Light moves quickly enough to transmit enormous amounts of information, but that speed creates a problem when a computer needs to hold, delay, or synchronize an optical signal. Researchers from Seoul National University and the University of Seoul have now designed a programmable photonic integrated circuit that can slow light whenever needed.

The rapid growth of generative AI and large-scale artificial intelligence models has sharply increased computing demands. Conventional electronic semiconductors face persistent constraints, including heavy power use and limited data transfer speeds, driving interest in optical computing systems that process information rapidly with less energy. Yet because light naturally travels at a fixed speed, creating the buffers and memory functions needed for optical computing has remained difficult.

The researchers addressed this limitation with a programmable photonic circuit that controls both the speed and shape of optical signals. Their approach provided greater control over “slow light” than previously proposed methods.

What dangers does smoke from wildfires pose? Who is most at risk? Here are some answers to health questions often asked, especially now with fires in France and Spain.

What is in the smoke?
Fires burning vegetation generate gases and particles in the air that are dangerous to our health, notes Anses, France's health safety agency.

Fine particles are especially harmful because they can penetrate deeply into the lungs.

Carbon monoxide is one of the major pollutants released by such fires, the agency says. It also listed other chemical substances, such as carbon dioxide, volatile organic compounds including acrolein, formaldehyde and benzene.

Other pollutants can be mixed in if vehicles or buildings are consumed by flames.

Who is most at risk?
Individuals closest to a fire can display symptoms of respiratory irritation. But effects will be felt more widely among the population if wind carries the smoke over the following hours or several days later, French pulmonologist Bruno Crestani told AFP.

Especially at risk are "vulnerable persons—those who are old, who have a respiratory disease, infants or asthmatics—because this (smoke) can unbalance a situation that was previously under control," said Crestani, who heads France's Respiratory Health Foundation.

The impact is "not only respiratory," he pointed out. "These particles can enter the circulatory system" and possibly trigger diabetes, a stroke or a heart attack, he said.

Because these particles are so fine and light, they can be carried long distances and affect people well away from the fire zone.

In September 2025, the World Meteorological Organization stressed that wildfires can send a toxic mix of pollutants thousands of kilometers. It noted that, in 2024, smoke from wildfires in Canada caused air pollution as far away as Europe.

A poor night’s sleep can affect far more than energy the next day. Research from Florida International University links sleep disorders with structural differences in brain regions that help control attention, motivation and decision-making.

Published in the journal Scientific Reports, the findings provide one of the broadest comparisons yet of how different sleep disorders are associated with the brain. The results could eventually support earlier diagnosis and treatments tailored to specific conditions.

Multiple disorders reveal shared brain changes
An estimated 50 to 70 million Americans live with sleep disorders. To search for common neurological patterns, researchers at FIU’s Center for Children and Families conducted a meta-analysis combining results from 57 brain imaging studies.

Rather than examining one condition at a time, the researchers compared two broad categories. Dyssomnias, such as insomnia and sleep apnea, interfere with falling asleep or remaining asleep. Parasomnias, including sleepwalking, nightmare disorder and sleep terrors, involve unusual events that disrupt the sleep cycle.

“As more people recognize how important sleep is, there’s growing urgency to understand what’s happening in the brain,” said Matthew Sutherland, a cognitive neuroscientist at FIU and senior author of the study. “By bringing together results from many studies, this research gives us a clearer picture of how sleep disorders affect brain structure and function and where we need to focus next.”

Attention centers show a common decline
Both categories were associated with decreases in the thalamus, a region that filters incoming information, supports concentration, and contributes to higher-level thinking. The researchers identified changes specifically in the pulvinar, an area within the thalamus that directs attention and helps manage cognitive control.

These differences were connected with wider brain networks that support concentration and task performance. That pattern may help explain why disrupted sleep is associated with slower reactions, poorer decision-making and a greater likelihood of errors and accidents.

One of the challenges of searching for technosignatures (i.e., signs that intelligent life somewhere in the universe has created technology) is understanding what to look for. Technology is a very broad area, and different types would show up as different features. One of the most commonly cited is a Dyson sphere, which attempts to encapsulate a star and capture its outgoing light to produce energy. But while we've looked for the mid-infrared waste heat these structures would produce for decades, we haven't found a definitive instance of one. According to a new paper, available as a preprint on arXiv by Turkish high school student Sahin Torlakcik, that might be because we are looking for the wrong type of energy altogether.

In his paper, Torlakcik introduces the concept of stellar J-harvesting—building a system that could deliberately extract a star's rotational angular momentum. To be clear, this solution wouldn't capture the same energy output as a full Dyson sphere (or, more accurately, swarm), but it does have two massive advantages—it requires much less physical material to build, and it would generate waste heat millions of times lower than the star's luminosity, essentially making it "invisible" to most infrared surveys.

