Feed aggregator

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.

A pleasant swim at the beach or pool can quickly turn deadly. Every year, over 4,000 people die from unintentional drowning across the United States. 

Swim safety experts say drowning is highly preventable. They recommend learning basic swimming skills, designating “water watchers” to keep an eye on children in the water, and avoiding swimming alone or under the influence.

But what if your outfit could stop you from drowning? Swim safety experts say wearing the right color on your next beach day is a good way to stay visible and out of harm’s way—especially for inexperienced swimmers and kids.

So what are the safest swimsuit colors?

Lisa Zarda, Executive Director of the U.S. Swim School Association, says people wearing bright, neon colors are easiest to spot in pools, lakes, and oceans, while blue, black, white, and gray swimsuits blend into the water. 

“When the water is moving and reflecting the sunlight, certain colors just disappear under the water,” she said. “Especially in open water, where it can be kind of murky and hard to see: The brighter the color, the better.” 

Wearing bright colors helps lifeguards and other safety officials identify and rescue people who are at risk of drowning. Vivid orange and super-bright, highlighter yellow are two standout colors for swim safety.

“Think safety vests and traffic cones,” Zarda said. “Those are bright colors also for a reason—so that they can be easily seen.”

An informal study by Alive Solutions, a public safety group, tested swimsuit visibility in three different conditions: in a pool with a standard light bottom, a pool with a dark bottom similar to dark blue ocean environments, and in an outdoor lake with brown-gray water. 

Across the board, the study identified bright, neon orange as the most visible color. But there was some slight variation of which colors stood out best in different environments. Against a dark pool bottom, neon yellow, green, and orange were the most eye-catching, while even brighter reds and pinks appeared darker, and both light and dark colors faded into the water. 

In a pool with a light bottom, most colors stood out, while light colors like white and light blue disappeared almost instantly. 

In a lake, only neon colors were visible while all other colors quickly blended. So bottom line: stick to a neon orange swimsuit if you want to be sure to be seen.

Dark colored swimsuits can be especially hard to spot in open water. Image: mrs / Getty Images / MARTINS RUDZITIS What makes neon stand out?

All visible color is the result of reflected light. A red apple, for instance, absorbs many wavelengths along the light spectrum, but bounces back red wavelengths. So to the human eye, an apple appears red.

Ordinary colors, like the red of an apple, only reflect the light they receive, but fluorescent pigments do more than that. They also absorb incoming nonvisible ultraviolet and some visible blue light and then re-emit part of that energy as intensely visible light. This is why fluorescent colors almost seem to glow.

Fluorescent shade’s high-contrast is why traffic safety signs, protective gear, and safety and rescue objects, like buoys, are often made with neon materials. It’s also what makes fluorescent swimsuits extra safe.

Swim safety for kids

As summer comes into full swing, Zarda says wearing a neon swimsuit is just one piece of the puzzle to prevent drowning, particularly for kids.

Children are extremely vulnerable to drowning accidents. Kids between ages one to four die from drowning more than any other cause of death, according to the Centers for Disease Control and Prevention. For children aged five to 14, drowning is the second leading cause of unintentional injury.

“Choosing the right swimsuit color doesn’t replace any of the other important layers of protection.” Zarda said. 

“Always having undistracted adult supervision, having a fence around your pool, enrolling your child in swim lessons so that they know how to swim and navigate in the water—those are all still very important.”

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.

Related 'Ask Us Anything' Stories

Yes, you can be allergic to water

How to stay safe riding roller coasters

Why you never forget how to ride a bike

Why did childhood summers feel endless?

Is crossing your eyes really bad for you? We asked an optometrist.

Why do we even have baby teeth?

The post What’s the safest swimsuit color? Skip blue and black. appeared first on Popular Science.

How much of a gamechanger is the Anthropic deal with SpaceX? What is the income statement impact ? What is likely to happen for the SpaceX IPO pricing and trading on the day and for the rest of the year. As a disclaimer and disclosure, Brian is an investor with stakes in Tesla, SpaceX, and ...

