Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: cosmology – Page 4

JWST Captures Stunning Evidence of How Supermassive Black Holes Feed

An international team using the JWST has found photographic evidence that brings astronomers closer to solving a long-standing mystery about black holes.

For decades, astronomers have faced a puzzle at the centers of massive galaxies: how can a supermassive black hole keep feeding when its own powerful jets heat the surrounding gas that supplies it? New observations from the James Webb Space Telescope, or JWST, are bringing that process into much sharper view.

The images provide the clearest look yet at gaseous filaments linking a galaxy’s hot atmosphere to the rotating disk that supplies material to its central supermassive black hole.

Galaxies May Be Mimicking the Dark Matter Signals Astronomers Have Been Hunting

Galaxies can create many of the same stellar stream distortions that astronomers have looked to as possible signs of dark matter.

Astronomers have long hoped that gaps, bends, and other distortions in long bands of stars around the Milky Way could reveal the hidden influence of dark matter. But new simulations suggest many of those features can arise from the galaxy itself, even without the small dark matter clumps thought to produce them.

University of Washington researchers modeled roughly 15,000 of these bands, known as stellar streams, across four Milky Way-sized galaxies. The simulations omitted small dark matter clumps called subhalos. After five billion simulated years, irregularities appeared in nearly every stream, and only 70 remained perfectly smooth.

Quantum Cyclic Cosmology with Sean Carroll

Could our universe be repeating—and could quantum mechanics solve one of cosmology’s strangest problems?
In this video I speak with theoretical physicist Sean Carroll about his new paper, “Toward a Phenomenologically Acceptable Quantum Cyclic Universe.” https://arxiv.org/abs/2605.30405
One of the deepest mysteries in cosmology is why the early universe began in such an extraordinarily low-entropy state. Attempts to explain this through random fluctuations can lead to the notorious Boltzmann-brain problem: if the universe persists for long enough, isolated observers produced by chance may vastly outnumber ordinary observers who evolved within galaxies.
Carroll and his collaborators investigate a radically different possibility. If the universe has a finite-dimensional quantum state space, its state could eventually return—not merely to something similar, but to exactly the same quantum state. The entire history of the universe could therefore repeat periodically without being dominated by Boltzmann-brains.
We discuss:
Why the Big Bang’s low entropy is so mysterious• Boltzmann’s proposed solution and the Boltzmann-brain problem• The difference between cyclic and genuinely periodic cosmologies• How spacetime might emerge from a more fundamental quantum description• Why the model assumes a finite-dimensional Hilbert space• How quantum recurrence could become exact repetition• Carroll’s “quantum Boltzmann entropy”• Whether the same people and events would recur eternally• What the proposal explains—and what remains unresolved• Whether it could ever make testable predictions.
timeline.
00:00 preview.
00:14 Introduction.
00:48 Big Bangs low entropy problem.
2;11 Boltzmann solution.
4:37 Boltzmann brains.
11:00 Boltzmann-brain in a single universe.
16: 20 Period vs cyclic universe.
21:22 Infinite dimensional loop hole.
24:14 Space From Hilbert Space.
32:15 Fundamental Time.
35:25 Finite Dimensional Loop Hole.
44:30 Many worlds and entropy.
48:57 How long is a cycle?
51:22 The Story of cycles.
57:07 The cosmological constant problem.
1:00:00 Carroll Chen model.
1:09:28 The future for the model.

Scientists may have detected the 1st direct evidence of dark matter

As LUX-ZEPPLIN continues to gather the largest dataset in dark matter science, the team will determine if this event has grown in significance or if its significance fades.

One definite positive is the fact that WIMP/ matter interactions are so rare that it wouldn’t take many detections such as this to confirm the existence of WIMP dark matter, thus solving the puzzle of what the universe’s most mysterious stuff actually is composed of.

“We expect dark matter events to be extremely rare, so only a handful could mark the first detection of WIMP dark matter,” Eriksen said.

