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Conversional Spacetime Model

November 2024

DOI:10.13140/RG.2.2.13604.28804

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REMspace

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Many theories of the nature of the Universe lack elegance and have black spots like dark matter and singularity. Extending the philosophy of unified field and string theories, the conversional spacetime model (CSM) proposes the idea of the homogenous basic nature of everything, meaning that all kinds of elementary particles and interactions consist of or represented by spacetime, which convert into each other under specific conditions. This philosophical and generalized model reduces enigmas and creates a relatively uniform picture of the Universe, which could lead to new insights regardless of CSM’s correctness.

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CONVERSIONAL SPACETIME MODEL

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Conversional Spacetime Model

v1.8 / March 20, 2025

(Detailed the Big Bang era and why BHs couldn't form too early. Partially addressed the baryon

asymmetry problem. Introduced new testing opportunities through BAO)

Michael Raduga

REMspace, Philosophical department

ORCID: https://orcid.org/0000-0002-1320-2467

Correspondence concerning this article should be addressed to Michael Raduga:

raduga@remspace.net (Redwood City, CA, US)

Statements and Declarations

The author has no affiliations with or involvement in any organization or entity with any

financial interest (such as honoraria; educational grants; participation in speakers’ bureaus;

membership, employment, consultancies, stock ownership, or other equity interest; and expert

testimony or patent-licensing arrangements) or non-financial interest (such as personal or

professional relationships, affiliations, knowledge, or beliefs) in the subject matter or materials

discussed in this manuscript.

CONVERSIONAL SPACETIME MODEL

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Abstract

Many theories of the nature of the Universe lack elegance and have black spots like dark matter

and singularity. Extending the philosophy of unified field and string theories, the conversional

spacetime model (CSM) proposes the idea of the homogenous basic nature of everything,

meaning that all kinds of elementary particles and interactions consist of spacetime (or its

possible substructures), which convert into each other under specific conditions. This

philosophical and generalized model reduces enigmas and creates a relatively uniform picture of

the Universe, which could lead to new insights regardless of CSM’s correctness.

Keywords: spacetime, black holes, dark matter, dark energy, big bang theory, theory of

everything.

CONVERSIONAL SPACETIME MODEL

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Conversional Spacetime Model

CSM Principles

Common sense and scientific discoveries reveal that any complex system consists of

simpler subsystems. This principle may lead to the conclusion that the Universe should be as

simple as possible in its basic nature. Ideally, it must be homogeneous. For this reason, theories

of everything often operate in the frameworks of the most fundamental fabric. It could be

multidimensional strings in string theories[1] or different kinds of fields in unified field

theories[2]. Despite all attempts, there are still no elegant model that could explain the Universe

without black spots like dark matter and dark energy, which clearly demonstrate how incomplete

our knowledge is. In an attempt to resolve the problem, the conversional spacetime model

(CSM) uses spacetime (ST) as the basic fabric of the Universe or medium that represents the

basic fabric and its features.

 The first principle of CSM is based on the fact that general relativity (GR)[3] and

gravitational waves[4] demonstrate that ST has a certain level of flexibility. CSM

pushes this ST flexibility to the proposal that, under certain conditions, ST could be

converted into particles and backwards. In this case, ST has to be the only fabric and

the media in the Universe.

 The second principle of CSM is that, if ST is indeed the only fabric in the Universe,

then everything should be explained by ST’s properties, including all unexplained

phenomena. At the same time, ST’s complex nature could be easier to reveal through

combined explained and unexplained mechanisms rather than studying ST directly.

As a result, CSM works via the hypothetical adjustment of ST’s properties to fill gaps

in the current knowledge until these modifications do not contradict each other or the

well-established scientific paradigm.

CONVERSIONAL SPACETIME MODEL

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 The third principle of CSM is that the knowledge of the Universe is currently

incomplete, meaning that theories of its nature have a high probability of containing

errors. CSM solves this problem by adopting an elastic approach to its creation. This

gives the model great flexibility because any of its future versions can be modified if

new discoveries or hypotheses create room for smoother causality.

