Hydrogen is the simplest element in the universe and the first entry on the periodic table. Each hydrogen atom contains just one proton in its nucleus and one electron orbiting around it. Because of this simplicity, hydrogen has long served as an important testing ground for studying the fundamental forces and particles that shape the universe.

Yet one seemingly basic property of hydrogen has puzzled physicists for more than a decade: the exact size of its proton. Known as the proton radius puzzle, the debate centered on conflicting measurements of the proton’s radius.

Researchers at Colorado State University (CSU) now report an exceptionally precise measurement that appears to settle the issue. The results, highlighted in Physical Review Letters, strengthen confidence in the Standard Model of particle physics while providing a foundation for future research.

Precision Measurement Confirms Standard Model
Previous experiments produced conflicting answers. Measurements that used electrons suggested one proton radius, while studies using heavier particles indicated a slightly smaller value. The disagreement was comparable to measuring the same house with two reliable tools and getting different dimensions.

The inconsistency raised important questions. It suggested either that earlier experiments contained hidden sources of error or that physicists might need to revise some of the fundamental principles used to describe the universe.

The new CSU measurement places the proton’s radius at about 0.84 femtometers, compared with the previously accepted value of 0.876 femtometers. Although the difference is extremely small, it is significant for precision physics. An independent team at the Max Planck Institute reached a similar conclusion using a different technique, providing additional confidence that the long-running discrepancy has finally been resolved.

While the adjustment to the proton’s size is tiny, its implications are substantial for our understanding of matter and the laws governing the universe...

Why do we decide to approach other people? According to new research, the answer may start unfolding in the brain several seconds before any movement takes place.

A team of scientists from the Hebrew University of Jerusalem has identified a distinctive pattern of brain activity that appears before social interaction begins. Their findings suggest that the brain is already preparing for a social encounter before an individual takes action, and that the strength of this neural activity may reflect how socially motivated someone is.

Tracking Social Decisions in Real Time
To investigate how social decisions are formed, the researchers used zebrafish, a popular model organism that allows scientists to observe activity across the brain at the level of individual cells.

The team created a new experimental system in which one fish watched and responded to another fish that was swimming nearby. While this happened, researchers recorded activity throughout the observing fish’s brain in real time.

This approach allowed them to follow the neural processes involved in social behavior as they unfolded, revealing how the brain transforms social information into action.

A Brain-Wide Signal Before Social Behavior
The researchers discovered that the brain begins shifting into a different state several seconds before a fish moves toward another fish.

Rather than relying on a single region dedicated to social behavior, the process involved coordinated changes across multiple parts of the brain.

Globally, humanity now produces a staggering 450 million tonnes of plastic every year. From food and drink containers to cosmetics packaging, sewage pipes, window frames and polyester clothing, we use plastics in almost every area of life. And nearly one-quarter of them end up in the environment, where they very slowly degrade into microscopic pieces.

These microplastics—particles between 1 micrometer and 5 millimeters wide—have been found in the deepest parts of the oceans, at the top of the tallest mountains, at the sparsely populated poles and even inside the human body.

It is very difficult for living organisms, including humans, to avoid ingesting microplastics. If these microplastics cross the lining of the digestive tract to enter the bloodstream or other tissues, they will persist in the body. Until now, it has been difficult for researchers to accurately assess whether this is happening.

Our research team has developed a new technique to identify the location of microplastics within an organism without dissecting it. We tested it on earthworms and discovered that microplastics ranging in size from 5 to 53 micrometers do not readily cross the lining of the gut to enter other tissues in the worms...

For decades, inflammatory bowel disease (IBD) has been treated as a single disorder, even though patients often experience dramatically different symptoms, disease courses, and responses to therapy. A new study suggests there may be a good reason for that: what doctors call IBD could actually be a collection of distinct diseases driven by different biological mechanisms.

Researchers from the University of Oxford’s Nuffield Department of Medicine, Newcastle University’s Translational and Clinical Research Institute, and the Department of Immunology at Cambridge University Hospitals NHS Foundation Trust have identified a key driver of disease in a subset of patients. Their findings, published in the New England Journal of Medicine, reveal an immune malfunction that not only triggers uncontrolled inflammation but also helps explain one of the strongest genetic risk factors linked to IBD.

