Science – Page 13

The UK got rid of coal—where’s it going next?

Energy, energy policy, renewable energy, Science, Sustainability / Kris Guyer / February 6, 2025

Clean, but not fully green

The UK has transitioned to a lower-emission grid. Now comes the hard part.

With the closure of its last coal-fired power plant, Ratcliffe-on-Soar, on September 30, 2024, the United Kingdom has taken a significant step toward its net-zero goals. It’s no small feat to end the 142-year era of coal-powered electricity in the country that pioneered the Industrial Revolution. Yet the UK’s journey away from coal has been remarkably swift, with coal generation plummeting from 40 percent of the electricity mix in 2012 to just two percent in 2019, and finally to zero in 2024.

As of 2023, approximately half of UK electricity generation comes from zero-carbon sources, with natural gas serving as a transitional fuel. The UK aims to cut greenhouse gas emissions by 42 percent to 48 percent by 2027 and achieve net-zero by 2050. The government set a firm target to generate all of its electricity from renewable sources by 2040, emphasizing offshore wind and solar energy as the keys.

What will things look like in the intervening years, which will lead us from today to net-zero? Everyone’s scenario, even when based in serious science, boils down to a guessing game. Yet some things are more certain than others, the most important of these factors being the ones that are on solid footing beneath all of the guesswork.

Long-term goals

The closure of all UK coal-fired power stations in 2024 marked a crucial milestone in the nation’s decarbonization efforts. Coal was once the dominant source of electricity generation, but its contribution to greenhouse gas emissions made it a primary target for phase-out. The closure of these facilities has significantly reduced the UK’s carbon footprint and paved the way for cleaner energy sources.

With transition from coal, natural gas is set to play a crucial role as a “transition fuel.” The government’s “British Energy Security Strategy” argued that gas must continue to be an important part of the energy mix. It positioned gas as the “glue” that holds the electricity system together during the transition. Even the new Starmer government recognizes that, as the country progresses towards net-zero by 2050, the country may still use about a quarter of the gas it currently consumes.

Natural gas emits approximately half as much carbon dioxide as coal when combusted, making it a cleaner alternative during the shift to renewable energy sources. In 2022, natural gas accounted for around 40 percent of the UK’s electricity generation, while coal contributed less than two percent. This transition phase is deemed by the government to be essential as the country ramps up the capacity of renewable energy sources, particularly wind and solar power, to fill gaps left by the reduction of fossil fuels. The government aims to phase out natural gas that’s not coupled with carbon capture by 2035, but in the interim, it serves as a crucial bridge, ensuring energy security while reducing overall emissions.

But its role is definitely intended to be temporary; the UK’s long-term energy goal is to reduce reliance on all fossil fuels (starting with imported supplies), pushing for a rapid transition to cleaner, domestic sources of energy.

The government’s program has five primary targets:

Fully decarbonizing the power system (2035)
Ending the sale of new petrol and diesel cars (2035)
Achieving “Jet Zero” – net-zero UK aviation emissions (2050)
Creating 30,000 hectares of new woodland per year (2025)
Generating 50 percent of its total electricity from renewable sources by 2030

Offshore wind energy has emerged as this strategy’s key component, with significant investments being made in new wind farms. Favorable North Sea wind conditions have immense potential. In recent years, a surge in offshore wind investment has translated into several large-scale developments in advanced planning stages or now under construction.

The government has set a target to increase offshore wind capacity to 50 GW by 2030, up from around 10 GW currently. This initiative is supported by substantial financial commitments from both the public and private sectors. Recent investment announcements underscore the UK’s commitment to this goal and the North Sea’s central role in it. In 2023, the government announced plans to invest $25 billion (20 billion British pounds) in carbon capture and offshore wind projects in the North Sea over the next two decades. This investment is expected to create up to 50,000 jobs and help position the UK as a leader in clean energy technologies.

This was part of investments totaling over $166 million (133 million pounds) to support the development of new offshore wind farms, which are expected to create thousands of jobs and stimulate local economies.

In 2024, further investments were announced to support the expansion of offshore wind capacity. The government committed to holding annual auctions for new offshore wind projects to meet its goal of quadrupling offshore wind capacity by 2030. These investments are part of a broader strategy to leverage the UK’s expertise in offshore industries and transition the North Sea from an oil and gas hub to a clean-energy powerhouse.

Offshore wind

As the UK progresses toward its net-zero target, it faces both challenges and opportunities. While significant progress has been made in decarbonizing the power sector, the national government’s Climate Change Committee has noted that emissions reductions need to accelerate in other sectors, particularly agriculture, land use, and waste. However, with continued investment in renewable energy and supportive policies, the UK is positioning itself to become a leader in the global transition to a low-carbon economy.

Looking ahead, 2025 promises to be a landmark year for the UK’s green energy sector, with further investment announcements and projects in the pipeline.

The Crown Estate, which manages the seabed around England, Wales, and Northern Ireland, has made significant strides in facilitating new leases for offshore wind development. In 2023, the Crown Estate Scotland announced the successful auction of seabed leases for new offshore wind projects, totaling a capacity of 5 gigawatts. And in 2024, the government plans to hold its next major leasing round, which could see the deployment of an additional 7 GW of offshore wind capacity.

The UK government also approved plans for the Dogger Bank Wind Farm, which will be the world’s largest offshore wind farm when completed. Located off the coast of Yorkshire, this massive project will ultimately generate enough electricity to power millions of homes. Dogger is a joint venture linking SSE Renewables, Equinor, and Vattenfall.

This is in line with the government’s broader strategy to enhance energy independence and resilience, particularly in light of the geopolitical uncertainties affecting global energy markets. The UK’s commitment to renewable energy is not merely an environmental imperative; it is also an economic opportunity. By harnessing the vast potential of the North Sea, the UK aims not only to meet its net-zero targets but also to drive economic growth and job creation in the green energy sector, ensuring a sustainable future for generations to come.

Recognizing wind’s importance, the UK government launched a 2024 consultation on plans to develop a new floating wind energy sector.

The transition to a greener economy is projected to create up to 400,000 jobs by 2030 across various sectors, including manufacturing, installation, and maintenance of renewable energy technologies.

Its growing offshore wind industry is expected to attract billions in investment, solidifying the UK’s position as a leader in the global green energy market. The government’s commitment to offshore wind development, underscored by substantial investments in 2023 and anticipated announcements for 2024, signals a robust path forward.

Moving away from gas

Still, the path ahead remains challenging, requiring a multifaceted approach that balances economic growth, energy security, and environmental sustainability.

With the transition from coal, natural gas is now poised to play the central role as a bridge fuel. While natural gas emits fewer greenhouse gases than coal, it is still a fossil fuel and contributes to carbon emissions. However, in the short term, natural gas can help maintain energy security and provide a reliable source of electricity during periods of low renewable energy output. Additionally, natural gas can be used to produce hydrogen, potentially coupled with carbon capture, enabling a clean energy carrier that can be integrated into the existing energy infrastructure.

