Recommendable, but basic!
Showing posts with label universe. Show all posts
Showing posts with label universe. Show all posts
Thursday, September 03, 2026
"The Axis of Evil": The Universe's Unexplained Center
Tuesday, September 01, 2026
Tuesday, March 31, 2026
New theory reshapes quantum view of earliest expansion of Big Bang
Amazing stuff!
"... Their work suggests that the universe’s rapid early expansion could have arisen naturally from a deeper, more complete theory of quantum gravity. ...
research team that explored a novel method of combining gravity with quantum physics, the rules that govern how the smallest particles in the universe behave. While general relativity has been successful for more than a century, it breaks down at the extreme conditions that existed at the birth of the universe. To address this problem, the team used Quadratic Quantum Gravity, which remains mathematically consistent even at extremely high energies — similar to the kind present during the Big Bang.
Most existing explanations for the Big Bang rely on Einstein’s theory of gravity, plus additional components added by hand. This new approach offers a more unified picture that connects the earliest moments of the universe to the well-tested cosmology scientists observe today.
The research team found that the Big Bang’s rapid early expansion can emerge naturally from this simple, consistent theory of quantum gravity, without adding any extra ingredients. This early burst of expansion, often called inflation, is a central idea in modern cosmology because it explains why the universe looks the way it does today.
Their model also predicts a minimum amount of primordial gravitational waves, which are tiny ripples in spacetime geometry created in the first moments after the Big Bang. These signals may be detectable in upcoming experiments, offering a rare chance to test ideas about the universe’s quantum origins. ..."
From the abstract:
"We present a quantum quadratic gravity inflationary scenario that can accommodate the new cosmological constraints, which have disfavored Starobinsky inflation. The theory is asymptotically free in the ultraviolet, but 1-loop running is found to dynamically lead to slow-roll inflation toward the infrared. When a large number of matter fields contribute to the beta functions, the spectral index and the tensor-to-scalar ratio can be phenomenologically viable. We find that as inflation ends, the theory approaches its strong coupling regime and general relativity must emerge, as an effective field theory, as the universe must reheat and enter its standard radiation era. In order to avoid strong coupling, a minimum tensor-to-scalar ratio of 0.01 is predicted for this theory. Our framework offers a laboratory for connecting a concrete ultraviolet completion (quantum quadratic gravity) with inflationary dynamics, reheating, and precise cosmological observations."
New theory reshapes quantum view of Big Bang "Researchers show how the universe’s earliest expansion may emerge directly from quantum gravity"
Fig. 2.
Plot of the scalar spectral index ns vs the tensor-to-scalar ratio r for Starobinsky inflation (in black), contrasted with our QQG model in color for different values of the coupling λtH. The purple and dashed contours correspond to a combination of CMB (Planck18+ACT+SPT+Lensing+BK) and BAO (DESI) observational constraints for ΛCDM and w0waCDM cosmologies, respectively
Saturday, January 31, 2026
Astronomers reveal new details about dark matter’s influence on universe
Amazing stuff! The reported overlap between dark matter and matter might be an artefact or may not represent the whole picture.
"... Dark matter doesn’t emit, reflect, absorb, or even block light, and it passes through regular matter like a ghost. But it does interact with the universe through gravity, something the map shows with a new level of clarity. Evidence for this interaction lies in the degree of overlap between dark matter and regular matter. According to the researchers, Webb’s observations confirm that this close alignment can’t be a coincidence but, rather, is due to dark matter’s gravity pulling regular matter toward it throughout cosmic history. ...
“Wherever we see a big cluster of thousands of galaxies, we also see an equally massive amount of dark matter in the same place. And when we see a thin string of regular matter connecting two of those clusters, we see a string of dark matter as well,” ...
Found in the constellation Sextans, the area covered by the new map is a section of sky about 2.5 times larger than the full Moon. ..."
From the abstract:
"Ordinary matter—including particles such as protons and neutrons—accounts for only about one-sixth of all matter in the Universe. The rest is dark matter, which does not emit or absorb light but plays a fundamental role in galaxy and structure evolution.
Because it interacts only through gravity, one of the most direct probes is weak gravitational lensing: the deflection of light from distant galaxies by intervening mass. Here we present an extremely detailed, wide-area weak-lensing mass map covering 0.77° × 0.70°, using high-resolution imaging from the James Webb Space Telescope as part of the COSMOS-Web survey. By measuring the shapes of 129 galaxies per square arcminute—many independently in the F115W and F150W bands—we achieve an angular resolution of .