The team analyzed more than 4,900 people with Crohn’s disease and ulcerative colitis, the two main forms of IBD. They discovered that some patients develop autoimmune responses against interleukin-10 (IL-10), a crucial molecule that normally acts as one of the body’s primary brakes on inflammation. They also found that this immune attack is closely tied to a genetic variant long associated with severe IBD.

Under normal circumstances, IL-10 helps prevent the immune system from overreacting and damaging healthy tissue. But when antibodies block IL-10, this protective mechanism is disabled, allowing inflammation to persist unchecked and potentially fueling disease.

The world relies on a modest number of countries to keep watch over the ocean. That arrangement is starting to fail. Europe and Asia must now decide whether to let the system unravel, or to take it up together.

Right now, in every ocean basin on Earth, a global network of instruments measures the state of the sea.

Research ships steam along oceanographic transects from surface to seafloor. Anchored buoys watch the tropical oceans for the first signs of El Niño or tropical cyclones and take the pulse of the thermohaline circulation. Some 4,000 autonomous floats sink every 10 days to 2,000 meters before rising to transmit temperature and salinity to ground stations via satellite. Underwater gliders patrol continental margins, and drifting buoys ride the surface in the most remote waters. Hundreds of elephant seals carry miniaturized sensors beneath the polar sea ice...

Together, this network produces invaluable information that allows societies to anticipate and respond to changing ocean and weather conditions, and protect the ocean in return.

It is also far more fragile than most people, and most governments, realize. A new study published in Nature Climate Change has measured for the first time just how fragile the ocean watch network is.

The result is alarming. If observations from a single major contributor, the United States, were withdrawn from the Global Ocean Observing System (GOOS), the errors in our estimate of how fast the ocean is warming would jump by 163%. That is worse than randomly losing 80% of all global ocean data. The reason is geographical: U.S. instruments cover every ocean basin and plug critical gaps that no other nation currently fills.

This is not a theoretical concern. Proposed cuts to National Oceanic and Atmospheric Administration and the National Science Foundation in the United States now threaten exactly this contribution. And the situation is barely better on the other side of the Atlantic.

The pressures are not confined to one side of the Atlantic, nor to the West. In China, scientists and policymakers are working to build a more resilient national contribution to ocean observation, but without the resources the moment requires. The marine monitoring system the world relies on is under strain almost everywhere.

19 years ago today: Space Shuttle Atlantis' main landing gear touches down at Edwards Air Force Base in California concluding a two-week assembly mission to the International Space Station.

Sunita Williams, a flight engineer on the Expedition 15 crew, returned to Earth on STS-117 completing 194 days in space, the longest single spaceflight ever by a female astronaut or cosmonaut to that date. This record is now held by Christina H Koch for her 2019–2020 spaceflight (328 days).

Working with researchers from institutions around the world, Nicholas Hedger (University of Reading) and Tomas Knapen (Netherlands Institute for Neuroscience & Vrije Universiteit Amsterdam) investigated one of neuroscience’s biggest questions: how humans experience the world around them.

Their research uncovered a remarkable process in which the brain converts visual information into touch-related representations, helping create the rich, physical reality we experience every day. According to Knapen, “This aspect of human experience is a fantastic area for AI development.”

Why Seeing Someone Get Hurt Makes You Flinch
Imagine preparing dinner with a friend when they accidentally cut themselves. Almost instantly, you may grimace, wince, or even jerk your own hand away.

Those reactions happen because the brain’s touch-processing region, known as the somatosensory cortex, becomes active even though nothing physically happened to you.

But how can simply watching another person trigger the brain’s sense of touch?

To investigate, researchers from the UK, USA, and VU, NIN (KNAW) in Amsterdam turned to an unexpected source of data: Hollywood movies.

“Quarks are basic building blocks of matter,” said Dr. Paula Collins, incoming deputy spokesperson of the LHCb Collaboration. “There are six types of quarks (up, down, charm, strange, top and bottom), which bond into pairs or triplets, known as mesons and baryons respectively.”

“Sixty years ago, as experiments started to reveal the underlying quark structure of matter, researchers began to build theoretical models to classify how quarks can combine into composite particles.”

