Physicists have found evidence of a particle decay so rare that it is expected to occur only around once in every 10 billion "beauty" particles. The result, from the upgraded LHCb experiment at CERN's Large Hadron Collider (LHC), follows a search spanning more than 40 years and brings physicists closer to exploring the "Zeptoverse"—an unexplored world that exists at distances of a billionth of a trillionth of a meter, or a "zeptometer," where new particles and forces of nature may be hiding.

Researchers from The University of Manchester have played key roles in the LHCb experiment and its major upgrade—which can now collect data at up to five times its previous rate—including developing detector technology that has helped make the new measurement possible.

The finding will allow physicists to test the Standard Model, our current best theory of fundamental particles and their interactions, with greater precision and search for signs of particles or forces that may lie beyond it.

Searching for signs of new physics
The LHCb studies particles containing beauty quarks, heavier relatives of the up and down quarks found in the ordinary matter around us.

Beauty quarks are produced in huge numbers in collisions at the LHC but exist for only around one and a half trillionths of a second before decaying.

By making precise measurements of the different ways beauty quarks decay, physicists can detect the influence of new particles that may be far too small to see at the LHC.

The rarer a decay is, the more sensitive it can be to the influence of new particles. These particles could alter how often the decay occurs.

The new result concerns a particularly rare decay known as 'Bd to mu mu,' in which a particle containing a beauty quark decays into two muons, heavier relatives of electrons.

Scientists predict that this happens only around once in every 10 billion beauty particles. Until now, no single experiment had found solid evidence for the process.

The new measurement reached a statistical significance of 3.2 sigma. This is sufficient for physicists to describe the result as the first evidence of the decay, although further data will be needed to reach the five-sigma threshold required to claim a discovery in particle physics...

After 22 years in orbit and a failed rescue mission this summer, it is highly likely that the Neil Gehrels Swift Observatory will crash into Earth sometime next week. It is not known where on the planet the spacecraft—which is roughly as big as a large elevator—will fall. Despite its size, experts say the risk to the public is relatively low.

What is now a useless piece of space junk was for a long time extraordinarily valuable to the scientific community. Launched on November 20, 2004, Swift was a space observatory equipped with three telescopes. It was designed primarily to detect and study gamma-ray bursts, which are among the most energetic explosions in the universe. Swift would locate these events and transmit their positions to observatories around the world for further study.

The observatory was designed to operate for a few years in low Earth orbit, but it far exceeded its expected lifespan, helping to make many important discoveries about the evolution of the cosmos, including the study of supernovas and the destruction of stars by black holes. However, in 2024, increased solar activity heated and expanded the upper layers of Earth’s atmosphere, increasing the drag on the satellite and accelerating its descent. Without a propulsion system capable of correcting its orbit, its days were numbered.

In July 2026, NASA launched a special $30 million mission to rescue Swift. A robotic spacecraft called LINK was supposed to drag Swift away from Earth by 150 miles, giving it a higher orbit and thus extending its operational life. Unfortunately, LINK failed. In August, NASA administrator Jared Isaacman explained that the difficulties that led to the mission’s cancellation were due to problems with the spacecraft’s control system, which made it impossible to keep it properly oriented and stable in space.
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On October 26, NASA announced that Swift was less than 170 miles from Earth’s surface—a very low orbit for a satellite. According to the agency, the telescopes on board could no longer maintain stable observations of their astronomical targets. Swift conducted its final observation on October 20, then the operations team based at Pennsylvania State University terminated its operational status.
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The US Space Force estimates Swift is likely to crash on or around Friday, November 6—or at least whatever remains of the satellite will. Most of the space observatory is expected to disintegrate as it reenters the atmosphere...

What’s on your mind right now? You can probably answer this question without thinking too hard about it. Being aware of our own thought processes — a capacity called introspection — seems to come naturally to us.

Yet among philosophers and psychologists, introspection is a subject of active debate. Some think it’s closely related to consciousness. Others argue that it’s an elaborate illusion. It’s tricky to test theories of introspection in the lab — or to pin down a precise definition in the first place.

