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An alternative model in which the universe is 26.7 billion years old and needs neither dark matter nor dark energy has held up against several major cosmology tests, according to a new University of Ottawa study. The research, titled "A Big Bang Nucleosynthesis Consistency Test of the CCC+TL Cosmology," is published in the journal Universe.

Fusion energy has the potential to provide abundant, clean power. Now, the race is on to develop the world’s first commercial plant.

For the first time, an international team of researchers from Germany, Thailand, India, China and the United States has created a three-component Hubbard system with tunable interactions in the laboratory. In doing so, the team used a quantum gas microscope to make the individual atoms visible. The study, published in Science, provides an important foundation for future quantum simulations of nuclear physics and materials science.

Optical cavities are pairs of light-trapping mirrors and underpin the operation of lasers, atomic clocks and many types of precision sensors. If the distance between the mirrors is changed rapidly enough, some theories predict that the waves inside them should bunch together into short, intense pulses. So far, however, this prediction has never been tested directly.

Penn State researchers have refined an atom-scale model of how silicon carbide changes from a solid into vapor during crystal growth, work that could help manufacturers produce higher-quality material for advanced electronics while reducing costly trial-and-error experiments.

Astronomers have filtered out starlight from James Webb Space Telescope observations to see a giant exoplanet emerge in the darkness.

Matter starts to behave differently at extremely low temperatures, creating conditions ideal for studying quantum physics and new states of matter. Now, researchers from China have achieved a new low-temperature record aboard their Tiangong space station. Their research, recently published in Science, might lead to a new generation of experiments in quantum physics and precision measurements in space.

Albert Einstein fought to save our everyday notion of reality from the strangeness of quantum mechanics. But those who set out to aid him keep poking holes in his argument. The post A Strange Quantum Theorem Has Killed Einstein’s Reality first appeared on Quanta Magazine

Skin is remarkably good at keeping things out of the body. Typically, that's a positive. It becomes an issue when medicine needs to get in. Swallow a pill to treat a skin condition, and the medicine enters your stomach, moves into your bloodstream and travels throughout your body—all to reach a problem in your skin.

We typically think of the Moon as a static, floating object that has remained the same for basically its entire lifetime, with an occasional asteroid impact serving as an exception. That understanding is grounded in physics - the Moon should have cooled rapidly after forming when a huge protoplanet hit the early Earth around 4.5 billion years ago. But, some lunar material returned from the Chang’e-5 mission was notably formed only around two billion years ago, yet appeared to be volcanic in origin. So how did a world that was supposed to have settled down without volcanism remain hot enough to create these materials more than two billion years after its violent birth? A new paper from Miao Chen of the Chengdu University of Technology and his colleagues, and recently published in the journal Planet, offers an explanation - tidal heating.

Levitating trains, ultra-efficient energy storage, and quantum computers: superconductivity could unlock a wealth of possibilities for the future. New research led by scientists from Utrecht, Leiden, and Munich has now shed light on one of the key requirements for achieving superconductivity at room temperature. Their findings, published in Science, bring scientists a step closer to understanding how this might be achieved.

Colloidal quantum dots are prized for their size-tunable optical properties and solution processability, making them attractive for next-generation displays and lighting.

Author(s): Rachel BerkowitzRandom tangles of vortex lines have been observed untangling in an ultracold gas. [Physics 19, s137] Published Thu Nov 05, 2026

Researchers revealed an ultralow-barrier collective sliding mechanism mediated by domain walls, as well as defect-induced pinning of the sliding motion. They found that twisted bilayer MoS₂ moiré superlattices can undergo spontaneous long-range interlayer sliding at room temperature, while a sulfur-vacancy concentration of only about 0.1% can turn the motion into localized oscillations.

Wolfspeed has commercially introduced its proprietary silicon carbide (SiC) technology (TSiC), expanding the potential of silicon carbide to enable next-generation augmented reality (AR), quantum computing, and advanced optical applications, according to the company. SiC's high refractive index, low birefringence, hardness, and thermal conductivity make it a promising material for next-generation AR waveguides, supporting wider fields of view, improved image quality, and more compact wearable devices. Wolfspeed’s optical-grade TSiC substrates are engineered for exceptionally low optical absorption and superior wafer flatness, building on more than 35 years of SiC development for applications including LED technology. ...

