Selection of posts

From https://github.com/orgs/a-cosmology-group/discussions

RedshiftDrift on

I figured it out a long time before
the post. I didn't change my mind, a word is missing: "the *appearance*
of jets".

> how are you sure that the jets are drains?

How are they sure the drains are jets? "The data * suggests*
... " because it fits their "jet" model, but despite the thousands
of papers and drawings, there's no more evidence for "jets" than
there is evidence for Santa. Nobody has ruled out a plasma drain.

This type of observation is difficult to interpret because in a
drain, the plasma's rotational speeds exceed the velocity along
the axis to the massive object. A **rotating plasma**
produces both a blue and a red Doppler shift, but
relativistic beaming increases the luminosity of the
blue-shifted spiralling plasma. Often, the massive nucleus will
have only one jet because of the asymmetric distribution of
infalling matter. (When interpreted as a "jet", this gives the
impression that the plasma is moving toward us and relativistic
beaming makes the counter "jet" invisible.)

While drains are natural phenomena generated by gravity and
magnetic lines in a plasma, a contrived model is needed to produce
"jets" and we still
“don’t fully understand how this acceleration process *[to
produce jets]* occurs...

Another argument in favour of a drain is the appearance of "shock bows". Astronomers often "suggest" that an explosion happened millions of years ago, but what caused the explosion always remains a mystery. Interpreted as a drain, these glowing regions are stationary (another word you won't like @sahil5d ;-) and well understood (see images below). They occur at the location where the infalling particles reach a high enough energy to produce a glowing plasma.

Look at these pictures and convince me that these are not infalling particles on a central massive object, with drains produced by the focusing action of magnetic fields and bows produced by infalling particles reaching a sufficient energy. With a plasma drain model these observations are no mystery and all understood with regular lab physics instead of contrived "jet models". It's time to go against mainstream and tell people to stop believing in Santa.

Real photo from here with lines added showing the direction of falling plasma and ejected matter. The infalling light-elements are converted to heavy elements by the stars of the galaxy and ejected as 'dust', clearly visible as dark lanes at the periphery of the rotating galactic disk.

Glow discharge regions from here.
The video
shows the *stationary* discharge in *action*.

The Fermi Bubbles of our Milky Way from here

RedshiftDrift on

@ExpEarth good observation. The "Hubble redshift" is a change of
wavelength produced by a change of coordinates as a function of
time between the emitter (E) and the observer (O). Just like the
Doppler redshift, *space expansion* produces a change of
distance between E and O. There is no loss of energy, light is
just seen in a different reference frame.

In tired-light models, the redshift is an actual loss of energy
of light to "something else" ("something else" varies from model
to model). However, not all tired-light models imply a
quantum effect that you call *individual photons* (e.g.
some of these).

However the last part of your comment is incorrect. "EM waves"
and "photons" are **two different ways to describe**
** the same thing**. "

RedshiftDrift on

If we apply any of the redshifts you listed only to the individual photons comprising these waves, then the waves will no longer be blackbody radiation. This is because the photon number would not be affected.

**That is correct**, the 'tired-light' redshift does
not preserve the blackbody spectrum. See comment on my
cosmology calculator (right-hand side column, fourth
paragraph). Redshifted radiation by tired-light appears brighter
by a factor $(1+z)^3$.

That is why high redshifted galaxies appear to be exceptionally bright, not because they are young (as LCDM explains) but because the redshift mechanism preserves the number of photons.

For tired light to work we need to...

What do you mean by "work"? Observations of galaxies and quasars
all show them to be ** too bright**, and
fantastic explanations have been made up to explain their
luminosity. With a tired-light mechanism that conserves the number
of photons, these extreme luminosities are easily understood. So
tired-light "works" since it explains observations!

I'm wondering if any of those TL papers you link to attempts to derive the Hubble redshift using the larger multiphotonic waves...

Most of these papers are written by physicists/engineers who
don't have a good understanding of optics, so it's never clear
what is in their model. (My STz model satisfies both *
multiphotonic waves* **and** *waves-as-photons*.)

I think it's okay to use 'Hubble redshift' when talking about TL models: Hubble himself had no commitment to the BBT interpretation.

I am aware of that, I like to quote from "the Observational
approach to cosmology" p. 21 *On the other hand, if red-shifts
are evidence of some unknown principle of nature, which does not
involve actual motion, then ... the observable region is an
insignificant fraction of the universe as a whole.*

Sadly, cosmologists have taken Hubble's idea and intrepreted it ** only**
in the framework of an expanding universe.

