Is Dark Energy a Mistaken Concept?

[MolaKule]

When you have 28 orders of Magnitude discrepancy between observations and expectations, DE and DM is in trouble.

And furthermore, what is this so-called dark energy, and why is it negative?



Time 11:20 and later.





As Thomas Kuhn said (I'm paraphrasing), "A new paradigm may be in order..."

https://www.lri.fr/~mbl/Stanford/CS477/papers/Kuhn-SSR-2ndEd.pdf

 

[KGMtech]

Imagine all the real life Sheldon Cooper's that will have to question their career focus! The collective angst will be Enormous^10

 

[Al]

I guess If we knew..................

 

[ripcord]

why is it negative?

Two atoms walk into a bar. One says to the other, "Dangit, I just lost an electron!" The other atom replied, "Are you sure?" "I'm positive!"

 

[supton]

Goes to show that one should not fall in love with a theory--at any time a better model may come along that may make a better explanation of the past, or better predict the outcome of future experiments. Of course, one had better have good math and even better data.

Of course it goes without saying that all of that went over my head...

 

[dubber09]

We know very little about universe, space, energy etc.
Where is universe expanding into?

 

[Pablo]

I knew it!

 

[henni]

Several alternative theories have emerged to explain cosmic phenomena traditionally attributed to dark energy and dark matter, focusing on magnetic fields and their interactions.

>> Galactic Magnetic Fields

^Formation and Structure^
Galaxies possess magnetic fields that are created through internal dynamo effects, where fluid-like motion and rotation convert kinetic energy into magnetic energy[1]. These fields are typically a million times weaker than Earth's magnetic field but play crucial roles in galactic structure and evolution[6].

^Early Universe Strength^
Contrary to previous beliefs, galactic magnetic fields were as strong in ancient galaxies 8-9 billion years ago as they are today[3]. This discovery challenges the slow dynamo theory and suggests that magnetic fields were amplified rapidly in the early universe, possibly through supernova explosions and black hole activity[3].

>> Alternative to Dark Energy

^Magnetic Dark Matter Theory^
A compelling model suggests that the universe's expansion could be explained without dark energy by attributing magnetic-like properties to dark matter[4]. This theory proposes that:

- Dark matter particles possess a special type of magnetic force that creates a constant repulsive effect[5]
- This force produces the same expansion effects traditionally attributed to dark energy[4]
- The model could eliminate the need for dark energy, which is currently thought to comprise 70% of the universe[8]

>> Magnetic Fields and Cosmic Structure

^Primordial Origins^
Recent research suggests that magnetic fields might have originated in the universe's earliest moments[9]. These primordial magnetic fields could:

- Influence dark matter density perturbations
- Lead to the formation of dark matter mini-halos
- Help explain the universe's current structure without requiring dark energy[9]

^Spiral Galaxy Formation^
The magnetic field theory of spiral arms suggests that:

- Magnetic forces are crucial in maintaining spiral arm structure
- Gravitational forces alone cannot explain spiral arm stability
- Magnetic fields influence gas movement and circulation patterns within galaxies[2]

This integrated approach to understanding cosmic structure through magnetic fields offers a potentially simpler explanation for observed phenomena, though more research is needed to fully validate these theories[8].

Citations:
[1] https://earthsky.org/space/images-of-magnetic-fields-in-galaxies/
[2] https://physicsfeed.com/post/magnetic-field-theory-spiral-arms-galaxy/
[3] https://www.universetoday.com/15856/ancient-galactic-magnetic-fields-stronger-than-expected/
[4] https://www.futurity.org/dark-energy-dark-matter-universe-expansion-2543202-2/
[5] https://room.eu.com/news/no-dark-energy-needed-just-dark-matter-with-a-magnetic-force-new-study-says
[6] https://physicsworld.com/a/distant-galaxy-sheds-light-on-the-magnetic-universe/
[7] https://www.quantamagazine.org/the-hidden-magnetic-universe-begins-to-come-into-view-20200702/
[8] https://newatlas.com/physics/magnetic-dark-matter-accelerating-universe-expansion/
[9] https://phys.org/news/2024-01-magnetic-fields-cosmos-dark.html

 

[MolaKule]

Goes to show that one should not fall in love with a theory--at any time a better model may come along that may make a better explanation of the past, or better predict the outcome of future experiments. Of course, one had better have good math and even better data.

Well here's my take on this: "And furthermore, what is this so-called dark energy, and why is it [a negative pressure]?"

Dark energy is that energy that is supposed to be causing the acceleration of the expansion of the universe. Generally speaking, Gravity attracts, so theoretically, the universe should contract or remain static, or expand depending on the pressure versus gravitational attraction and the value of the cosmological constant Lambda used in General Relativity. IF, IF, the the acceleration of the expansion of the universe is real, then this dark energy is causing the accelerated expansion of the universe, a "negative?" pressure beyond what is observable or provable.

