same association when sugar, instead of blood, was used as the reward. 

According to the team, they are seeing how the mosquito’s brain can rewrite its response based on their experiences. What they have learned matters just as much as what a chemical like DEET does. 

“If mosquitoes are repeatedly exposed to DEET, it becomes less effective as a repellent,” study co-author Claudio Lazzari from University of Tours in France added.

Keep the bug spray

Importantly, this does not mean you should stop using DEET completely. It is still one of the most effective ways to keep the dangerous insects away, particularly where mosquito-borne disease is common.

“If you’re in tropical regions where disease risk is real, you should use it,” Vinauger said. “Instead of applying a lot at once, you may want to reapply regularly so it’s always active and providing continuous protection.”

Treated clothing may also be a challenge since DEET concentrations in fabric decline over time. Additional study to understand their behavior is crucial for public health as mosquito-borne illnesses increase due to climate change. 

“We need to understand how mosquitoes keep outsmarting our control strategies,” Vinauger concluded. “And that takes understanding how they work—at the molecular level, the neural level, the behavioral level.”

The post Mosquitoes can learn that DEET means dinner is served appeared first on Popular Science.

As NASA looks ahead towards Artemis III in mid-2027, the agency is sharing new details on several projects, including a future permanent moon base and a drone mission called MoonFall. The mission will send four drones to survey the surface of the moon’s South Pole to spot potential landing sites for future Artemis astronauts. 

According to the update, the Jet Propulsion Laboratory (JPL) in Southern California has been developing the drone design and testing prototype hardware ahead of the scheduled 2028 launch. Each drone will land on the moon’s surface and gather high-resolution imagery of the terrain over the course of a single lunar day (up to 14 Earth days). After each drone’s last flight, its survive-the-night payload will continue to work for several months. Payloads that are designed to survive-the-night can endure the sub-zero temperatures of the lunar night, which can get as cold as -208 degrees Fahrenheit.

Each of the four drones should weigh about 550 pounds, and stand at four-feet tall and seven feet in diameter. They will use a Lunar Dashcam imaging system to create maps of the terrain. The drones will also be equipped with a laser retroflector array so that mission control can precisely locate the drones, a neutron spectrometer system to help determine how much (if any) subsurface water is present, and a spectrometer to measure radiation.

Texas-based Firefly Aerospace was selected to build the spacecraft that will transport the drones. Firefly’s Elytra spacecraft will carry the drones for a 45-day transit from the Earth to the moon. After entering lunar orbit, it will deorbit and perform a braking maneuver to send out the drones roughly 31 miles above the lunar South Pole.  

No stranger to lunar exploration, Firefly Aerospace’s Blue Ghost lander became the first commercially built lander to reach the lunar surface in March 2025. While on the moon, Blue Ghost delivered 10 NASA instruments designed to gather lunar subsurface data and also snapped some beautiful images of a solar eclipse. 

Some scientists worry that extracting resources from the moon could jeopardize research, while many Indigenous nations see the moon as sacred and are against any desecration. 

As of now, NASA and 66 other nations have signed the Artemis Accords. While not an international treaty, the Artemis Accords is an agreement for high-level principles of space exploration and provides a basic legal framework for exploring and developing the lunar surface during this century. However, the NASA-led Artemis group is in direct competition with an initiative led by China to explore the lunar South Pole and potentially extract its resources. 

The post Four drones will go where no astronaut have landed—yet appeared first on Popular Science.

For a few select evenings in the late spring and early summer, sunlight aligns with Manhattan’s grid. The city’s bustling streets are washed with golden light as the sun sets, while tourists and locals alike flood the streets to snap that perfect picture. This event is nicknamed Manhattanhenge and it will begin on May 28 and continue through July 12. 

However, you don’t need to live in the Big Apple to see a “henge” like Manhattanhenge. They actually pop up in a few places and a website called Hengefinder can help you find the closest henge.

Meet Hedgefinder

Data scientist and engineer Victoria Ritvo created the website, while software engineer John Pribyl built the accompanying app. Ritvo wrote about creating Hedgefinder in her blog, and details the three basic steps that scientists can use to find a henge. First, find the angle of the road, or its bearing relative to true north. Second, find the angle of the sun at sunset, or its azimuth. Third, find the dates when those two angles match. 

While you don’t have to do any of that high-level math, you can read about how Rivoto and Pribyl made their calculations. You simply put in an address or city and can get a calculation for the closet henge near you. 

