a-cosmology-group/acg

Cosmology Group repo for its public webpage, reviews & publications on tensions in ΛCDM, redshift and the CMB

Structure of the ACG Website

Navigation structure of the ACG website just-the-docs:

├─ A Cosmology Group [nav_order: 1]
│ ├─ Open Letter to the Scientific Community
│ ├─ ACG Organization
├─ ACG Newsletters [nav_order: 2]
├─ Essays [nav_order: 3]
│ ├─ [essay-1] ...
├─ Cosmological Models [nav_order: 4]
│ ├─ [model-1] ...
│ ├─ Time-Dependent Cosmologies
│ │ ├─ [models] ...
│ ├─ Spectral-Redshift Cosmologies
│ │ ├─ [models] ...
│ ├─ Non-Expanding Cosmologies
│ │ ├─ [models] ...
├─ Redshift Models [nav_order: 5]
│ ├─ [models] ...
├─ Gravity Models [nav_order: 6]
│ ├─ [models] ...
├─ Resources [nav_order: 7]
│ ├─ [resource-1] ...
├─ Cosmology Calculators [nav_order: 8]
│ ├─ [code-1] ...
├─ Videos [nav_order: 9]
│ ├─ [video-1] ...
├─ Conferences [nav_order: 10]
│ ├─ CCC-1
│ ├─ CCC-2
│ ├─ [conference-N] ...

Corresponding folder structure in a-cosmology-group/acg repo:

├─ index.md
├─ org
│  ├─ acg-organization.md
│  ├─ open-letter-on-cosmology.md
├─ newsletters
│  ├─ index.md [acg-newsletter.pdf] ...
├─ essays
│  ├─ index.md
│  ├─ [author_a]
│  │  ├─ [essay.md] [essay.pdf] ...
│  ├─ [author_b] ...
├─ models
│  ├─ index.md
│  ├─ time-dependent-cosmologies
│  │  ├─ index.md ...
│  ├─ spectral-redshift-cosmologies
│  │  ├─ index.md ...
│  ├─ non-expanding-cosmologies
│  │  ├─ index.md ...
├─ redshift
│  ├─ index.md
│  ├─ [model-1]
│  │  ├─ [model.md] [model.pdf] ...
│  ├─ [model-2] ...
├─ gravity
│  ├─ index.md
│  ├─ [model-1]
│  │  ├─ [model.md] [model.pdf] ...
│  ├─ [model-2] ...
├─ resources
│  ├─ index.md
│  ├─ [author_a]
│  │  ├─ [resource.md] [resource.pdf] ...
│  ├─ [author_b] ...
├─ code
│  ├─ index.md
│  ├─ [author_a]
│  │  ├─ [index.md] [code.md] [code...]
│  ├─ [author_b] ...
├─ videos
│  ├─ index.md
├─ conferences
│  ├─ index.md
│  ├─ CCC-1
│  │  ├─ [index.md] ...
│  ├─ CCC-2
│  │  ├─ [index.md] ...
│  ├─ [conference-N] ...

acg's Issues

Typos

A few typos on https://a-cosmology-group.github.io/acg/

• Despite of -> Despite

and

• newphysics
• cosmologistssuch
• consistentcosmology
• asmany
• tothe

All the official distances of galaxies are wrong. Redshift-distance was originally a linear relationship but later on it was contaminated by the SR based formulas that made it into non-linear relationship.

All the official distances of galaxies are wrong. Redshift-distance was originally a linear relationship but later on it was contaminated by the SR based formulas that made it into non-linear relationship.

How actually it is implemented is something like... Limit redshift approaching to infinity, distance approaching to 13.6 billion light years or may be 13.7 billion light years.

There are learned persons at this forum who might be the authors of online Cosmology Calculators. Anyone can check from any online cosmology calculator that for any insane high value of redshift e.g. 2 million or whatever, the (light travel) distance shall remain 13.6 billion light years or so.

For a simple linear relationship of redshift and distance, the (light travel) distance for a galaxy having redshift 13 corresponds to the distance of 181 billion light years.

Not only redshifts, there is also independent proof that actual distances are at much higher scale than official distances. That proof is Gravitational Lensing.

Yes, rather than the proof of the existence of "dark matter", Gravitational Lensing is actually a proof that official distances of galaxies are hugely understated.