So how would this work in practice? You can't simply set up a frictional braking system on a star. Instead, you would have to sap its energy by using one of a few different electromagnetic coupling techniques.

According to the paper, one technique would be to build a massive conducting structure embedded in the solar wind that extracts angular momentum using Alfvén-wave coupling. These low-frequency oscillations of magnetic fields can interact with the tether, transferring some of the star's angular momentum into the tether itself.

An alternative approach is to create what is essentially a giant orbital flywheel. Building a massive ring at approximately 1 AU (the distance from the Sun to Earth) could capture angular momentum from the star via Lorentz-force coupling. Using the Lorentz force, the fundamental force exerted on a charged particle by a magnetic field, this megastructure could scavenge angular momentum from the star by using its magnetic field to push on a massive electrically conductive ring.

Another interesting alternative is a synchrotron spin-down array. Synchrotron radiation is a form of radiation that occurs when a particle, such as an electron, travels a curved path near the speed of light. When these particles travel along a magnetic field line, they lose energy by emitting highly directional beams of radiation, known as synchrotron radiation.

By placing an array of extremely strong electrically conductive structures in the flow of the solar wind, this technosignature would accelerate those charged particles to near-relativistic speeds and thereby emit synchrotron radiation. Because Newton's third law holds that every action has an equal and opposite reaction, this radiation has a reactive torque that pushes the array. Since the array is coupled to the star's stellar wind, it opposes and slows the star's rotation. Crucially, this technique would also emit a specific technosignature of its own, in the form of radio waves or X-rays, depending on the speed and field strength of the system.

Some of these techniques are similar to those seen in another technosignature idea—starlifting—whereby an advanced civilization intentionally harvests material from a star, either to use that material to build megastructures or to artificially extend the star's life by lowering its mass. However, this particular use case has a very distinct pattern that we can easily search for—stars that are rotating more slowly than their peers.

Oxygen is declining across oceans, coastal waters, rivers, lakes and streams, threatening the organisms and chemical processes that depend on it. A review led by researchers at UC San Diego’s Scripps Institution of Oceanography warns that this widespread deoxygenation is moving Earth toward an “unsafe space,” with some effects potentially lasting beyond human timescales.

The researchers examined how aquatic deoxygenation, meaning the loss of dissolved oxygen from marine and freshwater environments, interacts with the nine processes included in the Planetary Boundaries framework. Introduced in 2009, the framework identifies major Earth systems and evaluates how human activity is pushing them beyond the conditions that support a stable and resilient planet.

Those nine boundaries cover climate change, ocean acidification, biodiversity loss, atmospheric aerosol loading, stratospheric ozone depletion, freshwater change, land use change, chemical pollution and biogeochemical flows (including the nitrogen cycle). The authors argue that dissolved oxygen should also be included.

Oxygen loss threatens planetary stability
“The health and stability of our planet depends on the health and stability of aquatic ecosystems, which need oxygen to function normally,” said lead author Erica Ferrer, a Scripps Oceanography alumna and current postdoctoral scholar at UC Santa Barbara’s National Center for Ecological Analysis and Synthesis. “This study is designed to elevate the profile of aquatic deoxygenation as a global threat and show that it does not operate in isolation.”

A pet gecko known for developing tumors at an exceptionally high rate could offer scientists a valuable new way to study how cancer begins, evolves, and spreads, according to research led by experts at the University of Nottingham.

Published in BMC Biology, the findings may also help researchers understand why certain animals are especially vulnerable to cancer while others develop the disease only rarely.

A Gecko With an Extraordinary Cancer Risk
Cancer appears to be uncommon in some reptiles, including turtles and tortoises. However, the leopard gecko color variety sold in the pet trade as the “lemon frost” morph presents a striking exception. Aggressive tumors develop in about 80% of these geckos.

Researchers have now identified genomic changes associated with the disease. Several of those changes involve genes and biological processes that are also connected to cancer in humans.

Dr. Chiari said: “By studying why some animals are so susceptible to cancer while others are remarkably resistant, we hope to uncover the different ways species have evolved to deal with cancer. Specifically, this gecko could become an incredible model in cancer research because tumors appear naturally at a relatively early age. Together, these natural strategies could inspire new ways of preventing, detecting, and treating cancer in humans.”

Sugars are central to life. They help form the structural backbone of DNA and RNA and participate in essential metabolic reactions.