To support the country’s core clean energy goals, the government is implementing specific initiatives, although the pace has been quite uneven. The UK Emissions Trading Scheme (ETS) is being strengthened to incentivize industrial decarbonization. The government has also committed to investing in key green industries alongside offshore wind: carbon capture, usage and storage (CCUS), and nuclear energy.

Combined, these should allow the UK to limit its use of natural gas and capture the emissions associated with any remaining fossil fuel use.

While both countries are relying heavily on wind power, the UK’s energy-generation transformations are different from Germany’s. While both governments push to make some progress on the path to net-zero carbon emissions, their approaches and timelines differ markedly.

Energiewende, Germany’s energy transition, is characterized by what some critics consider to be overly ambitious goals for achieving net greenhouse gas neutrality by 2045. Those critics think that the words don’t come close to matching the required levels of either government or private sector financial commitment. Together with the Bundestag, the chancellor has set interim targets to reduce emissions by 65 percent by 2030 and 88 percent by 2040 (both compared to 1990 levels). Germany’s energy mix is heavily reliant on renewables, with a goal of sourcing 80 percent of its electricity from renewable energy by 2030—and achieving 100 percent by 2035.

However, Germany has faced challenges due to continued reliance on coal and natural gas, which made it difficult to reach its emissions goals.

The UK, however, appears to be ahead in terms of immediate reductions in coal use and the integration of renewables into its energy mix. Germany’s path is more complex, as it balances its energy transition with energy security concerns, particularly in light of how Russia’s war affects gas supplies.

The UK got rid of coal—where’s it going next? Read More »

Parrots struggle when told to do something other than mimic their peers

animal behavior, Behavioral science, Biology, parrots, Science / Paul Patrick / February 6, 2025

There have been many studies on the capability of non-human animals to mimic transitive actions—actions that have a purpose. Hardly any studies have shown that animals are also capable of intransitive actions. Even though intransitive actions have no particular purpose, imitating these non-conscious movements is still thought to help with socialization and strengthen bonds for both animals and humans.

Zoologist Esha Haldar and colleagues from the Comparative Cognition Research group worked with blue-throated macaws, which are critically endangered, at the Loro Parque Fundación in Tenerife. They trained the macaws to perform two intransitive actions, then set up a conflict: Two neighboring macaws were asked to do different actions.

What Haldar and her team found was that individual birds were more likely to perform the same intransitive action as a bird next to them, no matter what they’d been asked to do. This could mean that macaws possess mirror neurons, the same neurons that, in humans, fire when we are watching intransitive movements and cause us to imitate them (at least if these neurons function the way some think they do).

But it wasn’t on purpose

Parrots are already known for their mimicry of transitive actions, such as grabbing an object. Because they are highly social creatures with brains that are large relative to the size of their bodies, they made excellent subjects for a study that gauged how susceptible they were to copying intransitive actions.

Mirroring of intransitive actions, also called automatic imitation, can be measured with what’s called a stimulus-response-compatibility (SRC) test. These tests measure the response time between seeing an intransitive movement (the visual stimulus) and mimicking it (the action). A faster response time indicates a stronger reaction to the stimulus. They also measure the accuracy with which they reproduce the stimulus.

Until now, there have only been three studies that showed non-human animals are capable of copying intransitive actions, but the intransitive actions in these studies were all by-products of transitive actions. Only one of these focused on a parrot species. Haldar and her team would be the first to test directly for animal mimicry of intransitive actions.

Parrots struggle when told to do something other than mimic their peers Read More »

Don’t panic, but an asteroid has a 1.9% chance of hitting Earth in 2032

asteroids, NASA, near earth object, planetary science, Science, solar system, Space / Mike M. / February 6, 2025

More data will likely reduce the chance of an impact to zero. If not, we have options.

Discovery images of asteroid 2024 YR4. Credit: ATLAS

Something in the sky captured the attention of astronomers in the final days of 2024. A telescope in Chile scanning the night sky detected a faint point of light, and it didn’t correspond to any of the thousands of known stars, comets, and asteroids in astronomers’ all-sky catalog.

The detection on December 27 came from one of a network of telescopes managed by the Asteroid Terrestrial-impact Last Alert System (ATLAS), a NASA-funded project to provide warning of asteroids on a collision course with Earth.

Within a few days, scientists gathered enough information on the asteroid—officially designated 2024 YR4—to determine that its orbit will bring it quite close to Earth in 2028, and then again in 2032. Astronomers ruled out any chance of an impact with Earth in 2028, but there’s a small chance the asteroid might hit our planet on December 22, 2032.

How small? The probability has fluctuated in recent days, but as of Thursday, NASA’s Center for Near Earth Object Studies estimated a 1.9 percent chance of an impact with Earth in 2032. The European Space Agency (ESA) put the probability at 1.8 percent. So as of now, NASA believes there’s a 1-in-53 chance of 2024 YR4 striking Earth. That’s about twice as likely as the lifetime risk of dying in a motor vehicle crash, according to the National Safety Council.

These numbers are slightly higher than the probabilities published last month, when ESA estimated a 1.2 percent chance of an impact. In a matter of weeks or months, the number will likely drop to zero.

No surprise here, according to ESA.

“It is important to remember that an asteroid’s impact probability often rises at first before quickly dropping to zero after additional observations,” ESA said in a press release. The agency released a short explainer video, embedded below, showing how an asteroid’s cone of uncertainty shrinks as scientists get a better idea of its trajectory.

Refining the risk

Scientists estimate that 2024 YR4 is between 130 to 300 feet (40 and 90 meters) wide, large enough to cause localized devastation near the impact site. The asteroid responsible for the Tunguska event of 1908, which leveled some 500 square miles (1,287 square kilometers) of forest in remote Siberia, was probably about the same size. The meteor that broke apart in the sky over Chelyabinsk, Russia, in 2013 was about 20 meters wide.

Astronomers use the Torino scale for measuring the risk of potential asteroid impacts. Asteroid 2024 YR4 is now rated at Level 3 on this scale, meaning it merits close attention from astronomers, the public, and government officials. This is the second time an asteroid has reached this level since the scale’s adoption in 1999. The other case happened in 2004, when asteroid Apophis briefly reached a Level 4 rating until further observations of the asteroid eliminated any chance of an impact with the Earth in 2029.

In the unlikely event that it impacts the Earth, an asteroid the size of 2024 YR4 could cause blast damage as far as 30 miles (50 kilometers) from the location of the impact or airburst if the object breaks apart in the atmosphere, according to the International Asteroid Warning Network (IAWN), established in the aftermath of the Chelyabinsk event.

The asteroid warning network is affiliated with the United Nations. Officials activate the IAWN when an asteroid bigger than 10 meters has a greater than 1 percent chance of striking Earth within the next 20 years. The risk of 2024 YR4 meets this threshold.