Our map has more than twice the resolution of earlier Hubble Space Telescope maps, revealing how dark and luminous matter co-evolve across filaments, clusters and underdensities. It traces mass features out to z ≈ 2, including the most distant structure at z ≈ 1.1. The sensitivity to high-redshift lensing constrains galaxy environments at the peak of cosmic star formation and sets a high-resolution benchmark for testing theories about the nature of dark matter and the formation of large-scale cosmic structure."
An ultra-high-resolution map of (dark) matter (no public access)
An ultra-high-resolution map of (dark) matter (preprint, open access)
Friday, January 30, 2026
Saturday, January 03, 2026
Cosmic Paradox Reveals the Awful Consequence of an Observer-Free Universe
Amazing stuff!
"When one applies the powerful tools of quantum gravity to an entire universe—not just black holes—a glaring paradox appears: in certain “observer-free” models of a closed cosmos, the universe seems to admit only a single possible quantum state. This conclusion, first raised by Juan Maldacena, Carl P. Feinberg Professor in the School of Natural Sciences, and several collaborators in the School—including Member Ahmed Almheiri; Raghu Mahajan, Member (2019–20) and Visitor (2017–19); and Ying Zhao, Member (2018–21)—challenges one of physics’s deepest ideals: the hope of an objective, observer-independent description of the universe. ..."
"... But almost 30 years ago, a landmark paper ..., showed that difficult string theory calculations could sometimes be sidestepped and carried out using familiar concepts from particle physics instead. The catch is that this approach only works if the universe has an unusual “anti-de Sitter” geometry. An anti-de Sitter universe has a boundary, often illustrated to resemble a tin can. Remarkably, everything that happens inside the can, from colliding particles to spinning black holes, is revealed by shadows on the can’s outer boundary. It’s as if the 3D universe inside were equivalent to an image on a flat screen, a concept physicists call holography. ...
The problem is that we don’t live in an anti-de Sitter tin-can cosmos. The nature of the universe’s expansion implies that it has no boundary. No matter how far you travel, you will never hit an edge. ...
In 2024, ... began to work on the problem of how to put an observer into a closed universe. ... thought of the observer as introducing a new kind of boundary: not the edge of the universe, but the boundary of the observer themself. When you consider a classical observer inside a closed universe, all the complexity of the world returns, Zhao and her collaborators showed.
The ... paper came out at the beginning of 2025, around the same time that another group came forward with a similar idea. ...
If the idea holds up, using the subjective nature of the observer as a way to account for the complexity of the universe would represent a paradigm shift in physics. Physicists typically seek a view from nowhere, a stand-alone description of nature. ..."
Cosmic Paradox Reveals the Awful Consequence of an Observer-Free Universe "Encouraged by successes in understanding black holes, theoretical physicists are applying what they’ve learned to whole universes. What they’re finding has them questioning fundamental assumptions about how physics ought to be done."
The Large N Limit of Superconformal Field Theories and Supergravity (preprint, open access)
Quantum mechanics and observers for gravity in a closed universe (preprint, open access)
The gravitational path integral from an observer's point of view (preprint, open access)
Monday, December 22, 2025
New mathematical framework reshapes debate over universe simulation hypothesis. Really!
Amazing stuff! I have wondered/speculated myself multiple times for several decades if not the universe is an aquarium created by some intelligent beings. See e.g. my 2020 blog post here. I blogged here in late October about a research paper that claimed to have a mathematical proof of impossibility of a computer simulation.
Has somebody already verified the proof for this mathematical framework?
How can a universe like ours be defined mathematically beyond physics? The study is from the perspective of computer science according to the title. This is a serious limitation, because we do not know what other intelligent beings are capable of!
The second serious limitation is that the author assumes the simulation is run by humans.
In my opinion, it is not clear from the abstract of this paper what the conclusion of the researcher is if any. Remains kind of nebulous!
The author David H. Wolpert has accumulated 47166 citations over his lifetime covering about 400 publications (great, but not impressive unless he is a niche researcher). However, about 63% of all citations are attributed to only two of his papers he published in 2002 and 1992. This professor is perhaps not exactly an Albert Einstein.
Caveat: I did not read the paper.
"The simulation hypothesis — the idea that our universe might be an artificial construct running on some advanced alien computer — has long captured the public imagination."
"The simulation hypothesis — the idea that our universe might be an artificial construct running on some advanced alien computer — has long captured the public imagination. ...