They are also thought to have been necessary for the formation of the earliest nucleic acids. Yet researchers studying life’s origins still face a major puzzle: laboratory experiments indicate that prebiotic conditions on early Earth would not have produced enough sugar.

Ribose and glucose have been found in meteorites and asteroid material, raising the possibility that some sugars formed in the ancient molecular cloud that gave rise to the Solar System. Until now, however, no sugar had been identified directly in interstellar space.

A four-carbon sugar appears in space
An international group led by CAB researcher Izaskun Jiménez-Serra has detected erythrulose, the first sugar identified in the interstellar medium. Erythrulose is the only possible ketose containing four carbon atoms. On Earth, it occurs naturally in raspberries and is also used in sunless tanning products.

Researchers found it toward G+0.693−0.027, a molecular cloud near the center of the Milky Way. The detection relied on highly sensitive broadband spectroscopic surveys conducted with the 40-m Yebes radio telescope and the 30-m telescope operated by the Institute for Radio Astronomy in the Millimeter Range (IRAM).

During sleep, the brain activates a cleanup network that helps remove accumulated waste. A review led by Victoria University (VU) researcher Dr. James Broatch examined whether exercise could strengthen this glymphatic system, which becomes increasingly important for maintaining brain health as people age.

Exercise is already closely associated with healthy aging, but exactly how it protects the brain remains uncertain. Understanding that mechanism is especially important because more than 10 million people worldwide are diagnosed with dementia each year, and no cure currently exists.

Published in Trends in Neurosciences, the peer-reviewed paper evaluated existing animal and human research on the glymphatic system. Although more evidence is needed (including research Dr Broatch is now conducting), the review found that exercise improves several biological processes involved in regulating brain waste clearance.

Exercise supports brain waste clearance
The reported effects include:
• Lower blood pressure and reduced vascular stiffness
• Improved activation of neurons in the brain
• Reduced inflammation in the brain
• Lower resting norepinephrine levels

Better sleep, including improved deep sleep and increased slow wave activity associated with waste clearance

Dr. Broatch said the connection between exercise and brain protection could help researchers identify scientifically supported physical activity strategies for limiting brain deterioration with age.

“If we don’t have opportunities for the brain to essentially clean out the junk from the day, we know that build-up is damaging, especially as we age. Sleep is more crucial than ever to play this role, but the irony is, good quality sleep can often be harder to get as we get older. This study asked, what if exercise could support that process?” Dr. Broatch said.

The face of a young woman crowned with a laurel wreath, buried in elaborate clothing and unusual cork sandals, has appeared nearly 1,700 years after her death.

She is one of 16 people from Aquincum, a Roman-era city in present-day Hungary, whose faces have been reconstructed for "Once We Were Like You," a new exhibition at the Aquincum Museum in Budapest. The display pairs skulls excavated in and around the ancient city with scientifically informed approximations of how their owners may have looked in life.

Six of the reconstructions are hyperrealistic silicone models, complete with artificial eyes, human hair, eyebrows, eyelashes and, in some cases, beards. The exhibition, which runs through Oct. 31, includes men, women and a child who lived during the region's period of Roman rule.

There's nothing more disorienting than falling asleep in transit only to wake up and find you've somehow drifted billions of miles beyond the orbit of Pluto.

Fortunately for NASA's New Horizon spacecraft, which scientists just awakened from a nearly yearlong hibernation at the solar system's edge, all systems are in "good health," according to a NASA statement. Now, with the probe recovered from its 321-day sleep and beginning to transmit science data again, New Horizons appears ready to continue its mission of studying the mysterious boundary where the sun's realm ends and interstellar space begins.

"Every status report through this hibernation period was 'green,' meaning all was well aboard New Horizons each and every week," Alice Bowman, the New Horizons mission operations manager at the Johns Hopkins Applied Physics Laboratory in Maryland, said in the statement.

New Horizons launched in 2006, breaking the record for fastest-ever space launch at roughly 36,400 mph (58,500 km/h). On its way to the edge of the solar system, the spacecraft picked up speed during a flyby of Jupiter in 2007 and then again while passing Pluto in 2015. Today, New Horizons is about 5.9 billion miles (9.5 billion kilometers) from Earth, or roughly 64 times the distance from Earth to the sun (64 astronomical units, or AU).

With the exception of the twin Voyager probes that launched in 1977, New Horizons is the farthest working spacecraft in the universe. (Two other probes, Pioneer 10 and 11, have traveled farther, but each stopped working several decades ago.)

Like the Voyager twins, New Horizons is on a trajectory toward the heliopause — the extreme outer edge of the sun's influence, where solar wind collides with the interstellar medium.