The red points on this image show the possible locations of asteroid 2024 YR4 on December 22, 2032, as projected by a Monte Carlo simulation. As this image shows, most of the simulations project the asteroid missing the Earth. Credit: ESA/Planetary Defense Office

Determining the asteroid’s exact size will be difficult. Scientists would need deep space radar observations, thermal infrared observations, or imagery from a spacecraft that could closely approach the asteroid, according to the IAWN. The asteroid won’t come close enough to Earth for deep space radar observations until shortly before its closest approach in 2032.

Astronomers need numerous observations to precisely plot an asteroid’s motion through the Solar System. Over time, these observations will reduce uncertainty and narrow the corridor the asteroid will follow as it comes near Earth.

Scientists already know a little about asteroid 2024 YR4’s orbit, which follows an elliptical path around the Sun. The orbit brings the asteroid inside of Earth’s orbit at its closest point to the Sun and then into the outer part of the asteroid belt when it is farthest from the Sun.

But there’s a complication in astronomers’ attempts to nail down the asteroid’s path. The object is currently moving away from Earth in almost a straight line. This makes it difficult to accurately determine its orbit by studying how its trajectory curves over time, according to ESA.

It also means observers will need to use larger telescopes to see the asteroid before it becomes too distant to see it from Earth in April. By the end of this year’s observing window, the asteroid warning network says the impact probability could increase to a couple tens of percent, or it could more likely drop back below the notification threshold (1 percent impact probability).

“It is possible that asteroid 2024 YR4 will fade from view before we are able to entirely rule out any chance of impact in 2032,” ESA said. “In this case, the asteroid will likely remain on ESA’s risk list until it becomes observable again in 2028.”

Planetary defenders

This means that public officials might need to start planning what to do later this year.

For the first time, an international board called the Space Mission Planning Advisory Group met this week to discuss what we can do to respond to the risk of an asteroid impact. This group, known as SMPAG, coordinates planning among representatives from the world’s space agencies, including NASA, ESA, China, and Russia.

The group decided on Monday to give astronomers a few more months to refine their estimates of the asteroid’s orbit before taking action. They will meet again in late April or early May or earlier if the impact risk increases significantly. If there’s still a greater than 1 percent probability of 2024 YR4 hitting the Earth, the group will issue a recommendation for further action to the United Nations Office for Outer Space Affairs.

So what are the options? If the data in a few months still shows that the asteroid poses a hazard to Earth, it will be time for the world’s space agencies to consider a deflection mission. NASA demonstrated its ability to alter the orbit of an asteroid in 2022 with a first-of-its-kind experiment in space. The mission, called DART, put a small spacecraft on a collision course with an asteroid two to four times larger than 2024 YR4.

The kinetic energy from the spacecraft’s death dive into the asteroid was enough to slightly nudge the object off its natural orbit around a nearby larger asteroid. This proved that an asteroid deflection mission could work if scientists have enough time to design and build it, an undertaking that took about five years for DART.

Italy’s LICIACube spacecraft snapped this image of asteroids Didymos (lower left) and Dimorphos (upper right) a few minutes after the impact of DART on September 26, 2022. Credit: ASI/NASA

A deflection mission is most effective well ahead of an asteroid’s potential encounter with the Earth, so it’s important not to wait until the last minute.

Fans of Hollywood movies know there’s a nuclear option for dealing with an asteroid coming toward us. The drawback of using a nuclear warhead is that it could shatter one large asteroid into many smaller objects, although recent research suggests a more distant nuclear explosion could produce enough X-ray radiation to push an asteroid off a collision course.

Waiting for additional observations in 2028 would leave little time to develop a deflection mission. Therefore, in the unlikely event that the risk of an impact rises over the next few months, it will be time for officials to start seriously considering the possibility of an intervention.

Even without a deflection, there’s plenty of time for government officials to do something here on Earth. It should be possible for authorities to evacuate any populations that might be affected by the asteroid.

The asteroid could devastate an area the size of a large city, but any impact is most likely to happen in a remote region or in the ocean. The risk corridor for 2024 YR4 extends from the eastern Pacific Ocean to northern South America, the Atlantic Ocean, Africa, the Arabian Sea, and South Asia.

There’s an old joke that dinosaurs went extinct because they didn’t have a space program. Whatever happens in 2032, we’re not at risk of extinction. However, occasions like this are exactly why most Americans think we should have a space program. A 2019 poll showed that 68 percent of Americans considered it very or extremely important for the space program to monitor asteroids, comets, or other objects from space that could strike the planet.

In contrast, about a quarter of those polled placed such importance on returning astronauts to the Moon or sending people to Mars. The cost of monitoring and deflecting asteroids is modest compared to the expensive undertakings of human missions to the Moon and Mars.

From taxpayers’ point of view, it seems this part of NASA offers the greatest bang for their buck.

Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

Don’t panic, but an asteroid has a 1.9% chance of hitting Earth in 2032 Read More »

Quantum teleportation used to distribute a calculation

Computer science, Physics, quantum computing, quantum mechanics, Science, teleportation / Tim Belzer / February 5, 2025

The researchers showed that this setup allowed them to teleport with a specific gate operation (controlled-Z), which can serve as the basis for any other two-qubit gate operation—any operation you might want to do can be done by using a specific combination of these gates. After performing multiple rounds of these gates, the team found that the typical fidelity was in the area of 70 percent. But they also found that errors typically had nothing to do with the teleportation process and were the product of local operations at one of the two ends of the network. They suspect that using commercial hardware, which has far lower error rates, would improve things dramatically.

Finally, they performed a version of Grover’s algorithm, which can, with a single query, identify a single item from an arbitrarily large unordered list. The “arbitrary” aspect is set by the number of available qubits; in this case, having only two qubits, the list maxed out at four items. Still, it worked, again with a fidelity of about 70 percent.

While the work was done with trapped ions, almost every type of qubit in development can be controlled with photons, so the general approach is hardware-agnostic. And, given the sophistication of our optical hardware, it should be possible to link multiple chips at various distances, all using hardware that doesn’t require the best vacuum or the lowest temperatures we can generate.

That said, the error rate of the teleportation steps may still be a problem, even if it was lower than the basic hardware rate in these experiments. The fidelity there was 97 percent, which is lower than the hardware error rates of most qubits and high enough that we couldn’t execute too many of these before the probability of errors gets unacceptably high.

Still, our current hardware error rates started out far worse than they are today; successive rounds of improvements between generations of hardware have been the rule. Given that this is the first demonstration of teleported gates, we may have to wait before we can see if the error rates there follow a similar path downward.

Nature, 2025. DOI: 10.1038/s41586-024-08404-x (About DOIs).

