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Giant Craters May Reveal if Psyche is a Lost Planetary Core When we think of asteroids, we almost immediately think of giant rocks bouncing around like the iconic chase scene in Empire Strikes Back, and we often hear how they are remnants from the birth of the solar system. While the asteroids that comprise the Main Asteroid Belt of our solar system are not only spread far apart from each other, they are also not all made of rock. One asteroid approximately the size of the State of Massachusetts called 16 Psyche is made of metal, which planetary scientists hypothesize could be the remnants ofRead More →

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Parabolic Flight Experiments Delve into Planetary Formation What happens in a protoplanetary disk to create planetesimals around a star? We know the general story — the material begins to clump together and eventually grows from dust grains to rocky bodies capable of sticking together to make planets. But, how does that dust begin the aggregation journey? That’s what a research team from the Switzerland wanted to know. So, they did experiments aboard parabolic micro-gravity flights to find an answer. Universe Today Go to SourceRead More →

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Shift in key cosmic inflation measurement could be a statistical artifact For the last few decades, researchers have been studying what the universe looked like in its first seconds. It is generally accepted that the universe expanded exponentially in the first fraction of a second after the Big Bang. Researchers use ns, the scalar spectral index, to characterize how primordial density fluctuations were distributed across different length scales in the early universe. The value of ns is a central observable in inflationary cosmology, since different inflationary scenarios predict distinct values for this quantity, making it a powerful discriminator between models. phys.org Go to SourceRead More →

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Rubin Alert Leads to First Follow-Up Observations and Detection of Four Supernovae NSF NOIRLab has completed end-to-end runs of its ecosystem for following up on alerts from NSF–DOE Vera C. Rubin Observatory. The runs demonstrated how multiple NOIRLab-developed software tools, plus a network of telescopes around the globe, will enable quick follow-up observations of the countless transient objects that Rubin will uncover during its ten-year survey. Universe Today Go to SourceRead More →

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Astronomers discover 87 stellar stream candidates in the Milky Way Stellar streams are trails of stars that astronomers can study to solve mysteries about the history of our Milky Way galaxy and, potentially, the dark matter that helps shape the cosmos despite eluding direct observation. These streams have largely been left behind by small dwarf galaxies and globular clusters, which have since petered out of existence. But there is a rare and important third type of stellar stream: streams from globular clusters that still survive. phys.org Go to SourceRead More →

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Astrophysicists resolve ‘negative superhump’ conundrum of deep-space binary star systems New UNLV-led research is helping to unravel clues to a cosmic mystery that has eluded scientists for decades. Cataclysmic variables (CVs) are binary star systems in which primary stars—incredibly dense and compact white dwarfs—accumulate material from nearby companion stars. The material spirals in towards the white dwarf through what is known as an accretion disk. These deep space systems are responsible for a number of cosmic phenomena, including sudden bursts of light known as classical novae that temporarily appear to resemble new stars before fading away over time. phys.org Go to SourceRead More →

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Hubble revisits Crab Nebula to track 25 years of expansion Nearly a millennium ago, astronomers witnessed a brilliant new star blazing in the sky—a supernova so bright it was visible in daylight for weeks. Today, its expanding remnant, the Crab Nebula, continues to evolve 6,500 light-years away. First linked to historical records by Edwin Hubble, the nebula has since been studied in exquisite detail by the NASA/ESA Hubble Space Telescope, which has now revisited this ancient explosion to trace its ongoing expansion and transformation. phys.org Go to SourceRead More →

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Vector-channel scattering of dark particles in a Sp(4) gauge theory Jong-Wan Lee, Ed Bennett, Yannick Dengler, Deog Ki Hong, Ho Hsiao, C. -J. David Lin, Biagio Lucini, Axel Maas, Maurizio Piai, Davide Vadacchino, Fabian Zierler arXiv:2603.19557v1 Announce Type: cross Abstract: We report new results obtained in our lattice studies of the $Sp(4)$ gauge theory coupled to two fundamental Dirac fermions. This theory provides a candidate for the dynamical origin of dark matter models within the strongly interacting massive particle paradigm. We employ L”uscher’s formalism to analyse finite-volume energy levels and study the scattering amplitude of two pseudoscalar states in the spin-1 channel. We present ourRead More →