“Having Hengefinder active means henges are now explorable outside of Manhattan, and I’ve been searching for them using the app,” Ritvo writes. “My favorite one so far, I haven’t actually seen. I’m intrigued by the Haarlemmertrekvaart, a canal which traces the southern edge of Westerpark in Amsterdam.”

Interestingly, much of Europe is left out of henge mania due to medieval street design. Amsterdam’s famed canals do offer an option, where sunlight can reflect off of the water. Henges may have been occurring twice a year for the past 400 years on the Haarlemmertrekvaart.

How henges work

The sun does not set in the same place every day. Its position changes along the horizon with the seasons. While the angle does not usually match the directions of a street, it will on a few days each year if the street is angled correctly.  

In 1997, the term Manhattanhenge was first coined by Neil deGrasse Tyson, an astrophysicist and director of the Hayden Planetarium at New York’s American Museum of Natural History. Tyson noted that the setting sun framed by Manhattan’s building was comparable to how the sun’s rays strike the center of England’s Stonehenge on the solstice. The Neolithic humans who built the stone circle in stages between 3100 BCE and 1600 BCE intended for the light to shine that way on the solstice. But the builders of Manhattan? Not so much.

Chicagohenge in Illinois and Baltimorehenge in Maryland both occur when the sunset  lines up with the grid systems in those cities around the spring and fall equinoxes in March and September. In Canada, Torontohenge occurs in February and October.

The post Manhattanhenge isn’t just for New Yorkers. Find a ‘henge’ near you. appeared first on Popular Science.

Animals are not the only stinky living things on this planet. The putrid corpse flower blooms with  the stench of rotting flesh, as does the lesser-known (but equally pungent) Bulbophyllum phalaenopsis. Then there is the elegant stinkhorn (Mutinus elegans), a fungus known for its phallic appearance and spores that give off the odor of rotting meat.

Also called the devil’s dipstick, elegant stinkhorns are found across most of eastern North America, particularly from spring to the earliest days of winter. It has also been found in parts of Europe and Asia. They typically prefer temperate climates and looser soils, springing up in gardens, mulch beds, forests, and wood debris during warm and wet weather. They can grow to about four to six inches tall, and a mature mushroom will only last a day or two before subsiding. 

All of that stench comes from the dark and slimy coating on the mushroom’s tip called the gleba, and it serves an important purpose. The fungi uses this dark and stinky spore mass to get the flies and other insects buzzing. Once they get a whiff of that rotten flesh smell, they will land on the stinkhorn and get covered in spores. As the bugs fly away, they spread the stinkhorn’s spores far and wide, so that more stinkhorn can pop up elsewhere.  

During the Victorian era, their penis-like appearance was reportedly distressing to some ladies. According to one story, naturalist Charles Darwin’s daughter Henrietta (or Etty), was openly combative towards the elegant stinkhorn. She would roam the woods armed with a spear, following her nose to the offensive mushrooms. Her niece recalled that Etty would find the fungi and “poke his putrid carcass into her basket.” After cleansing the territory, Etty would then secretly burn it to protect “the morals of the maids.”

If you encounter this bizarre fungus in the wild like Etty Darwin, don’t worry. Beyond offending your nostrils, it is not poisonous or dangerous to your health. But you still probably shouldn’t eat it anyway. 

The post This phallic fungus also smells like rotting flesh appeared first on Popular Science.

While a holiday weekend has come and gone, May 26 is not without a cause for celebration. It’s National Paper Airplane Day! 

The annual day commemorates the homemade aeronautical toy that has fascinated (and frustrated the less crafty) children and adults for generations. According to National Day, the practice of constructing paper planes is sometimes called aerogami, after origami, the Japanese art of folding paper. Building paper planes that can soar through the air like a bird is believed to have originated in ancient China, where paper was invented around 105 CE. However, the art of folding it into an airplane may have been perfected in Japan, as it is similar to origami.

Here in the United States, instructions for folding the Basic Dart were included in a children’s book published in 1859, so it is safe to say kids and adults alike have been making them for over 167 years. The term paper airplane was then coined in 1907 and replaced paper dart as the dominant term by the 1950s. In 2022, Kim Kyu Tae nabbed the Guinness World Record for the Longest Paper Airplane Throw Ever with a flight of 252.6 feet. According to Guiness World Records, the longest time flying a paper aircraft is 31.2 seconds and was achieved by Rao Chongyi and a team in China in February.  