Quantum teleportation used to distribute a calculation Read More »

Gecko feet inspire anti-slip shoe soles

biomimicry, chemistry, friction, geckos, polymers, Science / Kris Guyer / February 4, 2025

Just add zirconia nanoparticles…

diagram of wet ice's quasi slippery layer and design of anti-slip shoe soles inspired by gecko and toad foot pads — Credit: V. Richhariya et al., 2025

It’s the “hydrophilic capillary-enhanced adhesion”of gecko feet that most interested the authors of this latest paper. Per the World Health Organization, 684,000 people die and another 38 million are injured every year in slips and falls, with correspondingly higher health care costs. Most antislip products (crampons, chains, studs, cleats), tread designs, or materials (fiberglass, carbon fiber, rubber) are generally only effective for specific purposes or short periods of time. And they often don’t perform as well on wet ice, which has a nanoscale quasi-liquid layer (QLL) that makes it even more slippery.

So Vipin Richhariya of the University of Minho in Portugal and co-authors turned to gecko toe pads (as well as those of toads) for a better solution. To get similar properties in their silicone rubber polymers, they added zirconia nanoparticles, which attract water molecules. The polymers were rolled into a thin film and hardened, and then a laser etched groove patterns onto the surface—essentially creating micro cavities that exposed the zirconia nanoparticles, thus enhancing the material’s hydrophilic effects.

Infrared spectroscopy and simulated friction tests revealed that the composites containing 3 percent and 5 percent zirconia nanoparticles were the most slip-resistant. “This optimized composite has the potential to change the dynamics of slip-and-fall accidents, providing a nature-inspired solution to prevent one of the most common causes of accidents worldwide,” the authors concluded. The material could also be used for electronic skin, artificial skin, or wound healing.

DOI: ACS Applied Materials & Interfaces, 2025. 10.1021/acsami.4c14496 (About DOIs).

Gecko feet inspire anti-slip shoe soles Read More »

Bonobos recognize when humans are ignorant, try to help

Behavioral science, Biology, cooperation, Neuroscience, Science, theory of mind / Mike M. / February 3, 2025

A lot of human society requires what’s called a “theory of mind”—the ability to infer the mental state of another person and adjust our actions based on what we expect they know and are thinking. We don’t always get this right—it’s easy to get confused about what someone else might be thinking—but we still rely on it to navigate through everything from complicated social situations to avoid bumping into people on the street.

There’s some mixed evidence that other animals have a limited theory of mind, but there are alternate interpretations for most of it. So two researchers at Johns Hopkins, Luke Townrow and Christopher Krupenye, came up with a way of testing whether some of our closest living relatives, the bonobos, could infer the state of mind of a human they were cooperating with. The work clearly showed that the bonobos could tell when their human partner was ignorant.

Now you see it…

The experimental approach is quite simple, and involves a setup familiar to street hustlers: a set of three cups, with a treat placed under one of them. Except in this case, there’s no sleight-of-hand in that the chimp can watch as one experimenter places the treat under a cup, and all of the cups remain stationary throughout the experiment.

To get the treat, however, requires the cooperation of a second human experimenter. That person has to identify the right cup, then give the treat under it to the bonobo. In some experiments, this human can watch the treat being hidden through a transparent partition, and so knows exactly where it is. In others, however, the partition is solid, leaving the human with no idea of which cup might be hiding the food.

This setup means that the bonobo will always know where the food is and will also know whether the human could potentially have the same knowledge.

The bonobos were first familiarized with the setup and got to experience their human partner taking the treat out from under the cup and giving it to them. Once they were familiar with the process, they watched the food being hidden without any partner present, which demonstrated they rarely took any food-directed actions without a good reason to do so. In contrast, when their human partner was present, they were about eight times more likely to point to the cup with the food under it.

Bonobos recognize when humans are ignorant, try to help Read More »

Let us spray: River dolphins launch pee streams into air

animal behavior, animal communication, animals, Biology, dolphins, Science / Tim Belzer / February 3, 2025

According to Amazonian folklore, the area’s male river dolphins are shapeshifters (encantade), transforming at night into handsome young men who seduce and impregnate human women. The legend’s origins may lie in the fact that dolphins have rather human-like genitalia. A group of Canadian biologists didn’t spot any suspicious shapeshifting behavior over the four years they spent monitoring a dolphin population in central Brazil, but they did document 36 cases of another human-like behavior: what appears to be some sort of cetacean pissing contest.

Specifically, the male dolphins rolled over onto their backs, displayed their male members, and launched a stream of urine as high as 3 feet into the air. This usually occurred when other males were around, who seemed fascinated in turn by the arching streams of pee, even chasing after them with their snouts. It’s possibly a form of chemical sensory communication and not merely a need to relieve themselves, according to the biologists, who described their findings in a paper published in the journal Behavioral Processes. As co-author Claryana Araújo-Wang of CetAsia Research Group in Ontario, Canada, told New Scientist, “We were really shocked, as it was something we had never seen before.”

Spraying urine is a common behavior in many animal species, used to mark territory, defend against predators, communicate with other members of one’s species, or as a means of mate selection since it has been suggested that the chemicals in the urine carry useful information about physical health or social dominance.

Let us spray: River dolphins launch pee streams into air Read More »

It seems the FAA office overseeing SpaceX’s Starship probe still has some bite

Commercial space, elon musk, FAA, launch, Science, Space, spacex, starship, starship flight 7 / Paul Patrick / February 1, 2025

The political winds have shifted in Washington, but the FAA hasn’t yet changed its tune on Starship.

Liftoff of SpaceX’s seventh full-scale test flight of the Super Heavy/Starship launch vehicle on January 16. Credit: SpaceX

The seventh test flight of SpaceX’s gigantic Starship rocket came to a disappointing end a little more than two weeks ago. The in-flight failure of the rocket’s upper stage, or ship, about eight minutes after launch on January 16 rained debris over the Turks and Caicos Islands and the Atlantic Ocean.

Amateur videos recorded from land, sea, and air showed fiery debris trails streaming overhead at twilight, appearing like a fireworks display gone wrong. Within hours, posts on social media showed small pieces of debris recovered by residents and tourists in the Turks and Caicos. Most of these items were modest in size, and many appeared to be chunks of tiles from Starship’s heat shield.

Unsurprisingly, the Federal Aviation Administration grounded Starship and ordered an investigation into the accident on the day after the launch. This decision came three days before the inauguration of President Donald Trump. Elon Musk’s close relationship with Trump, coupled with the new administration’s appetite for cutting regulations and reducing the size of government, led some industry watchers to question whether Musk’s influence might change the FAA’s stance on SpaceX.

So far, the FAA hasn’t budged on its requirement for an investigation, an agency spokesperson told Ars on Friday. After a preliminary assessment of flight data, SpaceX officials said a fire appeared to develop in the aft section of the ship before it broke apart and fell to Earth.