Now, after over a century of studying introspection in humans and animals, researchers are beginning to explore the phenomenon in unlikely new subjects — large language models. These systems, which are based on mathematical structures called neural networks, excel at cognitive tasks that until recently seemed exclusive to humans. Can they introspect as well?

In 2025, Jack Lindsey, a researcher at Anthropic, devised a way to test introspection in language models by injecting “thoughts” into their neural networks — in a kind of targeted digital neurosurgery. Lindsey’s experiment demonstrated that models could at least sometimes detect and describe these injections. It looked a lot like introspection.

Lindsey’s paper was deliberately limited in scope — it didn’t make broader claims about consciousness. (In particular, it did not imply that language models have subjective first-person experiences.) Even so, it caused a stir online. Researchers rushed to replicate Lindsey’s study with other models.

In the year since, a clearer picture has emerged. Some aspects of the phenomenon Lindsey observed have simpler explanations unrelated to introspection. Others have proved harder to explain away, but whether they should count as introspection remains hotly contested...

It's the end of an era: NASA's Swift telescope has reached the conclusion of its nearly 22-year mission, burning up in Earth's atmosphere after studying some of the universe's most powerful and mysterious events.

According to NASA, the spacecraft reentered the atmosphere at "7:39 a.m. EST Wednesday over the North Sumatra region of Indonesia, at approximately 3.4 degrees north latitude and 98.6 degrees east longitude." NASA expected most of the telescope's structure to burn up during its passage through Earth's atmosphere, estimating a 1-in-2,100 chance of any surviving debris falling over a populated area. No damage or injuries have been reported.

Weighing approximately 3,200 pounds (1,450 kilograms), the Neil Gehrels Swift Observatory was initially designed for a two-year mission, but it far exceeded expectations. Over two decades, Swift became an important tool in the study of gamma-ray bursts, supernovas, black holes and other cosmic phenomena.

Exceeding expectations
Launched in November 2004, Swift was designed to detect gamma-ray bursts, powerful explosions that occur throughout the universe. Its three onboard telescopes let scientists observe cosmic events across different wavelengths, including ultraviolet, optical and X-ray light. The telescope could swivel to focus on different sky targets in a matter of minutes, allowing it to rapidly follow up on sudden events like supernova explosions.

NASA estimates that Swift's scientific observations have contributed to approximately 7,000 research papers, leaving behind an extensive collection that scientists can continue studying for years...

Martian dust is a major hurdle for human missions to Mars. Like Moon dust, its fine size and electrostatically charged nature allow it to stick to spacesuits, metal, and just about any other surface they come into contact with. Dust storms are also common on Mars, ranging from small whirlwinds that happen daily to global dust storms that occur once every 3 Martian years (~5.5 Earth years) and envelop the entire planet. Due to the low density of Mars' atmosphere, these storms don't generate much physical force.

The danger lies in how the dust plays havoc with instruments, machine parts, and astronaut health and safety. Given how well it adheres to surfaces, Apollo astronauts found that lunar dust accompanied them back into their landing modules, degrading mechanical joints and seals and causing respiratory problems. A recent study led by Washington University in St. Louis (WashU) highlights the need, using data from NASA's Perseverance rover, for sufficient astronaut training to prepare for the Martian environment.

In addition to its array of sensors, cameras, drilling equipment, and sample cache, Perseverance also carries small swatches of spacesuit material that are constantly exposed to Mars' atmosphere. Using data acquired by the rover's Planetary Instrument for X-ray Lithochemistry (PIXL), the team examined the swatches for signs of wear and tear. They also applied a method developed by VanBommel to estimate the size of each particle in the PIXL data, providing the first direct characterization of fine (≲2.5 µm) and ultrafine particles (≲0.1 µm).

Their analysis found that the swatches showed little visible wear after 1,645 Martian days (sols) of exposure, largely because the particles observed were much smoother than the jagged grains found on the Moon. In summary, the results showed that Martian dust may be less likely to be abrasive to equipment or harmful to astronaut health than lunar regolith. The PIXL data also allowed the team to analyze the chemical composition of the particles that had caked the swatches.

