Articles tagged with "astrophysics"
Real Dyson spheres? How alien megastructures might survive in space
A recent study by Professor Colin McInnes at the University of Glasgow explores the feasibility and stability of hypothetical megastructures known as Dyson spheres, which advanced alien civilizations might build to harvest energy from their stars. Dyson spheres, first proposed by Freeman Dyson in 1960, include various concepts such as stellar engines—large reflective disks that harness a star’s power to generate thrust—and Dyson bubbles, swarms of small energy-harvesting spacecraft surrounding a star. A major challenge for these structures is maintaining gravitational stability, as larger megastructures tend to be inherently unstable. McInnes developed mathematical models treating Dyson spheres as extended objects influenced by realistic gravitational and radiation-pressure forces. His findings suggest that stellar engines could achieve passive stability if their mass is concentrated in an outer supporting ring rather than uniformly distributed. Similarly, Dyson bubbles could remain stable if composed of a sufficiently large number of low-mass reflectors arranged densely enough to avoid gravitational instabilities. This research not only advances theoretical understanding of such
energyDyson-spherestellar-enginesspace-megastructuresenergy-harvestinggravitational-stabilityastrophysicsHandheld device democratizes study of cosmic particles from supernovae
University of Delaware physics professor Spencer Axani has developed CosmicWatch, a handheld, low-cost muon detector designed to democratize the study of high-energy cosmic particles produced by phenomena like supernovae and gamma-ray bursts. CosmicWatch detects muons—secondary particles created when cosmic rays collide with atoms in Earth’s atmosphere—and costs approximately $100 to build, making it accessible to both research institutions and high school students. The device, roughly the size of a small box, lights up and records data each time a muon passes through, enabling affordable and portable physics experiments that were previously limited to large, expensive equipment. Originally created as an educational tool during Axani’s graduate work at MIT, CosmicWatch has evolved into a valuable instrument for international astrophysics research and outreach. The latest third version, detailed in the Journal of Instrumentation, offers faster data collection, environmental monitoring, and radiation resistance. It is also being adapted for use aboard rockets and spacecraft to measure primary cosmic rays. With thousands of units
IoTparticle-detectorcosmic-raysmuonseducational-technologyportable-deviceastrophysicsDark energy could lead to a 'Big Crunch' end for our universe: Study
A new study from Yonsei University in South Korea challenges the long-held belief that the universe’s expansion is accelerating due to a constant dark energy force. By analyzing 300 host galaxies of Type Ia supernovae—previously considered “standard candles” for measuring cosmic distances—the researchers discovered that the intrinsic brightness of these supernovae varies with the age of their progenitor stars. Older stellar populations produce brighter explosions, while younger ones appear fainter, meaning that the observed dimming of distant supernovae may be partly due to stellar age rather than accelerated expansion. This finding calls into question the assumption that dark energy is a constant force driving eternal cosmic acceleration. After correcting for this age-related bias, the study finds evidence that the universe’s expansion is actually decelerating, suggesting that dark energy weakens over time rather than remaining steady. This conclusion aligns with independent measurements from the Cosmic Microwave Background and Baryonic Acoustic Oscillations, which also hint at a fading dark energy effect. If confirmed
energydark-energycosmologyuniverse-expansionBig-CrunchsupernovaeastrophysicsStudy spots fluffy ice grains that float and swirl inside cold plasma
Researchers at Caltech have recreated the extreme conditions found in deep space—combining icy dust, electrified gas, and freezing temperatures—to study the behavior of ice grains within cold plasma. Inside their cryogenic plasma chamber, they observed tiny ice grains spontaneously forming delicate, snowflake-like fractal structures. These grains became negatively charged as electrons accumulated on their fluffy surfaces, resulting in a high charge-to-mass ratio that caused electrical forces to dominate over gravity. Consequently, the grains did not settle but instead floated, spun, and swirled in complex vortices within the plasma, exhibiting unpredictable motion even as they grew much larger and fluffier. The negatively charged grains repelled each other and drifted through the neutral gas like feathers in the wind, influenced by inward-pointing electric fields that trapped them inside the plasma. This behavior has significant implications for understanding dusty plasma environments in astrophysics, such as Saturn’s rings, star-forming molecular clouds, and protoplanetary disks, where charged
materialsplasma-physicscharged-dustcryogenic-plasmafractal-structuresastrophysicselectric-fieldsCosmic 'big crunch' may end universe in 20 billion years: Physicist
Cornell physicist Henry Tye has proposed that the universe, currently 13.8 billion years old and expanding, may not continue expanding indefinitely as previously thought. Using new data from dark energy observatories—the Dark Energy Survey (DES) in Chile and the Dark Energy Spectroscopic Instrument (DESI) in Arizona—Tye updated cosmological models involving the cosmological constant, a concept introduced by Einstein. Contrary to the long-held belief that the cosmological constant is positive, implying eternal expansion, the new observations suggest it is negative. This would cause the universe to stop expanding, reach a maximum size in about 11 billion years, and then begin contracting, ultimately collapsing in a "big crunch" approximately 20 billion years from now. Tye and his collaborators introduced a model involving a hypothetical low-mass particle that behaved like a cosmological constant in the early universe but has changed behavior over time, aligning well with the latest data. This model not only supports the idea of a negative cosm
energydark-energycosmological-constantuniverse-expansionastrophysicsdark-energy-observatoriescosmologyWorld’s fastest supercomputer shows how black holes shape galaxies