A glass of water with ice serves as a simplified analogy for CSM. Although water and ice

appear different and interact in distinct ways, they continuously convert into each other while

also serving as mediums for various interactions, such as wave propagation and temperature

exchange. CSM applies this principle to ST (or its more fundamental building blocks, if any),

extending it across the entire Universe and giving rise to all its components and mechanisms.

Regardless of how CSM relates to the actual nature of the Universe, on a philosophical

level, this framework attempts to explain many well-established facts and unites them in one

system. Thus, CSM may predict some unknown mechanisms in the Universe despite its

speculative nature. As a result, CSM may be a useful tool in a wide range of disciplines like

quantum physics and cosmology.

Model for Observable Mechanisms

ST is the basic source of all particles, and it deposits its energy in them. Massless

particles are ST waives, while other particles are compressed or folded ST waives with the

wrapped curvature of ST fabric. Differences in spin, charge, and mass represent specific features

of their formation, as described later. They engage in all kinds of interactions because ST’s

properties can carry all four forces (gravitational[5], electromagnetic[6], strong nuclear[7], weak

nuclear[8]). Having a wave-like and uniform nature, matter made of ST particles obeys quantum

CONVERSIONAL SPACETIME MODEL

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mechanics (QM) on a smaller scale and GR on a larger scale. In this case, quantum fields[9]

become properties of ST.

Under normal conditions, ST particles attract each other, forming chemical elements.

Under high pressure and energy, particles collide, recombining and releasing energy[10]. When

their combined ST curvature reaches certain limits, collapsing events of different stages happen,

resulting in white dwarfs[11], neutron stars[12], and black holes (BHs)[13].

Particles trapped by BHs at a certain moment experience enough gravitational pressure to

be converted back into ST, causing a missing baryon problem[14]. Newly converted ST pushes

inner BHs’ ST outwards, which slows ST conversion while dissipating BHs much faster than the

Hawking radiation[15]. The ST conversion process is limited, allowing BHs to grow with an

excessive feeding source without which BHs dissipate quickly enough, leading to the formation

of more supermassive black holes (SMBHs) in the early Universe[16], when visible matter (VM)

was more abundant and concentrated.

Propagating from within BHs, converted ST incises the entropy of the Universe and it has

to push surrounding ST. This pressure results in the appearance of ST bulges (STBs)—regions

with higher ST density around individual BHs or regions with their high amount. They slowly

appear mostly starting from the centers of galaxies[17] and, due to the resulting in time

dilation[18], they are observed as dispersed gravitation, creating gravitational lensing (GL) and

the illusion of dark matter (DM)[19]. STBs’ gravitational potential exceeds their ST pressure,

allowing them to merge[20]. Because STBs propagate in all directions and are not affected by

VM, they are not flattened in galaxies like VM[21]. For the same reasons, STBs could exist apart

from VM (e.g., when moved from galaxies by collisions[22]). STBs are proportional to relevant

BHs’ activity and their concentrations[23] (additionally reflected in subhalos) and they vary in

shape and size.

CONVERSIONAL SPACETIME MODEL

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STBs eventually dissipate into intergalactic space, where gravitational potential unfolds

into actual ST volume. This process feeds cosmic voids[24], which help move VM into galaxy

filaments. Due to ST pressure, voids get GL and are perceived like dark energy (DE)[25].

Because ST pressure depends on varying BHs’ activity, the Hubble flow is slightly different in

all directions[26].

When summed up, relative ST expansion achieves high speed and collapses into other ST

expansions (i.e. Universes) with critical differences in speed (could exceed the speed of light by

several multiples); in turn, vast STBs appear, followed by regional energy surplus epochs

(ESEs), which later result in Big Bangs but without singularity[27]. Within ESEs, until the

external ST pressure exceeds the internal pressure, collapsing ST creates an abundance of

energy. It reverses entropy, time, and many natural mechanisms, including the Second Law of

Thermodynamics. Since ESEs are non-isolated systems and reversed causality becomes

impossible, the principle of maximum action drives effects to become new causes, leading to

globally diverse sequences. Converted back into particles within reversed BHs known as white

holes (WHs)[28], ST deposits its energy and volume into their characteristics. As the Universe

shrinks, more and more energy is applied to those particles, eventually converting them into hot,

dense plasma[29]. At this moment, the local universe reaches its lowest entropy and time

equilibrium (fluctuates between extreme dilations in both directions). Despite the extreme

concentration of plasma and energy due to external pressure, BHs cannot form because entropy

tends to decrease.

