Popular Science

T-shirt tycoons Fruit of the Loom are both makers of functional, printable T-shirts and unintentional originators of a long-standing piece of memory misinformation.

Fruit of the Loom’s distinctive logo includes a delicious-looking assortment of fruit. Some people, including the reality-questioning posters on the r/Retconned subreddit, will swear on all that is dear to them that the logo once also included a horned bowl called a cornucopia.

A recent Snopes article summarized this confusion, explaining that misremembering around the logo dates back decades. The imagined cornucopia is just one of many examples of the Mandela effect, named for the once-common misconception that the South African civil rights leader had died in prison in the 1980s, when in fact he passed away at the age of 95 in 2013.  

The Mandela effect is a communal example of a false memory. False memories are recollections of events that didn’t occur or facts that aren’t real. They are a particularly strong type of memory error, and some researchers contend that false and true memories are indistinguishable. But shared false memories of global events are only one small example of the broader phenomenon of false memory.

Academics have strongly debated how common these memories are, but everyone agrees that they do happen. In this story, we’ll explore what false memories are, why they happen, and what experts still don’t understand about them.  

There are two kinds of memory: episodic and semantic

Our memory can be roughly divided into two subtypes: episodic and semantic. Episodic memory concerns autobiographical events that have happened to us: Think going to Disneyland, eating dessert last Wednesday, or feeling sick after eating too much dessert last Wednesday. 

Semantic memories are recollections of facts or general knowledge. There are more well-known examples of communal false memories, or the Mandela effect, for semantic memories. That’s likely because there are few shared autobiographical experiences that would create a communal, semantic memory—only so many people will remember your fifth birthday party, for example.

That said, false memories do occur in personal, episodic memory. In one study, researchers used manipulated images to present volunteers with false evidence that they had taken a hot air balloon ride as a child. Some participants later said they vividly remembered the ride, which never occurred, and described it in detail. 

In one study, researchers used manipulated images to present volunteers with false evidence that they had taken a hot air balloon ride as a child. Some participants later said they vividly remembered the ride, which never occurred, and described it in detail. Image: DepositPhotos

False memories have also featured in court cases where testimony from childhood abuse survivors has been questioned as potentially false. Researchers acting as expert witnesses in these cases have engaged in fierce debate around how likely it is that trauma survivors may develop false memories of abuse that never happened. 

Misremembering v. a false memory

Our memories are not set in stone. Instead, they are built on shifting sands. Processes like re-encoding can update old memories over time, and memories may differ slightly each time we retrieve them. 

“Our memories are really like a filtered-down version of the original experience,” said Wilma Bainbridge, a psychologist at the University of Chicago who studies memory. “When you call that memory back to mind, you’re bringing back that compressed version.”

On top of this, our brains can’t store every single detail of our lives. Instead, they often add in missing details based on what we might expect from a given memory. We might add a set of beach umbrellas to a holiday scene from our childhood, because of how often the two appear together elsewhere. 

There isn’t a hard line differentiating a false memory and simply misremembering where you put your keys. But, in general, false memories are completely made up rather than a small memory error. In the above beach example, misremembering that there were umbrellas doesn’t make the entire memory false.

How do false memories form?

A classic psychology study that tests how false memories might form is the Deese-Roediger-McDermott (DRM) test. Volunteers will be presented with a list of words—for example, pupil, classroom, exam, teacher—that all have a key semantic “lure” word. The researchers will then test whether the participant misremembers the original list as featuring the lure—in this case, the word “school.”

Fuzzy trace theory (FTT) suggests that this confusion happens because we store two forms of memory. One is a direct representation of the original memory, and the other is based on a rough “gist” of the memory. Researchers think false memories tap into the “gist” version of the memory, especially when verbatim information is missing.

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An alternative theory, called activation-monitoring theory (AMT), suggests that when a person studies a list of words, it activates a memory that “spreads” to related words, like the lure word. 

When the lure is linked closely enough to the list words, researchers believe that the memory of looking at the list and the memory of the lure word become entangled, which explains why people taking the DRM test often swear that they remember seeing the lure word in the original list. Psychologists also believe that repetition, age, and lack of sleep can influence how likely it is that false memories will form. 

Some false memories remain a mystery

Bainbridge’s own research into the Mandela effect couldn’t find a single satisfying explanation for how the effect forms, but did identify that some images are simply harder to accurately recall than others. 

“We think it’s something about how that image fits in with the map of all of the images we have seen or how our brain understands the visual world,” said Bainbridge.

Regardless of how false memories form, Bainbridge says that they are a natural part of the human experience and that forgetting things, especially traumatic memories, can be helpful. If you’re worried about false memories, remember one thing: while we might often have fuzzy or unclear memories, complete false memories of events that never occurred don’t happen very often.

“False memories are actually still very rare,” said Bainbridge. “But that’s why when we encounter these false memories in the wild, like the Mandela effect, that’s why they feel so jarring.”

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

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Whitening your teeth often comes at a financial and physical cost. Many of today’s most popular products including gels, strips, and rinses rely on peroxide-based bleaching solutions. While effective, the chemical processes generate reactive oxygen species (ROS) compounds that not only destroy staining molecules—they can eventually erode tooth enamel. Over time, this can actually make it easier to stain again or cause long-term dental health problems.

According to a study published in the journal ACS Nano, researchers at the Chinese Academy of Sciences have developed an alternative solution that not only whitens teeth, but repairs them, too. Instead of harsh chemicals, the new method relies on vibrations.

The team swapped peroxide for their new ceramic powder creation called BSCT. To make it, they heated a solution of strontium and calcium ions as well as barium titanate. If shaken quickly enough (such as with an electric toothbrush), the mixture generates a tiny electric field through what’s called the piezoelectric effect. While commonly associated with guitar amplification and electric cigarette lighters, piezoelectricity also creates ROS chemical reactions that are similar to peroxide bleach.

After artificially staining human teeth with coffee and tea, researchers applied BSCT and saw visible whitening after four hours of utilizing an electric toothbrush. By 12 hours of brushing, the teeth were nearly 50 percent whiter than control teeth brushed with saline. Not only that, but BSCT actually regenerated damaged dentin and enamel thanks to healing deposits of barium, calcium, and strontium layered atop the teeth.

A second experiment involved rats fed with high-sugar diets. Researchers brushed the rodents’ teeth for one minute per day over four weeks, then measured their oral microbiomes. They discovered the BSCT powder killed common mouth bacteria such as Porphyromonas gingivalis and Staphylococcus aureus while also reducing inflammation.

The team hasn’t incorporated BSCT powder into an actual toothpaste yet, but hope to experiment with combinations in the future. In the meantime, they believe their alternative to harsh whitening products may soon find their way into dentist offices and stores.

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The black abalone mollusk (Haliotis cracherodii) is a delicacy in many regions of the world, with fancy restaurant diners doling out as much as $40 per 6 to 8 ounce serving. Although the sea snails are often grown in oyster farms, they are now considered critically endangered due to overdemand and black market harvesting. But while a woman’s recent abalone discovery along a beach in Australia is attracting worldwide attention, it’s not due to any illegal activity or a lucrative payout. Instead, researchers say the diminutive shell is part of a government tagging project that could help ongoing conservation efforts.

The random find occurred along the waterfront of Mettams Pool near the western Australian city of Perth. Local resident Elisha Blott noticed a broken shell fragment in the sand with an abalone’s telltale rough front and pearlescent back. The mollusk also included a strange accessory, however. Fused to the strong, calcium carbonate shell was a small, plastic tag with the number 5247 etched in red ink.

“I immediately saw the bright ID tag and was really intrigued. I’d never seen a shell with a tag before,” Blott told Yahoo News on January 24.

To help solve the mollusk mystery, Yahoo News contacted Western Australia’s Department of Primary Industries and Regional Development (DPIRD). There, DPIRD research scientist Jamin Brown quickly knew exactly what they were looking at—and what it meant for a multiyear scientific study. 