If you’re inspired to create the world’s best paper airplane, we have you covered. You can also look to the great minds at NASA for inspiration. After all, the first letter “A” in NASA stands for aeronautics. Their step-by-step NASA Space Crafts tutorial will not only help you make a colorful paper airplane, but also NASA’s X-57 Maxwell and the X-59 Quiet SuperSonic Technology.

May your National Paper Airplane Day be free of paper cuts.

The post It’s National Paper Airplane Day: How to make a NASA-approved plane appeared first on Popular Science.

An extremely rare piece of Olympics history hits the auction block this week. Sports enthusiasts with deep pockets have the chance to own an original gold medal from the 1924 Paris Summer Olympics. 

The 1924 Paris Games were a hallmark of Olympics and sports history. More than 3,000 athletes from 44 countries competed in the first Olympics to include a Closing Ceremony. American swimmer Johnny Weissmuller won three gold medals and later went on to play Tarzan in 12 films. Swiss tennis player Richard Norris Williams won gold, after surviving the sinking of the RMS Titanic in 1912. He almost lost both his legs after jumping into the freezing water, but made a full recovery. The Paris Games were also featured in the award-winning film Chariots of Fire.

The 1924 Paris Games were also the first to officially feature the iconic five-ring Olympic symbol. The rings were designed by Baron Pierre de Coubertin, the founder of the modern Olympics and symbolize five continents and athletic unity. 

The medals were designed by sculptor André Rivaud. The obverse side shows a winning athlete reaching out to help a fallen competitor, an image of sportsmanship that set the standard for future Olympic medal design. The five Olympic rings are beneath this scene. The reverse side features sports equipment alongside a harp, a nod to the Cultural Olympiad. This artistic and cultural program ran alongside the athletic competition to explore the links between art and sport and the values they both share.

The medal is about 2 inches in diameter and weighs 2.7 ounces. It is listed as “near fine condition,” is made from gold-plated gilt silver and has the “2ARGENT” stamp on the rim as a mark of authenticity. Only 304 gold medals were originally produced, making them one of the   rarest and most coveted pieces of Olympic history in existence. The auction will take place on May 28 with a minimum bid of $14,000.

Only 780 days to go until the 2028 Summer Olympic Games in Los Angeles, California. 

The post Extremely rare 1924 Olympic gold medal up for auction appeared first on Popular Science.

The spring’s hottest show is not on any streaming service. It’s the internet’s many live bird cams. Viewers can watch new life emerge, dramatic flights, plenty of eating, and more, all from the comfort of home. The Cornell Lab Bird Cams from Cornell University features birds from around the world, from delicate hummingbirds in South America to the wise-looking barred owls nesting in a backyard in Indiana. 

“Our viewers tell us that watching the cams is a life changing experience: an unprecedented learning experience that they liken to virtual field trips or field biology in their living room,” the organization writes. “We’re excited to continue sharing and learning with the community as we watch the world of birds together.”

Below are a few of this season’s highlights, in no particular order.

A flying squirrel breakfast

On the morning of April 30, a mother barred owl brought a flying squirrel to her chicks, Artemis and Apollo, for breakfast. In the video, the squirrel’s patagium is visible. This special membrane connects the front and hind legs, allowing it to glide long distances between trees and separating it from other squirrel species.

Sweet nectar

For some birds, it’s all about the plants. This rufous-tailed hummingbird stops by the Panama Fruit Feeder Cam for a sip of nectar. This hummingbird species is commonly found in Central America and is known for its reddish tail and bright pink bill. Most hummingbirds are migratory, but there are easy ways to attract hummingbirds to your yard.

Hail the (sleepy) royal albatross chick

To greet the new day, a 20-day-old royal albatross chick opens wide and flaps its tiny wing nubs. This 24-hour live stream shows a northern royal albatross nest during the breeding season at Pukekura/Taiaroa Head on the southeast tip of New Zealand’s South Island. The world’s oldest known bird happens to be a Laysan albatross who nests about 4,393 north of New Zealand on the Midway Atoll.

Cuteness overload

In this compilation, this year’s owlets from the Wild Birds Unlimited Barred Owl Cam sleep, investigate the camera, and bob their heads. Technically called “motion parallax,” owls bob their heads to compensate for the fact that their eyes are fixed in their eye sockets. It helps them create a better view of their surroundings. Owlets use head bobbing to learn how to coordinate their sight with their hearing. 