Eventually, external ST pressure drops below the pressure inside ESEs, triggering energy

deficit epochs (EDEs) with rising entropy and baryon acoustic oscillations (BAO)[30]. A

forward time arrow leads to expansion, cooling, recombination, and the emergence of

particles[31]. Because this process starts from ESEs borders and goes inwards, it creates

asymmetries in the cosmic microwave background (CMB) anisotropy field[32]. At this moment,

CONVERSIONAL SPACETIME MODEL

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inner ST pressure is still high and manifests as DM’s gravitational potential[33]. As the overall

density remains extreme relative to the Schwarzschild density[34], primordial black holes

(PBHs) form[35]. PBHs radiate newly converted ST outward, preventing VM from total collapse

by pushing against each other and everything else. Around this stage, most of VM is converted

into ST, creating the vast spaces of the visible Universe and its voids (Image 1).

Image 1. Graphical representation of the two fundamental epochs of CSM. WH – White

hole, BH – Black hole, V – volume, -t/+t – arrows of Time.

Later, some PBHs merge into SMBHs[36] in the early Universe and not trapped by them

VM forms nebulas, galaxies, and BHs. Due to the abundance of PBHs and condense VM, first

galaxies appear relatively quickly[37]. Because of BHs’ early age, new galaxies don’t have time

to convert ST into large STBs[23] and rotate slower[38].

Other Possible Outcomes of CSM

The current CSM Big Bang model remains valid only if the initial rise in entropy

somehow (it could be slow enough) prevented the formation of BHs. In this case, CSM at least

CONVERSIONAL SPACETIME MODEL

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partially aligns with well-established scientific knowledge. However, if plasma had immediately

collapsed into BHs at the beginning of a new entropy cycle, the entire scenario would change.

Since PBHs could form at Planck scales, they would have converted all primordial plasma into

ST. In this case, all existing VM could result from Hawking radiation, with baryon asymmetry

explained by the matter-antimatter ratio in the radiation process.

CSM creates many other subsequent propositions, some of which could be tested in the

future:

 Since everything at the fundamental level consists of ST, Planck's constants could

represent its core properties, helping to calculate the conversion ratio between ST and

particles.

 Singularity could not exist.

 Eventually, all particles could decay into ST even without conversion in BHs.

 ST conversion speed in BHs could be dependent on an STB’s size.

 ST conversion in BHs could affect galaxies’ structures, shapes, and types.

 ST pressure could reveal itself in the form of particles similar to gravitons, which later

decay into ST.

 Young BHs, which are not surrounded by STBs, could convert ST quicker than old BHs

due to the lower ST pressure around them, meaning their STBs could grow faster.

 Though converted ST could keep information about particles in its own properties, the

homogeneous basic nature of ST could make the conservation of information negligible,

possibly erased by BHs and/or WHs.

 STBs could have different layers depending on changing BHs’ activity.

 STBs apart from galaxies could dissipate faster without the feeding source, revealing

actual ST conversion and propagation speeds.

CONVERSIONAL SPACETIME MODEL

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 More actively feeding cosmic voids could have more DE and GL.

 When BHs convert different forms of matter into ST, WHs could convert ST into the

most basic particles/energy.

 During the early stages of ESEs, WHs could emerge in extremely high numbers.

 During ESEs, WHs could appear in the most low-density regions.

 ESEs could encompass vast spaces and have different shapes.

 ESEs could have different stages, which could be responsible for different particles and

their properties.

 Vast and deformed STBs apart from VM may indicate the beginnings of ESEs.

 ESEs could have different scales and final intensities.

 ESEs shapes could be observable by traces of their different stages.

 BAO could represent remnants of the first PBHs and ST they converted.

 Possible asymmetries in BAO could indicate the direction of the visible Universe's

expansion.

 Asymmetries in the CMB anisotropy field could indicate the centers of ESEs (denser

regions) and the direction of the visible Universe's expansion (less dense regions).

 Baryon asymmetry could reflect the ratio between matter and antimatter in Hawking

radiation.