“The FAA has directed SpaceX to lead an investigation of the Starship Super Heavy Flight 7 mishap with FAA oversight,” the spokesperson said. “Based on the investigation findings for root cause and corrective actions, the FAA may require a company to modify its license.”

This is much the same language the FAA used two weeks ago, when it first ordered the investigation.

Damage report

The FAA’s Office of Commercial Space Transportation is charged with ensuring commercial space launches and reentries don’t endanger the public, and requires launch operators obtain liability insurance or demonstrate financial ability to cover any third-party property damages.

For each Starship launch, the FAA requires SpaceX maintain liability insurance policies worth at least $500 million for such claims. It’s rare for debris from US rockets to fall over land during a launch. This would typically only happen if a launch failed at certain parts of the flight. And there’s no public record of any claims of third-party property damage in the era of commercial spaceflight. Under federal law, the US government would pay for damages to a much higher amount if any claims exceeded a launch company’s insurance policies.

Here’s a piece of Starship 33 @SpaceX @elonmusk found in Turks and Caicos! pic.twitter.com/HPZDCqA9MV

— @maximzavet (@MaximZavet) January 17, 2025

The good news is there were no injuries or reports of significant damage from the wreckage that fell over the Turks and Caicos. “The FAA confirmed one report of minor damage to a vehicle located in South Caicos,” an FAA spokesperson told Ars on Friday. “To date, there are no other reports of damage.”

It’s not clear if the vehicle owner in South Caicos will file a claim against SpaceX for the damage. It would the first time someone makes such a claim related to an accident with a commercial rocket overseen by the FAA. Last year, a Florida homeowner submitted a claim to NASA for damage to his house from a piece of debris that fell from the International Space Station.

Nevertheless, the Turks and Caicos government said local officials met with representatives from SpaceX and the UK Air Accident Investigations Branch on January 25 to develop a recovery plan for debris that fell on the islands, which are a British Overseas Territory.

A prickly relationship

Musk often bristled at the FAA last year, especially after regulators proposed fines of more than $600,000 alleging that SpaceX violated terms of its launch licenses during two Falcon 9 missions. The alleged violations involved the relocation of a propellant farm at one of SpaceX’s launch pads in Florida, and the use of a new launch control center without FAA approval.

In a post on X, Musk said the FAA was conducting “lawfare” against his company. “SpaceX will be filing suit against the FAA for regulatory overreach,” Musk wrote.

There was no such lawsuit, and the issue may now be moot. Sean Duffy, Trump’s new secretary of transportation, vowed to review the FAA fines during his confirmation hearing in the Senate. It is rare for the FAA to fine launch companies, and the fines last year made up the largest civil penalty ever imposed by the FAA’s commercial spaceflight division.

SpaceX also criticized delays in licensing Starship test flights last year. The FAA cited environmental issues and concerns about the extent of the sonic boom from Starship’s 23-story-tall Super Heavy booster returning to its launch pad in South Texas. SpaceX successfully caught the returning first stage booster at the launch pad for the first time in October, and repeated the feat after the January 16 test flight.

What separates the FAA’s ongoing oversight of Starship’s recent launch failure from these previous regulatory squabbles is that debris fell over populated areas. This would appear to be directly in line with the FAA’s responsibility for public safety.

During last month’s test flight, Starship did not deviate from its planned ground track, which took the rocket over the Gulf of Mexico, the waters between Florida and Cuba, and then the Atlantic Ocean. But the debris field extended beyond the standard airspace closure for the launch. After the accident, FAA air traffic controllers cleared additional airspace over the debris zone for more than an hour, rerouting, diverting, and delaying dozens of commercial aircraft.

These actions followed pre-established protocols. However, it highlighted the small but non-zero risk of rocket debris falling to Earth after a launch failure. “The potential for a bad day downrange just got real,” Lori Garver, a former NASA deputy administrator, posted on X.

Public safety is not sole mandate of the FAA’s commercial space office. It is also chartered to “encourage, facilitate, and promote commercial space launches and reentries by the private sector,” according to an FAA website. There’s a balance to strike.

Lawmakers last year urged the FAA to speed up its launch approvals, primarily because Starship is central to strategic national objectives. NASA has contracts with SpaceX to develop a variant of Starship to land astronauts on the Moon, and Starship’s unmatched ability to deliver more than 100 tons of cargo to low-Earth orbit is attractive to the Pentagon.

While Musk criticized the FAA in 2024, SpaceX officials in 2023 took a different tone, calling for Congress to increase the budget for the FAA’s Office of Commercial Spaceflight and for the regulator to double the space division’s workforce. This change, SpaceX officials argued, would allow the FAA to more rapidly assess and approve a fast-growing number of commercial launch and reentry applications.

In September, SpaceX released a statement accusing the former administrator of the FAA, Michael Whitaker, of making inaccurate statements about SpaceX to a congressional subcommittee. In a different post on X, Musk directly called for Whitaker’s resignation.

He needs to resign https://t.co/pG8htfTYHb

— Elon Musk (@elonmusk) September 25, 2024

That’s exactly what happened. Whitaker, who took over the FAA’s top job in 2023 under the Biden administration, announced in December he would resign on Inauguration Day. Since the agency’s establishment in 1958, three FAA administrators have similarly resigned when a new administration takes power, but the office has been largely immune from presidential politics in recent decades. Since 1993, FAA administrators have stayed in their post during all presidential transitions.

There’s no evidence Whitaker’s resignation had any role in the mid-air collision of an American Eagle passenger jet and a US Army helicopter Wednesday night near Ronald Reagan Washington National Airport. But his departure from the FAA less than two years into a five-year term on January 20 left the agency without a leader. Trump named Chris Rocheleau as the FAA’s acting administrator Thursday.

Next flight, next month?

SpaceX has not released an official schedule for the next Starship test flight or outlined its precise objectives. However, it will likely repeat many of the goals planned for the previous flight, which ended before SpaceX could accomplish some of its test goals. These missed objectives included the release of satellite mockups in space for the first demonstration of Starship’s payload deployment mechanism, and a reentry over the Indian Ocean to test new, more durable heat shield materials.

The January 16 test flight was the first launch up an upgraded, slightly taller Starship, known as Version 2 or Block 2. The next flight will use the same upgraded version.

A SpaceX filing with the Federal Communications Commission suggests the next Starship flight could launch as soon as February 24. Sources told Ars that SpaceX teams believe a launch before the end of February is realistic.

But SpaceX has more to do before Flight 8. These tasks include completing the FAA-mandated investigation and the installation of all 39 Raptor engines on the rocket. Then, SpaceX will likely test-fire the booster and ship before stacking the two elements together to complete assembly of the 404-foot-tall (123.1-meter) rocket.

SpaceX is also awaiting a new FAA launch license, pending its completion of the investigation into what happened on Flight 7.

It seems the FAA office overseeing SpaceX’s Starship probe still has some bite Read More »

To help AIs understand the world, researchers put them in a robot

AI, Computer science, language, robotics, Science / Paul Patrick / February 1, 2025

There’s a difference between knowing a word and knowing a concept.

