Cosmology - "A Cosmic Conundrum" in Scientific American of September 2004

This document contains comments about the article A Beacon from the Big Bang by Lawrence M.Kraus and Michael S. Turner In Scientific American of September 2004.
A new incarnation of Einstein's cosmological constant may point the way beyond general relativity

See also: ScientificAm_February_2021-Cosmic-Conundrum.htm

Reflection

"Introduction"

In desperation, Einstein added an extra, ad hoc cosmological term to his equations to counterbalance gravity and allow for a static solution.
Okay.
In the past six years, however, the cosmological term - now called the cosmological constant - has re-emerged to play a central role in the 21st-century physics.
Okay
But the motivation for this resurrection is actually very different from Einstein's original thinking; the new version of the term arises from recent observations of an accelerating universe and, ironically, from the principles of quantum mechanics, the branch of physics that Einstein so famously abhorred.
The whole question boils down to what extend quantum mechanics is really involved as part of the evolution of the universe. This answer can be different depending starting from the moment of the Big Bang to the present.
When you consider the solar system the influence of Quantum mechanics in general is minimal. Quantum mechanics defined as the study of the individual behaviour of protons, neutrons and electrons including all the members of the standard model and virtual particles. The same for photons, all forms of radiation, virtual particles, axions and darkmatter particles. I specific write darkmatter particles. Objects of the size like meteorites don't belong in this category.
Many physicists now expect the cosmological term to provide the key to moving beyond Einstein's theory, to a deeper understanding of space, time and gravity and perhaps to a quantum theory that unifies gravity with the other fundamental forces of nature.
The problem with the universe is that it exists. To explain that requires a very broad picture, maybe mostly completely outside what we consider the visible universe. The first problem is the concept gravity with is an attractive force. Considering that as the sole constitute of the universe, the universe can not exist.

Birth of a constant

page 54

The Energy of Nothing

page 54

page 55

Lorentz invariance, the fundamental symmetry associated with both the special and general theories of relativity implies that only empty space can have this kind of energy density.
It is the other way around. Lorentz invariance, which is a mathematical concept, is not the driving parameter. The driving concept is empty space and what it physical means. For example. Empty space is space without mass. The consequence is that it is free of gravity. A different definition is: Empty space is empty except it can contain virtual particles.
Instead virtual particle-antiparticle pairs pop out of the vacuum, travel for short distances and then disappear on timescales so fleeting that one cannot observe them directly.
Yet their indirect effects are very important and can be measured. For example, the virtual particles affect the spectrum of hydrogen in a calculable way that has been confirmed by measurements.
This sentence contains the same logical inconsistency as the previous sentence about Lorentz invariance.
First you must explain the experiment and what is observed (measured) initially and secondly you must explain how the behaviour of the spectrum is influenced and how that is observed (measured). And finally you must explain how these changes are caused by virtual particles.
I expect the experiment indicated is the Lamb Retherford experiment.
See Studying this original document you can ask yourself the question if a vacuum is involved, because hydrogen atoms are studied.

A Change of Meaning

(1) G uv = 8 pi G * Tuv
To create a model of static Universe, Einstein introduced the cosmological term Lambda to counterbalance gravity's attraction on cosmic scales.
(2) G uv + Lamba * guv = 8 pi G * Tuv
This term rho_vac, the energy density of the vacuum, multiplied by guv - must go on the right side of the field equation with the other forms of energy.
(3) G uv = 8 pi G ( Tuv + rho_vac*guv
Although Einstein's cosmological term and the quantum vacuum energy are mathematical equivalent, conceptual they could not be more different: the former is a property of space, the latter a form of energy that arises from virtual particle- antiparticle pairs.
That is a very clear description.
Quantum theory holds that these virtual particles constantly pop out of the vacuum, exist for a very brief time and then disappear.
Below this text is a sketch showing, what is involved. What the physical implications are is not clear.