“The tag numbers are linked to records in our database that contain key information about each individual abalone,” Brown explained.

The abalone known as 5427 is only one of 7,000 originally raised as roe, then tagged and deposited across three locations near Perth beginning in 2023. Each four-digit tag corresponds to a sea snail’s record featuring its date of birth, length and age when it was tagged, as well the date and location of its release. To attach each tag, researchers mounted the plastic label to a stainless steel spring they then placed on the growing edge of an abalone shell. Over multiple months in hatchery tanks, the shell slowly grew to encase the spring and keep the tag in place.

After around three years growing in the warm Australian waters, many of the molluscs are now large enough for recreational fishers to catch. Or, in Blott’s case, to wash ashore for beachgoers to discover.

“The tagging and release of tagged abalone has ceased, but the monitoring of the abalone will continue into the future,” Brown added.

The DPIRD is now encouraging anyone in the area to report their own tagged abalone finds through an easy-to-use online portal.

“If people find a tagged abalone, we urge them to take a clear photo of the abalone shell next to a ruler, ensuring the numbered tag is visible, and send it to DPIRD, along with details of date capture/location found,” said Brown.

As DPIRD starts to amass its abalone updates, scientists will gain a better understanding of how the endangered species is growing and surviving in the wild.

The post Mysterious, numbered mollusk discovered on Australian beach appeared first on Popular Science.

NASA’s Chandra X-Ray Observatory is considered one of the agency’s greatest achievements, but it’s not necessarily as recognizable as siblings like the James Webb and Hubble Space Telescopes. However, since 1999, the powerful spacecraft has peered deep into the cosmos to provide astronomers with never-before-seen glimpses of the Milky Way galaxy. As the observatory nears its 27th anniversary, NASA is highlighting its Chandra Source Catalog (CSC), an absolutely massive archive of visualization data collected over the years. 

The most recent CSC update adds more than 400,000 unique compact and extended X-ray sources, as well over 1.3 million individual X-ray light detections collected through 2021. The latest examples from CSC include an image the Galactic Center, the area surrounding the supermassive black hole called Sagittarius A* that anchors our Milky Way galaxy home. The image encompasses around 60 light-years of space, which NASA describes as a “veritable pinprick” in the night sky. Despite its comparatively small size, the final result required combining 86 separate images totaling over 3 million seconds of observation time. Within this, Chandra detected more than 3,300 individual X-ray sources.

While the observatory’s information is indispensable for other ground and space telescopes to study new areas of the galaxy, much of the raw data is essentially invisible to the human eye. Similar to previous projects, NASA used “sonification” techniques to convert observations into ethereal audio clips to better illustrate their grandeur. To compliment the view of Sagittarius A*, NASA also provided a sonification of 22 years of space sounds. Repeat observations are given different notes, resulting in a cosmic choir of tones showcasing the vastness of Chandra’s capabilities. If that weren’t enough, the audio clip is also layered onto a map of the Milky Way. Over nearly two-and-a-half minutes, viewers can watch as each X-ray detection is pinpointed within the galaxy, with larger circles representing locations with more frequent observations.

Chandra’s initial mission was only scheduled to last five years, but has continued to surprise astronomers by outperforming their wildest expectations. Despite a period of funding uncertainty in 2024, it appears that the observatory will continue shedding light on the galaxy for years to come.

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From physical fitness to doing puzzles to going out with friends, there’s a laundry list of advice out there to help protect our brains from cognitive decline as we age. Taking care of grandchildren may also help brain health, according to new research from the American Psychological Association published today in the journal Psychology and Aging.

“Many grandparents provide regular care for their grandchildren—care that supports families and society more broadly,” Flavia Chereches, a study co-author and Ph.D. candidate at Tilburg University in the Netherlands, said in a statement. “An open question, however, is whether caregiving for grandchildren may also benefit grandparents themselves. In this research, we wanted to see if providing grandchild care might benefit grandparents’ health, potentially slowing down cognitive decline.”

To take a deeper dive into how grandparenting affects the brain, Chereches and her team examined data from 2,887 grandparents. All of the participants were over the age of 50 (the average age was 67) and took part in the English Longitudinal Study of Ageing. Between 2016 and 2022, the volunteers completed cognitive tests and answered survey questions three times.

The survey asked whether or not the participants had provided care for a grandchild at any point during the past year. It also asked them detailed questions about how frequently they provided childcare and what kinds of care they provided. Types of childcare included watching their grandchildren overnight, caring for grandchildren when they were sick, playing or engaging in leisure activities with them, helping with homework assignments, driving grandchildren to school and activities, and preparing meals.

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Overall, the team found that those who spent time with their grandchildren scored higher on tests of memory and verbal fluency compared with those who didn’t. These results held even after adjusting for age, health, and other factors. More involved grandparents also scored higher on these tests regardless of the frequency and type of care they provided.

Additionally, they saw that grandmothers who provided care experienced less decline on cognitive tests over the course of their study compared with those who didn’t. 

“What stood out most to us was that being a caregiving grandparent seemed to matter more for cognitive functioning than how often grandparents provided care or what exactly they did with their grandchildren,” said Chereches. “More research is needed to replicate these findings, yet, if there are benefits associated with caregiving for grandparents, they might not depend on how often care is provided, or on the specific activities done with grandchildren, but rather on the broader experience of being involved with caregiving.”

Chereches added that future studies could explore the effects of family context and other variables on the aging brain. 

“Providing care voluntarily, within a supportive family environment, may have different effects for grandparents than caregiving in a more stressful environment where they feel unsupported or feel that the caregiving is not voluntary or a burden,” Chereches concluded. 

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Being pregnant and giving birth is hard work for any species—but epaulette sharks (Hemiscyllium ocellatum) might disagree. 

These fish and a number of other species are known as “walking sharks” for their ability to traverse both the seafloor and land with their fins. But as of now, that’s no longer the coolest thing about this rather adorable predator. Epaulette sharks’ energy use didn’t change during their reproduction cycle, as described in a study recently published in the journal Biology Open. 

“Reproduction is the ultimate investment … you are literally building new life from scratch,” Jodie Rummer, a marine biologist at James Cook University and co-author of the recent study, said in a university statement. “We expected that when sharks make this complex egg, their energy use would shoot up. But there was no uptick in energy use, it was completely flat,” she adds. They “appear to have adapted their physiology to be able to optimise their energy use.”  

Researchers broadly believe that reproduction is  a major  energy investment for a majority of species. The new study, however, represents the first time scientists have recorded sharks’ reproductive cycle’s direct energetic expenditure (or metabolic cost). The sharks in the new study were living in captivity, and the researchers analyzed the rates of their oxygen consumption as a way to track their metabolic rate. 

Furthermore, the team monitored shifts in blood and hormones while the mother  sharks laid eggs, explained lead-author Carolyn Wheeler, also from James Cook University.. The sharks proved to be, once again, unphased. 

“Everything was remarkably stable, so this research challenges our fundamental assumptions about chondrichthyan fishes (sharks, rays, skates and chimaeras),” Wheeler said. 

During times of environmental stress, many species will choose between reproduction and survival. However, the epaulette shark may still continue to produce eggs, even under major  stressors. According to the team, this is encouraging since healthy sharks equal healthy reefs and ecosystems. 

“This work challenges the narrative that when things go wrong—such as warming oceans—that reproduction will be the first thing to go,” Rummer explained. 

We need to understand the extent of this small shark’s apparent significant resilience in the face of the aforementioned issue, she added. 

“Sharks have been around since before the dinosaurs and have already shown incredible resilience to the earth’s changing climate,” Madoc Sheehan, media liaison officer and a senior lecturer at James Cook University, who is not one of the study’s authors , tells Popular Science, “these new observations reinforce [our understanding of] their capacity to endure change.”

Moving forward, the team plans to  investigate how much it takes wild epaulette sharks to produce eggs.

The post ‘Walking sharks’ lay eggs without breaking a sweat appeared first on Popular Science.

