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JWST may have found the Universe’s first stars powered by dark matter

New observations from the James Webb Space Telescope hint that the universe’s first stars might not have been ordinary fusion-powered suns, but enormous “supermassive dark stars” powered by dark matter annihilation. These colossal, luminous hydrogen-and-helium spheres may explain both the existence of unexpectedly bright early galaxies and the origin of the first supermassive black holes.

In the early universe, a few hundred million years after the Big Bang, the first stars emerged from vast, untouched clouds of hydrogen and helium. Recent observations from the James Webb Space Telescope (JWST) suggest that some of these early stars may have been unlike the familiar (nuclear fusion-powered) stars that astronomers have studied for centuries. A new study led by Cosmin Ilie of Colgate University, together with Shafaat Mahmud (Colgate ’26), Jillian Paulin (Colgate ’23) at the University of Pennsylvania, and Katherine Freese at The University of Texas at Austin, has identified four extremely distant objects whose appearance and spectral signatures match what scientists expect from supermassive dark stars.

“Supermassive dark stars are extremely bright, giant, yet puffy clouds made primarily out of hydrogen and helium, which are supported against gravitational collapse by the minute amounts of self-annihilating dark matter inside them,” Ilie said. Supermassive dark stars and their black hole remnants could be key to solving two recent astronomical puzzles: i. the larger than expected extremely bright, yet compact, very distant galaxies observed with JWST, and ii. the origin of the supermassive black holes powering the most distant quasars observed.

Amazon reveals 960 megawatt nuclear power plans to cope with AI demand — Richland, Washington site tapped for deployment of Xe-100 small modular reactors

The Cascade Advanced Energy Facility would use next-gen Xe-100 reactors to deliver 960 megawatts of carbon-free power — but it’s years from becoming reality.

China achieves important breakthrough in creating ‘shield’ for fusion reactor

Prototype component of the divertor of China’s Comprehensive Research Facility for Fusion Technology (CRAFT) Photo: Xinhua.

China has achieved an important breakthrough in the development of its next-generation “artificial sun” with the prototype component of the divertor of China’s Comprehensive Research Facility for Fusion Technology (CRAFT), passing expert evaluation and acceptance procedures on Monday, Xinhua News Agency reported.

The CRAFT is a platform on which engineers develop and test key components of fusion energy reactors.

Japan’s nuclear reactor robot inspector boosts power plant safety

Mitsubishi says that the robot has been developed to carry out non-destructive inspections of nuclear reactor vessels in underwater environments.

It states that the robot has been working at pressurized water reactor power plants across Japan since 1995, and has been used at least 50 times.

The robot can be controlled remotely using a computer and joystick by operators. The robot navigates around the hazardous environment, swimming in the water inside the nuclear reactor vessel, sticking to the walls with vacuum-pad feet, and using a probe to carry out ultrasonic testing.

Researchers discover a hidden atomic order that persists in metals even after extreme processing

For decades, it’s been known that subtle chemical patterns exist in metal alloys, but researchers thought they were too minor to matter—or that they got erased during manufacturing. However, recent studies have shown that in laboratory settings, these patterns can change a metal’s properties, including its mechanical strength, durability, heat capacity, radiation tolerance, and more.

Now, researchers at MIT have found that these chemical patterns also exist in conventionally manufactured metals. The surprising finding revealed a new physical phenomenon that explains the persistent patterns.

In a paper published in Nature Communications today, the researchers describe how they tracked the patterns and discovered the physics that explains them. The authors also developed a simple model to predict chemical patterns in metals, and they show how engineers could use the model to tune the effect of such patterns on metallic properties, for use in aerospace, semiconductors, nuclear reactors, and more.

Plasma rampdown prediction model could improve reliability of fusion power plants

Tokamaks are machines that are meant to hold and harness the power of the sun. These fusion machines use powerful magnets to contain a plasma hotter than the sun’s core and push the plasma’s atoms to fuse and release energy. If tokamaks can operate safely and efficiently, the machines could one day provide clean and limitless fusion energy.

Today, there are a number of experimental tokamaks in operation around the world, with more underway. Most are small-scale research machines built to investigate how the devices can spin up and harness its energy.

One of the challenges that tokamaks face is how to safely and reliably turn off a plasma current that is circulating at speeds of up to 100 kilometers per second, at temperatures of over 100 million degrees Celsius.

2025 Nobel Prize in Physics Peer Review

Introduction.

Grounded in the scientific method, it critically examines the work’s methodology, empirical validity, broader implications, and opportunities for advancement, aiming to foster deeper understanding and iterative progress in quantum technologies. ## Executive Summary.

This work, based on experiments conducted in 1984–1985, addresses a fundamental question in quantum physics: the scale at which quantum effects persist in macroscopic systems.

By engineering a Josephson junction-based circuit where billions of Cooper pairs behave collectively as a single quantum entity, the laureates provided empirical evidence that quantum phenomena like tunneling through energy barriers and discrete energy levels can manifest in human-scale devices.

This breakthrough bridges microscopic quantum mechanics with macroscopic engineering, laying foundational groundwork for advancements in quantum technologies such as quantum computing, cryptography, and sensors.

Overall strengths include rigorous experimental validation and profound implications for quantum information science, though gaps exist in scalability to room-temperature applications and full mitigation of environmental decoherence.

Framed within the broader context, this award highlights the enduring evolution of quantum mechanics from theoretical curiosity to practical innovation, building on prior Nobel-recognized discoveries like the Josephson effect (1973) and superconductivity mechanisms (1972).

Virtual particles: How physicists’ clever bookkeeping trick could underlie reality

A clever mathematical tool known as virtual particles unlocks the strange and mysterious inner workings of subatomic particles. What happens to these particles within atoms would stay unexplained without this tool. The calculations using virtual particles predict the bizarre behavior of subatomic particles with such uncanny accuracy that some scientists think “they must really exist.”

Virtual particles are not real—it says so right in their name—but if you want to understand how real particles interact with each other, they are unavoidable. They are essential tools to describe three of the forces found in nature: electromagnetism, and the strong and weak nuclear forces.

Real particles are lumps of energy that can be “seen” or detected by appropriate instruments; this feature is what makes them observable, or real. Virtual particles, on the other hand, are a sophisticated mathematical tool and cannot be seen. Physicist Richard Feynman invented them to describe the interactions between real particles.

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