Box 1

page 56

But GR implies that all forms of energy, even the energy of nothing, act as a source of gravity.
This sentence requires a clear definition of the terminology used.
Russian physicist YB Zel'dovich realized the significance of this problem in the late 1960's when he made the first estimates of the energy density of the vacuum.
Okay.
Since that time, theorists have been trying to figure out why their calculations yield such absurdly high values.
Okay.
Indeed they assumed that the most plausible value for the energy density is zero - even quantum nothingness should weigh nothing
The consequence of this reasoning is that in some sense GR is wrong.

Back with a Vengeance

page 57

In 2000, measurements of the angular size of the angular size of variations of the CMB across the sky were good enough for researchers to determine that the geometry of the universe is flat.
IMO what the measurements revealed that the variations were very small or differently that the temperature was every where the same. This does not mean that at an age of 400000 years the universe was flat and not expanding.
A spatial flat geometry requires that the universe average density must be equal to the critical density
The question is what a spatial flat geometry physical means.
An average density is defined as the total mass of the universe divided by the size of the universe. If the size increases the average density decreases. This implies that locally the density can fluctuate.
But many different measurements of all forms of matter -- showed that matter contributes only about 30% of the critical density.
What you must measure is all the forms of matter in the Universe. The physical problem is that the expansion of the universe is influenced by all the matter in the universe and not by a certain amount of matter such that the universe is in equilibrium and does not expand. Such a state of the universe we call flat and the amount of matter involved: the critical matter.
It is very important when we discuss the expansion of the universe we should discuss the total universe and not the visible universe based on what we humans observe.
A flat universe therefore requires some other form of smoothly distributed energy that would have no observable influence on local clustering and yet could account for 70% of the critical density.
This is a very tricky sentence, because we try to find the solution on a problem which is not clearly defined. The most different issue is exactly what means flat.
Vacuum energy, or something much like it, would produce precisely the desired effect.
This is not proper science. The problem is that the concept vacuum energy is not properly defined and as such it cannot be used to explain this missing matter.
Accordingly to Box 1 vacuum energy is caused by virtual particles. That cannot explain 60% of all matter.

The superworld

Geometry vs Destiny

Reflection 1 - Gravity versus Quantum theory

The problem with the universe is that it exists. To explain that requires a very broad picture, maybe mostly completely outside what we consider the visible universe.
The universe consists of objects. If we want to build or simulate a universe we should start with a huge piece of material. In the first step we break from this large part a small part off (we divide it in two) and bring this smaller part to a certain position in universe. To perform this step a certain amount of energy is required. In the second step we release the smaller part and both will move towards each other and collide. During this second step the same amount of energy is released. In both steps the force of gravity is involved. If you want to build a more stable universe than after step 1 you need an extra step and give the smaller part a rotational speed. This also requires energy. When you release the part in step 3 both will start to rotate around each other. You can repeat step 1 and step 2 as often as you like to create a universe filled with smaller objects. The problem with this scenario is that your starting position is a huge piece of material and energy is required to create the individual stars at a certain position with a certain speed. This energy is a reaction against the force of gravity embedded within the initial mass. The smaller and smaller you make these parts the more and more the force of gravity seems to disappear and the result is a universe only filled with individual particles (described by quantum physics). You could also say that gravity is smeared out in space. The point is that this space is not empty and cannot be called a vacuum. It looks more like the foam idea of Steve Carlip. The next issue is what is observed, when you measure the state of the universe from a common point. This part requires more clarification.

Reflection 2 - Background

The phylosophy behind Reflection 1 - Gravity versus Quantum theory is that the evolution of the universe is basically a physical process and not a mathematical process. It is the physical process that you try to understand. Of course this understanding must not be in conflict with the existing laws i.e. mathematics, but what is important these laws should be backed up by observations (experiments). The bottom line is that all explanations should be backup by observations.
In many cases the explanation of a certain phenomena or process is: General Relavity. Often the comment is that all predictions of GR are backed up by experiment. That is too simple, because the specific experiments involved are not mentioned.
A typical experiment is the Lamb - Retherford experiment which involves virtual particles. With the experiment is nothing wrong. Virtual Particles are part of the concept of Vacuum Energy. The problem is the relation of virtual particles versus vacuum energy, as relevant for the evolution of the universe.

Reflection 3 -

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