A new paper ... aims to change that. ... introduces the first mathematically precise framework for what it would mean for one universe to simulate another — and shows that several longstanding claims about simulations break down once the concept is defined rigorously. His results point to a far stranger landscape than previous arguments suggest, including the possibility that a universe capable of simulating another could itself be perfectly reproduced inside that very simulation. ..."
From the abstract:
"The simulation hypothesis has recently excited renewed interest in the physics and philosophy communities. However, the hypothesis specifically concerns computers that simulate physical universes. So to formally investigate the hypothesis, we need to understand it in terms of computer science (CS) theory.
In addition we need a formal way to couple CS theory with physics. Here I couple those fields by using the physical Church–Turing thesis. This allow me to exploit Kleene’s second recursion, to prove that not only is it possible for us to be a simulation being run on a computer, but that we might be in a simulation that is being run on a computer – by us.
In such a ‘self-simulation’, there would be two identical instances of us, both equally ‘real’. I then use Rice’s theorem to derive impossibility results concerning simulation and self-simulation; derive implications for (self-)simulation if we are being simulated in a program using fully homomorphic encryption; and briefly investigate the graphical structure of universes simulating other universes which contain computers running their own simulations.
I end by describing some of the possible avenues for future research. While motivated in terms of the simulation hypothesis, the results in this paper are direct consequences of the Church–Turing thesis. So they apply far more broadly than the simulation hypothesis."
I end by describing some of the possible avenues for future research. While motivated in terms of the simulation hypothesis, the results in this paper are direct consequences of the Church–Turing thesis. So they apply far more broadly than the simulation hypothesis."
Sunday, December 07, 2025
Astronomers spot one of the largest spinning structures ever found in the Universe
Amazing stuff!
"Their findings, published in the 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. Nearby filaments containing many galaxies spinning in the same direction – and where the whole structure appears to be rotating – are ideal systems to explore how galaxies gained the spin and gas they have today. They can also provide a way to test theories about how cosmic rotation builds up over tens of millions of light-years.
In the study ... found 14 nearby galaxies rich in hydrogen gas, arranged in a thin, stretched-out line about 5.5 million light-years long and 117,000 light-years wide.
This structure sits inside a much larger cosmic filament containing over 280 other galaxies, and is roughly 50 million light-years long. Many of these galaxies appear to be spinning in the same direction as the filament itself- far more than if the pattern of galaxy spins was random. This challenges current models and suggests that cosmic structures may influence galaxy rotation more strongly or for longer than previously thought.
The researchers found that the galaxies on either side of the filament's spine are moving in opposite directions, suggesting that the entire structure is rotating. Using models of filament dynamics, they inferred the rotation velocity of 110 km/s and estimated the radius of the filament’s dense central region at approximately 50 kiloparsecs (about 163,000 light-years).
“What makes this structure exceptional is not just its size, but the combination of spin alignment and rotational motion,” ...
The team used data from South Africa’s MeerKAT radio telescope, one of the world’s most powerful telescopes, comprising an array of 64 interlinked satellite dishes. This spinning filament was discovered using a deep survey of the sky called MIGHTEE, combined with optical observations from the Dark Energy Spectroscopic Instrument (DESI) and Sloan Digital Sky Survey (SDSS) to reveal a cosmic filament exhibiting both coherent galaxy spin alignment and bulk rotation."
From the abstract:
"Understanding the cold atomic hydrogen gas (H i) within cosmic filaments has the potential to pin down the relationship between the low density gas in the cosmic web and how the galaxies that lie within it grow using this material.
We report the discovery of a cosmic filament using 14 H i-selected galaxies that form a very thin elongated structure of 1.7 Mpc. These galaxies are embedded within a much larger cosmic web filament, traced by optical galaxies, that spans at least ~15 Mpc.
We find that the spin axes of the H i galaxies are significantly more strongly aligned with the cosmic web filament () than cosmological simulations predict, with the optically selected galaxies showing alignment to a lesser degree (). This structure demonstrates that within the cosmic filament, the angular momentum of galaxies is closely connected to the large-scale filamentary structure.
We also find strong evidence that the galaxies are orbiting around the spine of the filament, making this one of the largest rotating structures discovered thus far, and from which we can infer that there is transfer of angular momentum from the filament to the individual galaxies.