While winter is raging in an unusually large swath of the United States, the weather is balmy for the birds nesting on the Pacific Ocean’s Midway Atoll. As many as 75,000 pairs of Laysan albatrosses (or mōlī in Hawaiian) are nesting in the wildlife refuge on the northwestern edge of the Hawaiian Archipelago.

Now you can watch these brilliant snow-white birds while avoiding the actual snow with a 24/7 live cam. This live cam is run by Friends of Midway Atoll via memberships and donors.

Laysan albatrosses (or mōlī in Hawaiian) return to this same nesting site every year and will reunite with their mates. If all goes well, the pairs will lay a single egg and stay on the atoll to nest. 

As nesting progresses, you may see a single egg dotting some of the nests. In the distance, you may also catch a glimpse of ka‘upu (black-footed albatross), the endangered koloa pōhaka (Laysan duck), manu-o-Kū (white terns), kolea (Pacific golden plovers), and ʻakekeke (ruddy turnstones). Koaʻeʻula (red-tailed tropic birds) may also be seen doing their “magnificent aerial mating dance.”

In the evening hours on Midway Atoll—around 11 p.m. or midnight on the East Coast—nunulu (Bonin petrels) arrive by the thousands to take care of their nest sites in underground burrows. 

The nesting birds also include a record-breaker named Wisdom. The 75-year-old albatross is known as the world’s oldest breeding bird and was spotted on the atoll in November 2025. She was first identified and banded in 1956 by wildlife biologist Chandler Robbins after she laid one egg. Wisdom has since produced 50 to 60 eggs and as many as 30 chicks have fledged in her lifetime. In 2024, Wisdom became the world’s oldest known wild bird to successfully lay an egg at the estimated age of 74. 

The post Snowed in? Watch albatrosses nest on a sunny Pacific island instead appeared first on Popular Science.

“By definition, invasive species are harmful in some regard,” says Jacob Barney, a professor of invasive plant ecology at Virginia Tech University. So when we eat them, he adds, “we turn that harm into something positive.” Although just how positive an impact eating invasives has can vary.

Wherever human beings go, we introduce plants and animals from other places, both deliberately and accidentally. However, not all introduced species have the same impact on their new environments. 

An introduced species is only considered invasive if it poses a threat to native species, for example by competing with them for limited resources. In the absence of natural predators, invasive populations may swell far beyond what their new environment can support. Fortunately for those concerned about the ecological impact of these interloping plants and animals, it just so happens that a lot of them are pretty tasty. 

At the end of each semester, Barney challenges his students to bring dishes made with invasive ingredients to a class potluck. “I like to say it’s where we eat what we’ve been studying,” he says. 

Last semester’s banquet included cookies made with prickly pear cactus fruit, invasive in many desert regions, and sausage made from feral hogs, which Barney describes as “delicious.” Students voted on the most creative and best-tasting entries. This time, the winner in both categories was a riff on spinach-and-artichoke dip, using invasive kudzu vine leaves in place of spinach.

Many invasives have culinary value

In some cases, invasive species were introduced because they’re tasty. Barney points to the Mediterranean fig tree, introduced to California for cultivation and now invasive there, as one example. 

There are also many invasives that have a well-known culinary value in their place of origin, but were introduced for a different reason. Kudzu is one example. Introduced in the United States as an ornamental garden plant, it has since become known as the infamous “vine that ate the South” for its uncontrollable growth. But in its native Asia, kudzu’s leaves are eaten as a vegetable, and its potatoey roots provide starch for jellies such as Japanese kuzumochi. 

Kudzu, an invasive Asian vine, grows near the Mississippi river in Baton Rouge, Louisiana. The plant is often used in Japanese and Chinese cooking: Its leaves are similar to spinach and its potatoey roots provide starch for jellies, such as Japanese kuzumochi. Image: DepositPhotos

Barney notes that in the Chesapeake Bay watershed, where the invasive blue catfish has done damage, there’s currently an effort to industrialize harvesting catfish for food. “That’s the kind of scale that I think can have a meaningful impact,” he says. The effects of a large-scale commercial food operation on an invasive species would be far greater than occasional foraging by individuals. 

But such efforts are still relatively rare, and not all invasives are seen as a desirable food source, or even recognized as being edible. This has sometimes led environmentalists to get creative with marketing. In Illinois, invasive Asian carp meat has been sold under the name “copi” (for its copious numbers) since 2021, due to perceptions of carp as an inferior food fish. 

In Florida, the Reef Environmental Education Foundation (REEF) has been hosting “Lionfish Derbies” since 2009, in which divers compete to see how many invasive lionfish they can spear. These events culminate in free lionfish tastings. According to REEF, “tastings give the public a chance to see how delicious lionfish are and encourage the consumption of lionfish in local restaurants. Derbies also draw media attention to the Atlantic lionfish invasion and help promote development of the commercial lionfish market.”

Eating invasives teaches you about local ecology

Does this mean that if we all start eating invasives, it will completely get rid of them? Not exactly. “For the general, curious forager, or somebody looking to try something different, the impact [of eating invasives] on the environment is probably small to negligible,” says Barney. However, he adds, this doesn’t mean that we shouldn’t eat invasives. We just shouldn’t think of eradicating them as being the sole reason to do so.

While large-scale harvesting of an invasive species for food, such as blue catfish in the Chesapeake, can make a difference, eating invasives is not going to totally remove them any more than other strategies. Total elimination of an invasive species tends to only happen in more isolated environments, such as on small islands. Invasive zebra mussels have been successfully removed from Lake Waco, a manmade reservoir in Texas, as of 2021, but remain a problem in major bodies of water like the Mississippi River. In most cases, invasives are here to stay, and removal efforts focus on population management, minimizing impact by keeping numbers down. 

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Barney describes eating invasives as “a really nice entry point into understanding the species in your surroundings, and a different perspective on the role that they can play in our lives.” To eat invasive species, you have to first learn what species are invasive in your area and how to identify them. This means that eating invasives is a way of learning more about your environment and the relationships between the organisms that live there—including you.

How to find edible invasives

Commercial sale of edible invasives is often small-scale and localized. Once you know what invasives there are in your area, you can keep an eye out for them on restaurant menus and in local markets. But your best bet for sampling an invasive might be to forage it yourself (where permitted). Experts like “Forager Chef” Alan Bergo offer information on how to incorporate both native and invasive species collected from the wild into your diet. 

Barney cautions beginning foragers that “anytime you’re harvesting something from the wild, identification is first and foremost.” He recommends resources like iNaturalist and its Seek app for species identification. Users of iNaturalist can also upload their species sightings to a collaborative global map. This serves as a valuable database for scientists like Barney who study the spread of invasives. 

When asked his personal favorite invasive to eat, Barney recommends autumn olive. This silvery shrub, native to Asia, is a common invader of open grassland in the eastern United States. “It makes these really tasty fruits,” says Barney. Autumn olive’s tiny red berries are bitter when fresh, but their pulp can be processed with sugar into jams and sauces.

Eating invasives is not so much about eradication as it is about awareness. “Once you have your eyes exposed to the number of invasive plants and animals in the environment there, you can’t not see them,” says Barney. We may never be able to eat every single invasive out of existence. But eating some of them can make us see our surroundings in a whole new way. 

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

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At first glance, it looks like an alien eye—a gorgeous blue iris around a carmel-colored pupil, thick eyelashes radiating out like sun rays. The reddish/orange center looks a bit like the Eye of Sauron, but we aren’t in Mordor. We’re on the surface of the ocean, where a mysterious jellyfish relative is floating along, snacking on zooplankton.

Meet the blue button jelly (Porpita porpita). It’s a cnidarian (a group of mainly marine invertebrates, like corals, jellyfish, and Portuguese man-of-war), grows to be around an inch wide, and calls l many tropical and subtropical oceans home. The funky little creature consists of a float—the round part featured in the photograph—and a number of tentacles, some of which have stinging cells. 

