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Computational Cosmology - Lambda-CDM

This is a critique of the Lambda-Cold Dark Matter model using a document describing its software.

The title comes from the keyword for this academic paper:
Adaptive Techniques for Clustered N-Body Cosmological Simulations

link

Dark matter is the foundation of modern cosmology, not relativity as one might expect.

Neither spacetime nor relativity occur in this document about the model.

Perhaps the Lambda-CDM model is not of interest to most but I find it interesting with my background which included factory automation models though these models interacted with real machines and their operators.
The cosmological model attempts to describe the universe with no interface other than our remote observations over recent time.

Excerpts and comments will follow before a final conclusion.

From the document describing the techniques used in the cosmological model:

'
Constraints on cosmology are tightest on scales of tens of megaparsecs and larger
due to observations of the Cosmic Microwave Background, giving us detailed initial
conditions ; however our knowledge of the non–linear evolution of the Universe
and of the properties of galaxies is still imperfect, as the detailed properties of
Dark Matter and of Star Formation (SF) remain only partially understood. On the other hand,
simulations of large volumes of the Universe , and of individual galaxies at
high resolution have been fundamental in putting the standard hierarchical,
Cold Dark Matter dominated model, on a robust footing.
'

Comments:
The CMB defined the initial conditions.
If the CMB is noise from the Earth's oceans as explained by Robitaille then this model has invalid initial conditions.


'detailed properties of Dark Matter and of SF remain only partially understood' but in an apparent contradiction, this 'model is on a robust footing.'

I expect these poorly understood facets to be critical.

The model is hierarchical because dark matter is the foundation for the start of any structures created by the model.


excerpt:
'
 For example, understanding the development of structures at very high redshift will present different parameter and algorithm choices than simulations that model the observations of current large scale structure.
'

Mismanagement of red shifts is the major pitfall for modern cosmology.
Not all red shifts are the relative velocity of the object.  Only an emission line shift is usually accurate for that atom. This line is used to check the rotation of hydrogen gas clouds in a spiral galaxy.
However a quasar with a relativistic hydrogen atom is definitely not moving at that atom's velocity.

The hydrogen absorption line red shift was found to be roughly proportional to distance by V.M. Slipher before 1920; this shift is due to neutral hydrogen atoms in the intergalactic medium. Intervening hydrogen gas clouds will increase this red shift making the proportion inaccurate.

There is a significant challenge to explain high red shifts in large scale stuctures. 
Quasars near galaxies in a cluster have their anomalous velocity.
Chandra has imaged hydrogen gas clouds in some clusters  so these clouds could disturb a more uniform pattern.
The only blue shifted galaxies in the universe appear to be in the vicinity of the Local Group (those roughly in the direction of Andromeda M31 due to a calcium absorption line blue shift from atoms moving toward the Milky Way). The result is nearly every galaxy is receding and the most distant ones are faster (red shift by distance).

Galaxies that appear to be at a similar distance could appear to have the same recession velocity but there is no observed source for the force causing this velocity in this consistent direction (away). Since electromagnetic forces are ignored, dark matter as a weak force of gravity is claimed to be distributed in the area to 'pull' objects around.

excerpt:
'
When simulating dark matter and stars, the goal is to understand the evolution of a
smooth distribution function that closely approaches a Boltzmann collisionless fluid.
As the N-body code is sampling this distribution using particles, a more accurate representation of the underlying mass distribution is obtained if the particles are not treated as point masses, but instead have their potential softened.  Softened forces are also of practical use since they limit the magnitude of the inter-particle force. Typically, the softening length is set at the inter-particle separation at the center of DM (Dark Matter) halos.
'

A halo definition:
'
According to modern models of physical cosmology, a dark matter halo is a basic unit of cosmological structure.
Thought to consist of dark matter, halos have not been observed directly. Their existence is inferred through observations of their effects on the motions of stars and gas in galaxies. Dark matter halos play a key role in current models of galaxy formation and evolution. Theories that attempt to explain the nature of dark matter halos with varying degrees of success include Cold Dark Matter (CDM), Warm Dark Matter, and massive compact halo objects (MACHOs).
'