Read more

A 31-year-old New York native named Kelsey Pfendler is one week into her audacious quest to become the youngest woman to row unassisted from California to Hawaii. To complete her over 2,400-mile journey, she will need to face stormy seas and traverse waters teeming with all types of ocean life.  If she succeeds, Pfendler will become the first American woman ever to do so.

@yourowkelsey

A couple hours of napping and some food will make you feel like a new woman! Waves and wind are still big, but luckily they are becoming more favorable, allowing Kelsey’s boat to catch and ride the waves. Kelsey is rowing to raise funds for The Whale Foundation an organization whose mission is to support, restore, and celebrate the health and well-being of the Grand Canyon river guiding community. Links to learn more and donate are in our bio. @Concept2 @Recpak @insta360 official

♬ original sound – YouRowKelsey

Pfendler set off from Monterey, California on May 21 and has been posting daily updates on her TikTok. A separate live tracker  also plots her position on a digital map. As of May 28, the tracker shows her off the Southern California coast, moving at 1.6 knots. The multi-month voyage is a major test of physical strength and mental fortitude,  and it’s already proven grueling. In just her first week, Pfendler battled strong headwinds as she pushed away from the California coast, leaving her hands covered in blisters.

@yourowkelsey

Absolutely flying today! Waves are around 14ft and wind maxed about 22mph earlier, which gave her a good boost of speed. 229 miles so far, about 2,000 to go. @Concept2 @Recpak

♬ original sound – YouRowKelsey

And it has only gotten tougher. Pfendler’s route took her directly into the path of a weather front, bringing bone-chilling temperatures and punishing waves. Worse, while taking cover from the waves, she lost the cap to her heavy-duty freshwater bag. Though she has the ability to make more freshwater with a desalination device, it runs on solar power and the storm left the skies too dark and overcast for the device to work. As a result, Pfendler has had to tap into her emergency supply of 25 small water bottles, a scarcity that has also prevented her from using water to rehydrate her freeze-dried camp food.

“It’s tortillas and peanut butter until I get some sun,” Pfendler said. 

But the trip has had its lighter moments as well. Pfendler posted an update sharing her excitement when she crossed the continental shelf. At about 50 to 60 miles off the California coast, crossing the continental shelf is something few humans get to experience so intimately.  She also recounted a moment where she spotted either a sea lion or a dolphin hunting fish nearby, sending them leaping out of the water all around her boat.

“It was really cool, it was in the dark and it was kinda special for me,” Pfendler said, 

This quest  isn’t Pfendler’s first rodeo. She completed a similar rowing trip from California to Hawaii in 2024 with three companions, serving as the skipper. That trip took 40 days, 22 hours, and 14 minutes. Still, rowing in total isolation—even for an experienced oarswoman—adds another layer of challenge. If Pfendler completes the trip, she will be just the third woman ever to do so. The record, set by British rower Lia Ditton in 2020, currently stands at 86 days, 10 hours, and 56 seconds.

The post Kelsey Pfendler is trying to become the youngest woman to row solo from California to Hawaii appeared first on Popular Science.

Anthropic is likely at 75-90% profit margin most of the time on user subscriptions. Most users are likely in the 10-50% usage levels and some don’t use it all just like stored balance credit cards. This means that AI data center operators at 60-80% profit margin or chip and memory makers in the same range ...

Read more

For decades, scientists have known that Earth’s magnetic field helps migratory birds and homing pigeons navigate. Just how our feathered friends sense the invisible sphere around the Earth, however, has been less clear. 

At least part of the answer appears to be hiding inside a seemingly random organ. Immune cells inside pigeon livers called macrophages are sensitive to the planet’s magnetic field. These cells function like an internal compass, according to a new study published today in the journal Science. 