The Voyager probes proved that this dividing line is a measurable, physical boundary in space, marked by a hot, thick plasma barrier. However, New Horizons will eventually pass this boundary with far more sensitive instruments than the Voyagers held, enabling it to collect the most detailed data about this region ever.

Reliably generating controlled miniature rotations has long been a challenge: Chemical propulsion systems wear out, and methods that use electric or magnetic fields require complex setups. A team from KIT's Institute of Microstructure Technology (IMT) and the Suzhou Institute of Nano-tech and Nano-bionics (SINANO) at the Chinese Academy of Sciences has now demonstrated that flow at a water surface alone is sufficient to rotate a floating object in a fixed direction. Their research is published in the journal Science Advances.

"We were able to show that motion on a small scale can be controlled entirely without chemistry, electricity, or magnetic fields, relying solely on the forces acting at a water surface. This opens up a simple and versatile way to assemble ultrafine structures in a targeted manner," said Professor Jan G. Korvink from KIT's IMT.

Why speed determines direction
At the heart of the setup is a 3D-printed component with a spiral channel. It keeps a tiny object on the water surface without touching it. When the component moves slowly up and down, the object merely oscillates back and forth, leaving no net rotation. At a higher speed, however, small vortices form, tipping the balance. The object rotates bit by bit in the same direction—just like a ratchet—gradually accumulating the rotation.

Researchers at KIT were able to visualize this process through flow simulations. "In the simulation, we could accurately trace how the flow breaks the symmetry of motion at higher speeds. It is precisely this symmetry breaking that transforms a back-and-forth movement into a directed rotation," said Professor Yongbo Deng from IMT.

Fine fiber bundles for wires, sutures and artificial muscles
The effect can be used in a targeted way. The component behaves like a tiny motor powered solely by the water surface. Its torque is about 10⁻⁸ newton-meters, which is far below that of an electric motor but significantly greater than that of biological motors. Using this approach, the scientists gradually assembled silk fibers with diameters between 10 and 20 micrometers into multilayered twisted bundles. Such structures are also typical of Litz wires and surgical suture materials.

Potential applications are low-loss transmission cables in data centers, multifunctional suture materials and artificial muscles. Conventional braiding machines fail at this scale because the fibers break under tension. The novel approach, by contrast, requires no mechanical contact and thus opens an innovative way to manufacture helical structures in a controlled manner.

LINK, the robotic spacecraft from Katalyst Space designed to boost our Swift mission’s orbit, experienced issues with attitude control over the weekend, causing the spacecraft to spin and resulting in sporadic communications. The team is working to stop LINK’s spin over the next few days and then will update LINK’s guidance, navigation, and control to accommodate the spacecraft’s new configuration.

Learn more: go.nasa.gov/4xcuamQ

Minor cuts and scrapes usually heal in time, but losing a finger or a whole limb? For most vertebrates, that's a done deal. Unless, of course, you've got the self-healing machinery of an axolotl.

These unusually resilient and famously photogenic aquatic salamanders—native
to Mexico—can regenerate parts of their bodies, including limbs, eyes and even bits of their brain. With their frilly pink gills and heartwarming smiles, they're always camera-ready—even if they have to regrow an appendage or two first.

Axolotls are also the Peter Pans of the amphibian class. Like the fictional boy who never wanted to grow up, they skip the transitional stage that ushers most of their counterparts into adulthood on land and remain in tadpole form forever. While they don't have to worry about aging, certain diseases—as well as predators—do catch up with them in time. Most live 10 to 15 years.

So why can axolotls—these charismatic creatures—regrow a limb, whereas humans just undergo wound healing? And how is it that most organisms go through aging while a lucky few get to press a pause button?

Understanding regeneration could allow for an axolotl-style intervention into wound healing and the aging process, according to Northeastern University professor of biology and mathematics Calina Copos. The question at the heart of both pathways is what steers cells down one path versus the other, she said. Each decision point is a fork in the road.

Copos is investigating how cells, the basic building blocks of body tissues, respond differently to outside pressures.

Neural networks have transformed how machines find patterns in data, from recognizing faces in photos to predicting the shapes of proteins. So far, all of this progress has been made on ordinary classical computers, but with quantum computers now edging into practical use, there is a real possibility that neural networks could tap into distinctly quantum effects and operate in ways that classical machines never could. So far, however, neural networks have proven far more difficult to run on quantum hardware.

Through new research published in Physical Review Letters, Djamil Lakhdar-Hamina and colleagues at the University of Maryland, College Park, have built a neural network that runs on two different types of quantum computer, allowing them to test directly whether these systems can live up to their theoretical promise.