In the first fraction of a second following the Big Bang, matter existed as a trillion-degree plasma of quarks and gluons—subatomic particles that zinged around at close to the speed of light. This roiling soup lasted for just a few microseconds before the particles coalesced into more stable protons and neutrons.

A new biomechanical study has uncovered how elite volleyball players control ball spin during jump serves, offering fresh scientific insight into one of the sport's most decisive offensive skills.

Researchers at Tohoku University and the Japan Atomic Energy Agency (JAEA) have successfully controlled a unique quantum phenomenon—the quantum-geometric nonlinear Hall (QgNLH) state—using electric current for the first time. The breakthrough was achieved by revealing and exploiting the coupling between the spin structure and the QgNLH state in an electrically switchable chiral antiferromagnet.

Detecting a single photon is a challenge in itself. But what if you also want to know exactly how many photons arrive at a particular point at the same time? Physicist Erik Baalbergen is working on light detectors that can do just that. They form a key building block for the optical quantum computer of the future.

How do cells respond to drugs? A new microscopy technique could provide more precise answers to this question in the future. Researchers from Bielefeld University and the University of Vienna have developed a method as part of the European CHEM-SCAN project that makes the smallest cellular structures visible while also showing how their molecular environment changes.

Physicists at CERN report that they've detected evidence of a rare meson particle decay (B⁰→ µ⁺µ⁻) that occurs when the meson's beauty quark annihilates with a down-type quark. The pair decays into a muon and antimuon, which are particles similar to electrons. Because evidence for this decay helps test theoretical predictions from the Standard Model, physicists have been waiting for it since 1984, when it was first theorized.

Newton's theory of gravity has described the tides accurately for centuries. But could a tiny trace of Einstein's general relativity also be hidden in them? In a new study, a mathematician at Freie Universität Berlin has outlined how a targeted approach could be used to search for effects of this nature.

Around 4.5 billion years ago, a planet-sized object collided with the newly formed Earth, throwing out the debris that would later form the moon. The collision left Earth spinning extremely fast, with days lasting just two to five hours. Yet existing models of how Earth's first crust formed and evolved have largely overlooked how the planet's later slowdown might have affected it.

Johns Hopkins researchers searching the expanse of the universe for the existence of the first black holes are zeroing in on little red dots that may hold the key to the theoretical phenomenon.

Researchers have proposed a breakthrough technique for reading quantum information without destroying the delicate states that make quantum computers work. By detecting an electrical signal generated by the qubit itself, their method achieved up to 99.85% accuracy in simulations and could make future quantum computers simpler and more efficient.

Finding dim exoplanets hidden in the glare of their stars is an ongoing challenge in astronomy. Telescopes use coronagraphs to block out starlight, but even they have their limitations. Researchers have developed a new technique with the JWST that can find dim exoplanets more easily than ever.

A half-built neutrino telescope on the floor of the Mediterranean Sea searched for cracks in one of physics' most basic invariances. It came up empty, but its limits rival those of detectors many times its size.

Author(s): Susan CurtisUsing sheets of light to corral waves of ultracold atoms, researchers have created an experimental platform for studying the event horizons of black holes. [Physics 19, 149] Published Wed Nov 04, 2026

In the theoretical study of proton-nucleus collisions, the colliding projectiles can be described as streams of color charges moving along their respective trajectories. These color charges couple to gluons, which then produce the particles that are observed in the final state (gluons and quarks, which eventually produce hadrons).

University of Sydney researchers have made a breakthrough by directly observing hydrogen in the tiny spaces between the atoms in metal alloys. The world-first observation of hydrogen dissolving in these 'metal crystal lattices' offers fresh insights into why hydrogen can weaken metals and how more hydrogen-resistant materials might be developed.

The principle "Work smarter, not harder!" apparently also applies to controlling quantum materials with light. Many of their fascinating properties depend on how the atoms are arranged in the crystal. Ultrashort laser pulses can be used to alter these structures in a targeted way—the light first excites electrons, whose changed energy and dynamics exert forces on the atomic nuclei and can thereby set the atoms in motion. Such processes unfold within femtoseconds, a millionth of a billionth of a second.

