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Astronomers predict an unseen class of star-like bodies called “dark dwarfs” near our galaxy’s center. A new study suggests these objects could shine thanks to annihilating dark matter, not nuclear fusion. Dark matter makes up about a quarter of the universe and interacts via gravity. If WIMP-like dark matter particles collect in a brown dwarf, they would annihilate and heat it, causing a faint glow. Dark dwarfs would be too light to fuse hydrogen, but would keep lithium-7 in their atmospheres, offering a signature. This prediction comes from a JCAP study. The discovery of one could reveal dark matter’s nature.

Predicted Dark Dwarf Properties

According to the paper, sub-stellar objects just below the hydrogen-burning threshold would be powered by dark matter. The authors find that the minimum mass for hydrogen fusion shifts above ∼0.075 M⊙ in dense dark-matter environments, so lighter brown dwarfs instead become stable dark-matter–powered stars (‘dark dwarfs’) via WIMP annihilation inside them. They predict such objects only appear in regions with extremely high dark-matter density, like the Galactic center (ρ_DM ≳ 10^3 GeV/cm^3), because further out the halo is too tenuous. Crucially, dark dwarfs should retain lithium-7 in mass ranges where ordinary brown dwarfs burn it away, providing a clear observational signature.

Observational Prospects and Implications

Sakstein notes that powerful telescopes like the James Webb Space Telescope might even already detect extremely cold objects like dark dwarfs near the galactic center. Alternatively, astronomers could survey brown dwarf populations for a rare sub-class with anomalous lithium content. Notably, even one confirmed dark dwarf would strongly favor heavy, self-annihilating dark matter.

Sakstein explains that finding dark dwarfs would provide “compelling evidence” for dark matter that is massive and interacts with itself – essentially WIMPs or similar particles. He notes that lighter candidates (like axions) would not produce such stars, so a dark dwarf discovery would disfavor those models. While not a proof of WIMPs, a dark dwarf detection would imply dark matter behaves like WIMPs (heavy and weakly interacting). Indeed, future surveys and JWST observations will also test these predictions.

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Gold Defies Physics: Remains Solid at 14x Its Melting Point in Superheating Experiment

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15 hours ago

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August 2, 2025

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Gold Defies Physics: Remains Solid at 14x Its Melting Point in Superheating Experiment

In a groundbreaking experiment, gold has defied the expectations that it was still solid even after being heated above the standard temperature. With the help of rapid laser bursts, the scientists could superheat gold beyond the entropy catastrophe, which is a theoretical boundary at which solids need to melt due to extreme heat. To the surprise, the gold was in the structure temporarily, and then it led to the rethinking of how matter behaves when provided with intense conditions. Such a rare phenomenon is known as superheating, where the heating happens so fast that atoms don’t get enough time to reorganise themselves into a liquid.

Gold Withstands the Entropy Catastrophe: What Is Superheating?

As per Science Alert, the atomic structure of gold resisted melting and absorbed the heat quickly, even faster than the response of its atoms. Scientists performed this study at 19,000 Kelvin, and gold remained solid for 2 picoseconds, which is enough to challenge the theory of physics.

Conventionally, the physicist believed that solids could not survive heat more than three times their melting point. This experiment, although pushed gold to 14 times the threshold, with the help of advanced techniques, which involved X-ray reflections to track the heat absorption accurately. The findings suggest that the materials can resist melting beyond the previously known boundaries; however, only for brief moments, which are difficult to even imagine.

Could Other Solids Resist Melting Like Gold? What This Means for Future Research

The results found by the scientists don’t change the law of thermodynamics. However, they suggest that such laws cannot be completely applied in ultra-fast reactions, and atoms cannot move or rearrange in this much time. Most importantly, gold had no place to go, and this let it remain solid even after heating to unexpected temperatures.

This unlocks the new possibilities fr understanding the extreme situations, from the impact of asteroids to the nuclear reactors. Scientists now wonder if other solids could also show the same tolerance, and rule out the current model of melting points, which need to be known altogether. Science must revisit the question asked by one scientist that how hot can you make something before melting?