Switching gravity on and off leaves particles behind, mathematical model finds

That gravity is a product of a time gradient, without spatial distortion. And what’s more — the presence of the variable “time” in practically all formulas of physics probably means that all other “forces” are also derivatives of time. And the speed of light is a speedometer for the speed of time, not an independent physical constant. Could this be the “great unification”?

Hawking radiation causes black holes to eventually evaporate. This is because particle pairs are spontaneously created near the event horizon (the position of the last ray of light that can escape the black hole’s gravitational pull). A particle and its antiparticle are created for a brief moment and disappear immediately afterward. But sometimes a particle falls into the black hole, allowing the other particle to escape: This is Hawking radiation. According to Stephen Hawking, this would ultimately mean that no black holes would remain in the universe.

Astronomer Heino Falcke, physicist Michael Wondrak and mathematician Walter van Suijlekom from Radboud University had previously demonstrated that the event horizon plays a subordinate role in the origin of the radiation. In an article published in Communications in Mathematical Physics, they have now also provided mathematical proof for a similar problem.

Van Suijlekom said, “We wanted to formulate a mathematically rigorous model as precisely as possible. We wanted hard mathematical proof in the case that only a temporal horizon exists and that the universe ultimately resembles its initial state.”

Experiment sees surprising result in search for dark matter

For the better part of a century, people have been trying to understand dark matter. This invisible substance makes up roughly 85% of the mass in the universe but has never been directly detected. Determining exactly what it is remains one of the biggest questions about our world.

Now, a new analysis from the LUX-ZEPLIN (LZ) experiment has recorded a single particle interaction that researchers have great difficulty explaining with known background signals from normal matter. The result does not yet meet the statistical threshold required to claim a discovery but is the most compelling hint of dark matter reported by the experiment to date.

LZ is an international collaboration of 250 scientists and engineers from 39 institutions. The detector is managed by the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and operates nearly 1 mile (1.6 kilometers) below ground at the Sanford Underground Research Facility (SURF) in South Dakota. The experiment uses 10 tonnes of ultrapure liquid xenon to search for dark matter and is optimized to look for WIMPs, or weakly interacting massive particles.

JWST reveals likely Type II supernova from when universe was only 2 billion years old

Astronomers using the James Webb Space Telescope have identified one of the most distant exploding stars ever confirmed. The supernova, SN 2023aeaf, was found at a redshift of 3.195—so far away that its light has been traveling for roughly 11.7 billion years. The study, published in The Astrophysical Journal on Aug. 13, offers a close-up look at how massive stars die in the young universe’s primitive, metal-poor conditions.

Massive stars exploding in a core-collapse supernova explosion can be used as tracers for actively forming stars and the physical consequences their explosive deaths exert on the surrounding gas cloud. These explosions actively reshape the environment and set the stage for the next generation of stars to form. Their rate of occurrence tells astronomers indirectly about how vigorously stars were forming throughout the universe’s history.

But almost everything astronomers know about how these explosions actually behave comes from nearby, relatively recent examples. Because the early universe had very low metal content, a major question persists over whether these explosions behaved differently far back in the early universe. Testing this requires finding and studying distant supernova candidates, which are extremely faint and therefore hard to detect.

European scientists create ‘little Big Bang’ to study the universe’s origins

The experiment works by colliding the oxygen and neon nuclei to create a tiny blob of quark-gluon plasma — the same super-hot “soup” scientists think filled the universe right after the Big Bang.

The collision produces a droplet of that plasma that expands and cools in an instant, too fast for scientists to observe directly, so instead, scientists studied the particles it leaves behind, which turned out to reveal something unexpected, Zhou explained.

What they found, according to the study, is when two oxygen atoms smashed together, the particles sprayed out in a rounded pattern, but when two neon atoms collided, the particles actually came out shaped more like a bowling pin — which matches the true geometry of a neon nucleus, according to the study.

/* */