I have explained this thing in my second book (2019). Following is link to relevant section of book:

Gravitational Lensing Section - Book: "Philosophy Unscrambles Dark Matter"

Originally posted by @khuramonline in #28 (comment)

Broken links in the resources documents

The following links on the Resources page are broken. They ought to be updated or removed.

acg/resources/README.md

Line 31 in 694ed3f

[Dark energy is the biggest mystery in cosmology, but it may not exist at all](https://ec.europa.eu/research-and-innovation/en/horizon-magazine)<br>

acg/resources/README.md

Line 47 in 694ed3f

[Astrophysicists, References and Websites](https://cosmologyscience.com/ref.htm)<br>

acg/resources/README.md

Line 55 in 694ed3f

[Do We Have the Big Bang Theory All Wrong?](https://nautil.us/issue/15/turbulence/do-we-have-the-big-bang-theory-all-wrong)<br>

Broken link to cosmosandhistory.org in top-level readme

The link from has been qualified as "embarrassing" in the top level README.md file leads to a 400 Bad Request http error, presumably because the host www.cosmosandhistory.org is not valid.

acg/README.md

Line 17 in 3092134

After decades of development, ΛCDM cosmology is akin to an iceberg hiding 95% of its content under some unknown newphysics, a situation that [has been qualified as “embarrassing”](https://www.cosmosandhistory.org/index.php/journal/article/view/161) by leading cosmologists. Astronomers and cosmologistssuch as Edwin Hubble, Fritz Zwicky, Fred Hoyle, Chip Arp, Alan Guth and Adam Riess have failed to create a consistentcosmology. ACG encourages a dialogue with every scientist, as progress will be served best by attempting to engage asmany specialists as possible. You are especially welcome to join ACG if you have published work that is critical tothe development of contemporary cosmology.

Solve the Cauchy problem for the equation

Discussed in https://github.com/orgs/a-cosmology-group/discussions/174

^{Originally posted by brazenoptimist October 16, 2023}
$$ \frac{\partial^2u(x,t)}{\partial t^2} = \frac{\partial^2u(x,t)}{\partial x^2} - \sin(u(x,t)) $$

on a lattice from 0 to 10 with step $dx = 0.005$

and initial conditions:

• Take as initial data $u(x,t_0)$ and $u'(x,t_0)$ for $t_0$ a wave packet traveling at velocity $v$.

• Find $u(x,t)$ at $t = 150$.

• Match the velocity so that the packet travels from one edge of the grating to the other, but does not go outside the grating.

• Draw a picture of the motion of the packet.

i dont understand why my code doesnt work...

import numpy as np
import matplotlib.pyplot as plt
from scipy.integrate import solve_ivp
from scipy.sparse import diags
from matplotlib import animation

L = 10
x0 = 0
sigma = 0.5
p0 = 2
t_final = 150
v = L / t_final


def u0(x):
    return np.exp(-((x - x0) ** 2) / (2 * sigma**2)) * np.cos(p0 * x)


def u0_t(x):
    return -v * np.exp(-((x - x0) ** 2) / (2 * sigma**2)) * np.sin(p0 * x)


def du_dt(t, u):
    d2u_dx2 = D2.dot(u[:N])
    return np.hstack([u[N:], d2u_dx2 - np.sin(u[:N])])


dx = 0.005
x = np.arange(0, L + dx, dx)
N = len(x)

D2 = diags([1, -2, 1], [-1, 0, 1], shape=(N, N)) / dx**2

dt = 0.05

initial_conditions = np.hstack([u0(x), u0_t(x)][:N])

sol = solve_ivp(
    du_dt,
    t_span=[0, t_final],
    y0=initial_conditions,
    t_eval=np.arange(0, t_final, dt),
    method="RK45",
)

fig, ax = plt.subplots(figsize=(8, 6))
ax.set_xlim(0, L)
ax.set_ylim(-2, 2)
ax.set_title("Wave Packet Movement")
ax.set_xlabel("x")
ax.set_ylabel("u(x, t)")

(line,) = ax.plot([], [], lw=2)


def init():
    line.set_data([], [])
    return (line,)


def animate(i):
    line.set_data(x, sol.y[:N, i])
    return (line,)


frame_skip = 5
ani = animation.FuncAnimation(
    fig,
    animate,
    init_func=init,
    frames=range(0, len(sol.t), frame_skip),
    interval=200,
    blit=True,
)
# ani.save("wave_packe1.gif", writer="pillow", fps=60)
plt.show()
```</div>