So far, so good. Researchers believe it’s a “quasi colonial organism,” Larry Madin, a jelly expert at Woods Hole Oceanographic Institution in Massachusetts, tells Popular Science. 

“It’s considered sort of a colony because there are tentacles that some of them are for catching food, they have stinging cells on them. Some of them are defensive tentacles to sort of attack things that might attack this, and then it also has some reproductive structures that are suspended from the bottom of this float,” he explains. 

But the situation is far from certain. 

“People have been confused for a long time about is it really a colonial animal, you know, like a coral is, or is it just a single animal that has all these multiple parts?” Madin says. 

Blue button jellies appear to grow from a single larva that eventually changes into an adult. Unlike the Portuguese man-of-war, which have a number of parts that catch and digest food, the enigmatic blue button jellies secure prey with many tentacles and digest it in a central stomach area. 

On the topic of food, they themselves are also prey. One of their predators is a swimming snail called Glaucus, that looks like it popped straight out of a fantasy world, too (Avatar’s Pandora, specifically). Rather appropriately, it’s also known as the blue dragon. 

It remains to be seen if or when the blue button jelly’s status as a quasi colonial organism will be clarified. In the meantime, just keep floating…just keep floating…just keep floating, floating, floating.

The post Perplexing blue button jelly looks like something out of ‘Lord of the Rings’ appeared first on Popular Science.

To help figure out what makes stingrays such unique and unusual swimmers, a team of mechanical engineers at the University of California, Riverside (UCR) created a wavy robotic fin. After submerging the robot in underwater tunnels designed to mimic swimming near the sea floor, their tests indicate that different types of ray species may have evolved alternative swimming techniques that best suit their setting. Specifically, the findings suggest that some ray species swimming near the seafloor adjust the way their fins move and tilt to counter a downward force that would otherwise pull them toward the ground. 

It turns out that stingrays gracefully gliding along waves near seabeds aren’t doing it to look cool. Instead, the fancy flapping is likely an evolutionary adaptation for stability and durability while swimming. The team behind the mechanical fin believes those same principles could one day be applied to designing energy-efficient underwater mapping robots. And they aren’t alone in admiration for rays. Other researchers are already attempting to use insights from stingray swimming to develop stealthier next-generation underwater vehicles. 

The robotic fin study was published this week in the Journal of the Royal Society Interface.

Putting stingray swimming to the test  

When it comes to swimming, not all ray species are alike. Massive manta rays and other pelagic ray species tend to hover near the ocean surface using a flapping motion. Benthic rays, like stingrays who spend their time in more shallow waters, rely on a different undulating movement which often resembles the motion of the very waves they’re swimming in. This second wavy swimming style in particular has fascinated scientists for its apparent simplicity and efficiency. Past research on that swimming method has shown that the undulating motion used by stingrays actually appears to recycle energy from surrounding water more efficiently than brute-force fin flapping.

Varying styles of stingray fin movements. Image: Yuanhang Zhu/UCR.

UCR mechanical engineer and paper co-author Yuanhang Zhu had a hunch that the divergence in swimming styles might stem from the different environments ray species inhabit. To test that theory in controlled environments, the team set out to create the robotic fin. By testing the fin under different conditions, the researchers could observe how physical forces in the water affected its movement. The final fin design measured only 9.5 millimeters (about 0.4 inches) thick and was molded from silicone rubber. They also constructed a large water tunnel designed to simulate ocean flow.

During their experiments, the team placed the robot both near the surface of the tunnel and lower, closer to the artificial sea floor. In both cases, they were looking to see how various levels of ocean flow impact the amount of lift imparted on the fins. Understanding lift is important because it  plays a key role in determining whether or not objects moving through space can stay level.  For example, birds flying close to the ground experience positive lift keeping them more level and steady. The researchers expected to see something similar occur for the robotic ray swimming near the sea floor. Instead, the exact opposite happened. Their robot was being sucked downwards.

“This wasn’t what we expected,” Zhu said in a UCR blog post. “Instead of gaining extra lift near the ground, the rays were pulled downward. 

Surprised by the findings, the team made slight adjustments to the robot to try compensate for the negative lift. They found that the downward force could be reduced simply by tilting the robot fin upward by a few degrees. Extrapolating out from that, the researchers suggest that stingrays and other benthic rays naturally swim with a slight upward fin angle, something that wasn’t clear before. During testing with, the stingray-like undulating motion also consistently maintained better clearance from the seafloor than the flapping motion used by pelagic ray species.

“Nature seems to have already solved the problem,” Zhu added. 

Robots and underwater vehicles of the future

This isn’t the first time engineers have tried to apply a ray’s unique biology to the world of robotics. In 2018, engineers from UCLA designed a 10 millimeter long tissue-based stingray-style robot made up of a mix of heart cells and flexible electrodes. Researchers from Harvard made an arguably even stranger stingray biohybrid robot in 2017, powered by rat muscles and propelled forward by a propulsion system triggered by light. 

Elsewhere, researchers at the University of Washington are already exploring ways to apply stingray swimming techniques to next generation underwater vehicles. Ultimately, they  hope to adapt rays’ structural characteristics to create vehicles that are both more energy-efficient and quieter than current submarines and submersibles.

When it comes to designing mechanisms of the future, the natural world remains undefeated. 

The post Stingray-inspired robot cracks the mystery of how rays swim appeared first on Popular Science.

One of most recognizable comets in astronomy may require rebranding. But even if everyone continues to call the famed space rock Halley’s comet, some researchers say an eccentric 11th century monk deserves at least some credit. According to a review of historical materials including the famous Bayeux tapestry, a team from Leiden University in the Netherlands believes it makes more sense to name the icy space rock in honor of Aethelmaer of Malmesbury—a member of the Order of Saint Benedict who also lived with an ill-fated fascination with flying.

Every 76 years, a comet from the depths of our solar system reaches its nearest point to Earth. Its orbit is anything but new, however. Chinese observers recorded the appearance of a bright light traveling from east to north in the night sky as far back as 240 BCE, while Roman historian Cassius Dio described a similar sounding event in 12 BCE. It wasn’t until 1705 that the English astronomer Edmond Halley concluded that these regularly returning sights weren’t different objects, but a single comet traveling along a predictable trajectory. Today, his discovery is reflected in both the comet’s everyday name as well as its official classification, 1P/Halley.

But if one really wanted to name the comet after the first person in England to note its significance, some astronomers recommend the honor goes to Aethelmaer of Malmesbury. Also known as Eilmer, the Benedictine monk was already an elderly resident of his abbey when Halley’s comet returned in 1066 CE. However, that particular sighting was of special importance because it’s documented on the famous (and bawdy) Bayeux tapestry. The 770-pound scroll depicts the events surrounding the Battle of Hastings, during which William II invaded England from Normandy, France. The embroidered art also illustrates William II’s victory, as well as his short-lived reign before the last Anglo-Saxon king died in battle.

King William should have seen his demise coming, according to the medieval omen experts of his era. Halley’s comet appeared not long after he assumed the throne, and everyone at the time knew such cosmic sightings warned of impending disaster. Everyone including the monk, Eilmer. 

Simon Zwart, an astronomer at the Leiden University in the Netherlands, realized this while reviewing the writings of the 12th century chronicler, William of Malmesbury. According to William, when Halley’s comet brightened the sky in 1066 CE, it also jotted Eilmer’s memory. The monk recalled first seeing the same event about 76 years earlier in 989 CE.

Based on this account, it technically wasn’t Edmond Halley who first proposed that the comet was making regular reappearances. Then again, it’s somewhat understandable why Eilmer’s claims didn’t gain more traction. After all, this was the monk who is otherwise best known for attempting to fly after reading the Greek myth of Daedalus as a child. To test his own theories, young Eilmer strapped a set of makeshift wings to his hands and feet, then jumped off a tower at Malmesbury Abbey. The confident—if misguided—leap of faith broke both his legs and incapacitated him for the rest of life.

