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Earlier ultra-relativistic freeze-out could revive a decades-old theory for dark matter

A new theory for the origins of dark matter suggests that fast-moving, neutrino-like dark particles could have decoupled from Standard Model particles far earlier than previous theories had suggested.

Through new research published in Physical Review Letters, a team led by Stephen Henrich and Keith Olive at the University of Minnesota proposes that this “ultra-relativistic freeze-out” mechanism could have produced dark matter particles which are almost undetectable, but still compatible with the observed history of the universe.

Despite comprising some 85% of the universe’s total mass, dark matter has never been seen to interact with regular matter except via gravity, making its origins one of the most enduring mysteries in cosmology.

Astrophysicists test a new piece of the sky to probe dark matter and dark energy

In the leading model of cosmology, most of the universe is invisible: a combined 95% is made of dark matter and dark energy. Exactly what these dark components are remains a mystery, but they have a tremendous impact on our universe, with dark matter exerting a gravitational pull and dark energy driving the universe’s accelerating expansion.

What scientists know about dark matter and dark energy comes from observing their effects on the visible universe. Astrophysicists from the University of Chicago have measured those effects on a new patch of sky to illuminate the invisible cosmos.

Astronomers find vast spinning filament of galaxies 140 million light-years away

An international team led by the University of Oxford has identified one of the largest rotating structures ever reported: a “razor-thin” string of galaxies embedded in a giant spinning cosmic filament, 140 million light-years away.

The findings, published in Monthly Notices of the Royal Astronomical Society, could offer valuable new insights into how galaxies formed in the early universe.

Cosmic filaments are the largest known structures in the universe: vast, thread-like formations of galaxies and dark matter that form a cosmic scaffolding. They also act as “highways” along which matter and momentum flow into galaxies.

The Mystery of the Impossible Neutrino. A Dark Matter Detection?

An exploration of the mystery of the impossible neutrino detection and how that might be our first direct detection of dark matter.

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How Ramanujan’s formulae for pi connect to modern high energy physics

Most of us first hear about the irrational number π (pi)—rounded off as 3.14, with an infinite number of decimal digits—in school, where we learn about its use in the context of a circle. More recently, scientists have developed supercomputers that can estimate up to trillions of its digits.

Now, physicists at the Center for High Energy Physics (CHEP), Indian Institute of Science (IISc) have found that pure mathematical formulas used to calculate the value of pi 100 years ago has connections to fundamental physics of today—showing up in theoretical models of percolation, turbulence, and certain aspects of black holes.

The research is published in the journal Physical Review Letters.

Euclid dataset of a million galaxies proves connection between galaxy mergers and AGN

Astronomers have long debated the role of galaxy mergers in powering active supermassive black holes. Now an unprecedented dataset of a million galaxies from the Euclid telescope provides evidence that mergers play a dominant role and are even the primary trigger for the most luminous black holes.

Almost all massive galaxies harbor a supermassive black hole (SMBH) at their centers. Most of them simply lurk in the dark while quietly reeling in gas, dust and stars from their surroundings. These materials gather in the black hole’s accretion disk before their irreversible dive into the abyss, thereby emitting the only slight hint of radiation that gives away the black hole’s location.

A small fraction of galaxies possess an SMBH that shines brightly or even pushes out material from its poles. These are called active galactic nuclei (AGN). Some astronomers have hypothesized that violent collisions between galaxies may play an important role in the ignition of AGN. The resulting turbulence could cause the extra material to pile up in an SMBH’s accretion disk, where friction and compression make it hot enough to shine brightly. In the most extreme cases, the AGN are so bright that they completely outshine their host galaxies.

New levitating sensors could pave way to dark matter detection and quantum sensing

A new type of sensor that levitates dozens of glass microparticles could revolutionize the accuracy and efficiency of sensing, laying the foundation for better autonomous vehicles, navigation and even the detection of dark matter.

Using a camera inspired by the human eye, scientists from King’s College London believe they could track upwards of 100 floating particles in what could be one of the most sensitive sensors to date.

Levitating sensors typically isolate small particles to observe and quantify the impact of outside forces like acceleration on them. The higher the number of particles which could be disturbed and the greater their isolation from their environment, the more accurate the sensor can be.

Surprise! Solar System Moves 3x Faster Than Predicted

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According to new data analysis, our solar system is traveling through the universe roughly 3 times faster than our current models predict it should be moving. Why is this, and why does it matter? Let’s take a look.

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💌 Support me on Donorbox ➜ https://donorbox.org/swtg.
👉 Transcript with links to references on Patreon ➜ / sabine.
📝 Transcripts and written news on Substack ➜ https://sciencewtg.substack.com/
📩 Free weekly science newsletter ➜ https://sabinehossenfelder.com/newsle
👂 Audio only podcast ➜ https://open.spotify.com/show/0MkNfXl
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/ @sabinehossenfelder.
📚 Buy my book ➜ https://amzn.to/3HSAWJW

#science #sciencenews #physics #cosmology

Scientists may have finally ‘seen’ dark matter for the 1st time

And this isn’t the only close match. The energy signature of these gamma-rays closely matches those predicted to emerge from the annihilation of colliding WIMPs, which are predicted to have a mass around 500 times that of a proton, the ordinary matter particles found at the heart of atoms. Totani suggests there aren’t any other astronomical phenomena that easily explain the gamma-rays observed by Fermi.

“If this is correct, to the extent of my knowledge, it would mark the first time humanity has ‘seen’ dark matter. And it turns out that dark matter is a new particle not included in the current standard model of particle physics,” Totani said. “This signifies a major development in astronomy and physics.”

While Totani is confident that what he and his colleagues have detected is the signature of dark matter WIMPs annihilating each other at the heart of the Milky Way, the scientific community in general will require more hard evidence before the book is closed on this nearly century-old mystery.

Scientists mapped the shape of a supernova for the first time ever — and it’s not what we expected: Space photo of the week

Astronomers using data from the Very Large Telescope (VLT) have revealed that the initial “breakout” phase of a supernova is elongated, not perfectly spherical.

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