RedshiftDrift on

@ExpEarth in earlier discussions I tried to describe the CMB in
terms of photons reaching an equilibrium between **redshift**
and the **Sunyaev-Zel'dovich** (SZ) effect. However,
it might be easier to describe the process with waves, more
specifically with the kind of waves that don't have a specific
direction of propagation and come from everywhere (like the waves
on a lake!)

*So thanks to you as well, Matt.* The description we use
doesn't change the physical process, but the *multi-photon-wave*
picture could be a better way to explain some properties of the
CMB:

- waves have no specific direction of propagation,
- waves come from everywhere,
- waves have the same spectral amplitude everywhere,
**no blurring**: the stern wake created by a boat propagates across the lake along a precise direction,- the waves on the lake are statistically random with peak amplitude at a wavelength of ~60 cm,
- CMB waves follow
*Bose-Einstein statistics*that produces a*Planck spectrum*with a peak amplitude at λ~2 mm.

RedshiftDrift on

@HanDeBruijn *Dimensional analysis* is the name of what
you do when you "check dimensions". Scientists learn that in
kindergarden, so there is no need to explicitly show how the
calculation is done. I have been doing this for 52 years and every
scientist does it.

To the physicist, equations have a physical meaning [dimension]. The equation above

$$H_0 = \zeta \frac{\alpha h^2}{m_e^2 c} n_e \quad \mbox{is the product of} \quad \begin{cases} \delta_z = \zeta \frac{h\nu}{mc^2} & \mbox{the redshift per scattering events } [1], \ \sigma = \frac{\alpha h}{m_e \nu} & \mbox{the scattering cross section } [area], \ n_e & \mbox{the electron number-density } [1/length^3], \ c & \mbox{the speed of light } [length/time], \end{cases}$$

which gives inverse $[time]$ as the dimension of the Hubble constant.

When an article presents equations with incoherent units, it means that the author did not understand the physical meaning of the equation. Unless it's an obvious typo, the article is probably meaningless.

Scientists also learn in kindergarden that the displayed digits of a number also have a physical meaning. The digits represent knowledge. In maths, in makes sense to write $\pi = 3.1415926535897932384626433832795028841971...$ (I can't remember the rest :smile:)

However in the physical sciences, the most accurate measurements rarely have an absolute accuracy below $1\times 10^{-6}$, and in cosmology numbers are presented on a $\log_{10}$-scale because most astronomical measurements give "order-of-magnitude" results. When engineers and mathematicians copy the output of their calculators to convey the result of their calculations 😮 it is a mistake that is just as bad as using incoherent [dimensions]. This shows that the author doesn't understand the physical meaning of the numbers they give.

That being said, I gave the values of $\zeta$ and $n_e$ to ** one**
significant digit because they have no physical meaning below 10%
uncertainty. The result $H_0 = 71.53222672$ km/s/Mpc is
meaningless since even the best measurements of the Hubble
constant by Riess have >1% uncertainties!

RedshiftDrift on

@HanDeBruijn The geometrical factor $\zeta$ is obtained from:

$$ \zeta = \frac{\int_0^\pi R(\Theta) \ \sin^2 \left( \frac{\theta}{2} \right) \ \rm d \Theta}{\int_0^\pi R(\Theta) \ \rm d \Theta} \approx 0.6174... $$

where

$$ R(\Theta) = \sin \frac{\Theta}{2} \ \sin \Theta \ \left[ 1 - \left( 1-\frac{2}{\pi} \right) \sin^2 \Theta \right] $$

Each term has a physical meaning (light interference, intensity gradient, momentum recoil, etc.) However, this equation is an approximation for isotropic and polarized light. A more precise calculation would have to consider that between galaxies, light is not perfectly isotropic and is usually not polarized (the $1-2/\pi$ term is the result of another integral over polarization states.)

So although the value of $\zeta$ is mathematically defined exactly by the model, it depends on conditions in space that are not well known. When the actual conditions found in space are considered in this calculation, the value should be near $\zeta = 0.6$.

The number-density of free electrons in the observation path is a
measured quantity. The integrated value $\int n_e(r) dr$ along the
path from *source* to *us* is obtained from Fast
Radio Bursts (FRBs) dispersion. Again, a constant $n_e$ is an
approximation since the density varies as a function of position
in space. Variations by a factor of two can be seen from one FRB
to another. I analyzed 12 FRBs a few years ago using the Euclidean
metric of a static cosmology and obtained an average $n*e =
0.25*{-0.1}^{+0.2}$, a value comparable to the published
values obtained in the ΛCDM framework. There are now about 20(?)
FRBs with a known redshift, but a new analysis would not reduce
the uncertainty significantly.