Scientists have utilized Frontier, the world’s fastest supercomputer located at Oak Ridge National Laboratory, to simulate how supermassive black holes influence the stability and evolution of galaxy clusters over billions of years. By modeling a black hole with a billion solar masses at the center of a galaxy cluster weighing a quadrillion Suns, researchers tracked the activity of black hole jets and their impact on the surrounding environment. These jets, which move at speeds up to 5% of the speed of light in the simulation, inject heat, dust, and gas into the cluster, regulating energy and preventing the collapse of these massive cosmic structures. The simulation required immense computational resources, including 700,000 node hours and over 17,000 GPUs, highlighting the unique capability of Frontier to handle such large-scale astrophysical problems. The study revealed new insights into the formation of gas filaments around galaxy clusters, phenomena previously observed but never successfully reproduced in simulations. These filaments arise from the turbulence created by interactions between cold gases, hot
energysupercomputerblack-holesastrophysicsgalaxy-clusterssimulationcomputational-scienceFirst proof links plasma ripples to fusion and universe origins
Researchers at Seoul National University have experimentally confirmed for the first time the phenomenon of multiscale coupling in plasma, demonstrating how microscopic magnetic ripples can trigger large-scale structural changes. Led by Professor Hwang Yong-Seok, the team integrated fusion experiments with cosmic plasma theory to show that tiny magnetic turbulence initiates magnetic reconnection—a process where magnetic energy rapidly converts into heat and motion—resulting in a cascade of effects that reorganize plasma on a macroscopic scale. This breakthrough provides the first direct experimental evidence supporting theoretical models that small-scale disturbances can influence larger plasma dynamics. The study involved injecting a strong electron beam into plasma confined within a fusion device, inducing localized turbulence and increased plasma resistivity, which then triggered magnetic reconnection. High-resolution particle simulations performed on the KAIROS supercomputer closely matched the experimental results, reinforcing the discovery. This finding is significant for both fusion energy development and astrophysics, as it sheds light on fundamental plasma processes that power stars and cosmic events like solar flares and
fusion-energyplasma-physicsmagnetic-reconnectionmultiscale-couplingnuclear-fusionastrophysicsplasma-turbulenceWhen stars die, black holes possibly turn their remains into dark energy
A recent study using data from the Dark Energy Spectroscopic Instrument (DESI) challenges the long-held belief that dark energy—the force driving the accelerated expansion of the universe—is constant. By mapping millions of galaxies over three years, DESI’s observations suggest that dark energy’s influence has changed over cosmic time. The researchers propose the cosmologically coupled black hole (CCBH) hypothesis, which posits that black holes formed from the collapse of massive stars convert some ordinary matter into dark energy. This model predicts that dark energy density should correlate with the star formation rate, a relationship that DESI’s data supports. Beyond explaining the evolving nature of dark energy, the CCBH model also addresses other cosmological puzzles. It provides a physically consistent estimate for neutrino masses, aligning with ground-based experiments, unlike previous interpretations that yielded unphysical results. Additionally, the model helps reconcile discrepancies in measurements of the universe’s expansion rate (the Hubble tension) by suggesting that the conversion of matter into dark energy accelerated
robotdark-energyblack-holesastrophysicscosmologyDESI-telescopespace-explorationThe Mysterious Origins of the Most Energetic Neutrino Ever Detected
In February 2023, a deep-sea cosmic particle detector in the Mediterranean recorded an extraordinarily energetic neutrino, designated KM3-230213A, with an estimated energy of 220 petaelectronvolts (PeV). This energy level is 20 to 30 times greater than any neutrino previously documented, surpassing the former record of 10 PeV. Neutrinos are fundamental, chargeless particles with very small mass that rarely interact with matter, earning them the nickname “ghost particles.” The detection of such an ultra-energetic neutrino sparked excitement and debate among physicists, who considered whether the event represented a novel cosmic phenomenon or a measurement error. Subsequent analysis published in Physical Review X confirmed that the neutrino was not a statistical anomaly. Despite confirming the neutrino’s authenticity, scientists remain uncertain about its exact origin. The data available do not allow firm conclusions about whether KM3-230213A signals a new ultra-high-energy component in the neutrino
energyneutrinocosmic-particlesparticle-physicshigh-energy-physicsastrophysicscosmic-raysCosmic glow 10 billion light-years away reveals high-energy activity
Scientists have detected a giant cloud of high-energy particles, known as a mini-halo, surrounding a distant galaxy cluster located 10 billion light-years away. This discovery, made using the Low Frequency Array (LOFAR)—a powerful radio telescope with 100,000 antennas across Europe—marks the most distant observation of such a structure. The mini-halo emits faint radio waves across a million light-years, indicating that energetic particle activity was already prevalent in the universe when it was less than a third of its current age. This challenges previous assumptions that such high-energy processes occurred only later in cosmic history. The origin of these particles is still under investigation, but researchers propose two main sources: jets of high-energy particles emitted by supermassive black holes at the centers of cluster galaxies, or collisions among particles within the hot gas permeating the cluster. Both mechanisms suggest that energetic particles have influenced galaxy cluster evolution for billions of years longer than previously thought. This finding provides new insights into the role of black
energyhigh-energy-particlesgalaxy-clusterradio-signalscosmic-evolutionLOFAR-telescopeastrophysics