Macrophages destroy old red blood cells, which makes them accumulate iron. The iron makes the macrophages  superparamagnetic, a kind of magnetism that takes place in particular nanoparticles. The nanoparticles can then be magnetized if a magnetic field is applied to them. 

“When pigeons fly, the nanoparticles align with the magnetic field and become ‘magnetized,’” Clivia Lisowski, a co-author of the study and a post-doctoral researcher in Immunology at the University of Bonn, tells Popular Science. “Like that, pigeons can sense Earth’s magnetic field.”

Electron microscopy image of pigeon liver tissue shows hepatic macrophage (blue) in contact with nerve fiber (yellow), which enables them to transmit (“magnetic”) information to the pigeon brain. Image: Lisowski et al. (2026) Science.

To understand how these particles help the pigeons navigate, Lisowski and her team tracked down where magnetic cells are in pigeons’ bodies. Because the liver and spleen store significant quantities of iron, researchers thought these might be good candidate organs. The  liver had a significantly stronger magnetic response than any of the other tissues in the study, according to study co-author Ulf Wiedwald, an expert in nanoscience at the University of Duisburg-Essen in Germany, 

From there they homed in on macrophages, and put these important immune cells  to the test. They studied  pigeons that were trained to fly back to their aviary in Konstanz, Germany, from over 12.4 miles away. Pigeons whose macrophages had been removed got lost when the weather was overcast. But when the sun was out, the pigeons reached the aviary, probably with the aid of solar cues. 

The findings show  how the birds employ magnetic sensing to find their way, as well as the sun’s orientation. 

“Our study has implications for both the immune research landscape as well as for research on animal navigation or magnetoreception, respectively. For animal navigation it’s a new concept of how animals sense/perceive Earth’s magnetic field,” Lisowski says. “We think that this ferrimagnetic mechanism can actually explain how birds migrating at night, or sharks or bats or other animals migrating in dark environments can perceive Earth´s magnetic field.”

The team also found that the iron-rich macrophages are close to nerve fibers, indicating that magnetic information can get to the brain via this route. Ultimately, this shows how important  interdisciplinary research, involving immunologists, behavioral biologists, and physicists, carries  significance for more than just birds. 

As for the immune system, Lisowski explains that to accomplish its different fuctions—such as defending our bodies from pathogens and healing wounds—it has to sense the environment.

“Our finding that the immune system can also sense the Earth´s magnetic field is a complete new layer in this concept of ‘immuno-sensation’ and opens the door to new research,” Lisowski explains. 

The post Pigeons use their livers to sense Earth’s magnetic field appeared first on Popular Science.

Anthropic has introduced Claude Opus 4.8. It builds on Opus 4.7 with improvements across benchmarks, and is a more effective collaborator. It’s available today for the same price. Opus 4.8 launches alongside several new features. Users on claude.ai now have control over the amount of effort Claude puts into a task. Claude Code has a ...

Read more

New York, USA, 28th May 2026, CyberNewswire

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.  

A female yellow fever mosquito (Aedes aegypti), feeding on a bag of warm blood. Image: Romina Barrozo.

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.

Elon is saying SpaceX built its own super-optimized AI training software from scratch in the C programming language. It is 10 times faster than Google JAX framework. It’s designed to run on a massive cluster of 220,000 cutting-edge NVIDIA GB300 GPUs connected by ultra-fast 800G networks. They use pipeline parallelism and get as close to ...

Read more

Anthropic added ~$11B ARR in one month which is more than the combined 10-year build of Palantir, Snowflake, and Databricks (which employed tens of thousands collectively). No precedent in capitalism history. SaaS/cloud created $5–10T value over decades, yet one model company matched the output of the top three recent SaaS giants instantly. Growth rates (500%+ ...

Read more

Elon Musk and SpaceX Have the High Ground. How much will that matter? SpaceX already has almost all of the satellites and launches. He will is making the satellites and the rockets ten to 100 times better in the year or two. Are the bears right when they say that SpaceX will only be a ...