 There could be regions near ESEs that could not be affected by ESEs directly but can be

affected by their radiation and upcoming ST pressure.

Testing CSM

Regardless of its overall accuracy, CSM may successfully predict certain complex

mechanisms in the Universe. This suggests that CSM should be tested on multiple levels to

CONVERSIONAL SPACETIME MODEL

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evaluate the integrity of the entire model. For instance, it could be tested on quantum, particle,

galactic, intergalactic, and primordial levels. A few examples are listed in this section but actual

tests may include different aspects of CSM.

Particle level

We cannot create a BH to directly test ST conversion on the most fundamental level, but

some processes could indicate its existence on a global scale. For instance, characteristics of the

missing baryon problem should represent ST conversion on the particle level: 1) With varying

intensity, the overall amount of VM should consistently decrease since the last ESE. 2) The

expansion of the Universe should directly correlate with the decrease in VM.

Galactic level

The longevity of lone BHs, especially out of STBs, should be significantly shorter than

predicted by Hawking radiation. One of the most promising directions would be studying STBs

displaced from galaxies or galaxy clusters by collisions: 1) After adjusting to the volume of

separated VM, STBs’ sizes should negatively correlate with the time elapsed since the collisions

due to ST dissipation. For example, the more time that passes, the fewer STBs remain. 2) Over

time, new STBs should start to appear within the separated VM. For instance, the more time that

passes, the larger the new STBs become.

Intergalactic level

The speed of the Hubble flow in a given direction should directly correlate with the

intensity of ST conversion in adjacent voids and galaxy filaments. For instance, more active

galaxy clusters may correspond to a slightly faster flow. Additionally, voids surrounded by a

higher density of active galaxy clusters should exhibit more prominent gravitational lensing (GL)

compared to others.

CONVERSIONAL SPACETIME MODEL

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Primordial level

CSM predicts that a significant fraction, or almost all, of the current ST in the visible

Universe could have been converted from matter by PBHs after the local ESE. This implies that

the proportion of PBHs in the early Universe should have been very high, with relatively close

distances between them and frequent collisions, which should have specific traces in the cosmic

gravitational wave background (GWB). Additionally, as CSM predicts no singularity before the

Big Bang, BAO should exhibit linear asymmetry.

Limitations

The basis of CSM includes completely new ST properties like the possibility of mutual

conversion with particles, regions with different ST pressures, and irregular amounts of ST

fabric. Though it is helpful to unite many processes in the Universe into one system, this radical

approach is highly controversial because none of its features have been confirmed. At the same

time, unified field theories, string theories, and loop quantum gravity theories[39] at least

partially follow the same path.

Currently, CSM cannot definitely explain the Baryon asymmetry problem[40]. It could be

explained by asymmetric Hawking radiation (if all plasma had immediately collapsed into BHs

during the Big Bang), the possibly wrong nature of CSM or its incompleteness, by the initial

abundance of matter compared to antimatter, or by the interchanging dominance between them

during subsequent ESEs, among other possible reasons[41]. As more arguments supporting the

Baryon asymmetry emerge, the more CSM should explain it.

One of the biggest challenges arises from the fact that reversed processes inside ESEs

occur in a non-isolated system, meaning that matter and energy are always being added or lost.

As a result, fully reversed causality becomes impossible unless the same process occurs

CONVERSIONAL SPACETIME MODEL

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everywhere simultaneously. Currently, CSM addresses this problem by suggesting that during

entropy decrease, reversed causality is not necessary as long as the principle of maximum action

becomes valid. This implies that a reversed universe will increasingly diverge from the original

one. In this scenario, effects become independent causes, generating their own effects, which

may completely differ from the original sequence. To justify CSM, this controversial issue must

be further examined.

Since CSM is a philosophical model with a generalized approach, it doesn’t explain

exactly how processes happen. For example, it doesn’t explain exactly how ST carries all four

forces, how ST converts into particles and backwards in BHs and WHs, how ST density converts

into actual ST, and so on. Without clear explanations and correct formulas, this approach can be

only philosophical.