“He used to relate as the cause of his failure, his forgetting to provide himself a tail,” his friend William later wrote.

The post Halley’s comet may need a new, medieval name appeared first on Popular Science.

NASA’s Hubble Space Telescope has captured a trio of young stars in the process of becoming their best selves in the constellation Scorpius. Posted to the agency’s site on January 16 as part of its Hubble Stellar Construction Zones series, the three T Tauri stars—seen at the bottom right, upper center, and left along with many other stellar objects in the background—are forming inside the hazy Lupus 3 cloud about 500 light-years from Earth. While the image appears somewhat serene, the interior forces at play are anything but tranquil. 

A T Tauri star is a young star, usually less than 10 million years old. During this phase, the still-growing stellar object sees the dust and gas surrounding it begin to disappear as stellar winds, radiation, and other ionized particles bombard it. This dynamic environment is reflected in the star’s brightness, which randomly fluctuates depending on the material interactions underway in its accretion disk. More regular shifts in brightness can also occur as sunspots move in and out of view to astronomers here on Earth.

The T Tauri examples seen in Hubble’s image have a long way to go before they resemble the stars most observers recognize. Gravity will continue to bear down on the object until it forces hydrogen and helium elements to fuse in the star’s core, at which point it will finally become a main sequence stellar object.

The stars in Scorpius are further along in their growth than the protostars highlighted by NASA on January 14, however. About 1,300 light-years away, protostars in the “sword” of Orion are getting their start inside the constellation’s Orion Molecular Cloud complex. Astronomers aimed Hubble toward this area of the sky to better understand outflow cavities—areas where a protostar’s gas and dust is shaved away by nearby stellar winds.

The post Hubble spots three young stars going through growth spurts appeared first on Popular Science.

A 7,000-year-old grave site in present-day Oman indicates that the region’s Neolithic communities sometimes turned to an unexpected trade to not only survive, but thrive in the harsh desert landscape. According to findings published in the journal Antiquity, the people of southern Arabia actually hunted sharks and even stingrays.

Since 2020, researchers from the Archaeological Institute of the Czech Academy of Sciences, Prague (ARÚ) have investigated Wadi Nafūn, an ancient grave site megalith (a structure built with large stones) used by Neolithic locals during the 5th century BCE. Amid their excavations, researchers found the skeletal remains of over 70 men, women, and children. But this wasn’t a single generation of people. The crypt’s size and subsequent radiocarbon dating indicate that Wadi Nafūn was built and maintained communally for over 300 years. 

“This monument was not built by a single small group. It represents cooperation, shared beliefs, and repeated return to a common ceremonial landscape,” project director lžběta Danielisová recently told Arkeonews.

Neolithic hunters likely also wore shark teeth as pendants. Credit: ARÚ Prague

However, Danielisová and collaborators faced an immediate challenge. Biological materials like teeth and skeletal fragments usually do not retain many organic components after being exposed to Oman’s arid climate for thousands of years. To properly understand their discoveries, the team needed to ship the materials back to the Czech Republic. There, they utilized isotopic analysis to examine a mineralized substance called bioapatite that remains on bones even after collagen disappears.

They particularly focused on traces of carbon, oxygen, and strontium to pinpoint some of each Neolithic person’s dietary sources of protein. But it was the discovery of certain nitrogen isotopes that surprised them most, as these compounds are only found in very specific marine animals.

“We know that these were not just ordinary proteins, but proteins from the top of the food chain,” Danielisová said in a university statement.

For hundreds of years, it appears the Neolithic communities of southern Arabia regularly hunted and consumed sharks. They didn’t only eat the apex predators, either. Throughout Wadi Nafūn, archaeologists excavated shark tooth pendants, additional tiger shark teeth, fishing tools, and stingray barbs. In order to harvest all these materials, the Neolithic hunters appear to have even used their own teeth to help process and prepare their catches.

“The teeth of this community have an interesting pattern. This indicates a specific diet and also that people used their teeth as tools,” explained ARÚ Prague anthropologist Jiří Šneberger.

Additional evidence gleaned from the isotopic analysis also showed that some of the individuals buried at Wadi Nafūn weren’t technically locals. Strontium and oxygen levels suggest certain adults buried here at least spent their childhoods over 30 miles inland. Taken altogether, the shark and human evidence illustrate a highly dynamic, resourceful, and collaborative region that used everything at their disposal to flourish.

“For the very first time, we were able to use natural science data to document specialized hunting of marine predators, directly by analyzing the local buried community,” said Danielisová. “The connection of this burial community with sharks is very interesting and is a new finding not only in prehistoric Arabia, but in the area of ​​all Neolithic cultures of the arid zone.”

The post In ancient Arabia, people dined on sharks and stingrays appeared first on Popular Science.

In Florida, giant invasive pythons, the state’s signature alligators, and bears that sometimes roam around theme parks are typically among the most upfront wildlife in the news. But when the temperatures drop, one reptile stands ready to take the limelight and also drop—iguanas. 

When air temperatures get cold enough, the reptiles will get stunned (or freeze) and fall from trees. Today, morning temperatures in Jacksonville and Tallahassee dipped as low as 20 degrees Fahrenheit overnight, while Orlando hit the mid-30s, and Miami fell to the upper 40s. All temperatures that are cold enough to temporarily freeze an iguana. 

Reptiles like iguanas are cold-blooded—or ectothermic—reptiles that rely on external environmental conditions to regulate their body temperature. By comparison, warm-blooded or endothermic animals like humans and other mammals have a more consistent body temperature. Since the outside temperature has such a drastic effect on their bodies, cold-blooded animals often adapt their behavior as a response. They may bask in the sun to warm up or find shade to cool down and achieve a more balanced body temperature. 

CREDIT: Florida Lad.

When it gets cold, iguanas may also enter a dormant state called cold-stunning or freezing since they are not adapted to life in colder temperatures. Iguanas can start to slow down if the temperature gets below 50 degrees, and stun once they hit the 40s or 30s. 

“When that happens, they may lose their grip and fall from the trees,” said AccuWeather Meteorologist Brandon Buckingham. “It’s a unique cold-weather hazard in Florida.”

After they fall from a tree, they may appear to be dead. However, their critical body functions will all still be working and they will continue to breathe. Once temperatures rise, they can jump back into action as if nothing happened. 

Iguanas can grow up to seven feet long and weigh upwards of 30 pounds, so it is best to be cautious when walking under palm trees in colder weather. Getting hit by a reptile of that size could be dangerous. 

If you see a frozen iguana on the ground, do not rush in to warm them up. Joe Gonzalez from the Iguana Police told WPTV in West Palm Beach that relocating or interfering with an iguana can lead to more problems.

“If you capture an iguana in your own yard and don’t move it anywhere else, that’s fine,” Gonzalez said. “But if you relocate it, you’re essentially taking your problem and dumping it somewhere else. This can have legal consequences, including fines.”

Instead, it’s best to just leave the iguana alone. It will usually be fine once it gets over 50 degrees again. 

The post Don’t pick up frozen iguanas appeared first on Popular Science.

If you’ve ever been around a cat, you know they can get the sudden urge to groom themselves at just about any moment. You’re petting them on the couch. They’re purring. Everything seems lovely and content. Then, they lose all interest in you and start licking their butt. 

But some felines don’t just lick themselves: They also lick you. A cat will be busy grooming themselves. Then, without warning, they’ll turn their spiky tongues on their unsuspecting humans. Other cats can’t be bothered and won’t ever groom or lick their human friends, or other kitty friends for that matter. 

So, why do some cats lick their owners? Are they trying to clean you, too? We asked an animal behaviorist and cat expert to help us sort out exactly what is going on when your cat licks you.

Mama cats regularly groom their babies

For a mother cat, grooming is an important part of child rearing. When a mama cat licks her kittens it serves two important purposes: keeping her kittens clean and promoting social bonds, Kristyn Vitale, an animal behaviorist at Maueyes Cat Science and Education tells Popular Science. 