From this, the team confirmed the presence of perchlorates and other toxins, as well as high levels of sulfur, iron, and silica in the dust grains. In addition, Martian dust can be exceptionally fine, with some ultrafine particles measuring as little as 100 nanometers (nm) in diameter. On Earth, ultrafine particles typically come in the form of smoke and air pollution, which can cause significant health problems because they can sink deep into the lungs and enter the bloodstream. With Martian dust carrying perchlorates and other toxins, the health risk is magnified...

What if a robot could be squishy? Soft, flexible robots could be useful for a wide variety of applications, including artificial muscles and wearable devices—or really any application where a robot must be especially delicate.

This is what has fueled development of “soft actuators” that can flex like a bicep and have a fine-tuned sense of touch as in the human hand. Like your stereotypical robot, soft actuators convert energy—such as electricity, heat, or light—into mechanical motion, but they look nothing like the metal and wire constructs that the word “robot” most often evokes.

One variety of these soft robots, known as bioactuators, utilizes the functions of living cells to generate motion. These biological machines have attracted particular attention in recent years, and now a research team at Delft University of Technology in the Netherlands has developed a soft robotic arm colonized by algae on its surface, and when the microbes photosynthesize, the arm moves.

“We didn’t start with a specific application. Our goal has always been to bring the research of living materials to new levels,” Marie-Eve Aubin-Tam, who led the research, explained in a press release. “We wanted to explore what becomes possible when living cells are integrated into functional materials.” ...

Has AI tackled a problem in physics that has been open for more than half-a-century? It seems so. Brian Greene explains OpenAI’s claim that a dominant component of the Standard Model of Particle Physics – so called, Yang-Mills Gauge Theory – has now been proven mathematically sound.

For decades, physicists have used the equations of the Standard Model to make exquisitely precise predictions, borne out by a mountain of experimental results. But getting to these results has required intermediate steps of questionable mathematical rigor. OpenAI says its models have now filled in the missing math, finally placing years of calculations on a firm mathematical footing, and addressing half of a million-dollar Millennium Prize problem. Brian walks through what that proof covers, what still sits with the review committee, and why the other half of the million-dollar problem, the Mass Gap problem, remains open.

Exposure to toxic metals like cadmium has been associated with adverse pregnancy outcomes such as miscarriage, preterm birth and low birth weight. Because these effects are difficult and ethically challenging to study directly in pregnant women, how such exposures affect pregnancy has remained poorly understood.

The placenta-on-a-chip model developed by Dan Huh, J. Peter Skirkanich professor in bioengineering, and colleagues at Penn Engineering offers a way to investigate these questions using living human cells. In a study published in Nature Biomedical Engineering, the team led by Huh, together with collaborators at Princeton, Sogang University in Seoul, Korea, and Rutgers University, used the bioengineered model to examine how cadmium, a toxic metal found in food, drinking water and tobacco smoke, affects the placenta's ability to support a developing fetus.

The group's experiments revealed that cadmium can impair the placenta even at relatively low exposure levels that do not kill cells. The researchers also identified a protein that helps protect placental tissue, along with metabolic changes that could provide clues to exposure-related damage.

Recreating the maternal–fetal interface
In the placenta, maternal and fetal blood circulate in separate compartments and exchange nutrients and other substances across a thin layer of tissue. Huh and his collaborators developed a microfluidic device that recreates key features of this maternal–fetal interface.

The device is built with human placental cells isolated from donated placentas. On one side, a layer of these cells is exposed to flowing fluid that simulates maternal blood. On the other, a three-dimensional tissue structure contains a network of fetal blood vessels embedded in a hydrogel scaffold.

The model also incorporates oxygen conditions that more closely reflect those inside the placenta than conventional cell culture systems. Researchers can introduce additional cell types, including placental immune cells, to investigate more complex biological responses.

Huh's earlier placenta-on-a-chip research focused on how drugs cross the placental barrier.

"Our new work expands the original capabilities of the technology and allows us to emulate the human maternal–fetal interface with greater fidelity and study the effect of environmental toxins under more realistic conditions," says Huh. "We can now ask not only whether cadmium crosses the barrier but also how it affects the placenta's ability to perform its key physiological functions." ...