Furthermore, this dark energy has very low energy density: "The nature of dark energy is more hypothetical than that of dark matter, and many things about it remain in the realm of speculation. Dark energy is thought to be very homogeneous and not dense, and is not known to interact through any of the fundamental forces other than gravity. Since it is rarefied and un-massive—roughly 10^−27 kg/m3—it is unlikely to be detectable in laboratory experiments. The reason dark energy can have such a profound effect on the universe, making up 68% of universal density in spite of being so dilute, is that it is believed to uniformly fill otherwise empty space." Wiki.

If it so DILUTE, and is not known to interact through any of the fundamental forces other than gravity, how can it have such a profound effect on expansion?

The second Youtube presentation shows that the Modified Newtonian Dynamics (MOND) theory is not out of consideration as a cosmological model.

https://arxiv.org/pdf/astro-ph/0601478

Also: https://dn790008.ca.archive.org/0/items/arxiv-astro-ph0403694/astro-ph0403694.pdf

 

[MolaKule]

An explanation of the cosmological principle.

In most cosmological models, it is assumed that at any given time, all of the universe is filled with matter of the same average matter density and at the same average pressure. This assumption of, "homogeneity." is otherwise known as the cosmological principle.

"The adoption of the cosmological principle for purposes of speculation has no basis in logic, or in the theory of relativity, but is a simplifying assumption in the absence of incontrovertible evidence to the contrary."

"To repeat once more, the general theory of relativity neither requires the cosmological principle or its variants..."

Peter Bergmann, The Riddle of Gravity.

Recent observations have shown great clumps of matter and large voids, so maybe the cosmological principle should be dropped from cosmology?

 

[Pablo]

An explanation of the cosmological principle.

In most cosmological models, it is assumed that at any given time, all of the universe is filled with matter of the same average matter density and at the same average pressure. This assumption of, "homogeneity." is otherwise known as the cosmological principle.

"The adoption of the cosmological principle for purposes of speculation has no basis in logic, or in the theory of relativity, but is a simplifying assumption in the absence of incontrovertible evidence to the contrary."

"To repeat once more, the general theory of relativity neither requires the cosmological principle or its variants..."

Peter Bergnmann, The Riddle of Gravity.

Recent observations have shown great clumps of matter and large voids, so maybe the cosmological principle should be dropped from cosmology?

It seems a odd assumption on multiple levels. Pure observation, all forms of attraction, and deeper measurements, even in theory - doesn't make sense.

 

[ripcord]

My limited understanding of dark energy is that it was postulated as an explanation for observational evidence that suggests that the expansion of the universe is accelerating. Dark matter was postulated to provide the missing gravitational force to explain why the universe is expanding slower than it should be given what we think we know about the age of the universe and it's current size.

My dad likes to read about this stuff. His speculation about the discrepancies that lead to the dark matter and energy theories could be explained by theorizing that maybe the speed of light, while being uniform across the universe, is very gradually slowing down, thus causing our other estimates to be wrong.

It's all way outside my wheelhouse.

 

[KrisZ]

We know very little about universe, space, energy etc.
Where is universe expanding into?

We don't really know if it is expanding, that's an assumption on redshift. The redshift may simply be the light passing though a medium, like a dust cloud, a huge meteor cluster or something else.

 

[burbguy82]

Recent observations have shown great clumps of matter and large voids

Would this not suggest gravity to be more powerful than "dark energy" as witness to the Laws of Angular Momentum?

Dark matter would seem to me to be like an ancient element, "Aether":

https://www.historicmysteries.com/science/aether/35788/

I do see some merit, at face value to the idea, and I find it interesting that such an old idea, has resurfaced in the mainstream scientific topics of debate.

Einstein's theory, (being really not so much a theory as a law) has been proven time and time again to be accurate. From that, we know that the earth, for instance, travels through space and "distorts or bends" the space around it. That being said, there is ""something" being bent, not just nothingness like theorized by some others.

On the universe expansion idea, and its effects..... I have thought about this explosion model and just cant get past two things....the first is obvious: how can their be a effect without a cause.......but the second is more based in science than anything else:

If the expansion of the universe was started by a single event, and everything that exists in the universe either existed or was created at that point......it would seem to me that the gravity caused by all that matter/mass, would be more powerful than any potential expansion event that could be created, at that time.

 

[PandaBear]

My money is on our understanding of the universe is incomplete so our equation is incomplete to begin with, unless we eventually finds the missing pieces if we ever. For now we need to plug in "dark energy" and "dark matters" to balance the equation.