On the one hand, “mother cats are going to groom their kittens to help keep them clean and healthy,” says Vitale. Kittens can be especially susceptible to diseases, and “anybody who’s raised young kittens knows how dirty they can get, and a mother cat is not going to obviously bathe their kitten in a tub. They’re going to use their tongue to clean them.”

Cats learn to groom from their mothers. Image: DepositPhotos

But grooming also helps a mother cat strengthen her relationship with her kittens, says Vitale. A mother licking her babies is “one of the kitten’s first forms of social interaction.” 

It’s essentially a way for mothers to say, “I love you and I care for you.”

How grooming shifts for cats in adulthood

Kittens learn to groom from their mom, and usually start grooming themselves when they’re around four weeks old. Pretty soon after that, some cats “begin to reciprocate [their mother’s] grooming and they’ll groom their siblings or other unrelated cats and also preferred people in the house,” says Vitale. 

If your cat grooms other cats, animal behaviorists like Vitale call those cats their “preferred associates.” For instance, bonded cats often groom each other as a way to reinforce their bestie status. For cats, grooming other cats becomes “a very important social behavior that helps build bonds between the individuals.”

Wild cats lick each other, too

We also see the same behavior in wild cats where mothers groom their cubs to keep them clean and strengthen their connection, says Vitale. In adulthood, wild cats might continue to groom others. You don’t have to search hard to find adorable videos online of lions and tigers licking their besties.

Like domestic cats, lions will lick their feline buddies. Video: Lions Cuddling and Licking Each Other/ DerpDerp

But Vitale says there is one big difference here. A lot of wild cats, like tigers or even the closest relative of domestic cats, the African wild cat, “don’t live in social groups the same way the domestic cat does.” So they don’t always have the same opportunities to shower their buddies with love, because, well, they just don’t really have many buddies.

Cats lick humans to strengthen your relationship

So why, then, do some cats licks their owners? In general, if your cat licks you, it’s them saying (in so many licks) that they love you. 

Vitale says when her cat licks her, she sees it as them “engaging in a social behavior with me” that’s strengthening our relationship. “I’m thinking in my mind that they’re just in a happy mood and looking to hang out together and interact a little bit.” 

What if your cat doesn’t lick you?

While all cats groom themselves (which is why you don’t really need to worry about baths for most cats), not all cats groom other cats or their human friends. But should you feel bad if your cat doesn’t lick you? Does it mean they don’t love you? “No!” says Vitale. 

“Licking’s just one social behavior they could engage in. If your cat just sits on your lap, or sits near you, or your cat’s rubbing up against you, or your cat plays with you, those are all other social behaviors that show there’s a bond,” she says. Cats show love for their owners in all sorts of ways, she emphasizes. “Licking is just one thing a cat could do.”

Vitale has three cats, and of the three she says only one licks her, “very, very sparingly, like once or twice a month.” 

So, don’t worry, whether they’re a licker or not, your cat loves you. They might just have a different way of showing it. 

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

The post Why do cats lick you? An expert explains. appeared first on Popular Science.

A supermassive black hole is reawakening inside a distant galaxy cluster—and after almost 100 million years of slumber, astronomers now say it’s making up for lost time. According to a study published today in Monthly Notices of the Royal Astronomical Society, J1007+3540 is erupting like a volcano and spewing plasma across interstellar space.

A black hole isn’t constantly devouring its unfortunate galactic neighbors. In fact, it can lay dormant for eons. But when one of these gargantuan entities finally reawakens, the resulting display isn’t only impressive—it illustrates the chaotic battle between its own cosmic forces and the pressures of the universe around it.

One of the most striking glimpses of such an event was recently captured by a team led by Shobha Kumari at India’s Midnapore City College. Supermassive black holes rarely emit magnetized, radio-emitting plasma, but according to Kumari, J1007+3540 is especially unique. After analyzing data collected by the Low Frequency Array (LOFAR) in the Netherlands and India’s Giant Meterwave Radio Telescope (uGMRT), researchers say there is undeniable evidence of multiple eruptions stretching deep into the universe’s past.

“It’s like watching a cosmic volcano erupt again after ages of calm—except this one is big enough to carve out structures stretching nearly a million light-years across space,” Kumari said in a statement.

The same images with labels showing the compressed northern lobe, curved backflow signature of plasma and the inner jet of the black hole. Credit: LOFAR / Pan-STARRS / Kumari et al.

Radio imaging revealed a small, bright interior jet indicative of J1007+3540’s internal forces revving back up. But surrounding this illumination is an older layer of fading, distorted plasma from previous active eras.

“This dramatic layering of young jets inside older, exhausted lobes is the signature of an episodic [active galactic nucleus]—a galaxy whose central engine keeps turning on and off over cosmic timescales,” added Kumari.

The supermassive black hole’s forces are unfathomably strong, but the influences of the giant galaxy cluster around it can’t be ignored either. The surrounding plumes of incredibly hot gas exert their own pressure, in this case even higher than most other radio galaxies. These cosmic regions then mangle and distort J1007+3540’s plasma jets as they race outward. For example, LOFAR’s imaging depicts a compressed northern lobe that is curving to one side due to the galactic gas. Complimentary data from uGMRT reveals a very steep radio spectrum indicative of old, weakened plasma particles.

“J1007+3540 is one of the clearest and most spectacular examples of episodic AGN with jet-cluster interaction, where the surrounding hot gas bends, compresses, and distorts the jets,” added Surajit Paul, a study coauthor and astronomer at the Manipal Center for Natural Sciences in India.

Moving forward, Kumari, Paul, and their collaborators hope to employ higher-resolution equipment to peer into J1007+3540’s core. In doing so, researchers can better chart how the black hole’s reignited jets travel through the galaxy cluster, as well as how often such events actually occur.

The post Black hole space volcano erupts after 100 million year nap appeared first on Popular Science.

Seven naturally-mummified cheetahs are more than just an exciting paleontological find. The specimens discovered in five caves near the city of Arar in northern Saudi Arabia offer a glimpse of hope for reintroducing the species to the Arabian Peninsula. The findings are described in a study published today in the journal Communications Earth & Environment.

Cheetahs once lived in much of Africa, and Western and Southern Asia, but their range in Asia has decreased by 98 percent over the past several thousand years. As a whole, cheetahs only occupy nine percent of the territory they used to. On the Arabian Peninsula (Saudi Arabia, Yemen, Oman, United Arab Emirates, Qatar, Bahrain, and Kuwait) cheetahs were found as recently as 1977, when a hunter in Oman killed an adult female cheetah. However, the animals are now considered locally extinct in the region. There are five cheetah subspecies, and the Asiatic cheetah (Acinonyx jubatus venaticus) is believed to have been the only subspecies that lived in present-day Saudi Arabia. The Asiatic cheetah is currently considered critically endangered, with only one small wild population remaining in Iran. Whether or not cheetahs could be reintroduced in the area is debated, largely due to continued habitat destruction.

During digs in five caves in 2022 and 2023, field biologist Ahmed Boug from Saudi Arabia’s National Center for Wildlife and his team uncovered skeletal remains of 54 other cats and seven naturally-mummified cheetahs. In desert regions, natural mummification is common due to the dry conditions where fungi and bacteria can’t thrive on a decomposing corpse. Deserts also have the right mineral content in the sand for preservation.

The oldest of the cat skeletal remains date back about 4,000 years ago. The mummified cheetah remains were much younger—ranging from only 130 to 1,870 years ago. 

They also extracted complete genome sequences from three of the seven mummified cheetahs. According to the team, this is the first time that this kind of genetic material extraction has been done on naturally-mummified big cats. While the most recent specimen is genetically closest to the Asiatic cheetah, the two older specimens are more similar to the Northwest African cheetah (Acinonyx jubatus hecki). This critically endangered species is found in the Sahara and several countries in northwestern Africa.