By modeling the James Webb Space Telescope’s tiny movements, a new technique can reveal up to 15 times fainter alien worlds

SPIE, the international society for optics and photonics, has named its finalists for the 2027 Prism Awards. The 21 products — selected in seven categories — will be honored during a Feb. 3, 2027 gala evening at Photonics West in San Francisco. The annual event, now in its 19th year, recognizes commercialized innovations in photonics, honoring companies bringing transformative products to market. The 2027 SPIE Prism Awards will honor companies for breakthrough photonics innovations. The awards, presented in a ceremony at Photonics West, will recognize awardees in seven categories. Courtesy of SPIE. Fast-moving technology areas like biophotonic imaging, optical components, metaoptics design software, metrology tools, and...

So far, observations by instruments including the James Webb Space Telescope have revealed the presence of surprisingly massive black holes in the early universe. Even less than a billion years after the Big Bang, some of these bodies already weighed billions of times the mass of the sun, and to date, astronomers are unclear as to how they could have grown so large so quickly.

Condensed natter: Physics World editors give their compressed verdicts on top new books The post The physics of weather, a literary look at gravity, plus philosophical takes on uncertainty and space exploration: micro reviews of recent books appeared first on Physics World.

Even the world's most powerful telescopes have their blind spots. Although NASA's James Webb Space Telescope (JWST) can peer billions of years into the past, it still struggles to photograph planets orbiting nearby stars. Stars shine with such extraordinary brightness that their glare overwhelms nearby planets' faint glow.

Researchers have observed unusual fractional quantum Hall states in very thin gallium arsenide quantum wells The post New fractional quantum Hall states appeared first on Physics World.

Are the laws of physics truly the same everywhere in the universe? This fundamental principle, known as Lorentz invariance, lies at the heart of Einstein's theory of relativity. Yet some theories that seek to reconcile gravity with quantum physics suggest that it might not always hold. To investigate this possibility, researchers from the international KM3NeT collaboration analyzed 5,828 atmospheric neutrino candidate events detected by KM3NeT/ORCA, a neutrino telescope located deep in the Mediterranean Sea.

Imagine shuffling a deck of cards where some of the cards are fading just because of the way they interact with the external environment as you shuffle them. Your job is to figure out the interplay between the shuffling, or "imposed randomness," due to the way you shuffle your cards and how that relates to the fading as cards are exposed to the external environment.

Chinese researchers have developed a new way to improve sodium–sulfur battery performance by changing the atomic structure of a catalyst. Led by professors Wang Hui and Zheng Fangcai from the High Magnetic Field Laboratory at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, the study is published in Angewandte Chemie.

There have been decades of regulations to make vehicles greener and improve air quality in London and Beijing, as well as a popular shift toward less polluting road transport. Now, total emissions of harmful air pollutants from vehicle exhausts are lower than those from cooking in the centers of these two megacities, a study has found.

Researchers from the Faculty of Physics at the University of Warsaw, the Military University of Technology (Poland), IBM Research Zurich and the French National Centre for Scientific Research (CNRS) have observed a new quantum state of matter known as a supersolid in an exciton-polariton Bose-Einstein condensate. Remarkably, the phenomenon occurs not at temperatures close to absolute zero, but at room temperature. The results have been published in Science Advances.

Researchers at the University of Regensburg and their international partners have found a way to significantly reduce errors in quantum bits. In an experiment, they demonstrated that a single additional measurement before a series of quantum operations can cut the error rate by more than half. The results have been published in Applied Physics Reviews.

With their mysterious glow and swirling veils of color, auroras enchant even experienced researchers. When a particularly intense solar storm reached Earth on the night of May 10, 2024, and relevant websites predicted auroras even for southern Lower Saxony, several researchers from the Technical University of Braunschweig, the Fraunhofer Institute for Surface Engineering and Thin Films IST, the University of Göttingen, and the Max Planck Institute for Solar System Research (MPS) took to the outdoors.

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.

Astrophysicists think that the supermassive black holes (SMBH) we see in the modern universe are the result of a long, drawn-out process. That process is referred to as the hierarchical black hole mergers framework. It explains how some SMBHs can reach such staggering masses. Some of the most massive appear to have billions of solar masses.

Nonlocal correlations draw heat from a bath The post Cool correlations: quantum steering can make cooling more efficient appeared first on Physics World.