Many theories propose the existence of more fundamental structures underlying ST,

which remain unknown. In this case, CSM describes their properties through ST. It is possible

that CSM describes the conversion of vacuum rather than ST itself. In this scenario, unless

vacuum is considered interchangeable with ST, CSM cannot serve as a complete theory of

everything, as it would lack a comprehensive explanation of ST.

However, since CSM is an elastic model, future versions could address some or all of

these problems.

Conclusions

CSM proposes the idea of a homogeneous basic nature of matter and processes in the

Universe. Regardless of its accuracy, this philosophical approach could help reveal alternative

solutions to some basic and unexplained mysteries of the Universe. At the same time, the model

provides hints that the Universe could be much larger than the remnants of the local ESE,

CONVERSIONAL SPACETIME MODEL

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meaning that the age and origin of the Universe could have nothing to do with the Big Bang and

remain unknown.

CONVERSIONAL SPACETIME MODEL

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ResearchGate has not been able to resolve any citations for this publication.

DESI dark energy time evolution is recovered by cosmologically coupled black holes

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Full-text available

Aug 2024

We report the first results from a deep near-infrared campaign with the Hubble Space Telescope to obtain late-epoch images of the Hubble Ultra Deep Field, 10–15 yr after the first epoch data were obtained. The main objectives are to search for faint active galactic nuclei (AGN) at high redshifts by virtue of their photometric variability and measure (or constrain) the comoving number density of supermassive black holes (SMBHs), n SMBH , at early times. In this Letter, we present an overview of the program and preliminary results concerning eight objects. Three variables are supernovae, two of which are apparently hostless with indeterminable redshifts, although one has previously been recorded as a z ≈ 6 object precisely because of its transient nature. Two further objects are clear AGN at z = 2.0 and 3.2, based on morphology and/or infrared spectroscopy from JWST. Three variable targets are identified at z = 6–7 that are also likely AGN candidates. These sources provide a first measure of n SMBH in the reionization epoch by photometric variability, which places a firm lower limit of 3 × 10 ⁻⁴ cMpc ⁻³ . After accounting for variability and luminosity incompleteness, we estimate n SMBH ≳ 8 × 10 ⁻³ cMpc ⁻³ , which is the largest value so far reported at these redshifts. This SMBH abundance is also strikingly similar to estimates of n SMBH in the local Universe. We discuss how these results test various theories for SMBH formation.

An Early Dark Matter–dominated Phase in the Assembly History of Milky Way–mass Galaxies Suggested by the TNG50 Simulation and JWST Observations

Article

Full-text available

May 2024

Whereas well-studied galaxies at cosmic noon are found to be baryon dominated within the effective radius, recent JWST observations of z ∼ 6–7 galaxies with stellar masses of only M * ∼ 10 ⁸⁻⁹ M ⊙ surprisingly indicate that they are dark matter dominated within r e ≈ 1 kpc. Here, we place these high-redshift measurements in the context of the TNG50 galaxy formation simulation by measuring the central (within 1 kpc) stellar, gas, and dark matter masses of galaxies in the simulation. The central baryon fraction varies strongly with galaxy stellar mass in TNG50, and this M * dependence is remarkably constant across 0 < z < 6: galaxies of low stellar mass ( M * ∼ 10 ⁸⁻⁹ M ⊙ ) are dark matter dominated as f baryon (<1 kpc) ∼ 0.25. At z = 6, the baryonic mass in the centers of low-mass galaxies is largely comprised of gas, exceeding the stellar mass component by a factor ∼4. We use the simulation to track the typical evolution of such low-mass, dark matter–dominated galaxies at z = 6 and show that these systems become baryon dominated in their centers at cosmic noon, with high stellar-to-gas mass ratios, and grow to galaxies of M * ∼ 10 10.5 M ⊙ at z = 0. Comparing to the dynamical and stellar mass measurements from observations at high redshifts, these findings suggest that the inferred star formation efficiency in the early Universe is broadly in line with the established assumptions for the cosmological simulations. Moreover, our results imply that the JWST observations may indeed have reached the early low-mass regime where the central parts of galaxies transition from being dark matter dominated to being baryon dominated.