Elusive quantum advantage
A neural network is built from layers of simple units, each taking in signals and passing on an output depending on what it receives. To train a network, the connections between these units are adjusted until the network reliably produces the right answer for a given task.

In the quantum world, a similar structure can be built using qubits: the basic unit of quantum information, whose measurement outcomes stand in for the signals passed between layers. Researchers have long suspected that quantum versions of these networks could offer genuine advantages over classical ones, perhaps by exploiting quantum uncertainty. However, very few of these ideas have actually been tested on physical devices.

Researchers at Rensselaer Polytechnic Institute (RPI) have found that today's leading artificial intelligence tools for predicting protein structures routinely generate results that are physically and chemically impossible, exposing critical blind spots in how AI is being applied across scientific research. The work, published in the Proceedings of the National Academy of Sciences, serves as a cautionary reminder that AI still requires human oversight and physics-based verification to produce reliable results in the lab.

The paper, authored by George I. Makhatadze, professor of biological sciences and Constellation Endowed Chair at RPI, evaluated widely used deep learning tools for predicting how flat sequences of amino acids fold into the three-dimensional structures that determine a protein's function. Makhatadze found that these tools frequently overlook the underlying scientific rules of protein folding—and, notably, that every tool tested rated its own accuracy higher than the results warranted.

"The major conclusion of the paper essentially is: trust but verify," Makhatadze explained. "You have to verify [AI outputs] using physics-based methods."

Where the models break down
AI has become indispensable for analyzing the massive data sets used to predict protein folds. For example, Google's DeepMind AI laboratory—known for AlphaFold2—shared the 2024 Nobel Prize in Chemistry for its contributions to protein structure prediction.

But according to Makhatadze's work, AlphaFold2 and RoseTTAFold2—a similar deep learning-based prediction platform developed at the University of Washington—both produced "implausible structures for variant sequences" by "[prioritizing] statistical patterns over the underlying thermodynamic principles of folding." Both tools are trained on evolutionary data and structural databases.

"AlphaFold is considered the gospel of the field," Makhatadze said. "It is very good, and it does many things well. But occasionally it makes mistakes, because there simply isn't enough of the right kind of data in the model yet."

Makhatadze found fewer scientific impossibilities in a different class of tools—"transformer-based protein language models" that rely on protein sequences rather than structural data. Tools in this class included OmegaFold and the Meta-developed ESMFold. However, neither category of model performed well when proteins contained ionizable residues, meaning amino acid side chains that can gain or lose a proton depending on their surrounding environment.

Researchers have uncovered a surprising mechanism that allows plants to carefully coordinate the formation and growth of new leaf parts. The study shows that the hormone auxin regulates different phases in organ formation by oppositely affecting the activity of another hormone, gibberellin, to trigger the formation of new leaf structures before reversing course and boosting gibberellin to drive their expansion. The findings offer new insight into how plants build complex organs and could eventually help scientists develop crops with improved growth and architecture.

A plant's ability to produce leaves, flowers and other organs depends on precise location and timing. It must first determine where a new structure will form before allowing it to expand. Now, researchers have uncovered the molecular switch that coordinates these two steps, revealing how plants carefully alternate between putting on the brakes and stepping on the accelerator during organ development.

If you own a strong enough telescope, you might be able to witness history on Wednesday: A dead rocket is going to crash into the moon. On August 5, at around 6:34 am UTC, a spent SpaceX Falcon 9 upper stage is expected to hit the moon's sunlit western limb near Einstein crater at more than 5,400 mph. If it unfolds as predicted, the crash could throw up a plume of debris bright enough to briefly see from Earth with the right equipment.

That would be a first. No impact flash has ever been recorded on the sunlit face of the moon, and that's exactly where the Falcon 9 crash is forecast to happen, kicking up plumes of dust that could stand out against the blackness of space. The findings are based in part on two new preprint studies.

That includes one posted July 27 to arXiv and led by William Jo, a doctoral candidate at the University of Texas at Austin's Cockrell School of Engineering, that forecasts just how big the impact could be. To predict the plume, Jo ran the crash through a high-resolution physics simulation that allowed him to model what would happen when 3,900 kilograms of hollow metal hit the lunar surface. That’s different from solid meteorites making impact.

"It's like an empty eggshell, because it had all the fuel in it, and there is a rocket engine at one end that's denser," David Goldstein, an aerospace engineering professor at UT Austin who supervised the work, says of the Falcon 9.

Rather than burrowing in like a cannonball, the shell will collapse from its edges inward, throwing up a broad, low curtain of soil spreading as far as 183 kilometers wide as well as a thin, faster spike nearly straight up. All told, the crash is forecast to displace about 12,700 kilograms of debris.