In the consumer electronics playbook, custom silicon is the final step in the marathon: you use off-the-shelf components to prove a product, achieve mass scale and only then invest in proprietary chips to create differentiation, improve operations, and optimize margins. In the modern satellite communications (SATCOM) ecosystem, this script has been flipped. For the industry’s […]

The post Silicon as strategy: the hidden battleground of the new space race appeared first on SpaceNews.

A Senate committee has delayed consideration of a bill intended to expedite Federal Communications Commission reviews of satellite license applications amid concerns that the proposal may be too permissive.

The post Senate committee delays consideration of bill to streamline FCC satellite licensing appeared first on SpaceNews.

After helping place proliferated LEO constellations at the center of U.S. military space planning, the SmallSat Alliance is now tackling how these networks can be used together as a unified system.

The post SmallSat Alliance shifts focus from proliferation to coordination appeared first on SpaceNews.

Gen. Shawn Bratton, the Space Force’s vice chief of space operations, spoke with SpaceNews’ Sandra Erwin as part of an event focused on the Space Force 2040 at the Johns Hopkins University Bloomberg Center on Jan. 21. Here are six takeaways from their conversation: Planning for 2040 means more space superiority A long-range planning initiative […]

The post As satellites become targets, Space Force plans a broader role appeared first on SpaceNews.

A growing legion of “zero trimester” influencers are convincing followers that healthy pregnancies are a choice—and that raw milk, watching sunsets, and pricey specialized courses can help.

Quantum entanglement is a uniquely quantum link between particles that makes their properties inseparable. It underlies the power of many quantum technologies from secure communication to quantum computing, by enabling correlations impossible in classical physics.

Entanglement nevertheless remains poorly understood and is therefore the subject of a lot of research, both in the fields of quantum technologies as well as fundamental physics.

In this context, the idea of separability refers to a composite system that can be written as a simple product (or mixture of products) of the states of its individual parts. This implies there is no entanglement between them and to create entanglement, a global transformation is needed.

A system that remains completely free of entanglement, even after any possible global invertible transformation is applied, is called absolutely separable.  In other words, it can never become entangled under the action of quantum gates.

Necessary and sufficient conditions to ensure separability exist only in the simplest cases or for highly restricted families of states. In fact, entanglement verification and quantification is known to be generically an NP-hard problem.

Recent research published by a team of researchers from Spain and Poland has tackled this problem head-on. By introducing new analytical tools such as linear maps and their inverses, they were able to identify when a quantum state is guaranteed to be absolutely separable.

These tools work in any number of dimensions and allow the authors to pinpoint specific states that are on the border of being absolutely separable or not (mathematically speaking, ones that lie on the boundary of the set). They also show how different criteria for absolute separability, which may not always agree with each other, can be combined and refined using convex geometry optimisation.

Being able to more easily and accurately determine whether a quantum state is absolutely separable will be invaluable in quantum computation and communication.

The team’s results for multipartite systems (systems with more than two parts) also reveal how little we currently understand about the entanglement properties of mixed, noisy states. This knowledge gap suggests that much more research is needed in this area.

The post Quantum states that won’t entangle appeared first on Physics World.

When we interact with everyday objects, we take for granted that physical systems naturally settle into stable, predictable states. A cup of coffee cools down. A playground swing slows down after being pushed.  Quantum systems, however, behave very differently.

These systems can exist in multiple states at once, and their evolution is governed by probabilities rather than certainties. Nevertheless, even these strange systems do eventually relax and settle down, losing information about their earlier state. The speed at which this happens is called the relaxation rate.

Relaxation rates tell us how fast a quantum system forgets its past, how quickly it thermalises, reaches equilibrium, decoheres, or dissipates energy. These rates are important not just for theorists but also for experimentalists, who can measure them directly in the lab.

Recently, researchers discovered that these rates obey a surprisingly universal rule. For a broad class of quantum processes (those described by what physicists call Markovian semigroups) the fastest possible relaxation rate cannot exceed a certain limit. Specifically, it must be no larger than the sum of all relaxation rates divided by the system’s dimension. This constraint, originally a conjecture, was first proven using tools from classical mathematics known as Lyapunov theory.

In a new paper published recently, an international team of researchers provided a new, more direct algebraic proof of this universal bound. There are a number of advantages of the new proof compared to the older one, and it can be generalised more easily, but that’s not all.

The very surprising outcome of their work is that the rule doesn’t require complete positivity. Instead, a weaker condition – two‑positivity is enough. The distinction between these two requirements is crucial.

Essentially, both are measures of how well-behaved a quantum system is, how it is protected from providing nonsensical results. The difference is that two-positivity is slightly less stringent but far more general, and hence very useful for many real-world applications.

The fact that the new proof only requires two-positivity means that it this new universal relaxation rate can actually be applied to a lot more scenarios.