First Batch of z ≈ 11–20 Candidate Objects Revealed by the James Webb Space Telescope Early Release Observations on SMACS 0723-73

Article

Full-text available

Dec 2022

On 2022 July 13, NASA released to the whole world the data obtained by the James Webb Space Telescope (JWST) Early Release Observations (ERO). These are the first set of science-grade data from this long-awaited facility, marking the beginning of a new era in astronomy. In the study of the early universe, JWST will allow us to push far beyond z ≈ 11, the redshift boundary previously imposed by the 1.7 μ m red cutoff of the Hubble Space Telescope (HST). In contrast, JWST’s NIRCam reaches ∼5 μ m. Among the JWST ERO targets there is a nearby galaxy cluster SMACS 0723-73, which is a massive cluster and has been long recognized as a potential “cosmic telescope” in amplifying background galaxies. The ERO six-band NIRCam observations on this target have covered an additional flanking field not boosted by gravitational lensing, which also sees far beyond HST. Here we report the result from our search of candidate objects at z > 11 using these ERO data. In total, there are 87 such objects identified by using the standard “dropout” technique. These objects are all detected in multiple bands and therefore cannot be spurious. For most of them, their multiband colors are inconsistent with known types of contaminants. If the detected dropout signature is interpreted as the expected Lyman break, it implies that these objects are at z ≈ 11–20. The large number of such candidate objects at such high redshifts is not expected from the previously favored predictions and demands further investigations. JWST spectroscopy on such objects will be critical.

Possible Systematic Rotation in the Mature Stellar Population of a z = 9.1 Galaxy

Article

Full-text available

Jul 2022

We present new observations with the Atacama Large Millimeter/submillimeter Array for a gravitationally lensed galaxy at z = 9.1, MACS1149-JD1. [O iii] 88 μm emission is detected at 10σ with a spatial resolution of ∼0.3 kpc in the source plane, enabling the most distant morphokinematic study of a galaxy. The [O iii] emission is distributed smoothly without any resolved clumps and shows a clear velocity gradient with ΔVobs/2σtot = 0.84 ± 0.23, where ΔVobs is the observed maximum velocity difference and σtot is the velocity dispersion measured in the spatially integrated line profile, suggesting a rotating system. Assuming a geometrically thin self-gravitating rotation disk model, we obtain

{V}_{\mathrm{rot}}/{\sigma }_{V}={0.67}_{-0.26}^{+0.73}

, where Vrot and σV are the rotation velocity and velocity dispersion, respectively, still consistent with rotation. The resulting disk mass of

{0.65}_{-0.40}^{+1.37}\times {10}^{9}

M⊙ is consistent with being associated with the stellar mass identified with a 300 Myr old stellar population independently indicated by a Balmer break in the spectral energy distribution. We conclude that the most of the dynamical mass is associated with the previously identified mature stellar population that formed at z ∼ 15.

Measurements of the Hubble Constant: Tensions in Perspective*

Article

Full-text available

Sep 2021

W. Freedman

Measurement of the distances to nearby galaxies has improved rapidly in recent decades. The ever-present challenge is to reduce systematic effects, especially as greater distances are probed and the uncertainties become larger. In this paper, we combine several recent calibrations of the tip of the red giant branch (TRGB) method. These calibrations are internally self-consistent at the 1% level. New Gaia Early Data Release 3 data provide an additional consistency check at a (lower) 5% level of accuracy, a result of the well-documented Gaia angular covariance bias. The updated TRGB calibration applied to a sample of Type Ia supernovae from the Carnegie Supernova Project results in a value of the Hubble constant of H0 = 69.8 ± 0.6 (stat) ± 1.6 (sys) km s⁻¹Mpc⁻¹. No statistically significant difference is found between the value of H0 based on the TRGB and that determined from the cosmic microwave background. The TRGB results are also consistent to within 2σ with the SHoES and Spitzer plus Hubble Space Telescope (HST) Key Project Cepheid calibrations. The TRGB results alone do not demand additional new physics beyond the standard (λCDM) cosmological model. They have the advantage of simplicity of the underlying physics (the core He flash) and small systematic uncertainties (from extinction, metallicity, and crowding). Finally, the strengths and weaknesses of both the TRGB and Cepheids are reviewed, and prospects for addressing the current discrepancy with future Gaia, HST, and James Webb Space Telescope observations are discussed. Resolving this discrepancy is essential for ascertaining if the claimed tension in H0between the locally measured and CMB-inferred values is physically motivated.