Comment:
The model assumes matter is just a fluid. The only way it can develop into a structure with only gravity within the fluid is with an outside force which comes from DM halos.
An alternative is any ionized atoms or free protons and electrons could behave as plasma, bringing into the fluid electric fields and also magnetic fields from plasma in motion. This alternative is ignored.

excerpt:
'
In order to efficiently and accurately simulate a portion of an infinite Universe, we
perform the calculation assuming periodic boundary conditions. Because of the long
range nature of gravity, the sum over the infinite number of periodic replicas converges very slowly.
'

comment: when limited to weak gravity the outcome is reached 'very slowly.'

excerpt:

'
Despite being a small fraction of the energy density of the Universe, baryons play a
significant role in the evolution of structure. Not only are they the means by which
we can measure structure (e.g. via star light), they can also directly influence the
structure of the dark matter via gravitational coupling. Therefore following the
physics of the baryonic gas is essential for accurate modeling of structure formation.

comment:

[Mass] plays a significant role in the evolution of the structure of dark matter through coupling.'

Clearly when electromagnetic forces are ignored, leaving only gravity, dark matter must have the primary role in the evolution of a structure. Hence its estimate of 85% of matter in the universe even though none of the dark matter can be detected. At only 15%, matter has a minor role.

With 85% invisible this is certainly a magic trick.

Here is a very simple analogy:
I provide a recipe for a cake. 15% of the ingredients when mixed  can be treated as a fluid.

After adding a secret ingredient, amounting to 85% of the final, total ingredients, the batter will thicken to achieve the desired taste and firmness. I can tell you nothing about this secret ingredient though you wish to make a cake.

This secret ingredient, dark matter, has no defined characteristics, not even the composition of its particles; certainly it has no defined quantity to be distributed at some density.
This is an utterly useless recipe.

This is a preposterous cosmological model, providing no defined mechanism to explain how the secret stuff is so much more important than what we can observe and measure

excerpt:
'
 Hence we need a prescription for where the stars are forming.
Furthermore, it is clear that star formation is a self-regulating process due to the injection of energy from supernova, ionizing radiation and stellar winds into the star forming gas.
'

comment:

Again something outside  this 'structure' is required including radiation and winds.
Unfortunately the source (stars and supernovae) of those must arise before that source can affect this fluid.
excerpt:
'
We have implemented the "blast-wave" and "superbubbles" feedback models. In both models SF occurs in high gas density regions and the time distance scale for energy injection into the gas is then determined by physically motivated models. The "blastwave" prescription follows an analytic model of the Sedov blast wave and it has allowed us to successfully model a number of trends in galaxy populations.
'

comment:

Electromagnetic forces with or without plasma can bring structure more effectively with normal physics. The interaction of attractive and repulsive forces can achieve equilibrium. Gravity alone must lead to collapse. Instead the chaos of "blastwave" events and 'winds'  are assumed capable of bringing structure.

excerpt from the conclusion:

'
With these features, we can bring to bear the computational resources of many 100s of thousands of processor cores on the highly clustered, large dynamic range simulations that are necessary for understanding the formation of galaxies in the context of large
scale structure.
'

comment:

They achieved their goal of simulating 'the formation of galaxies in a large stucture.'
Whether this model's outcome has any relevance to the real universe is not described.
The critical fundamental assumption is dark matter determines the formation and evolution of the structure and yet dark matter is 'partially understood.'

This model is obviously a work in progress.
However its reliance on dark matter must impede any progress.

The big challenge for Electric Universe is this established base.

Eventually there must be a 'battle of cosmologies' but using logical arguments based on observations.
The big bang cosmology is fatalistic as it must end in either a final black hole, or an infinitely expanded universe with widely dispersed objects.
It is also a fantasy to claim one huge explosion evolved into what we see with a structure in our solar system and even structures at the scale of galaxy clusters.

The EU cosmology is one of evolution not disintegration as birkelund currents create filaments, then stars and galaxies.
The LMHSM does not consume matter (via fusion) but uses matter for planets and for  electromagnetic radiation when ionized as plasma, within electric currents.
Intergalactic plasma filaments are the foundation of large galactic structures.

The Lambda-CDM model is a failure.

 
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Last updated (09/02/2019)
Here is the list of topics in this Cosmology Topic Group , including my research.


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