What’s more, even when weakened even further, a slightly softer version of the universal constraint still holds. This shows that the structure behind these bounds is richer and more subtle than previously understood.

The post The secret limits governing quantum relaxation appeared first on Physics World.

Loss of a limb can significantly impact a person’s independence and quality-of-life, with arm amputations particularly impeding routine daily activities. Prosthetic limbs can restore some of the lost function, but often rely on surface electrodes with low signal quality. A research team at the University of Michigan has now shown that implanted electrodes could provide more accurate and reliable control of hand and wrist prostheses.

Today, most upper-limb prostheses are controlled using surface electrodes placed on the skin to detect electrical activity from underlying muscles. The recorded electromyography (EMG) signals are then used to classify different finger and wrist movements. Under real-world conditions, however, these signals can be impaired by inconsistent electrode positioning, changes in limb volume, exposure to sweat and artefacts from user movements.

Implanted electrodes, tiny contacts that are surgically sutured into muscles, could do a better job. By targeting muscles deeper in the arm, they offer higher signal-to-noise ratios and less susceptibility to daily variations. And although amputation can eliminate many of the muscles that control hand functions, techniques such as regenerative peripheral nerve interface (RPNI) surgery – in which muscle tissue is grafted to nerves in the residual limb – enable electrodes to target missing muscles and record relevant signals for prosthetic control.

Senior author Cynthia Chestek points out that such RPNI grafts are also beneficial for the nerve itself. “They provide a target for nerve endings that prevent the formation of painful neuromas, and that may in turn help reduce phantom limb pain,” she explains “In future, it would also be possible to place electrodes and a wireless transmitter during that same surgery, such that no additional surgeries are required other than the original amputation.”

In their latest work, reported in the Journal of Neural Engineering, Chestek and colleagues investigated whether implanted electrodes could provide stable and high-quality signals for  controlling prosthetic hand and wrist function.

Performance comparisons

The study involved two individuals with forearm amputations and EMG electrodes implanted into RPNIs and muscles in their residual limb. The subjects performed various experiments, during which the team recorded EMG signals from the implanted electrodes plus dry-domed and gelled (used to improve contact with the skin) surface electrodes.

In one experiment, participants were tasked with controlling a virtual hand and wrist in real time by mimicking movements (various grips) on a screen. The researchers used the recorded EMG signals to train linear discriminant analysis classifiers to distinguish the cued grips, training separate classifiers for each electrode type.

They then evaluated the performance of these grip classifiers during a posture classification experiment, in which the subjects actively controlled hand or wrist movements of a virtual hand. Participants achieved faster, more accurate and more reliable control using the implanted electrodes than the surface electrodes.

With participants sitting and keeping their arm still, the implanted electrodes achieved average per-bin accuracies (the percentage of correctly classified time bins) of 82.1% and 91.2% for subjects 1 and 2, respectively. The surface electrodes performed worse, with accuracies of 77.1% and 81.3% for gelled electrodes, and 58.2% and 67.1% for dry-domed electrodes, for subjects 1 and 2, respectively.

The researchers repeated this experiment with the subjects standing and moving their arm to mimic daily activities. Adding movement reduced the classification accuracy in all cases, but affected the implanted electrodes to a far smaller degree. The control success rate (the ability to hold a grip for at least 1 s, within 3 s of seeing a movement cue) also diminished between still and moving conditions, but again, the implanted electrodes experienced smaller decreases.

Overall, the performance of online classifiers using implanted electrodes was only slightly affected by arm movements, while classifiers trained on surface electrodes became unstable. Investigating the reasons underlying this difference revealed that implanted electrodes exhibited higher EMG signal amplitudes, lower cross-correlation between channels, and smaller signal deviations between still and moving conditions.

The Coffee Task

To examine a real-world scenario, subject 1 completed the “Coffee Task”, which involves performing the various grips and movements required to: place a cup into a coffee machine; place a coffee pod into the machine; push the start button; move the filled cup onto a table; and open a sugar packet and pour it into the cup.

The subject performed the task using an iLimb Quantum myoelectric prosthetic hand controlled by either implanted or dry surface electrodes, with and without control of wrist rotation. The participant performed the task faster using implanted electrodes, successfully completing the task on all three attempts. For surface-based control, they reached the maximum time limit of 150 s in two out of three attempts.

Although gelled electrodes are the gold standard for surface EMG, they cannot be used whilst wearing a standard prosthetic socket. “With the Coffee Task, use of the physical prosthetic  hand is needed, so this was only performed with dry-domed surface electrodes and implanted electrodes,” explains first author Dylan Wallace.

The researchers also assessed whether simultaneous wrist and hand control can reduce compensatory body movements (measured using reflective markers on the subject’s torso), compared with hand control alone. Without wrist rotation, the subject had to lean their entire upper body to complete the pouring task. With wrist rotation enabled, this lean was greatly reduced.