“Soon, scientists were able to predict the properties of as-yet-undiscovered particles.”

“Included in these predictions were the doubly charmed baryons.”

“These are particles that each consist of two charm quarks and either an up, a down or a strange quark as the third of the triplet.”

“Physicists are particularly interested in this family of particles as the large mass differences between the quarks could provide useful insight into the strong force, which binds quarks together into composite particles.”

“However, the experiments of the time were neither able to produce the doubly charmed baryons, nor did they have sensitive enough equipment to detect them.”

The LHCb physicists discovered the first of these doubly charmed baryons in 2017 and the second earlier this year.

The discovery of Ωcc⁺, the third and final member of this particle family, is based on data collected in 2024 from high-energy proton-proton collisions at the LHC.

These collisions produced the new doubly charmed baryons, which are short-lived, travelling a fraction of a millimeter in the detector before decaying into more stable particles.

The LHCb team traced the tracks left by these particles in the detector back to their points of origin.This revealed the characteristic signature of the new short-lived particle with a distinct mass around four times heavier than a proton.

“This is a moment of beautiful historical significance,” Dr. Collins said. “Out of the 85 composite particles discovered so far at the LHC, these three doubly charmed baryons are unique.”

“They decay by the weak force and live long enough to give measurable flight distances in our experiment.”

A scientist at the University of Birmingham has created a “mini universe” that could help answer one of science’s most fundamental questions: What is time?

In a study published in Physical Review Research, Professor Giovanni Barontini demonstrates that it is possible to track the passage of time without relying on a clock. The research introduces a model in which a form of time emerges naturally from the behavior of the system being studied.

Some physics theories, including the Wheeler–DeWitt equation, suggest that time is not a fundamental property of the universe. Instead, the universe may exist as a single quantum state that does not change, with particles displaying both wave-like and particle-like behavior. In this view, there is no external clock, and the experience of time arises from relationships between different parts of the system.

It has often been suggested that we now live in a "post-truth" world. People increasingly rely on their own feelings as a yardstick for what is true. Psychologists at the University of Amsterdam (UvA) have now developed the "Youniversalism" scale to allow them to measure people's belief in subjective and experiential truths. The research is published in the journal Personality and Individual Differences.

When emotions and personal beliefs outweigh facts and expertise, it makes it harder to recognize and correct disinformation. "That can have serious consequences," says Bastiaan Rutjens, a psychologist at the UvA and one of the researchers involved. "For example, people could negatively impact their health by following unfounded medical advice, such as we see increasingly on social media."

Researchers call this way of thinking "intuitive epistemology": the idea that you can sense what is true and that everyone's truth is equally valid. "This concept has been described before in the humanities, by Wouter Hanegraaff among others, but until now there was no good way to measure it," says Rutjens.

The new term 'youniversalism'
By combining "you" and "universalism," the new term encompasses the idea that the individual sees themselves as central in constructing and explaining the world around them. The scale has been tested on more than 1,500 people...

Topology is a field of math that focuses on how molding or stretching a shape alters the space it takes up.

In a way, topology is similar to geometry. Both fields study shapes. However, geometry focuses on rigid measurements, such as the length of lines in a triangle. It answers questions like: If I change the length of this line, how will the other lines change? In geometry, the new triangle is considered a different triangle altogether.

But topology does not focus on such rigid measurements. Instead, topology treats the study of shapes like a game. As in a game, a topologist sets out certain rules. Then, they explore what shapes are possible within those rules.

For instance, a rule might be that all the shapes in a certain family can morph into one another without tearing or gluing parts together. You could explore this yourself by squeezing a water balloon. As you watch the balloon warp, you see continuous changes to its shape. Squeezing the middle causes the outsides to bulge. But the balloon doesn’t break or form new connections. So, all the shapes the balloon takes still obey the rule.

A mathematician might say that all the shapes of this balloon belong to the same topological group...

When astronauts explore the Moon, Mars, and other destinations far from Earth in the future, they will need to be as self-sufficient as possible. This is an absolute necessity, given that missions operating beyond Low Earth Orbit (LEO) cannot be resupplied within hours. This essentially means that deep-space exploration and outposts will need to produce enough air, water, food, propellant, and other necessities to see to their needs and keep the mission going.