To answer your question, the STz model has no adjustable parameter but depends on measurements of the light distribution along the observation path for $\zeta$ and the electron number-density $n_e$. It predicts a value for the Hubble constant $\log_{10}(h) = 1.8\pm 0.3$ consistent with observations (the dimensionless Hubble constant $h$ is defined from $H_0 = h \times 100$ km/s/Mpc).

RedshiftDrift on

"Detection of the Cosmological Time Dilation of High Redshift Quasars" by Geraint F. Lewis and Brendon J. Brewer http://arxiv.org/abs/2306.04053

It is notable that author Geraint Lewis is
deeply worried that someone will beat the Big Bang. In this
work, he cites papers from ** three** ACG
members.

Regards, Louis

"*However, it has been claimed that the variability displayed
by quasars over a broad range of redshifts does not show the
expected cosmological time dilation[...] This has led to the
suggestion that quasar variability is not intrinsic, but is due
to microlensing due to the presence of cosmologically
distributed black holes[...] Others have stated that this points
to more fundamental issues with our cosmological ideas*
[e.g. 23–25]"

"*Hence, as well as demonstrating the claim that the lack of
the redshift dependence of quasar variability represents a
significant challenge to the standard cosmological model, this
analysis further indicates that the properties of quasars are
consistent with them being truly cosmologically distant sources*."

"*This has an immediate impact on various claims, such as the
presence of a cosmologically significant population of
microlensing black holes [...] or more esoteric ideas about the
framework of the universe* [39], *and is further
evidence that we inhabit an expanding relativistic universe*."

[24] López-Corredoira, M. Tests and Problems of the Standard
Model in Cosmology. Foundations of Physics 47 (6), 711–768 (2017).
https: //doi.org/10.1007/s10701-017-0073-8, https://arxiv.org/abs/1701.08720
[astro-ph.CO].

[25] Crawford, D. F. A problem with the analysis of type Ia
supernovae. Open Astronomy 26 (1), 111–119 (2017). https://doi.org/10.1515/
astro-2017-0013, https://arxiv.org/abs/1711.11237
[astro-ph.CO].

[39] Sanejouand, Y.-H. A framework for the next generation of
stationary cosmological models. International Journal of Modern
Physics D 31 (10), 2250084–459 (2022). https://doi.org/10.1142/S0218271822500845,
https:
//arxiv.org/abs/2005.07931 [astro-ph.CO].

RedshiftDrift on

The ** obvious flaw in their analysis** is
that they select quasars based on their absolute luminosity, a
luminosity calculated using the LCDM framework. However, in a
static universe, LCDM equations overestimate the absolute
luminosity of quasars by a factor (1+z), and therefore their
selection of quasars is biased by a factor (1+z) in luminosity.

What they effectively measure is that the quasar temporal variability scales as (Luminosity)$^{1.28}$, which is consistent with the data in reference [19] Hawkins ApJ 553 (2), p. L97, 2001.

A second flaw in their analysis is that quasars are closer than the cosmological distances implied by their redshift (see Fulton, etc.) This also produces an overestimation of their luminosity by some power of (1+z) that is not included in their analysis.

RedshiftDrift on

**"Watersheds of the Universe: Laniakea and five newcomers
in the neighborhood"** A. Dupuy, H.M. Courtois, submitted
to A&A (AA/2023/46802) arXiv:2305.02339
(2023-5-3)

"This article delivers the dynamical cosmography of the Local
Universe within $z = 0.1$. Laniakea, our home supercluster's size
is confirmed to be $2\times 10^6$ (Mpc $h^{-1})^3$. Five more
superclusters are now dynamically revealed in the same way: Apus,
Hercules, Lepus, Perseus-Pisces and Shapley. Also, the central
repellers of the Bootes and Sculptor voids are found and the
Dipole and Cold Spot repellers now appear as a single gigantic
entity. Interestingly ** the observed superclusters are
an order of magnitude larger than the theoretical ones
predicted by cosmological ΛCDM simulations**."

RedshiftDrift on

Two weeks ago Anton Petrov posted a video claiming that JWST
galaxies were explained by the *Renaissance* simulation
of the early universe. The work published on ArXiV
uses a statistically **rare** occurrence of
developed galaxies in the simulation to claim that it explains
JWST observations. Indeed it explains observations with the
corresponding statistically low degree of confidence - in other
words it doesn't explain anything but a fluke in the simulation.

This other video published a week ago, Evidence That Some JWST
Galaxies May Instead Be Something Exotic, proposes another
explanation for the galaxies observed by JWST (needed because the
*Renaissance* explanation is worthless...)

The explanation (one of many others that don't work) is based on
the hypothesis of *dark stars*, a dense accumulation of
dark matter with some hydrogen and helium gas orbiting around the
dark star.