Observation of Gravitational Waves from a Binary Black Hole Merger

Article

Full-text available

Feb 2016

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 × 10 − 21 . It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1 σ . The source lies at a luminosity distance of 41 0 − 180 + 160 Mpc corresponding to a redshift z = 0.0 9 − 0.04 + 0.03 . In the source frame, the initial black hole masses are 3 6 − 4 + 5 M ⊙ and 2 9 − 4 + 4 M ⊙ , and the final black hole mass is 6 2 − 4 + 4 M ⊙ , with 3. 0 − 0.5 + 0.5 M ⊙ c 2 radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger. Published by the American Physical Society 2016

Primordial black holes as supermassive black holes seeds

Preprint

Nov 2024

The presence of supermassive black holes (SMBHs,

M_{\bullet}\sim 10^{6-10}~M_{\odot}

) in the first cosmic Gyr (

z\gtrsim 6

) challenges current models of BH formation and evolution. We propose a novel mechanism for the formation of early SMBH seeds based on primordial black holes (PBHs). We assume a non-Gaussian primordial power spectrum as expected in inflationary models; these scenarios predict that PBHs are initially clustered and preferentially formed in the high-

\sigma

fluctuations of the large-scale density field, out of which dark matter (DM) halos are originated. Our model accounts for (i) PBH accretion and feedback, (ii) DM halo growth, and (iii) gas dynamical friction. PBHs lose angular momentum due to gas dynamical friction, sink into a dense core, where BH binaries form and undergo a runaway merger, eventually leading to the formation of a single, massive seed. This mechanism starts at

z\sim 20-40

in rare halos (

M_h\sim 10^7\ M_\odot

corresponding to

\sim 5-7\sigma

fluctuations), and provides massive (

\sim 10^{4-5}~ M_{\odot}

) seeds by

z\sim 10-30

. We derive a physically-motivated seeding prescription that provides the mass of the seed,

M_{\rm seed}(z)=3.1\times 10^{5}\ { M_{\odot}}[(1+z)/10]^{-1.2}

, and seeded halo,

M_{h}(z)=2\times 10^{9}\ {M_{\odot}}[(1+z)/10]^{-2}e^{-0.05z}

as a function of redshift. This seeding mechanism requires that only a small fraction of DM is constituted by PBHs, namely

f_{\rm PBH}\sim 3 \times 10^{-6}

. We find that

z\sim 6-7

quasars can be explained with

6\times 10^4 M_{\rm \odot}

seeds planted at

z\sim 32

, and growing at sub-Eddington rates,

\langle\lambda_{\rm E}\rangle\sim 0.55

. The same scenario reproduces the BH mass of GNz11 at z=10.6, while UHZ1 (z=10.1) and GHZ9 (z=10) data favour instead slightly later (

z\sim 20-25

), more massive (

10^5~M_{\rm \odot}

) seeds. [Abridged]

Concentrations of dark haloes emerge from their merger histories

Article

Sep 2020
MON NOT R ASTRON SOC

The concentration parameter is a key characteristic of a dark matter halo that conveniently connects the halo’s present-day structure with its assembly history. Using ‘Dark Sky’, a suite of cosmological N-body simulations, we investigate how halo concentration evolves with time and emerges from the mass assembly history. We also explore the origin of the scatter in the relation between concentration and assembly history. We show that the evolution of halo concentration has two primary modes: (1) smooth increase due to pseudo-evolution; and (2) intense responses to physical merger events. Merger events induce lasting and substantial changes in halo structures, and we observe a universal response in the concentration parameter. We argue that merger events are a major contributor to the uncertainty in halo concentration at fixed halo mass and formation time. In fact, even haloes that are typically classified as having quiescent formation histories experience multiple minor mergers. These minor mergers drive small deviations from pseudo-evolution, which cause fluctuations in the concentration parameters and result in effectively irreducible scatter in the relation between concentration and assembly history. Hence, caution should be taken when using present-day halo concentration parameter as a proxy for the halo assembly history, especially if the recent merger history is unknown.