No other traveler has ever journeyed so far from home.

Voyager 1 is about to become the first human-made object to reach a distance of one light-day from Earth, or about 16 billion miles. ½

Like most cats, Cooper used to love climbing into cardboard boxes. But one day, a box full of foam packing peanuts caught this tabby by surprise. Her owner, Sean McGrath, soon heard a commotion coming from the box and pulled her out. Thanks to static electricity, foam pellets now clung to her fur from head to tail.

Cooper seemed stunned. “She just stood there, frozen,” says McGrath, 44, of St. John, Canada. He snapped a photo before brushing her off. That picture, taken 20 years ago, eventually found its way to Wikipedia. Cooper unwittingly came to embody static electricity. She has appeared in textbooks, college lectures and more — all to help explain this sticky science.

Static electricity is common in everyday life. It’s why rubbing a balloon on your head makes your hair cling to it. It’s why clothing fresh from the dryer can stick to your legs. It’s also behind the painful shock you sometimes get when you touch a doorknob.

But the science of static electricity is surprisingly mysterious.

We know it’s caused by an electric charge moving between objects when they touch. But how — exactly — does that happen? In most situations, “we really have no clue,” says Galien Grosjean. A physicist, he works at the Autonomous University of Barcelona in Spain. He’s one of a small, quirky group of scientists who are obsessed with static electricity. The crew includes physicists, engineers, chemists and materials scientists.

Each researcher in this group holds a piece of the static-electricity puzzle. But they’re finally putting some of the pieces together to make progress...

One of a human’s earliest developmental milestones is an understanding of object permanence. It generally takes less than a year for a baby to realize that when an adult hides their face behind their hands in a game of peek-a-boo, they don’t cease to exist. There’s more to the world around us than what we perceive.

This suggests — or at least, it suggested to Albert Einstein — that the world is “real,” in the sense that things in the world have properties that are intrinsically true no matter what anyone thinks. A red billiard ball is red, even in the dark, and even if no one is checking its color. The redness is a property belonging to the ball, not to some device measuring the ball, and not to the mind of some person operating the measuring device.

Yet quantum mechanics, a thoroughly validated theory of how the world works, seems to suggest otherwise. The theory’s math assigns redness to the billiard ball at the moment you measure it. Before then, the theory gives you only a set of probabilities telling you what color the ball might be. Key founders of quantum mechanics suggested that this math reflects the nature of reality — that in some sense, a single, objective reality doesn’t really exist.

In 1935, Einstein rebelled against this surreal reading of quantum theory, proposing one of the 20th century’s most famous thought experiments. But his rebellion was doomed. In 1964, the physicist John Stewart Bell showed with a thought experiment of his own that reality had to be stranger than Einstein assumed. Subsequent work would put Bell’s thought experiment to the test — and prove him right.

Then, 50 years after Bell, Matthew Pusey, at the time a graduate student at Imperial College London, took on what remained of Einstein’s notion of reality and — without originally intending to — delivered the killing blow.

The paradigm-shifting theorem became known as PBR, for Pusey and his academic accomplices, Jonathan Barrett and Terry Rudolph. Since the publication of PBR in 2012, many theorists have come to accept that it rules out our most commonsense understanding of reality.

“From the moment [PBR] came out, people knew it would be a landmark,” said Jacques Pienaar, a physicist now at the Federal University of Rio de Janeiro in Brazil.

At the time, Pienaar, like Pusey, had been walking in Einstein’s footsteps, dabbling in theories designed to show that objective reality exists and that quantum mechanics merely describes our incomplete knowledge of it. But when the PBR theorem appeared, Pienaar remembers thinking, “That’s it. The program’s dead.”

This is the story of how Einstein, Bell, and finally Pusey and his collaborators killed reality as we know it. In three theorems, they proved that quantum mechanics is incompatible with the world we perceive. And since experiment after experiment — including a recent realization of PBR — has established that quantum mechanics is the law of the land, something about reality has to go.

The question that remains is: How much do we have to give up? ...