Read more

Everyone who has ever owned a hamster knows the sound: the small, relentless squeak of the exercise wheel, usually starting around two in the morning.

As you watch your cute furball running toward no destination whatsoever, you might wonder: What’s going on here? Is little Hammy acting out of restlessness or boredom? 

For decades, scientists assumed it was exactly that: a neurosis, an artifact of captivity, the hamster equivalent of doing push-ups in prison. 

But in 2014, researcher Johanna Meijer conducted a study that suggested a less depressing scenario. When wild mice came across a wheel in their natural habitat, they got on the wheel and ran—sometimes for up to 18 minutes at a stretch.

So if it’s not boredom or neurosis (wild mice surely have plenty of more important tasks than wheel running), what is it? 

Dr. Theodore Garland Jr., a professor of biology at UC Riverside, has spent more than 30 years trying to figure that out. 

“There’s still a lot of controversy about what, exactly, wheel running means to an organism,” Garland says. “What is it? What is the organism trying to do?”

Why wild mice run on wheels just like your hamster

In Meijer’s 2014 study, published in Proceedings of the Royal Society B, she and her colleagues placed exercise wheels in two different locations: a green urban area and a dune area not accessible to the public. For more than three years, they recorded wildlife activity at both locations.

They found that wild mice closely mirrored the behavior of their cage-dwelling counterparts. At both locations, the mice frequently ran on the wheels—often for lengths of time equal to the “workout” durations of captive mice.

Although food was initially used to attract animals to the wheel, the researchers found that wheel running continued even after the food was removed. This suggests that the animals not only ran voluntarily on the wheel, but did so without any external reward. 

The wheels attracted more than just mice, too. Shrews, frogs, and even slugs were recorded using the equipment (a few snails were excluded from the study due to “haphazard” movements on the wheel). But wild mice used the wheel far more than another animal, accounting for 88 percent of all wheel runners. 

Hamsters aren’t the only creatures that like running on wheels. Video: Wild Animals Caught On Hamster Wheel, Live Science

So, why do rodents specifically enjoy a run to nowhere? Are slugs simply less committed to their cardio?

According to Garland, rodents are simply built for it—bigger home ranges, faster metabolisms, and the aerobic capacity to sustain speed over distance.

“A toad isn’t going to be running 10 kilometers in a day,” Garland says. “Whereas a chipmunk could be.”

Dopamine keeps mice and hamsters coming back for more

But that’s only part of the story. The more interesting question is why any animal would choose to do it at all.

According to Garland, the drive to run on wheels among free-ranging animals is not fully understood, but the behavior is likely tied to the reward centers of the brain. 

“Dopamine is viewed as the final common denominator,” Garland says, referencing the neurotransmitter that delivers a sense of pleasure to the brain’s reward system. Similar to a human working out at the gym, mice get a dopamine boost every time they run on their trusty wheel. 

In Garland’s own lab, mice placed in larger, rat-sized wheels will sometimes slow down mid-run and rather than jumping off as the wheel keeps spinning, complete a full 360, and keep going. It serves no obvious purpose. It looks, for all the world, like a bit of acrobatics, as if the little mouse is creating its very own roller coaster.

“I’m hesitant to use the ‘F-word’ about lower vertebrates,” he says, “but it’s hard to ignore the idea that they’re getting some sort of pleasure or enjoyment out of it.” 

Related 'Ask Us Anything' Stories

Do dogs smile? Not like us.

How marine mammals stay hydrated in a salty sea

Do any bugs live in the ocean? Short answer: Not really.

No, bears don’t actually hibernate

Can animals read? Not in the human way.

Why some animals eat their babies

The reward system may explain the drive, but Garland sees something even more elemental at work—something similar to the “zoomies” dogs and other young animals get. 

A baby horse, Garland notes, will sometimes just tear around a field for no apparent reason—solo, unprompted, burning energy for the sheer joy of it. “We used to call it nip-norting,” he says, “just going crazy, even without another individual to egg it on.”