To make this hypothesis work one needs to assume:

- that dark matter (DM) exists,
- that DM is composed of particles,
- DM particles can self-annihilate, producing energy that's released as light (now it interacts with light?),
- the dark stars are supermassive (how can that be so early after the Big Bang?),
- the composite object is DM at its centre and baryonic matter
surrouding it (H, He, and
*possibly*other matter), - the gas cloud somehow remains at low density so there is no fusion,
- the released energy prevents the collapse of the cloud (but why not for other clouds that form galaxies?),
- the numerous previous assumptions are required to explain galaxy JADES-GS-z13-0 and three others (overfitting),
- that another model (Population-III stars) can co-exist and explain early stars after the Big Bang,
- that the observed Lyman-break in the spectrum does not come from regular galaxies,
- that the observed HeII spectral lines are not from Pop-III stars (despite seeing Pop-III signatures in other galaxies).

The large number of assumptions to make this work is a sign of very bad science. The article, as described by Anton Petrov, is not credible at all.

P.S. JADES-GS-z13-0 and other galaxies look small because at redshift z = 13.2 their distance is 35 Gly.

This is a followup to the post by Mitchell on May 29th

Hey everyone, I've noticed that both Dr. Becky and Anton Petrov, two youtubers running science channels, have put out videos that purport to explain away the too massive and old galaxies observed in the early universe. We already discussed Becky's video recently, but Anton recently put out some videos of his own.

[...]This video brings up the new simulations claiming that the JWST galaxies are in agreement with LCDM Major Explanation For JWST Galaxies That Broke Modern Theories

RedshiftDrift on

Han, you write:

The Hubble Constant: A Historical Review . Thanks for that reference in the first place. I didn't know that an

accuracy of 1%is claimed for the Hubble parameter usingthe current preferred ΛCDM cosmological model.Best values of$H_0$from the distance ladder lie in the range 73 - 75 km/s/Mpc, which may be much less accurate, but better physics I think. In (not really) my own theory, there are two (mathemacist :-) approaches to the Hubble tension. The first one is expressed by $H = 2/t$. The second one is expressed by $H = \sqrt{\chi G \rho}$ , where $\chi = 8 \pi/3$ if according to ΛCDM. Symbols are: $t =$ age of "the universe", $G =$ gravitational constant, $\rho =$ "density" of mass in "the universe". I guess your favorite @marmetl is not among these two. Whatever, allow me to proceed along these lines anyway.In the G. de Vaucouleurs section at my website we find, instead of the $\chi = 8 \pi/3$ value according to ΛCDM, a slightly greater value. Namely: $\chi = 8 \pi \times 0.3883945571$. Let us suppose that ΛCDM is employing the wrong value $(8 \pi/3)$ for that mathematical constant $\chi$. And suppose that it must be the latter instead, according to UAC: $\chi = 8 \pi \times 0.3883945571$. Then we get: $\boldsymbol{H :=} \sqrt{0.3883945571 / (1/3)} \times 67.4 =$

72.75403614, with 1% accuracy.Best values of$H_0$from the distance ladder lie in the range 73 - 75 km/s/Mpc. (Coincidence, of course :-)

Coincidence, of course! Here's why.

Historically, the published values of $H_0$ based on the distance-ladder went as low as 50 km/s/Mpc in the 1950s before increasing to $\approx 70$ km/s/Mpc in 2000.

The CMB-based value of $H_0$ was found by **selecting**,
*out of several cosmologies*, the model
that gave the nearest value to the distance-ladder measurements.
So in the 1990s cosmologists

Riess *et al.* improved distance-ladder measurements
which eventually gave $H_0 \approx 73.3$ km/s/Mpc, with a low
uncertainty. At the same time, refined measurements of the CMB
were analyzed using 1990s-derived parameters, and unsurprisingly
obtained $H_0 \approx 67.4$ km/s/Mpc with a low uncertainty.

The ratio you are considering, $72.75/67.4$, is the ratio of historical values of the distance-ladder measured $H_0$ , one in 2022, the other in 1997. The difference between these values depends on a random statistical uncertainty of measurements. Since it's a random number, it's a coincidence that it matches $\sqrt{0.3884 / (1/3)}$, of course!

From THE HUBBLE CONSTANT by John P. Huchra.

RedshiftDrift on

Original article:

by R. Brent Tully arXiv:2305.11950

"As the 20th century came to an end, ladder measurements of the Hubble constant were at odds with the favored cosmological model of the time of cold dark matter with Λ = 0. The new favorite became the ΛCDM model with dark energy giving rise to acceleration of space in a topologically flat universe. Yet ladder measurements, continuously improving, create doubts that this currently favorite model is complete. Yes, there is a Hubble tension."

RedshiftDrift on

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