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Can QCD Axions Survive the Cosmological Constant Problem? Carsten van de Bruck, C. P. Burgess, Adam Smith arXiv:2603.20008v1 Announce Type: cross Abstract: Mechanisms that dynamically relax the vacuum energy offer a concrete way to approach the cosmological constant problem, but because relaxation is not confined to the vacuum energy alone it can have consequences for the rest of low-energy physics. We explore this issue using the recently proposed ‘yoga’ relaxation models as an explicit framework and show how relaxation differentially suppresses ‘slow’ physics relative to a characteristic timescale set by the mass of the relaxon. It therefore need not alter e.g. Higgs & collider physicsRead More →

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Scalar-Mediated Inelastic Dark Matter as a Solution to Small-Scale Structure Anomalies Zihan Wang arXiv:2512.18959v2 Announce Type: replace-cross Abstract: We propose a scalar-mediated Self-Interacting Dark Matter (SIDM) model to address small-scale structure anomalies such as the core-cusp and diversity problems. The model is composed by a leptophilic scalar mediator and a pseudo-Dirac dark matter candidate with a mass splitting of 100ev.We imposed a dark discrete $mathbb{Z}_2$ symmetry forbids tree-level elastic scattering. Therefore creates kinematic threshold that suppresses scattering in ultra-faint satellite galaxies while enabling large self-interaction cross-sections in dwarf galaxies via resonant enhancement. To satisfy Big Bang Nucleosynthesis (BBN) requirements, we introduce a dimension-5 magnetic dipoleRead More →

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Toward universal coalescence models for antideuteron production Mattia di Mauro, Jordan Koechler, Lorenzo Stefanuto, Francesca Bellini, Fiorenza Donato, Nicolao Fornengo arXiv:2603.19352v1 Announce Type: cross Abstract: Cosmic-ray (CR) antinuclei, especially antideuteron $overline{rm D}$ and antihelium-3 nuclei ${}^3overline{rm He}$, are among the most promising messengers for indirect dark matter (DM) searches. This is because secondary production in CR interactions with the interstellar medium is strongly suppressed at kinetic energies $Ksimeq (0.1 – 1)$ GeV/$n$, typically one to two orders of magnitude below fluxes expected in standard DM scenarios. From the theoretical side, the formation of $overline{rm D}$ and ${}^3overline{rm He}$ is governed by coalescence, whose dynamics cannotRead More →

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JWST probes emerging young star clusters in nearby spiral galaxy NGC 628 Using the James Webb Space Telescope (JWST), an international team of astronomers has observed a nearby spiral galaxy known as NGC 628. Results of the observational campaign, published March 10 on the arXiv pre-print server, shed more light on the population of emerging young star clusters in this galaxy. phys.org Go to SourceRead More →

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Saturn-mass world discovered orbiting two low-mass stars You just established a settlement on an Earth-like planetary body far from our solar system. You did your evening chores after eating dinner, and you want to go out for the evening view, which consists of two setting stars, reminiscent of the infamous scene in Star Wars. However, there’s one major difference: a large planetary body is in the sky. As you were aware before arriving, you’re on an exomoon orbiting a Saturn-sized exoplanet, both of which orbits two stars. Universe Today Go to SourceRead More →

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This Pair Of Brown Dwarfs Can’t Get Enough Of Each Other Astronomers have found the first case of a brown dwarf binary pair experiencing mass transfer. The pair are very close to one another, with an orbital period of only 57 minutes. The pair will eventually merge into one, brighter star, or the accretor will become massive enough to trigger fusion. At only 1,000 light-years away, the system is a strong candidate for more detailed, follow-up observations. Universe Today Go to SourceRead More →

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ShadowCam search casts doubt on abundant lunar ice New observations by a team of US astronomers have cast fresh doubt on whether the lunar surface could host abundant water ice. Publishing their results in Science Advances, a team led by Shuai Li at the University of Hawaii at Manoa has shown that relatively pure ice (making up more than about 20–30% of the surface material) is likely absent from the moon’s permanently shadowed regions. phys.org Go to SourceRead More →