One of the mummified cheetahs as it was found in situ in a cave in northern Saudi Arabia. Image: National Center for Wildlife – Saudi Arabia

The authors say that their results indicate that cheetah subspecies could support the re-establishment of cheetahs in Saudi Arabia. An increased available genetic pool from other subspecies would make rewilding efforts more feasible, as subspecies can generally interbreed and create fertile offspring that further the population. The team also suggests that their method shows that ancient DNA records from similar specimens can inform future reintroduction plans for other endangered species.

The post Mummified cheetahs could help save the critically endangered big cats appeared first on Popular Science.

A young woman pushes a balled-up piece of napkin into a cup of Jell-O, asking the viewer to imagine that it is an airplane, high in the air.

“That is you flying through the sky,” she tells the camera. “There’s pressure from the bottom, pressure from the top, from the sides, pressure coming from everywhere.”

She taps the top of the Jell-O, making the suspended napkin ball quiver.

“This is what happens when there’s turbulence,” she says. “You feel the plane shaking, but [it] is not just going to fall down.”

The video is by Australian TikToker Anna Paul. Just days after she uploaded it in June 2022, it had accumulated more than 15 million views and thousands of comments from people saying it had cured their fear of flying. Paul says she got the tip “from a real pilot.”

But how accurate is the analogy? Is turbulence really like Jell-O?

@anna..paull

Fear of flying tip

♬ original sound – Anna Paul The origins of the Jell-O analogy

The Jell-O analogy is the brainchild of former airline captain Tom Bunn, who is now a licensed therapist and founder of the SOAR program, which helps people overcome their fear of flying. Over years of listening to clients express their worries, Bunn realized that explaining the science of flight was often not enough to reassure people that flying was truly safe.

“Clients would say they look up in the sky and see a plane and it doesn’t look like it should be there,” he says. “It should fall because they don’t see anything holding it up.”

Because these nervous flyers lacked understanding of the forces holding a plane in the air, they would feel the jolts during turbulence and panic, imagining the plane was about to drop from the sky. To help them overcome this fear, Bunn looked for an analogy that would convince the emotional part of their brains that the plane was not going to fall.

He found it by asking them to recall the familiar sense of air resistance growing as speed increases.

“If you walk across the room, air doesn’t slow you down,” he says. However, “if you’re in a car and push forward with your hand out the window, it feels about the same as putting your hand in a swimming pool and pushing against the water.”

Appealing to this logic, Bunn would ask his clients to imagine the air getting thicker as the plane accelerated down the runway. By the time they were in the air, it was the consistency of Jell-O, supporting them on all sides.

Bunn acknowledges that the analogy is not completely accurate scientifically. But it is an emotionally resonant way of visualizing the forces that hold a plane up during flight.

“Technically, it involves Bernoulli’s theorem,” he says. “It has to do with the fact that the bottom of the wing is pretty much flat and the top is curved.”

If you’ve ever put your hand out of the window in a car, you’ve felt the same kind of pressure that helps keep planes in the air when they fly. Image: DepositPhotos The science that keeps planes flying

Daniel Bernoulli was an 18th-century Swiss mathematician and physicist who formulated several key concepts in fluid dynamics. The most famous is Bernoulli’s principle, which states that an increase in the speed of a fluid decreases the pressure exerted by the fluid.

In a river, for example, water speeds up as it passes through narrower sections. The water pressure is lower in these constricted areas, as the acceleration is caused by higher pressure behind the constriction than within it.

Air behaves much like a fluid. When it encounters an obstacle, it compresses or speeds up as it flows around the object in its path.

“When the plane runs into the air, the air that goes across the top of the wing has to catch up,” Bunn explains. Because of the curve on the wing’s top, the air “has to take a longer route, so the molecules spread out slightly. So, they don’t push as much on the top of the wing as on the bottom.”

As Paul says in her TikTok video, there is pressure coming from the air above and below the airplane. But the wing’s design means that the air pressure is greater below it than in the faster-moving air above it, pushing the wing upwards. This is the phenomenon known in aerodynamics as “lift.” 

“The faster you go, the more powerful the Bernoulli effect,” Bunn explains. This is why, as a plane flies through the air at nearly 600 miles an hour, the pressure under the wings holds it in the sky as securely as a napkin ball in Jell-O.

Turbulence happens when blocks of air rub past each other at different temperatures, pressures or speeds. It can have many different causes, from thunderstorms to the centrifugal force of the earth’s rotation, which pushes bands of air outwards. Its strength ranges from mild, causing little more discomfort than a slight trembling, to severe, in which passengers or flight crew can be thrown around the cabin and risk injury if not wearing seatbelts.

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Turbulence is less scary than it feels

But while strong turbulence can feel alarming, Patrick Smith, a commercial pilot and writer of the Ask the Pilot blog, says that “people tend to have a very exaggerated sense of what the airplane is actually doing.”

“Airplanes have what we call positive stability,” he says. “When they’re disturbed from their position in space, by their nature they want to return to where they were.”

During turbulence, every jolt down is matched by an equivalent jolt up, holding the plane steady on its course—as if it were suspended in Jell-O.

“There has never been a plane crash from turbulence,” Paul says in her video. Is this true?

Bunn recalls one incident in the 1960s when a flight departing Japan’s Tokyo airport encountered severe turbulence off the side of Mount Fuji, causing it to suffer structural damage and crash into a forest. But, he emphasizes, such an incident would never happen today. For one, commercial jets would never fly so close to a mountain, knowing that these can disrupt air flows and cause strong forms of turbulence close to solid ground, where planes are naturally most vulnerable.

For another, improvements in airplane technology mean that planes are now much better constructed to withstand even the strongest forms of turbulence.

During testing of modern airliners, “you can almost bend the wing double [in half] and it won’t break,” Bunn says. In real situations, “you never see even a tenth that much wing flex.”

So, is turbulence really like Jell-O? Not exactly. But if you’re a nervous flyer, perhaps the image can help reassure you that the only real dangers from turbulence can be solved by simply wearing a seatbelt.

As Paul says: “You can just chill there. You’re just wriggling in jelly.”

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

The post Is turbulence really like Jello-O? Pilots weigh in. appeared first on Popular Science.

A young woman pushes a balled-up piece of napkin into a cup of Jell-O, asking the viewer to imagine that it is an airplane, high in the air.

“That is you flying through the sky,” she tells the camera. “There’s pressure from the bottom, pressure from the top, from the sides, pressure coming from everywhere.”

She taps the top of the Jell-O, making the suspended napkin ball quiver.

“This is what happens when there’s turbulence,” she says. “You feel the plane shaking, but [it] is not just going to fall down.”

The video is by Australian TikToker Anna Paul. Just days after she uploaded it in June 2022, it had accumulated more than 15 million views and thousands of comments from people saying it had cured their fear of flying. Paul says she got the tip “from a real pilot.”

But how accurate is the analogy? Is turbulence really like Jell-O?

@anna..paull

Fear of flying tip

♬ original sound – Anna Paul The origins of the Jell-O analogy

The Jell-O analogy is the brainchild of former airline captain Tom Bunn, who is now a licensed therapist and founder of the SOAR program, which helps people overcome their fear of flying. Over years of listening to clients express their worries, Bunn realized that explaining the science of flight was often not enough to reassure people that flying was truly safe.

“Clients would say they look up in the sky and see a plane and it doesn’t look like it should be there,” he says. “It should fall because they don’t see anything holding it up.”

Because these nervous flyers lacked understanding of the forces holding a plane in the air, they would feel the jolts during turbulence and panic, imagining the plane was about to drop from the sky. To help them overcome this fear, Bunn looked for an analogy that would convince the emotional part of their brains that the plane was not going to fall.

He found it by asking them to recall the familiar sense of air resistance growing as speed increases.

“If you walk across the room, air doesn’t slow you down,” he says. However, “if you’re in a car and push forward with your hand out the window, it feels about the same as putting your hand in a swimming pool and pushing against the water.”