Typically, this falls under the heading of In-Situ Resource Utilization (ISRU), in which local resources are harvested and used to produce building materials and necessities. Otherwise, astronauts need to bring what they need with them, including plants that remove carbon dioxide, produce oxygen, and even provide a source of plant-based protein. According to new research being conducted at the University of California San Diego (UCSD), bringing plants along on the journey could have the added benefit of producing medicines.

The research was led by engineers with the UCSD Aiiso Yufeng Li Family Department of Chemical and Nano Engineering. They were joined by researchers from the UCSD Center for Nano-ImmunoEngineering, the Shu and K.C. Chien and Peter Farrell Collaboratory, the Institute for Materials Discovery and Design, the Moores Cancer Center, the Center for Engineering in Cancer at the Institute of Engineering in Medicine, and more. The interdisciplinary team's findings were published on June 5th in npj Science of Plants.

In their paper, the team described a simple method for growing and repeatedly harvesting pharmaceuticals from plants in microgravity, without destroying the plants or generating large amounts of waste. For more than a decade, Steinmetz and her colleagues have been studying a plant virus called cowpea mosaic virus (CPMV). This virus is commonly known to infect legumes, but Steinmetz's team was focused on its ability to stimulate the immune system to attack cancer cells.

In 2025, Yonsei University’s Professor Young-Wook Lee and colleagues shocked the space community with claims that the evidence of dark energy was weakening such that the expansion is no longer accelerating.

They suggested the methods used to measure the Universe’s expansion using supernovae were fundamentally flawed.
...
“What we find is that when we calibrate these supernovae, accounting for different host environments and populations, the evidence for cosmic acceleration remains remarkably consistent.”

To measure the Universe, the authors looked closely at Type Ia supernovae to calculate vast cosmic distances.

The 2025 study had claimed that, as the Universe aged, these supernovae had different maximum brightnesses, tricking astronomers into thinking the cosmos was accelerating when it was slowing.

However, the new study found the error lay in how the age of these stars was estimated.

They proved that the previous findings incorrectly assumed the age of a galaxy was the same as the age of the star that exploded.

They also said the 2025 paper failed to account for the mass of host galaxies, a standard correction used in modern cosmology to prove accuracy.

“Challenging accepted theories and observations is fundamental to science,” said University of Southampton’s Professor Mark Sullivan, co-author of the study.

“This is how progress is made. Although this idea did not turn out correct, it has opened up new ways of thinking about how supernovae explode and how we can measure dark energy more accurately.”

Most of the universe is not made of stars, galaxies, or beautiful glowing nebulae. Instead, the majority of it is what seems to be vast, silent emptiness. Huge cosmic voids stretching hundreds of millions of light years across, containing almost nothing at all. But these dark regions are not just empty space. They are dynamic structures that grow, merge, and shape the entire architecture of the universe.

What exactly are cosmic voids and how did they form? What makes them so strange, and what role might they play in the future of the universe?

Prime editing can potentially repair the vast majority of known disease-causing human mutations, but the technology, first developed in 2019, has not yet been widely used in the body, or in vivo, to treat genetic disease. The only clinical application of prime editing that has been publicly announced uses the technology to edit cells outside the body before transplanting them back into the patient.

Now, scientists from the David Liu lab at the Broad Institute have addressed bottlenecks that previously impeded the use of prime editing in animals and human patients. In two studies published last month in Nature Biotechnology and one published today in Nature Nanotechnology, the team described multiple changes to key components of the prime editing system and also optimized prime editing for delivery with lipid nanoparticles, which deliver genetic medicines to tissues in the body and are already used in several approved therapeutics. These advances together increase the efficiency and potency of prime editing and improve its potency when delivered into the body, a key requirement for in vivo prime editing therapeutics.

"Collectively, these three papers improve the overall efficiency and clinical relevance of prime editing, which we hope will make the technique more useful both for research purposes and for therapeutic clinical applications," said Liu, who is also the Richard Merkin Professor and director of the Merkin Institute for Transformative Technologies in Healthcare at Broad, the Dudley Cabot Professor of the Natural Sciences in the Faculty of Arts and Sciences at Harvard University, and a Howard Hughes Medical Institute investigator.