Exercising at a young age leads to lifelong habits, even for hamsters

Rodents’ love of running on wheels might even have implications for humans. Some of Garland’s work suggests that, when introduced at a young age, wheel running can become a lifelong habit.

In his study, Garland found that mice given access to a running wheel immediately after weaning, at just three weeks old, ran significantly more as adults.

“It’s got to be something up here,” Garland says, indicating the brain. “Their reward system has been permanently tweaked.”

Whatever it is keeping these little guys running, an early start seems to predict an ongoing practice. The implications, Garland believes, extend well beyond mice. For instance, cutting physical education from school curricula, he says, could be “a huge public policy disaster,” leading to adults who aren’t used to exercising.

“If you’re a kid who never gets to play basketball or tennis,” he says, “and then you get to college, and your friends are playing pickup games, it’s probably not even on your radar to do that kind of thing.”

Of course, none of this is on your hamster’s radar at all. They’re just galloping away, keeping you awake with the endless rotation of their squeaky wheel. But all that running can also lead to some good: Recently, a resourceful young YouTuber rigged his brother’s hamster wheel to charge his phone.  

But no need to worry—the clever teen isn’t exploiting the toil of a joyless captive. Hammy, it seems, is just doing what comes naturally. 

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 Hamsters run on wheels for a surprisingly joyful reason appeared first on Popular Science.

Frankfurt am Main, Germany, 27th May 2026, CyberNewswire

This article was originally featured on The Conversation.

On May 22, 2026, the Pentagon released a second batch of previously classified photos and videos showing what appear to be unexplained flying objects. These file dumps were the culmination of a process that was set in motion back in July 2023, when a group of government whistleblowers testified before Congress that the U.S. government was secretly in possession of extraterrestrial spacecraft and suspected alien body parts.

That congressional hearing marked the beginning of a cultural shift in which UFO reports are increasingly treated as a matter for serious discussion, both within the government and the scientific community.

The Pentagon released over 200 previously classified UFO files in May 2026. Image: Department of Defense

But is this newfound legitimacy deserved? As an aerospace scientist who studies aircraft and spacecraft design, I approach this question using math, physics and the principles of engineering. To assess the plausibility of alien visitors, it’s necessary to understand the obstacles that an extraterrestrial vessel would need to overcome to reach Earth.

The tyranny of distance

There is no evidence of intelligent alien life in our solar system. So any extraterrestrial visitors would likely have to come from another star system within our Milky Way galaxy.

Proxima Centauri, the star closest to our Sun, is located 4.25 light-years (about 25 trillion miles or 40 trillion kilometers) away.

For perspective, if Earth were the size of a pea, the distance to Proxima Centauri would roughly equal the distance between New York and Sydney, Australia.

Even the stars closest to Earth are incredibly far away.

Since only a fraction of stars are thought to host intelligent life, the nearest alien civilization – if one exists – is surely much farther away than Proxima.

A need for speed

Given the scale of interstellar distances, it’s inevitable that any alien voyage to Earth would span many years and possibly several centuries. But as the time spent in transit increases, so does the risk of catastrophic accidents or system malfunctions that could jeopardize the mission. So it’s important to avoid an overly lengthy journey by traveling as fast as possible.

No object can reach or exceed the speed of light (roughly 186,000 miles or 300,000 kilometers per second). But well before approaching that threshold, engineering constraints begin to assert themselves. Limited fuel availability and the potential for structural damage will restrict the spacecraft’s peak velocity.

There is no universally accepted upper limit on interstellar flight speeds, but studies tend to converge around 19,000 miles per second (30,000 km/s) – 10% of the speed of light – as a realistic cruise velocity. At this speed, a journey of 10 light-years will take approximately 100 years to complete.

Fueling the dream

Finding a way to accelerate the ship to its target cruise speed is the central challenge facing any would-be alien explorers.