Appealing to this logic, Bunn would ask his clients to imagine the air getting thicker as the plane accelerated down the runway. By the time they were in the air, it was the consistency of Jell-O, supporting them on all sides.

Bunn acknowledges that the analogy is not completely accurate scientifically. But it is an emotionally resonant way of visualizing the forces that hold a plane up during flight.

“Technically, it involves Bernoulli’s theorem,” he says. “It has to do with the fact that the bottom of the wing is pretty much flat and the top is curved.”

If you’ve ever put your hand out of the window in a car, you’ve felt the same kind of pressure that helps keep planes in the air when they fly. Image: DepositPhotos The science that keeps planes flying

Daniel Bernoulli was an 18th-century Swiss mathematician and physicist who formulated several key concepts in fluid dynamics. The most famous is Bernoulli’s principle, which states that an increase in the speed of a fluid decreases the pressure exerted by the fluid.

In a river, for example, water speeds up as it passes through narrower sections. The water pressure is lower in these constricted areas, as the acceleration is caused by higher pressure behind the constriction than within it.

Air behaves much like a fluid. When it encounters an obstacle, it compresses or speeds up as it flows around the object in its path.

“When the plane runs into the air, the air that goes across the top of the wing has to catch up,” Bunn explains. Because of the curve on the wing’s top, the air “has to take a longer route, so the molecules spread out slightly. So, they don’t push as much on the top of the wing as on the bottom.”

As Paul says in her TikTok video, there is pressure coming from the air above and below the airplane. But the wing’s design means that the air pressure is greater below it than in the faster-moving air above it, pushing the wing upwards. This is the phenomenon known in aerodynamics as “lift.” 

“The faster you go, the more powerful the Bernoulli effect,” Bunn explains. This is why, as a plane flies through the air at nearly 600 miles an hour, the pressure under the wings holds it in the sky as securely as a napkin ball in Jell-O.

Turbulence happens when blocks of air rub past each other at different temperatures, pressures or speeds. It can have many different causes, from thunderstorms to the centrifugal force of the earth’s rotation, which pushes bands of air outwards. Its strength ranges from mild, causing little more discomfort than a slight trembling, to severe, in which passengers or flight crew can be thrown around the cabin and risk injury if not wearing seatbelts.

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Turbulence is less scary than it feels

But while strong turbulence can feel alarming, Patrick Smith, a commercial pilot and writer of the Ask the Pilot blog, says that “people tend to have a very exaggerated sense of what the airplane is actually doing.”

“Airplanes have what we call positive stability,” he says. “When they’re disturbed from their position in space, by their nature they want to return to where they were.”

During turbulence, every jolt down is matched by an equivalent jolt up, holding the plane steady on its course—as if it were suspended in Jell-O.

“There has never been a plane crash from turbulence,” Paul says in her video. Is this true?

Bunn recalls one incident in the 1960s when a flight departing Japan’s Tokyo airport encountered severe turbulence off the side of Mount Fuji, causing it to suffer structural damage and crash into a forest. But, he emphasizes, such an incident would never happen today. For one, commercial jets would never fly so close to a mountain, knowing that these can disrupt air flows and cause strong forms of turbulence close to solid ground, where planes are naturally most vulnerable.

For another, improvements in airplane technology mean that planes are now much better constructed to withstand even the strongest forms of turbulence.

During testing of modern airliners, “you can almost bend the wing double [in half] and it won’t break,” Bunn says. In real situations, “you never see even a tenth that much wing flex.”

So, is turbulence really like Jell-O? Not exactly. But if you’re a nervous flyer, perhaps the image can help reassure you that the only real dangers from turbulence can be solved by simply wearing a seatbelt.

As Paul says: “You can just chill there. You’re just wriggling in jelly.”

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

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If you’re someone who mosquitoes just adore, we feel your pain. Unfortunately, new data indicates the number of mosquito species that feed on humans is increasing—and it’s likely to get worse.

Dr. Sérgio Lisboa Machado, a microbiologist from the Universidade Federal do Rio de Janeiro in Brazil, is the co-author of a study published today in the journal Frontiers in Ecology and Evolution on a potential link between deforestation and mosquitoes’ increasing preference for human blood. 

Whose blood is it anyway?

In the study, Machado and his colleague Dr. Jeronimo Alencar examined the feeding habits of several mosquito species in the Atlantic Forest, a moist broadleaf forest that stretches along the eastern coast of South America.

According to Machado, the project began as an attempt to figure out which local animals these mosquitoes were feeding on. 

“When we started our research, our main goal was to find the preferred blood source that some species of female mosquitoes use for reproduction,” Machado tells Popular Science

The process of identifying the blood in the creatures’ stomachs was time-consuming. The first step was identifying which of the region’s roughly 40 mosquito species were biting. This involved careful scrutiny of the creatures with a stereoscope. 

“The identification itself is not complicated,” Machado says, “but there is a shortage of entomologists to perform it.”

This fact, along with the need to transport the mosquitoes back to Rio de Janeiro for analysis, meant by the time the samples were analyzed, the DNA and RNA inside of them had started to break down. Even with these difficulties, the analysis provided Machado with a pretty good idea of which mammal species the mosquitoes in question preferred for dinner. In several cases, this blood was human.

 “This was something we didn’t expect,” Machado says. “Since we were in a forest reserve, we expected to find DNA from vertebrates in the local fauna.”

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Shifting tastes

So why so much human blood? The researchers hypothesize that the Atlantic Forest’s changing environment has led these species to develop a taste for human blood. 

“We believe it’s a matter of opportunity given the lack of a preferred food source,” Machado says. “It seems that if mosquitoes can’t find their preferred blood source, they seek out whatever is available.”

As biodiversity declines and animal species go extinct, more mosquito food sources are disappearing. However, unlike many of the animals on which they feed, mosquitoes are adaptable creatures. There’s almost always a ready-made alternative, including humans. 

While this might be good news for the mosquitoes, it risks being terrible news for humans. As an increasing number of mosquito species develop a taste for humans, so too does the risk that species which have not been particularly problematic in the past could act as new vectors for blood-borne diseases.

Once mosquitoes acquire a new food source, they tend to develop a preference for that particular blood—and humans are one species whose availability is most definitely not declining. Today, the Atlantic Forest occupies barely a quarter third of its former area, and it’s not alone. With every passing year, more wilderness is lost to human incursion.

The answer seems to be first arresting, and then reversing, this process of deforestation and habitat destruction. But it’s not altogether clear that the damage is so easily reversible. Humans certainly aren’t going anywhere, so who’s to say that the mosquitoes won’t just keep feeding merrily on us regardless?

Machado expresses cautious optimism on how we can address how deforestation affects what mosquitoes eat.  

“We believe this is a reversible process, but this will require restoring the biome while simultaneously continuing our study. We are still seeking more evidence that [these] mosquitoes have a preferred food source. For now, we are observing that there is a possibility that they are adapting to different sources and do not [prefer] human blood.”

Jumping species

Nevertheless, humanity continues to play with fire as it pushes further and further into previously unspoilt ecosystems. A landmark 2001 study found that new diseases are twice as likely to be zoonotic—transmissible between animals and humans—than existing ones. The danger posed by such diseases was exemplified by COVID-19, which jumped from bats to humans to catastrophic effect.

While disastrous scenarios surrounding a novel pathogen spread by mosquitoes are hypothetical, there are also very real dangers linked to deforestation. For instance, the malaria parasite in the Amazon is largely spread by the Anopheles darlingi mosquito. It was thought to have been eradicated in the 1960s, but re-emerged in the 1990s, and is now common. Another study found that cleared forest patches had created a perfect breeding environment for the insect, helping its return.

Ultimately, Machado stresses that it’s important to control the emergence of new disease vectors and thus mitigate further risks. 

“The re-establishment of ecosystems will certainly contribute to this and should minimize the climate changes we are experiencing,” he says. “We need to learn that our actions today, however small, will always have global repercussions in the future.”

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