Violation of CP Invariance C Asymmetry and Baryon Asymmetry of the Universe

Article

Jan 1986

A. D. Sakharov

Article

Full-text available

Classical color fields as a dark matter candidate

June 2007 · Open Physics

Vladimir Dzhunushaliev

The model of Dark Matter is proposed in which the Dark Matter is a classical color field. The color fields are invisible as they may interact with colored elementary particles like 't Hooft - Polyakov monopole only. The comparison with the Universal Rotation Curve is carried out.

Article

Full-text available

A response to arXiv:1310.2791: A self-consistent public catalogue of voids and superclusters in the...

October 2013

Recently, Nadathur & Hotchkiss (2013) submitted a paper discussing a new cosmic void catalog. This paper includes claims about the void catalog described in Sutter et al. (2012). In this note, we respond to those claims, clarify some discrepancies between the text of Sutter et al. (2012) and the most recent version of the catalog, and provide some comments on the differences between our catalog ... [Show full abstract] and that of Nadathur & Hotchkiss (2013). All updates and documentation for our catalog are available at http://www.cosmicvoids.net.

Preprint

Gravitational Lensing as a Consequence of Spacetime Expansion: A Theoretical and Observational Analy...

March 2025

Shipei Lin

Gravitational lensing is a fundamental prediction of general relativity, commonly interpreted as the deflection of light due to spacetime curvature. In this study, we propose an alternative theoretical framework in which light deflection arises from variations in the local spacetime expansion rate rather than curvature. We construct a model based on the gradient of the spacetime expansion rate ... [Show full abstract] and derive the corresponding gravitational lensing formulae. For strong gravitational lensing, our model successfully reproduces Einstein's lensing equation, and its validity is confirmed through observational data from celestial objects such as Abell 1689 and SDSS J1004+4112, with computational results differing from observed values by less than 1%. Furthermore, we derive the standard weak gravitational lensing convergence (κ), shear (γ), and deflection angle (α) equations and demonstrate their consistency with those in general relativity. Finally, we apply our model to the gravitational lensing effect of the Bullet Cluster and find that our calculations are consistent with the observed lensing deflection angle. This suggests that the necessity of dark matter may warrant reconsideration. Our findings indicate that inhomogeneities in the spacetime expansion rate may provide an alternative mechanism to explain gravitational lens-ing. Future work will explore the implications of this model in large-scale cosmic structures, the gravitational lensing effect of the cosmic microwave background (CMB), and galactic rotation curves.

Preprint

Full-text available

STUDY OF THE UNIVERSE AS A SET OF SPATIAL CONTRACTIONS AND A RELATIVELY COMMON PHYSICAL OBJECT, VACU...

August 2024

Alexandre Georges

We will study the Universe as a set of spatial contractions, as proposed at the beginning of the study of radial gravitational waves in 2019, in order to associate quantum fluctuations of the vacuum with variations in the curvature of Space-Time. We will then describe elementary particles as expressions of the properties of space itself, offering on this occasion a possible solution to the ... [Show full abstract] problem of dark matter, by quantum fluctuations of the vacuum causing pairs of weakly interactive particles emergence by variations in the curvature of Space-Time. This conception of the Universe will then push us to attribute to space itself a scalar field of heat. We will then extract from these developments a cosmological constant Λ Γ describing an expansion alternating between phases of acceleration and slowdown and predicting a progressive decline of dark energy that should already be perceptible. By considering the Universe as a set of spatial contractions and therefore as a physical object that would be the expression of the properties of space itself, we will then be able to attribute to its initial singularity properties such as a magnetic moment of spin, preserved in the primordial Universe and causing, in fact, an asymmetry explaining the difference in probability in the set of particle-antiparticle pairs during the inflationary era. We would live today within the residue resulting from the bursting of a completely common singularity. These reflections will strongly suggest the existence of the multiverse, modeled as a set of "bubbles" each containing an infinity of "bubbles" of universes emerging from the evaporation of the black holes populating it, then transmitting to these emerging universes their helicity and other characteristics. The properties of Space-Time and the entropy intrinsic to space itself would then be common to the universes of the multiverse, consequently preserving the fundamental laws of physics.

Last Updated: 20 Mar 2025