Interstellar space is unforgivingly vast, but the emptiness has some advantages. The lack of atmosphere means there is no aerodynamic drag. So when the ship reaches its cruise speed, it can shut down its propulsion system and coast toward the final destination. Unfortunately, the lack of atmosphere also means there is nothing to slow the ship down prior to arrival. So ideally, the propulsion system would be used for both acceleration at the start of the trip and deceleration at the end.

One of the more exotic propulsion strategies employs high-powered laser beams to push the ship through space. The beam is projected from a stationary array near the travelers’ home planet and directed toward a thin reflective sail attached to the ship. The beam’s photons exert radiation pressure on the sail, propelling the ship forward.

This approach has a major advantage in that it requires no onboard fuel. But the amount of energy and infrastructure needed to operate the laser would be staggering. Also, beamed propulsion provides no mechanism for deceleration. At best, this method could be deployed as part of a hybrid strategy that uses a separate system for deceleration.

A more practical approach is to use rocket propulsion. Rockets generate propulsive force, also known as thrust, by expelling high-velocity exhaust in a rearward stream. By reversing the direction of the exhaust, rockets can also be used to slow the ship down.

Their main disadvantage is that rockets must carry their own fuel in addition to carrying the passengers, the habitat and other life-sustaining systems. The extra load necessitates even more fuel. In other words, you need fuel to transport your fuel. The result is a costly snowball effect that can cause the total fuel requirement to balloon to absurd proportions.

Rocket propulsion can be divided into three broad categories.

Chemical propulsion uses chemical reactions – typically combustion – to extract energy from the bonds between atoms. All human space missions thus far have used chemical propulsion. The problem with this method is that it accesses only a tiny fraction of the energy contained within the fuel.

Consequently, using chemical propulsion on a spacecraft with a cruise velocity of 19,000 miles per second (30,000 km/s) would require more fuel than all the mass in the observable universe.

Antimatter propulsion is theoretically the most efficient option. When antimatter comes into contact with ordinary matter, the two undergo mutual annihilation and 100% of their combined mass is converted into energy. This makes it possible to achieve the same cruise velocity – one-tenth the speed of light – with fuel accounting for less than a quarter of the ship’s total mass. This is science fiction-level fuel efficiency, which makes antimatter an attractive option for interstellar propulsion.

The downside is that antimatter is extremely unstable and difficult to make. To date, particle physicists have produced less than 20 billionths of a gram of antimatter. Moreover, these particles had lifespans lasting only fractions of a second and a price tag in the hundreds of millions of dollars.

Nuclear fusion offers a more viable alternative to antimatter. This approach harvests energy stored inside the nucleus of an atom using the same process that powers the Sun. With current technology, fusion engines remain aspirational, but they could, in theory, produce 10 million times more energy per kilogram than chemical rockets.

NASA has been working to develop nuclear propulsion. This artist’s impression shows what a nuclear-powered rocket could look like. Image: Public Domain, John Frassanito & Associates/Wikipedia

Still, a fusion-powered ship with a cruise velocity of 19,000 miles per second (30,000 km/s) would require fuel equivalent to 150 times the mass of the ship itself.

A delicate balancing act

These numbers assume that our extraterrestrial visitors have figured out how to efficiently convert the energy released by their reactor – whether nuclear fusion or antimatter – into thrust.

Just as importantly, they must be able to create optimized fuel tank structures that are ultra lightweight yet highly secure. Designing the structure of the ship, from the fuel tanks to the hull, would be one of the biggest engineering challenges of the entire mission.

Interstellar space contains a sparse smattering of hydrogen atoms and microscopic grains of cosmic dust. At 19,000 miles per second (30,000 km/s), dust particles would smash into the ship’s hull with the energy of a .22-caliber bullet. The bombardment of hydrogen atoms would produce a violent cascade of radiation that could erode even the most resilient engineering materials.