The abundance of H i galaxies along the filament and the low dynamical temperature of the galaxies within the filament indicates that this filament is at an early evolutionary stage where the imprint of cosmic matter flow on galaxies has been preserved over cosmic time."
Figure 2.Top left: the on-sky distribution of H i galaxies (squares), SDSS and DESI optical galaxies (circles and lines, depending on the availability of optical PA measurements), and the cosmic filament. The MIGHTEE COSMOS footprint is shown in a block. Other panels show the DESI multiband cutout image and the H i moment-1 map of each H i-selected galaxy. ...
Friday, October 31, 2025
Mathematical proof debunks the idea that the universe is a computer simulation. Really!
I am not convinced! Maybe the universe, as we know it, is just a huge aquarium or simulation. Our current knowledge is still far too limited to make such sweeping generalizations.
"[the authors] have shown that the fundamental nature of reality operates in a way that no computer could ever simulate.
Their findings ... go beyond simply suggesting that we're not living in a simulated world like The Matrix. They prove something far more profound: the universe is built on a type of understanding that exists beyond the reach of any algorithm. ..."
From the abstract:
"General relativity treats spacetime as dynamical and exhibits its breakdown at singularities.
This failure is interpreted as evidence that quantum gravity is not a theory formulated {within} spacetime; instead, it must explain the very {emergence} of spacetime from deeper quantum degrees of freedom, thereby resolving singularities. Quantum gravity is therefore envisaged as an axiomatic structure, and algorithmic calculations acting on these axioms are expected to generate spacetime.
However, Gödel’s incompleteness theorems, Tarski’s undefinability theorem, and Chaitin’s information-theoretic incompleteness establish intrinsic limits on any such algorithmic program.
Together, these results imply that a wholly algorithmic “Theory of Everything’’ is impossible: certain facets of reality will remain computationally undecidable and can be accessed only through non-algorithmic understanding.
We formalize this by constructing a “Meta-Theory of Everything’’ grounded in non-algorithmic understanding, showing how it can account for undecidable phenomena and demonstrating that the breakdown of computational descriptions of nature does not entail a breakdown of science. Because any putative simulation of the universe would itself be algorithmic, this framework also implies that the universe cannot be a simulation."
Wednesday, July 23, 2025
Rethinking the Big Bang: Gravity and quantum ripples may explain cosmic origins
Amazing stuff! However, the abstract of the paper is anything but interpretable for a layperson.
I personally think the Big Bang theory is bogus like deus ex machina! E.g. what came before the Big Bang?
That the new theory appears to depend on dark energy may not instill much confidence, as dark energy is another unexplained obscurity.
"A team of scientists ... has presented a revolutionary theory about the origins of the universe. The study ... introduces a radical change in the understanding of the first moments after the Big Bang, without relying on the speculative assumptions that physicists have traditionally assumed.
For decades, cosmologists have worked under the inflationary paradigm, a model that suggests that the universe expanded extremely rapidly, in a fraction of a second, thus paving the way for everything we observe today. But this model includes too many adjustable parameters—the free parameters—which can be modified. Scientifically, this poses a problem, as it makes it difficult to know whether a model is truly predicting or simply adapting to the data.
In a significant breakthrough, the team has proposed a model in which the early universe does not require any of these arbitrary parameters. Instead, it begins with a well-established cosmic state called De Sitter space, which is consistent with current observations of dark energy.
Gravitational Waves: the key to cosmic structure
The new model doesn’t rely on hypothetical fields or particles such as the inflaton. Rather, it suggests that natural quantum oscillations of space-time itself, gravitational waves, were enough to seed the tiny differences in density that eventually grew into galaxies, stars, and planets. These gravitational ripples evolve nonlinearly, meaning they interact and build complexity over time, leading to testable predictions that researchers can now compare with real-world data. ..."
From the abstract:
"We propose a novel scenario in which scalar perturbations, which seed the large-scale structure of the universe, are generated without relying on a scalar field (the inflaton).
In this framework, inflation is driven by a de Sitter space time, where tensor metric fluctuations (i.e., gravitational waves) naturally arise from quantum vacuum oscillations, and scalar fluctuations are generated via second-order tensor effects. We compute the power spectrum of such scalar fluctuations and show it to be consistent with near scale invariance. We derive the necessary conditions under which scalar perturbations become significant and much larger than the tensor modes, and we identify a natural mechanism to end inflation via a transition to a radiation-dominated phase. Our proposed mechanism could remove the need for a model-dependent scenario: the choice of a scalar field, as the inflaton, to drive inflation."