Large language models like ChatGPT display conversational skills, but the problem is they don’t really understand the words they use. They are primarily systems that interact with data obtained from the real world but not the real world itself. Humans, on the other hand, associate language with experiences. We know what the word “hot” means because we’ve been burned at some point in our lives.

Is it possible to get an AI to achieve a human-like understanding of language? A team of researchers at the Okinawa Institute of Science and Technology built a brain-inspired AI model comprising multiple neural networks. The AI was very limited—it could learn a total of just five nouns and eight verbs. But their AI seems to have learned more than just those words; it learned the concepts behind them.

Babysitting robotic arms

“The inspiration for our model came from developmental psychology. We tried to emulate how infants learn and develop language,” says Prasanna Vijayaraghavan, a researcher at the Okinawa Institute of Science and Technology and the lead author of the study.

While the idea of teaching AIs the same way we teach little babies is not new—we applied it to standard neural nets that associated words with visuals. Researchers also tried teaching an AI using a video feed from a GoPro strapped to a human baby. The problem is babies do way more than just associate items with words when they learn. They touch everything—grasp things, manipulate them, throw stuff around, and this way, they learn to think and plan their actions in language. An abstract AI model couldn’t do any of that, so Vijayaraghavan’s team gave one an embodied experience—their AI was trained in an actual robot that could interact with the world.

Vijayaraghavan’s robot was a fairly simple system with an arm and a gripper that could pick objects up and move them around. Vision was provided by a simple RGB camera feeding videos in a somewhat crude 64×64 pixels resolution.

The robot and the camera were placed in a workspace, put in front of a white table with blocks painted green, yellow, red, purple, and blue. The robot’s task was to manipulate those blocks in response to simple prompts like “move red left,” “move blue right,” or “put red on blue.” All that didn’t seem particularly challenging. What was challenging, though, was building an AI that could process all those words and movements in a manner similar to humans. “I don’t want to say we tried to make the system biologically plausible,” Vijayaraghavan told Ars. “Let’s say we tried to draw inspiration from the human brain.”

Chasing free energy

The starting point for Vijayaraghavan’s team was the free energy principle, a hypothesis that the brain constantly makes predictions about the world based on internal models, then updates these predictions based on sensory input. The idea is that we first think of an action plan to achieve a desired goal, and then this plan is updated in real time based on what we experience during execution. This goal-directed planning scheme, if the hypothesis is correct, governs everything we do, from picking up a cup of coffee to landing a dream job.

All that is closely intertwined with language. Neuroscientists at the University of Parma found that motor areas in the brain got activated when the participants in their study listened to action-related sentences. To emulate that in a robot, Vijayaraghavan used four neural networks working in a closely interconnected system. The first was responsible for processing visual data coming from the camera. It was tightly integrated with a second neural net that handled proprioception: all the processes that ensured the robot was aware of its position and the movement of its body. This second neural net also built internal models of actions necessary to manipulate blocks on the table. Those two neural nets were additionally hooked up to visual memory and attention modules that enabled them to reliably focus on the chosen object and separate it from the image’s background.

The third neural net was relatively simple and processed language using vectorized representations of those “move red right” sentences. Finally, the fourth neural net worked as an associative layer and predicted the output of the previous three at every time step. “When we do an action, we don’t always have to verbalize it, but we have this verbalization in our minds at some point,” Vijayaraghavan says. The AI he and his team built was meant to do just that: seamlessly connect language, proprioception, action planning, and vision.

When the robotic brain was up and running, they started teaching it some of the possible combinations of commands and sequences of movements. But they didn’t teach it all of them.

The birth of compositionality

In 2016, Brenden Lake, a professor of psychology and data science, published a paper in which his team named a set of competencies machines need to master to truly learn and think like humans. One of them was compositionality: the ability to compose or decompose a whole into parts that can be reused. This reuse lets them generalize acquired knowledge to new tasks and situations. “The compositionality phase is when children learn to combine words to explain things. They [initially] learn the names of objects, the names of actions, but those are just single words. When they learn this compositionality concept, their ability to communicate kind of explodes,” Vijayaraghavan explains.

The AI his team built was made for this exact purpose: to see if it would develop compositionality. And it did.

Once the robot learned how certain commands and actions were connected, it also learned to generalize that knowledge to execute commands it never heard before. recognizing the names of actions it had not performed and then performing them on combinations of blocks it had never seen. Vijayaraghavan’s AI figured out the concept of moving something to the right or the left or putting an item on top of something. It could also combine words to name previously unseen actions, like putting a blue block on a red one.

While teaching robots to extract concepts from language has been done before, those efforts were focused on making them understand how words were used to describe visuals. Vijayaragha built on that to include proprioception and action planning, basically adding a layer that integrated sense and movement to the way his robot made sense of the world.

But some issues are yet to overcome. The AI had very limited workspace. The were only a few objects and all had a single, cubical shape. The vocabulary included only names of colors and actions, so no modifiers, adjectives, or adverbs. Finally, the robot had to learn around 80 percent of all possible combinations of nouns and verbs before it could generalize well to the remaining 20 percent. Its performance was worse when those ratios dropped to 60/40 and 40/60.

But it’s possible that just a bit more computing power could fix this. “What we had for this study was a single RTX 3090 GPU, so with the latest generation GPU, we could solve a lot of those issues,” Vijayaraghavan argued. That’s because the team hopes that adding more words and more actions won’t result in a dramatic need for computing power. “We want to scale the system up. We have a humanoid robot with cameras in its head and two hands that can do way more than a single robotic arm. So that’s the next step: using it in the real world with real world robots,” Vijayaraghavan said.

Science Robotics, 2025. DOI: 10.1126/scirobotics.adp0751

Jacek Krywko is a freelance science and technology writer who covers space exploration, artificial intelligence research, computer science, and all sorts of engineering wizardry.

To help AIs understand the world, researchers put them in a robot Read More »

Bogus research is undermining good science, slowing lifesaving research

research, research fraud, Science, syndication / Mike M. / February 1, 2025

In 2022, Byrne and colleagues, including two of us, found that suspect genetics research, despite not immediately affecting patient care, informs scientists’ work, including clinical trials. But publishers are often slow to retract tainted papers, even when alerted to obvious fraud. We found that 97 percent of the 712 problematic genetics research articles we identified remained uncorrected.

Potential solutions

The Cochrane Collaboration has a policy excluding suspect studies from its analyses of medical evidence and is developing a tool to spot problematic medical trials. And publishers have begun to share data and technologies among themselves to combat fraud, including image fraud.

Technology startups are also offering help. The website Argos, launched in September 2024 by Scitility, an alert service based in Sparks, Nevada, allows authors to check collaborators for retractions or misconduct. Morressier, a scientific conference and communications company in Berlin, offers research integrity tools. Paper-checking tools include Signals, by London-based Research Signals, and Clear Skies’ Papermill Alarm.