Surviving the onslaught would require no less than a flying fortress with complex magnetic shielding. This would increase the total mass of the ship, which further drives up the demand for fuel.

This example is just one of the hundreds of delicate design trade-offs that would plague any interstellar vessel. Each individual design requirement acts as a filter, reducing the number of feasible solutions.

Finding a single system that simultaneously satisfies all the requirements is analogous to shopping for a car online. With each new filter you apply – four-wheel drive, black exterior, less than 10,000 miles on the odometer – the number of available options dwindles.

When design requirements are in tension with one another – for example, requiring a structure that is lightweight but also supremely durable – the number of feasible solutions can drop to zero.

No single law of physics prohibits an interstellar voyage to Earth. But the combined effects of hundreds of extreme, often conflicting engineering requirements may render it physically infeasible.

It’s also possible that alien civilizations have discovered novel technologies that outperform anything currently known to humans. But like the examples discussed here, any such technology will inevitably encounter its own engineering hurdles.

The trillion-dollar question

Ultimately, engineering challenges are just some of the many barriers to interstellar travel. Any prospective alien visitors must also have sufficient cognitive ability, technological maturity, physical resources, collective desire and proximity to Earth.

That said, if the stars were to align and an alien vessel made it to Earth intact, it would trigger a torrent of burning questions: Where are they from? What do they want? What are they made of?

But the question that would go furthest in shedding light on the deeper mysteries of the universe is, “How on Earth did they get here?”

The post Could aliens ever visit Earth? An aerospace scientist unpacks the challenges of interstellar spaceflight. appeared first on Popular Science.

I have an article about replatforming and how business can become radically bigger, faster and more profitable with new technologies and processes. But here we focus on actual transformation and step changes to the world and industries. The Industrial revolution had 10-20X the annual GDP growth rate of the Agrarian or pre-industrial ages. The stone ...

Read more

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. 

The sticky (and stinky) brown spore substance attracts insects to help the fungi spread. Image: Tina Shaw/USFWS.

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.”

Henrietta “Etty” Darwin (1843-1927) was the eldest of Charles Darwin’s daughters to reach adulthood. Image: Cambridge University Library. 

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.

When Sachita Shah sent her cardiologist brother an ultrasound of her patient’s heart, he was very confused. The heart was huge, and the left ventricle incredibly muscular. His confusion was warranted, as the ultrasound was not of a human heart. It belonged to another primate—a gorilla. Shah, emergency physician and VP of Global Health at medical equipment manufacturer Butterfly Network, tells Popular Science that if she had shown an ultrasound of a gorilla fetus to a radiologist, they would have assumed it was a human baby. 

Shah is on the gorilla care team currently looking after Jamani and Olympia, two western lowland gorillas (Gorilla gorilla gorilla) mothers at Woodland Park Zoo in Seattle, Washington. Jamani gave birth on Monday May 18, and Olympia is expected to deliver her new baby imminently. Shah and her colleagues’s work involves conducting ultrasounds of Jamani and Olympia’s baby bump—though now probably just Olympia’s—to keep an eye on the baby’s growth and position. 

“We got a really pretty baby face,” Shah says, speaking of the ultrasounds. “We could see nose and lips and fetal breathing movements and heartbeat and drinking fluid, opening mouth and swallowing. For all intents and purposes, it was very much the same [as a human baby].” 

The endangered gorilla mothers were trained to take part in the exams and procedures conducted by the gorilla care team, and they could choose whether to participate or not. The gorillas put their bellies against the edge of the enclosure for the scan (and received snacks), where there is a small opening through which the care team can reach through with the ultrasound probe. 

As such, the zoo needed a small and portable imaging device. That’s where Butterfly Network and their all-in-one ultrasound probe came in. 

“When you think of an ultrasound, you might think of a big cart with lots of different probes—a different probe if you wanted to do a pregnancy scan, or a heart scan, or a pediatric scan might have a tiny probe,” Shah says. 