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New Inelastic Dark Matter Model Could Bypass Current Limits of Particle Detection

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16 hours ago

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August 2, 2025

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New Inelastic Dark Matter Model Could Bypass Current Limits of Particle Detection

A group of physicists at the University of São Paulo’s Institute of Physics has proposed a model of the behaviour of dark matter (DM) in the presence of dark energy (DE) that is compatible with current astronomical observations. A model of inelastic DM can be realised from light-weight particles, which are collectively interacting through the massive vector mediator, and the model is an alternative explanation for DM relics in the universe. Importantly, this framework may have the potential to circumvent the experimental hurdles for the detection of DM that have thus far kept it in the dark. The findings are published in the Journal of High Energy Physics, and its authors believe it has the potential to “revolutionise” how particle physics analyses are conducted in the future.

Light Mediator ZQ Offers New Clues to Elusive Dark Matter and Its Cosmic Origins

As per the users’ report, they have developed the following new model: a heavy, stable DM from a light, unstable one. This can be expressed as a heavy stable DM due to a heavy unstable one, which may give rise to the “thermal freeze-out” in the universe. It doesn’t just interact with visible matter but with dark matter as well, and that’s how you get the new observational windows.

To explain why the dark matter has not been observed until now, the model further involves a decay of the unstable dark matter χ2 to some species not disturbing the CBR, and thus also not presenting a visible/observable decay signal. The picture is consistent with current astrophysical and experimental constraints, avoiding simpler `vanilla’ DM scenarios.

ZQ-induced vector mediators are light portals connecting the two sectors and may mediate the direct interactions between the dark sector and the SM particles. The black line indicates the region in the parameter space where dark matter can be hiding unobserved — this is to be addressed in future experiments.

The study suggests the search for dark matter should pivot from the “discovery frontier”, in which exquisitely sensitive instruments scan for signals, to the “intensity frontier”, which seeks ever-finer measurements to tease out anomalies. Future experiments will seek to dig more deeply into these unexplained corners of particle physics with a new online tool.

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Massive 200-Light-Year Cloud May Be Channeling Matter to the Milky Way’s Core

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17 hours ago

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August 2, 2025

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Massive 200-Light-Year Cloud May Be Channeling Matter to the Milky Way's Core

Astronomers have found a vast, never-before-noticed reservoir of stellar material, hundreds of light-years across, lurking in a cold, dark, starless swath of our galaxy. It’s dubbed the Midpoint Cloud and was identified using the Green Bank Telescope; it appears to channel dense clouds of material into the heart of our galaxy. It harbours active regions filled with dense dust lanes and star formation possibilities. These lanes could be bringing twisted matter into the galaxy’s central bar, shaping how stars form in this extreme environment and offering a rare snapshot of the first stages of a galaxy’s evolution.

Newly Found Midpoint Cloud May Be Key to Star Formation in the Milky Way’s Core

As per the study, researchers at the National Radio Astronomy Observatory and Green Bank Observatory confirmed the size and shape of the GMC based on mass, density, and movement. The gassy chaos in the cloud mirrors the caustic turmoil at the galactic centre, yielding measurements from a faint object that says something about an energetic event 200 light-years distant. That could be a link from the field-like tranquillity of our own Milky Way’s disk to the mayhem of its core.

Perhaps analogously to gas channels, a thick dust lane in the Midpoint cloud could supply the central stellar bar fragment with fresh gas, again supporting an interpretation that star formation is inhibited in this region by the strong gravitational potential. But regions like the Midpoint could collect such thick gas, spurring the birth of new stars.

The team classified Knot E as a compact gas clump whose material has been eroded by both star radiation and a maser, or microwave emission, within a cloud. A shell-like feature suggests earlier supernova explosions, like those the deaths of massive stars in the region might have initiated.

The Midpoint cloud Larry Morgan, of the Green Bank Observatory, discovered is a valuable clue in our knowledge of how galaxies evolve and form stars near their centers. The finding could give scientists a way to learn how matter flows inward across the cosmos, one hidden cloud at a time.

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