But Alam acknowledges that the fight against paper mills won’t be won as long as the booming demand for papers remains.

Today’s commercial publishing is part of the problem, Byrne said. Cleaning up the literature is a vast and expensive undertaking. “Either we have to monetize corrections such that publishers are paid for their work, or forget the publishers and do it ourselves,” she said.

There’s a fundamental bias in for-profit publishing: “We pay them for accepting papers,” said Bodo Stern, a former editor of the journal Cell and chief of Strategic Initiatives at Howard Hughes Medical Institute, a nonprofit research organization and funder in Chevy Chase, Maryland. With more than 50,000 journals on the market, bad papers shopped around long enough eventually find a home, Stern said.

To prevent this, we could stop paying journals for accepting papers and look at them as public utilities that serve a greater good. “We should pay for transparent and rigorous quality-control mechanisms,” he said.

Peer review, meanwhile, “should be recognized as a true scholarly product, just like the original article,” Stern said. And journals should make all peer-review reports publicly available, even for manuscripts they turn down.

This article is republished from The Conversation under a Creative Commons license. This is a condensed version. To learn more about how fraudsters around the globe use paper mills to enrich themselves and harm scientific research, read the full version.

Frederik Joelving is a contributing editor at Retraction Watch; Cyril Labbé is a professor of computer science at the Université Grenoble Alpes (UGA); and Guillaume Cabanac is a professor of computer science at Institut de Recherche en Informatique de Toulouse.

Bogus research is undermining good science, slowing lifesaving research Read More »

Research Roundup: 7 cool science stories we almost missed

Archaeology, Physics, Science / Tim Belzer / February 1, 2025

Peruvian mummy tattoos, the wobbly physics of spears and darts, quantum “cat states,” and more.

Lasers revealed tattoos on the hand of a 1200-year-old Peruvian mummy. Credit: Michael Pittman and Thomas G Kaye

It’s a regrettable reality that there is never time to cover all the interesting scientific stories each month. In the past, we’ve featured year-end roundups of cool science stories we missed. This year, we’re experimenting with a monthly collection. January’s list includes papers on using lasers to reveal Peruvian mummy tattoos; the physics of wobbly spears and darts; how a black hole changes over time; and quantum “cat states” for error correction in quantum computers, among other fascinating research.

Tracking changes in a black hole over time

Left: EHT images of M87from the 2018 and 2017 observation campaigns. Middle: Example images from a general relativistic magnetohydrodynamic (GRMHD) simulation at two different times. Right: Same simulation snapshots, blurred to match the EHT’s observational resolution. Credit: EHT collaboration

In 2019, the Event Horizon Telescope announced the first direct image ever taken of a black hole at the center of an elliptical galaxy, Messier 87 (M87), located in the constellation of Virgo some 55 million light-years away. Astronomers have now combined earlier observational data to learn more about the turbulent dynamics of plasma near M87*’s event horizon over time, according to a paper published in the journal Astronomy and Astrophysics.

Co-author Luciano Rezzolla of Goethe University Frankfurt in Germany likened the new analysis to comparing two photographs of Mount Everest, one year apart. While the mountain’s basic structure is unlikely to change much in that time, one could observe changes in clouds near the peak and deduce from that properties like wind direction. For instance, in the case of M87*, the new analysis confirmed the presence of a luminous ring that is brightest at the bottom, which in turn confirmed that the rotational axis points away from Earth. “More of these observations will be made in the coming years and with increasing precision, with the ultimate goal of producing a movie of what happens near M87*,” said Rezolla.

Astronomy and Astrophysics, 2025. DOI: 10.1051/0004-6361/202451296 (About DOIs).

Lasers reveal Peruvian mummy tattoos

A tattooed forearm of a Chancay mummy. Credit: Michael Pittman and Thomas G Kaye

Humans across the globe have been getting tattoos for more than 5,000 years, judging by traces found on mummified remains from Europe to Asia and South America. But it can be challenging to decipher details of those tattoos, given how much the ink tends to “bleed” over time, along with the usual bodily decay. Infrared imaging can help, but in an innovative twist, scientists decided to use lasers that make skin glow ever so faintly, revealing many fine hidden details of tattoos found on 1,200-year-old Peruvian mummies, according to a paper published in the Proceedings of the National Academy of Sciences.

It’s the first time the laser-stimulated fluorescence (LSF) technique has been used on mummified human remains. The skin’s fluorescence essentially backlights any tattoos, and after post-processing, the long-exposure photographs showed white skin behind black outlines of the tattoo art—images so detailed it’s possible to measure density differences in the ink and eliminate any bleed effects. The authors determined that the tattoos on four mummies—geometric patterns with triangles and diamonds—were made with carbon-based black ink skillfully applied with a pointed object finer than a standard modern tattoo needle, possibly a cactus needle or sharpened bone.

PNAS, 2025. DOI: 10.1073/pnas.2421517122 (About DOIs).

Sforza Castle’s hidden passages

Ground-penetrating radar reveals new secrets under Milan's Sforza Castle — Ground-penetrating radar reveals new secrets under Milan’s Sforza Castle Credit: Politecnico di Milano

Among the many glories of Milan is the 15th-century Sforza Castle, built by Francesco Sforza on the remnants of an earlier fortification as his primary residence. Legends about the castle abound, most notably the existence of secret underground chambers and passages. For instance, Ludovico il Moro, Duke of Milan from 1494–1499, was so heartbroken over the loss of his wife in childbirth that he used an underground passageway to visit her tomb in the Basilica of Santa Maria delle Grazie—a passageway that appears in the drawings of Leonardo da Vinci, who was employed at the court for a time.

Those underground cavities and passages are now confirmed, thanks to a geophysical survey using ground-penetrating radar and laser scanning, performed as part of a PhD thesis. Various underground cavities and buried passageways were found within the castle’s outer walls, including Ludovico’s passageway and what have may have been secret military passages. Those involved in the project plan to create a “digital twin” of Sforza Castle based on the data collected, one that incorporates both its current appearance and its past. Perhaps it will also be possible to integrate that data with augmented reality to provide an immersive digital experience.

Physics of wobbly spears and darts

Image sequence of a 100-mm long projectile during a typical ejection in experiments. — Image sequence of a 100-mm-long projectile during a typical ejection in experiments. Credit: G. Giombini et al., 2025

Among the things that make humans unique among primates is our ability to throw various objects with speed and precision (with some practice)—spears or darts, for example. That’s because the human shoulder is anatomically conducive to storing and releasing the necessary elastic energy, a quality that has been mimicked in robotics to improve motor efficiency. According to the authors of a paper published in the journal Physical Review E, the use of soft elastic projectiles can improve the efficiency of throws, particularly those whose tips are weighted with a mass like a spearhead.