Instead, the Butterfly probe they use at Woodland Park Zoo is a handheld ultrasound that plugs into a smart phone. It is around as big as an electric shaver, and it functions with a number of different softwares for either veterinarian or human health use. Notably, an app allows the team to use it for different types of scans—from a pregnant gorilla to a child’s lungs—that would traditionally require distinct probes and machines. 

Jamani’s baby was born on May 18 at 5:50 a.m. Image: Jeremy Dwyer-Lindgren / Woodland Park Zoo.

Shah and her colleagues also used the Butterfly ultrasound device to scan the heart of Nadaya, the silverback gorilla father of both babies. In fact, the heart ultrasound Shah sent to her brother belonged to Nadaya.  They used human software for that scan, even though their vet software is optimized for fur. Fortunately, Nadaya’s chest isn’t very furry. 

Shah, who has gone through a pregnancy herself, was most moved by working with the gorilla mothers. 

“We could tell the baby’s head had dropped and we thought, ‘oh man, she must be so uncomfortable.’ And she was waddling and walking a little differently. I was like, ‘oh, I remember that, girl.’ It was just amazing to remember that we’re all connected in that way,” she says. 

Western lowland gorillas are critically endangered, so babies are always excellent news.

UPDATE May 27 8:19 a.m EDT

On Sunday, May 24, at 1:44 p.m. PDT, Olympia’s baby was delivered by an emergency C-section performed by a medical team who typically works on humans. This 5.4-pund boy is the western lowland gorilla’s second baby.

The post Pregnant gorillas undergo ultrasounds and the results might look familiar 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.

Small as a grain of rice, polka-dotted, and everything nice. These are some of the ingredients that come together to make Thecacera sesama, a newly identified species of sea slug, or nudibranch, found swimming in Taiwan.

“Taiwanese divers call it ‘sesame’ in Chinese and it is also small like a sesame seed, hence the name,” researchers explain in a statement. Indeed, T. sesama is less than 0.12 inches long. The tiny bugger is also translucent and speckled black and yellow, and Ho-Yeung Chan “accidentally discovered” it while diving in 2019. 

A sketch of Thecacera sesama showing its appearance and morphological features. Image: Chen-Lu Lee.

Chan is a researcher at the National Taiwan Ocean University’s Institute of Marine Biology and Center of Excellence for the Oceans, but was an undergraduate student when he made the discovery. Chan didn’t realize he’d found a previously unknown species until after he’d spoken with sea slug identification expert Hsini Lin via Facebook. Chan is now lead author of a recently published ZooKeys study officially introducing T. sesama to the world. 

The new sea slug seems to enjoy a simple life. It displays just four main actions: feeding, searching, mating, and laying eggs on bryozoans. Also known as moss animals, bryozoans are a group of small aquatic invertebrates. The bryozoan that hosts T. sesama might also be a previously unknown species. 

Living specimens of Thecacera sesama. Image: Ho-Yeung Chan et al., 2026

While you might assume that the most difficult aspect of researching T. sesama is its miniscule size, the hardest part of the study for the team was the explosive weather of Taiwan’s Keelung coast. The island as a whole often has summer typhoons and large waves in the winter monsoon season, during which the sea is frequently colder than 60.8 degrees Fahrenheit. 

With these challenging conditions, researchers can only dive to investigate sea slugs for around a third of the year. The narrow window means that spotting the sesame-sized slugs is completely a toss-up.

“Nudibranchs are one of the key players in the marine food web,” the team explained. “They are extremely colourful and can be spotted on coral reef ecosystems. However, many nudibranchs are very small in size and are extremely difficult to spot underwater with the naked eye.”

Chan and colleagues believe that Taiwan’s marine environment is probably home to many other unknown tiny species. It remains to be seen what new strange creature will emerge from the island’s turbulent waters. 

The post Seed-size sea slug looks like an everything bagel appeared first on Popular Science.