This finding emphasizes how wrist control provides significant functional benefit for prosthesis users during daily activities. Chestek notes that in a previous study where participants wore a prosthesis without an active wrist, “almost everything we asked them to do required large body movements”.

“Fortunately, the implantable electrodes provide highly specific and high-amplitude signals, such that we were able to add that wrist movement without losing the ability to classify multiple different grasps,” she explains. “The next step would be to pursue continuous, rather than discrete, movement for all of the individual joints of the hand –  though that will not happen quickly.”

The post Implanted electrodes provide intuitive control of prosthetic hand appeared first on Physics World.

Experts worry Robert F. Kennedy Jr.’s Health Department will use an internal AI tool to analyze vaccine injury claims in a way that furthers his anti-vaccine agenda.

NASA officials defended their preparations for the Artemis 2 mission after a fueling test experienced the same type of hydrogen leaks that bedeviled Artemis 1 more than three years ago.

The post NASA examining hydrogen leaks during Artemis 2 fueling test appeared first on SpaceNews.

Ditching ghrelin genes may have helped a wide variety of reptiles deal with a boom-or-bust feeding schedule

Lawmakers on both sides of the aisle decry disruptions to biomedical research under Jay Bhattacharya

Shed from the surfaces of astrocytes, “zombosomes” flit between cells, carrying proteins linked to disease

Learn how looking in Archaeopteryx’s fossilized mouth uncovered weird features unique to birds, supporting their ability to fly.

Learn how nitrogen isotope tests made meat-eating cats appear plant-based, and what their protein metabolism reveals about interpreting animal diets.

Learn about the continent-sized rocks hidden deep within Earth's mantle that have influenced the magnetic field for millions of years. 

Learn more about the rare instances when seismic and magma activity overlap in Yellowstone National Park. 

Recent winter storm traced the path of an emerging ice corridor

Learn more about how whales communicate and how researchers are working to find out if humans and whales could one day communicate with each other. 

Learn more about the Artemis II launch delay, what concluded the fuel test, and how NASA plans to move forward with its next crewed Moon mission.

In space procurement, there are few phrases that carry more weight than “flight heritage.” Once a supplier claims it, the rest of the room can relax. The hardware has flown, goes the thinking. It worked. The risk of using such hardware is vanishingly small, even absent. This is understandable. Space is famously unforgiving, and if […]

The post Flight heritage? It isn’t what you think appeared first on SpaceNews.

Astronomers have created the most detailed map to date of the vast structures of dark matter that appear to permeate the universe. Using the James Webb Space Telescope (JWST), the team, led by Diana Scognamiglio at NASA’s Jet Propulsion Laboratory, used gravitational lensing to map the dark matter filaments and clusters with unprecedented resolution. As a result, physicists have new and robust data to test theories of dark matter.

Dark matter is a hypothetical substance that appears to account for about 85% of the mass in universe – yet it has never been observed directly. Dark matter is invoked by physicists to explain the dynamics and evolution of large scale structures in the universe. This includes the gravitational formation of galaxy clusters and the cosmic filaments connecting them over 100-million-light–year distances.

Light from very distant objects beyond these structures is deflected by the gravitational tug of dark matter within the clusters and filaments. This can be observed on Earth as the gravitational lensing of these distant objects. This distorts images of the distant objects and affects their observed brightness. These effects can be used to determine the dark-matter content of the clusters and filaments.

In 2007, the Cosmic Evolution Survey (COSMOS) used the Hubble Space Telescope to create a map of cosmic filaments in an area of the sky about nine times larger than that occupied by the Moon.

“The COSMOS field was published by Richard Massey and my advisor, Jason Rhodes,” Scognamiglio recounts. “It has a special place in the history of dark-matter mapping, with the first wide-area map of space-based weak lensing mass.”

However, Hubble’s limited resolution meant that many smaller-scale features remained invisible in COSMOS. In a new survey called COSMOS-Web, Scognamiglio’s team harnessed the vastly improved imaging capabilities of the JWST, which offers over twice the resolution of its predecessor.

Sharp and sensitive

“We used JWST’s exceptional sharpness and sensitivity to measure the shapes of many more faint, distant galaxies in the COSMOS-Web field – the central part of the original COSMOS field,” Scognamiglio describes. “This allowed us to push weak gravitational lensing into a new regime, producing a much sharper and more detailed mass map over a contiguous area.”

With these improvements, the team could measure the shapes of 129 galaxies per square arcminute in area of sky the size of 2.5 full moons. With thorough mathematical analysis, they could then identify which of these galaxies had been distorted by dark-matter lensing.

“The map revealed fine structure in the cosmic web, including filaments and mass concentrations that were not visible in previous space-based maps,” Scognamiglio says.