A bold leap in understanding the origins of the Universe: Scientists propose a new model for Cosmic Inflation (original news release) "This new simpler, testable model removes speculative elements like the inflaton field and shows that gravitational waves alone could explain how cosmic structures formed, reshaping our understanding of the early Universe."
Inflation without an inflaton (open access, this is a very short paper filled with mathematical formulas)
Monday, April 21, 2025
A slowly spinning universe could solve the Hubble tension at a full rotation in about 500 billion years
Amazing stuff! However, it is computer modeling!
"... Current models say the universe expands evenly in all directions, with no sign of rotation. This idea fits most of what astronomers observe. But it doesn't explain the so-called Hubble tension—a long-standing disagreement between two ways of measuring how fast the universe is expanding. ...
team developed a mathematical model of the universe. First, it followed standard rules. Then they added a tiny amount of rotation. That small change made a big difference. ...
"Much to our surprise, we found that our model with rotation resolves the paradox without contradicting current astronomical measurements. Even better, it is compatible with other models that assume rotation. ...
Their model suggests the universe could rotate once every 500 billion years—too slow to detect easily, but enough to affect how space expands over time. ..."
From the abstract:
"The discrepancy between low and high redshift Hubble constant measurements is the highest significance tension within the concordance Lambda cold dark matter paradigm.
If not due to unknown systematics, the Hubble Puzzle suggests a lack of understanding of the universe’s expansion history despite the otherwise spectacular success of the theory. We show that a Gödel inspired slowly rotating dark-fluid variant of the concordance model resolves this tension with an angular velocity today Gyr−1. Curiously, this is close to the maximal rotation, avoiding closed time-like loops with a tangential velocity less than the speed of light at the horizon."
UH astronomer finds the universe could be spinning (original news release)
Can rotation solve the Hubble Puzzle? (open access)
Figure 1.Time evolution (log–log scale) of the Hubble parameter for non-rotating (analytical) and rotating (numerical) solutions at different rotation parameter values as of today. Small figures show the evolution (normal scale) at the decoupling period and today.
Sunday, March 23, 2025
Astronomers Detect Oxygen Just 300 Million Years Post-Big Bang in one of the most distant galaxies
Amazing stuff! Discovery raises serious questions about current, established models of the universe.
"Now papers published in Astronomy & Astrophysics and the Astrophysical Journal suggest astrophysicists need to update their theories on how galaxies evolve."
Friday, March 21, 2025
Thursday, March 20, 2025
Webb telescope captures its first direct images of carbon dioxide outside our solar system
Besides global warming, we have now cosmic warming? We are doomed, no escape possible! 😊 Caution: irony.
"Key Takeaways
- The Webb Telescope captured its first direct images of carbon dioxide in an exoplanet.
- The findings suggest planets in a system 130 light-years away likely built up solid cores before attracting gas, much like our solar system’s gas worlds.
- Webb’s coronagraphs allow direct atmospheric analysis, paving the way for deeper studies of distant worlds.
"
From the abstract:
"High-contrast observations with JWST can reveal key composition and vertical mixing dependent absorption features in the spectra of directly imaged planets across the 3–5 μm wavelength range. We present novel coronagraphic images of the HR 8799 and 51 Eri planetary systems using the NIRCam Long Wavelength Bar in an offset "narrow" position. These observations have revealed the four known gas giant planets encircling HR 8799, even at spatial separations challenging for a 6.5 m telescope in the mid-infrared, including the first ever detection of HR 8799 e at 4.6 μm. The chosen filters constrain the strength of CO, CH4, and CO2 absorption in each planet's photosphere. The planets display a diversity of 3–5 μm colors that could be due to differences in composition and ultimately be used to trace their formation history.
They also show stronger CO2 absorption than expected from solar metallicity models, indicating that they are metal enriched. We detected 51 Eri b at 4.1 μm and not at longer wavelengths, which, given the planet's temperature, is indicative of out-of-equilibrium carbon chemistry and an enhanced metallicity. Updated orbits fit to the new measurement of 51 Eri b validate previous studies that find a preference for high eccentricities (), which likely indicates some dynamical processing in the system's past. These results present an exciting opportunity to model the atmospheres and formation histories of these planets in more detail in the near future, and are complementary to future higher-resolution, continuum-subtracted JWST spectroscopy."