Quantum Design's acquisition of Oxford Instruments NanoScience has created a global company with the engineering firepower to create innovative measurement solutions and large-scale cryogenic systems for quantum computing and physics research The post Technology companies join forces to boost scientific discovery and quantum scale-up appeared first on Physics World.

Scientists at CERN's Large Hadron Collider have uncovered compelling new evidence that even relatively small atomic collisions can recreate the extraordinary state of matter that filled the universe moments after the Big Bang. Known as quark-gluon plasma, this exotic substance forms at temperatures more than 100,000 times hotter than the center of the Sun, causing ordinary particles to break apart into their fundamental building blocks.

Scientists have discovered a possible loophole in the laws that normally prevent black holes from splitting apart, suggesting that extremely fast-spinning black holes might divide into two. The surprising finding raises the possibility of an entirely new black hole phenomenon that future telescopes could potentially detect.

Author(s): Yiqin Chen, Shi-Yi Zhao, Xingjiang Zhu, N. D. Ramesh Bhat, Jacob Cardinal Tremblay, Małgorzata Curyło, Valentina Di Marco, George Hobbs, Wenhua Ling, Rami F. Mandow, Richard N. Manchester, Saurav Mishra, Daniel J. Reardon, Sparrow Roch, Christopher J. Russell, Ryan M. Shannon, Jingbo Wang, Shuangqiang Wang, and Andrew Zic (PPTA Collaboration)Researchers have used radio observations of rapidly spinning neutron stars to search for signals from supermassive black hole pairs at the dawn of galaxy formation. [Phys. Rev. Lett. 137, 191401] Published Mon Nov 02, 2026

Author(s): Sarah Burke-SpolaorResearchers have used radio observations of rapidly spinning neutron stars to search for signals from supermassive black hole pairs at the dawn of galaxy formation. [Physics 19, 146] Published Mon Nov 02, 2026

A research team wanted to better understand how the forces between particles inside a material change. They discovered that by confining one-dimensional classical spin chains inside a mirror box cavity with light, they could force these magnetic particles to organize and undergo a phase transition. Their work provides the simplest exactly solvable examples showing that light can create new phase transitions with materials.

Ruthenium (Ru) is a valuable metal used in catalysts to speed up chemical reactions in many industrial processes. It can help improve efficiency and reduce the energy needed for chemical production. However, because it is rare and expensive, scientists are looking for ways to make better use of it.

Astrophysicists think that black holes grow through a hierarchical merger framework. But the elusive Intermediate Mass Black Holes are the missing link between stellar mass black holes, and the gargantuan supermassive black holes like the one at the center of the Milky Way. The JWST may have found the ancient sources of IMBH heavy seeds: young massive clusters in the high-redshift Universe.

One approach to making information storage in quantum computing less prone to errors is known as topological quantum computing. It relies on special quantum states that are expected to be more resistant to local disturbances.

The findings are another clue towards understanding the origins of 3I/ATLAS and the planet-forming conditions around other stars.

Quantum computers rely on qubits as their units of information. To connect them into a larger network across long distances, they need to transmit quantum information using light.

“One day, fusion energy could dramatically increase demand for diode lasers,” said Hagen Zimer, CEO for laser technology and a member of the managing board of TRUMPF. If laser-driven fusion power plants become reality, they could create demand far beyond today’s laser market across the supply chain — from gallium-arsenide (GaAs) semiconductor fabs to automated packaging, power electronics, optics, and high-energy laser systems. Whatever the prevailing fusion architecture, demand for diode lasers could vastly exceed the capacity of today’s diode laser industry. According to TRUMPF’s Hagen Zimer, ‘We are talking about millions of bars, potentially 10 million bars for just one power plant.’...

Dig a little deeper and you’ll find a thriving research program with exotic atoms that won’t solve the energy crisis but stretches the boundaries of physics. The post Is There Anything Left in the Dream of Cold Fusion? first appeared on Quanta Magazine

Mysterious particles called neutrinos constantly stream through our bodies, and scientists are now detecting incredibly powerful versions arriving from distant cosmic sources using a massive observatory buried in Antarctic ice. These elusive “ghost particles” could hold extraordinary clues about the Big Bang, extreme cosmic events, and some of the universe’s greatest mysteries.