Peak star formation

The map allowed the team to identify lensing structures out to distances of roughly 5 billion light–years, corresponding to the universe’s peak era of star formation. Beyond this point, galaxies became too sparse and dim for their shapes to be measured reliably, placing a new limit on the COSMOS-Web map’s resolution.

With this unprecedented resolution, the team could also identify features as small as the dark matter halos encircling small clusters of galaxies, which were invisible in the original COSMOS survey. The astronomers hope their result will set a new, higher-resolution benchmark for future studies using JWST’s observations to probe the elusive nature of dark matter, and its intrinsic connection with the formation and evolution of the universe’s largest structures.

“It also sets the stage for current and future missions like ESA’s Euclid and NASA’s Nancy Grace Roman Space Telescope, which will extend similar dark matter mapping techniques to much larger areas of the sky,” Scognamiglio says.

The observations are described in Nature Astronomy.

The post New cosmic map will put dark-matter theories to the test appeared first on Physics World.

Some 20 papers from researchers based in North America have been recognized with a Top Cited Paper award for 2025 from IOP Publishing, which publishes Physics World.

The prize is given to corresponding authors who have papers published in both IOP Publishing and its partners’ journals from 2022 to 2024 that are in the top 1% of the most cited papers.

Meanwhile, 29 papers from India have been recognized with a Top Cited Paper award for 2025.

Below, some of the winners of the 2025 top-cited paper award from India and North America outline their tips for early-career researchers who are looking to boost the impact of their work.

Answers have been edited for clarity and brevity.

Shikhar Mittal from Tata Institute of Fundamental Research in Mumbai: Early-career researchers, especially PhD students, often underestimate the importance of presentation and visibility when it comes to their work. While doing high-quality research is, of course, essential, it is equally important to write your paper clearly and professionally. Even the tiniest of details, such as consistent scientific notation, clean figures, correct punctuation and avoiding typos can make a big difference. A paper full of careless errors may not be taken seriously, even if it contains strong scientific results.

Another crucial aspect is visibility. It is important to actively advertise your research by presenting your work at conferences and reaching out to researchers who are working on related topics. If someone misses citing your relevant work, a polite message can often lead to recognition and even collaboration. Being proactive in how you communicate and share your research can significantly improve its impact.

Sandip Mondal from the Indian Institute of Technology Bombay: Don’t try to solve everything at once. Pick a focused, well-motivated question and go deep into it. It’s tempting to jump on “hot topics”, but the work that lasts – and gets cited – is methodologically sound, reproducible and well-characterized. Even incremental advances, if rigorously done, can be very impactful.

Another tip is to work with people who bring complementary skills — whether in theory, device fabrication or characterization. Collaboration isn’t just about co-authors; it’s about deepening the quality of your work. And once your paper is published, your job isn’t done. Promote it as visibility breeds engagement, which leads to impact.

Sarika Jalan from the Indian Institute of Technology Indore: Try to go in-depth into the problem you are working on. Publications alone cannot give visibility, its understanding and creativity that will matter in the long run.

Marcia Rieke from the University of Arizona: Write clearly and concisely. I would also suggest being careful with your choice of journal – high-impact-factor journals can be great but may lead to protracted refereeing while other journals are very reputable and sometimes have faster publication rates.

Dan Scolnic from Duke University: At some point there needs to be a transition from thinking about “number of papers” to “number of citations” instead. Graduate students typically talk about writing as many papers as possible – that’s the metric. But at some point scientists start getting judged on the impact of their papers, which is most easily understood with citations. I’m not saying one should e-mail anyone with a paper to cite them, but rather, to think about what one wants to put time in to work on. One should say “I’d like to work on this because I think it can have a big impact”.

P Veeresha from CHRIST University in Bangalore: Build a strong foundation in the fundamentals and always think critically about what society truly needs. Also focus on how your research can be different, novel, and practically useful. It’s important to present your work in a simple and clear way so that it connects with both the academic community and real-world applications.

Parasuraman Swaminathan from the Indian Institute of Technology Madras: Thorough research is critical for good quality research, be bold and try to push the boundaries of your chosen topic.

Arnab Pal from the Institute of Mathematical Sciences in Chennai: Focus on asking meaningful, well-motivated questions rather than just solving technically difficult problems. Write clearly and communicate your ideas with simplicity and purpose. Engage with the research community early through talks, preprints and collaborations. Above all, be patient and consistent; impactful work often takes time to be recognized.

Steven Finkelstein from the University of Texas at Austin: Work on topics that both you think are interesting, and that others find interesting, and above all work with people who you trust.

The post Top-cited authors from India and North America share their tips for early-career researchers appeared first on Physics World.

Learn about the latest model of Jupiter's deep atmosphere that reveals how much oxygen the planet contains.