Guillaume Giombini of the Université Côte d’Azur in Nice, France, and co-authors wanted to explore this “superpropulsion” effect more deeply, using a combination of experimental data, numerical simulation, and theoretical analysis. The projectiles they used in their experiments were inspired by archery bows and consisted of two flat steel cantilevers connected by a string, essentially serving as springs to give the projectile the necessary elasticity. They placed a flat piece of rigid plastic in the middle of the string as a platform. Some of the projectiles were tested alone, while others were weighted with end masses. A fork held each projectile in place before launch, and the scientists measured speed and deformation during flight. They found that the wobble produced by the weighted tip projectiles yielded a kinetic energy gain of 160 percent over more rigid, unweighted projectiles.

Physical Review E, 2025. DOI: 10.1103/PhysRevE.00.005500 (About DOIs).

Quantum “cat states” for error detection

Left to right: UNSW researchers Benjamin Wilhelm, Xi Yu, Andrea Morello, and Danielle Holmes, all seated and each holding a cat on their lap — Left to right: UNSW researchers Benjamin Wilhelm, Xi Yu, Andrea Morello, and Danielle Holmes. Credit: UNSW Sydney/CC BY-NC

The Schrödinger’s cat paradox in physics is an excellent metaphor for the superposition of quantum states in atoms. Over the last 20 years, physicists have managed to build various versions of Schrödinger’s cat in the laboratory whereby two or more particles manage to be in two different states at the same time—so-called “cat states,” such as six atoms in simultaneous “spin up” and “spin down” states, rather like spinning clockwise and counterclockwise at the same time. Such states are fragile, however, and quickly decohere. Physicists at the University of New South Wales came up with a fresh twist on a cat-state that is more robust, according to a paper published in the journal Nature Physics.

They used an antimony atom embedded within a silicon quantum chip. The atom is quite heavy and has a large nuclear spin that can go in eight directions rather than just two (spin up and spin down). This could help enormously with quantum error correction, one of the biggest obstacles in quantum computing, because there is more room for error in the binary code. “As the proverb goes, a cat has nine lives,” said co-author Xi Yu of UNSW. “One little scratch is not enough to kill it. Our metaphorical ‘cat’ has seven lives: it would take seven consecutive errors to turn the ‘0’ into a ‘1.’” And embedding the atom in a silicon chip makes it scalable.

Nature Physics, 2025. DOI: 10.1038/s41567-024-02745-0 (About DOIs).

New twist on chain mail armor

how polycatenated architected materials look in their fluid or granular state, conforming to the shape of the vessel in which it is held. — Credit: Wenjie Zhou

Scientists have developed a new material that is like “chain mail on steroids,” capable of responding as both a fluid or a solid, depending on the kind of stress applied, according to a paper published in the journal Science. That makes it ideal for manufacturing helmets or other protective gear, as well as biomedical devices and robotics components. The technical term is polycatenated architected materials (PAMs). Much like how chain mail is built from small metal rings linked together into a mesh, PAMs are composed of various interlocking shapes that can form a wide range of different 3D patterns.

The authors were partly inspired by the lattice structure of crystals; they just replaced fixed particles with rings or cage-like shapes made out of different materials—such as acrylic polymers, nylon, or metals—to make small 3D-printed structures small enough to fit in the palm of one’s hand. They then subjected these materials to various stressors in the laboratory: compression, a lateral shearing force, and twisting. Some of the materials felt like hard solids, others were squishier, but they all exhibited the same kind of telltale transition, behaving more like a fluid or a solid depending on the stressor applied. PAMs at the microscale can also expand or contract in response to electrical charges. This makes them a useful hybrid material, spanning the gap between granular materials and elastic deformable ones.

W. Zhou et al., Science, 2025. DOI: 10.1126/science.adr9713 (About DOIs).

Kitty robot mimics headbutts

Any cat lover will tell you that cats show humans affection by rubbing their heads against the body (usually shins or hands). It’s called “bunting,” often accompanied by purring, and it’s one of the factors that make companion animal therapy so effective, per the authors of a paper published in ACM Transactions on Human-Robot Interactions. That’s why they built a small robot designed to mimic bunting behavior, conducting various experiments to assess whether human participants found their interactions with the kitty-bot therapeutic. The robot prototypes were small enough to fit on a human lap, featuring a 3D-printed frame and a head covered with furry polyester fabric.

The neck needed to be flexible to mimic the bunting behavior, so the authors incorporated a mechanism that could adjust the stiffness of the neck via wire tension. They then tested various prototypes with university students, setting the neck stiffness to low, high, and variable. The students said they felt less tense after interacting with the robots. There was no significant difference between the settings, although participants slightly preferred the variable setting. We know what you’re thinking: Why not just get an actual cat or visit your local cat cafe? The authors note that many people are allergic to cats, and there is also a risk of bites, scratches, or disease transmission—hence the interest in developing animal-like robots for therapeutic applications.

ACM Transactions on Human-Robot Interactions, 2025. DOI: 10.1145/3700600 (About DOIs).

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

Research Roundup: 7 cool science stories we almost missed Read More »

Stem cells used to partially repair damaged hearts

Biology, heart disease, heart musle, medicine, Science, stem cells / Kris Guyer / January 29, 2025

When we developed the ability to convert various cells into a stem cell, it held the promise of an entirely new type of therapy. Rather than getting the body to try to fix itself with its cells or deal with the complications of organ transplants, we could convert a few adult cells to stem cells and induce them to form any tissue in the body. We could potentially repair or replace tissues with an effectively infinite supply of a patient’s own cells.

However, the Nobel Prize for induced stem cells was handed out over a decade ago, and the therapies have been slow to follow. But a group of German researchers is now describing tests in primates of a method of repairing the heart using new muscle generated from stem cells. The results are promising, if not yet providing everything that we might hope for. But they’ve been enough to start clinical trials, and similar results are being seen in humans.

Heart problems

The heart contains a lot of specialized tissues, including those that form blood vessels or specialize in conducting electrical signals. But the key to the heart is a form of specialized muscle cell, called a cardiomyocyte. Once the heart matures, the cardiomyocytes stop dividing, meaning that you end up with a fixed population. Any damage to the heart due to injury or infection does not get repaired, meaning damage will be cumulative.

This is especially problematic in cases of blocked blood vessels, which can repeatedly starve large areas of the heart of oxygen and nutrients, killing the cardiomyocytes there. This leads to a reduction in cardiac function and can ultimately result in death.

It turns out, however, that it’s relatively easy to convert induced pluripotent stem cells (IPSC, with pluripotent meaning they can form any cell type). So researchers tried injecting these stem-cell-derived cardiomyocytes into damaged hearts in experimental animals, in the hope that they would be incorporated into the damaged tissue. But these experiments didn’t always provide clear benefits to the animals.

Stem cells used to partially repair damaged hearts Read More »