How atoms are arranged inside materials can influence the behavior of electrons and the resulting electronic states. Kagome lattices, repeating arrangements of atoms forming triangles that share corners (with hexagonal spaces between them), have been linked with the emergence of unusual electronic states.

Blue Laser Fusion, a developer of advanced pulsed laser technology targeting directed energy defense systems and inertial confinement fusion energy, completed its financing transaction and alternative public offering. Financing was executed via a private placement offering yielding total proceeds of $34 million, including an initial closing of $25 million in private placement units. Proceeds from the capital raise will serve to accelerate Blue Laser Fusion’s engineering milestones, operational expansion and technology deployment, according to the company. Concurrent with the transaction, Blue Laser Fusion additionally completed a business combination and reverse merger with Unite Acquisition 2 Corp. In directed energy,...

In a recent Nature Communications study, researchers have reported the realization of an anti-spin ice, a system that does the opposite of conventional spin ices by breaking the ice rule that governs them.

A mysterious particle overlooked for decades may hold the key to why matter survived the Big Bang, allowing stars, planets, and life to exist. Scientists believe this forgotten neutrino reshaped the early universe and may have left detectable gravitational wave signals that could help unlock the cosmos’s deepest mysteries.

According to quantum electrodynamics, the theory describing interactions between light and electrically charged particles, a sufficiently strong electric field can, in principle, convert some of its energy into particles and their antimatter partners. A particle's antimatter partner has the same mass and, for electrically charged particles, the opposite electric charge.

As quantum computers grow more ambitious, many researchers believe the best way forward is to build them in multiple interconnected parts. In these modular designs, separate quantum processors are linked so they can work together as one larger machine. For this to happen, however, connections must carry fragile quantum information without destroying it.

Scientists have recreated a primordial state of matter from the dawn of the universe by colliding oxygen nuclei at nearly the speed of light. The surprising results show that this exotic substance can form in smaller, lower-energy collisions than previously demonstrated, challenging the known boundaries of early-universe physics.

A major production milestone in a global mission to understand one of the Universe’s biggest mysteries — why

A Qubit Built by Chemists Most light-linked qubits come from defects that physicists find inside crystals such as

Author(s): C. A. Argüelles, M. DuVernois, P. W. Graham, T. Kovachy, and J. MitchellAtom interferometers promise access to the decihertz gravitational-wave band, below LIGO’s reach and above LISA’s, where compact binaries radiate for hours to days before merger. This paper makes the case for building a kilometer-scale vertical atom interferometer in the Antarctic ice at the South Pole, where seismic noise is among the lowest on Earth, hot-water drilling and heavy-cargo logistics have already been proven by IceCube, and the southern location completes global source triangulation. Beyond early-warning alerts for multimessenger follow-up, such an instrument would enable precision tests of the equivalence principle and searches for wavelike dark matter. [Phys. Rev. Research 8, 043111] Published Fri Oct 30, 2026

Author(s): Sophia ChenA new device uses millimeter-wave radiation to accurately read the states of superconducting qubits without altering them. [Physics 19, s140] Published Fri Oct 30, 2026

Neutrinos are funny little particles that weigh almost nothing, making them one of the universe's most elusive building blocks. They can come from objects as mundane as bananas and as exotic as supernovas—the exploding death throes of massive stars. Most neutrinos stream through space and pass through the Earth without interacting with anything.

We all know that black holes can collide. It has happened since black holes began to form, early in cosmic time. The result is always a clash that gives off gravitational waves and a giant bang. Since black holes have such strong gravity, it's almost impossible to imagine a way that any force could break one apart. Yet, that's the task that a group of scientists in Europe set for themselves.

Dig a little deeper and you’ll find a thriving research program with exotic atoms that won’t solve the energy crisis but stretches the boundaries of physics. The post Is There More to Cold Fusion Than Failure and Fraud? first appeared on Quanta Magazine

Particle accelerators are expensive. Not just to build or to run, but also to predict the outcome of measurements obtained from them.

Copilot Fusion Arrives Developers on paid Copilot plans used 47 different AI models in September, and no single

In 2016, a binary star system emitting unusually strong gamma rays was discovered in our galactic neighborhood. Now, astronomers have found the smoking gun, or rather, a smoking trail of cool molecular gas that suggests jets emanating from a microquasar—one of the few known outside the Milky Way—are responsible.