Bananas are not just for monkeys

A keel-billed toucan was spotted eating a banana in the tropical trees of Panama. Toucans eat bananas by tossing pieces of the fruit into the air and swallowing them whole. Keel-billed toucans mostly eat bananas and are vital seed dispersers for fruiting trees in their habitat. The Panama Hummingbird Feeder Cam is about 35 miles north of Panama City  in a vibrant tropical rainforest on top of Semaphore Hill within Soberanía National Park.

An unexpected guest

Since anything can happen in a rainforest, more than just birds pop up on a birdcam. While a gecko was lounging on the hummingbird feeder cam, a moth tried to join in. After the insect and reptile stare at each other for a bit, the gecko tries to grab the moth, but the moth escapes. 

The post 6 bird cam highlights to celebrate nesting season appeared first on Popular Science.

Last year, 4.8 million people ventured to Yellowstone National Park, one of the most famous of our nation’s “best ideas.” And it’s not surprising why. The park, spread across 2.2 million acres and three states, includes half of Earth’s active geysers, the Grand Canyon of the Yellowstone River, and stunning wildlife. 

Ahead of the 2026 summer tourist season, Yellowstone National Park recommends following these 10 steps for making the most out of your visit. And remember what not to do when visiting any national park and to hold on to your hat. 

No reservations

Unlike a trendy new restaurant or theme park, Yellowstone does not require a reservation to enter. Visitors just need a park entrance pass. However, it’s important to remember that the summer is very busy, so bring your patience along with that bear spray and be ready for crowds and lines at entrances. 

Check road status

Most of Yellowstone’s park roads are open to personal vehicles in mid-April and will close in early November. Still, weather may temporarily close roads, so use Yellowstone’s website and app to check the status of park roads before arriving. 

Plan, plan, plan

As with any popular tourist attraction, it pays to plan. While the park does not require  reservations to enter, campgrounds and lodging do. Visitors often need to   book well in advance, and operating hours and service levels may change with little notice. Check before you go for the latest on fishing permits, current weather, places to go, etc. 

Give wildlife lots of space

Yellowstone’s wildlife are one of the park’s biggest draws. But remember that  wild animals are dangerous if you get too close. You must respect safety regulations and view them from a safe distance. Always maintain a minimum of 100 yards from predators like bears, wolves, and cougars and 25 yards from all other animals, including bison and elk. Also, all of Yellowstone is bear country, so carry bear spray and know how to use it before you go. You should also review how to watch wildlife safely and travel safely while in bear country.

Be a responsible driver (and parker)

Observe all of the posted speed limits and use the designated pullouts to watch wildlife, take pictures, and let other cars pass you. Also, do not stop your vehicle in the middle of the road. When pulling over, be sure to park with all four of your vehicles tires fully to the right of the white line.

Boardwalks are your friends

Please keep on the park’s boardwalks. People have been severely injured or even killed after stepping off of them into thermal areas. Here, the thin, fragile ground can suddenly give way, and visitors risk falling directly into scalding hot springs. The springs can reach temperatures of over 200 degrees Fahrenheit. 

Unplug, but remember the app

Download the free National Park Service app (and all of the offline content) before you arrive in the park. The app has interactive maps, tours of park places, on-the-ground accessibility information, and more that can help enhance your visit.

Expect limited connectivity

That said, don’t be surprised if you can’t receive calls or texts, even in the few areas of the park that may have cell reception. This is why it is important to remember to download that map before entering the park.

Prepare for all kinds of weather 

Yellowstone’s weather is unpredictable. You can expect big temperature swings, rain, or even snow during every month of the year. Make sure you have a warm jacket, rain gear, and several layers. You should also check current weather conditions before arrival. .

Branch out 

Consider attending a ranger program, exploring the Yellowstone Tribal Heritage Center, or participating in the free Junior Ranger program are extra ways to make the most out of your trip.

The post 10 must-know tips for visiting Yellowstone National Park appeared first on Popular Science.

Leafy vegetables could be used to extract toxic metals from contaminated soil for use in medical technologies and

Researchers from the University of Twente and Harvard University have developed a new way to generate ultraviolet (UV)

Nature, Published online: 27 May 2026; doi:10.1038/d41586-026-01089-4

Supply and demand.

A noninvasive treatment called high-intensity focused ultrasound helped relieve the shaking, stiffness and pain that accompany Parkinson’s disease.

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.”