JWST-TST High Contrast: Living on the Wedge, or, NIRCam Bar Coronagraphy Reveals CO2 in the HR 8799 and 51 Eri Exoplanets' Atmospheres (open access, but this website uses a strange and cumbersome humans test)
The clearest look yet in the infrared at the iconic multi-planet system HR 8799.
Figure 9. SED of 51 Eri b and best-fitting Exo-REM models. The top panel illustrates the transmission functions for each photometric filter. (Hint: CO2 is shown on the middle panel to the far right)
Wednesday, March 19, 2025
Thursday, February 20, 2025
Will The Big Bang Happen AGAIN (and Again)? with Matt O'Dowd
Recommendable! However, it seems the theories presented do not pass the Ockham's razor test, they are too complicated.
I speculated here that the universe is perhaps an aquarium.
By the way, the Big Bang theory is pretty absurd, because what came before the Big Bang?
Does planetary evolution favor human-like life? Study ups odds we're not alone
Good news! We are not alone! Evolution as a repeatable process of milestones.
"Humanity may not be extraordinary but rather the natural evolutionary outcome for our planet and likely others, according to a new model for how intelligent life developed on Earth. ...
A team of researchers at Penn State, who led the work, said the new interpretation of humanity's origin increases the probability of intelligent life elsewhere in the universe. ...
In the new study, a team of researchers that included astrophysicists and geobiologists argued that Earth's environment was initially inhospitable to many forms of life, and that key evolutionary steps only became possible when the global environment reached a "permissive" state. ..."
From the abstract:
"According to the “hard-steps” model, the origin of humanity required “successful passage through a number of intermediate steps” (so-called “hard steps”) that were intrinsically improbable in the time available for biological evolution on Earth. This model similarly predicts that technological life analogous to human life on Earth is “exceedingly rare” in the Universe.
Here, we critically reevaluate core assumptions of the hard-steps model through the lens of historical geobiology. Specifically, we propose an alternative model where there are no hard steps, and evolutionary singularities required for human origins can be explained via mechanisms outside of intrinsic improbability.
Furthermore, if Earth’s surface environment was initially inhospitable not only to human life, but also to certain key intermediate steps required for human existence, then the timing of human origins was controlled by the sequential opening of new global environmental windows of habitability over Earth history."
Does planetary evolution favor human-like life? Study ups odds we’re not alone (original news release) "New theory proposes that humans — and analogous life beyond Earth — may represent the probable outcome of biological and planetary evolution"
Fig. 1. The temporal distribution of our candidate hard steps.
Thursday, January 23, 2025
How a Belgian Priest Discovered the expansion of the universe and the Big Bang theory: Georges Lemaître
Very recommendable! Major discoveries are often made by multiple human beings.
Tuesday, January 21, 2025
New measurement confirms universe is expanding too fast for current models
Amazing stuff!
"... This discrepancy between model and data became known as the Hubble tension. Now, results ... provide even stronger support for the faster rate of expansion. ...
"The Universe really seems to be expanding fast. Too fast, even.
A new measurement confirms what previous — and highly debated — results had shown: The Universe is expanding faster than predicted by theoretical models, and faster than can be explained by our current understanding of physics. ...
Determining the expansion rate of the universe—known as the Hubble constant—has been a major scientific pursuit ever since 1929, when Edwin Hubble first discovered that the universe was expanding. ...
Measuring the Universe requires a cosmic ladder, which is a succession of methods used to measure the distances to celestial objects, with each method, or “rung,” relying on the previous for calibration. ..."
From the abstract (regrettably, an abstract written only for a few specialists):
"The Dark Energy Spectroscopic Instrument (DESI) collaboration measured a tight relation between the Hubble constant (H0) and the distance to the Coma cluster using the fundamental plane (FP) relation of the deepest, most homogeneous sample of early-type galaxies. To determine H0, we measure the distance to Coma by several independent routes, each with its own geometric reference. We measure the most precise distance to Coma from 13 Type Ia supernovae (SNe Ia) in the cluster with a mean standardized brightness of
Dan Scolnic Shows that the Universe Is Still Full of Surprises (original news release)
Figure 1. (Left) The locations of the SNe Ia identified to be in the Coma cluster (yellow stars) and the galaxies identified to be in the Coma group as from the full S24 Coma group catalog (light gray circles), the S24 FP sample (dark blue circles), and the T15 Coma group catalog (light blue circles). The center of the cluster is marked in red. ...
(Right) For the rectangular box on the left, a colored image of that sky area with the SNe within that location marked.
Wednesday, December 25, 2024
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