In March 2026, NASA's Fermi Gamma-ray Space Telescope detected a GRB with an unusual light signature. Its initial gamma radiation was dim, and the afterglow exhibited unusual, delayed peaks. As it turns out, we were seeing it from a side angle, and the GRB actually packed one billion years of the Sun’s energy output into a thin beam.

Quantum networks could one day connect quantum computers into more powerful systems and enable new forms of secure communication. But a fundamental obstacle stands in the way: Quantum information is extraordinarily fragile, and the entanglement between particles of light on which such networks would depend is easily disrupted.

Before a stick of deodorant reaches a consumer's bathroom counter, it moves through a complex supply chain. Raw materials and packaging components are sourced, assembled into a finished product and shipped through warehouses and distribution centers before finally reaching a store shelf.

Astronomers using the James Webb Space Telescope (JWST) have found evidence that a distant, exceptionally blue galaxy may allow most of its ionizing radiation to escape into space. Known as EBG-1, the gravitationally lensed galaxy is seen at a redshift of 9.244, about 530 million years after the Big Bang. The paper was posted to the arXiv preprint server on Oct. 16.

Graphene, a material consisting of a sheet of carbon atoms arranged in a honeycomb pattern, has proved promising for various technological applications. Materials in which several layers of graphene are stacked together can exhibit different advantageous properties.

Using optogenetics, combined with holographic light patterning, researchers uncovered new information about how the brain drives learned movements and activities like learning to play the piano. Their findings could be used to boost learning, restore memory, and develop brain-computer interfaces that support motor skills. Previous studies show that during the execution of learned motor skills, the neural population in layer 2/3 of the primary motor cortex demonstrates a reproducible, spatiotemporal activity pattern. It is unclear whether the motor cortex actively participates in generating this learned pattern, and whether this pattern drives the learned movement in a cause-and-effect manner. Researchers at the University of...

Intel Corporation has entered into a definitive agreement to acquire Classiq, a provider of quantum computing software. The acquisition of Classiq would combine Intel’s quantum software platform, scalable silicon spin-qubit technology and advanced semiconductor manufacturing expertise with Classiq’s automated quantum algorithm synthesis platform. The combination would enable Intel to become a full-stack quantum solutions provider, while also allowing the company to add quantum processing units to its already diverse compute platform portfolio spanning CPUs, GPUs, and application-specific integrated circuits (ASICs). Intel intends to continue to support Classiq’s existing multi-platform integrations and ensure a modality-...

Albert Einstein called quantum entanglement ‘spooky action at a distance,’ and the nickname has stuck for nearly 80

Star formation is a complicated process. It involves metallicity, gas temperature and density, dust grains, and stellar feedback from existing stars. Sometimes, studying all these factors and how they work means studying some of Nature's most beautiful structures, like the Cat's Head nebula in the Carina Nebula.

The word "vacuum" may conjure the image of empty space. Maybe you think of a region far outside the solar system without planets, debris, gas clouds or light. According to quantum theory, however, a vacuum is never truly empty. Quantum mechanics extends the Heisenberg uncertainty principle—which states that we cannot measure the position and the velocity of an object exactly at the same time—to a vacuum. The result is that a vacuum can never be still.

Scientists at Rutgers and in Estonia have used invisible light to look into tiny magnetic whirlpools, called vortices, inside a superconductor, revealing details that could help researchers develop better materials for carrying electricity.

Soft, flexible hydrogels have enabled significant advancements in engineering biological tissue by mimicking the natural scaffolding that provides structure and support to cells. Existing engineered hydrogels, however, fall short in a significant way. Unlike in nature, they do not have the dynamic ability to change their structure or support depending on what the biological tissue needs. The answer may rest in shining a light on the problem—literally, according to a team led by researchers at Yokohama National University.

Beating the X-Ray Cutoff With Helium High-harmonic generation turned ordinary lasers into sources of attosecond X-ray pulses and

Many chemical processes that sustain modern society depend on molecules binding to metal surfaces. The production of synthetic fertilizer, for example, relies on heterogeneous catalysis, in which gases react on the surface of a solid catalyst. Yet, until now, an important question has remained unresolved: How much of the metal surface actually participates in determining the strength of a chemical bond on the surface?