The dust cloud induced redshift is a likely explanation already, we may not be able to observe as a tiny civilization on a tiny planet with limited amount of energy and know how.

 

[Astro14]

We don't really know if it is expanding, that's an assumption on redshift. The redshift may simply be the light passing though a medium, like a dust cloud, a huge meteor cluster or something else.

The red shift is more fundamental than that. When you’re looking at spectral lines, particularly from stars, the lines associated with hydrogen are clear and unambiguous.

They don’t get red shifted by passing through something, which merely attenuates the number of photons, they get red shifted by velocity alone.

The relationship between red shift and distance is also well established. Hubble first noted it over a century ago, and none of the current observational data is in conflict with that fundamental relationship between distance and velocity.

We can debate the rate of expansion, the degree of which the universe will expand in the future, all of that is somewhat indeterminate.

But it is expanding.

 

[MolaKule]

Here is an interesting paper on Einstein's later thinking about his relativistic cosmological model.

https://arxiv.org/pdf/1312.2192

Einstein’s cosmic model of 1931: an analysis and translation of a forgotten model of the universe

"Nowadays, there is strong evidence that the expansion of the universe is currently accelerating, a finding that many cosmologists interpret in terms of a non-zero cosmological constant, although the physical nature of the phenomenon remains the subject of much debate.12..."

"It is interesting to ask why the instability of his static solution was not apparent to Einstein in 1917. One answer may be that the instability is more easily seen from the differential equations (2) and (3) above, equations that only arise if one allows for the possibility of time-varying solutions for the world radius. Thus Einstein’s original static universe is a good example of the risks of a priori assumptions,7 while Friedmann, “uninfluenced by observations”, allowed for all possibilities.84. On the cosmological constant, A is well-known, Einstein introduced the cosmological constant to the field equations of general relativity because of his assumption of a universe of “spatial structure and density that was constant over time” (see section 2). In the absence of any observational evidence known to him for a dynamic universe, he added the term in order to counterbalance the attraction of gravity, giving a universe of cylindrical curvature that was static in time. Thus the ‘cosmological constant’ allowed Einstein to postulate a finite universe of closed spatial geometry whose radius could be calculated from the density of matter.10..."
Emphasis mine.

 

[PWMDMD]

We know very little about universe, space, energy etc.
Where is universe expanding into?

I'd argue we know quite a lot. We can predict quite a lot based on what we know and observation and experimental data agrees. It appears as if the physics locally is the same everywhere in the universe and so what we know to be true here on earth is also true a billion light years from earth. Most physicists believe space is not expanding into anything. Space itself is expanding, all points in space are equally expanding away from all other points in space, equally in every direction, but there's no larger volume that our universe is expanding into. Our universe is all that there is, there is nothing "outside" to expand into, as there is no space-time there.

 

[MolaKule]

They don’t get red shifted by passing through something, which merely attenuates the number of photons, they get red shifted by velocity alone.

Shao differs in that interpretation in that photons do lose energy, and thus the redshift is affected by that energy loss.

The energy loss of photons and cosmological redshift*

PHYSICS ESSAYS 26, 2 (2013)

Halton Arp also explains some of these problems with Hubble's theory:

Arp, H., Seeing Red, Redshifts, Cosmology and Academic Science, Apeiron, Montreal, 1998.

The relationship between red shift and distance is also well established. Hubble first noted it over a century ago, and none of the current observational data is in conflict with that fundamental relationship between distance and velocity.

The main physical explanations for the redshift are 1) a Doppler shift due to an expanding universe, 2) a plasma effect, or 3) a tired light effect, or 4) Compton scattering.

Hubble's law is based on the hypothesis of the ‘Redshift-distance law” in that an object’s distance from us is proportional to its redshift value (the usual interpretation of Hubble’s Law).

Hubble's Law and Hubble's constant H0 are based on a rather complex set of equations involving the Doppler shift Z and the relative Luminosity of the light source. The Hubble constant H0 is defined as the ratio of a galaxy’s redshift to its distance estimated with respect to its apparent magnitude.

Shu, F., The Physics of Astrophysics, Vol. 1, II: University Science Books, 1992.

 

[Astro14]

Shao differs in that interpretation in that photons do lose energy, and thus the redshift is affected by that energy loss.

The energy loss of photons and cosmological redshift*

PHYSICS ESSAYS 26, 2 (2013)

Halton Arp also explains some of these problems with Hubble's theory:

Arp, H., Seeing Red, Redshifts, Cosmology and Academic Science, Apeiron, Montreal, 1998.

The main physical explanations for the redshift are 1) a Doppler shift due to an expanding universe, 2) a plasma effect, or 3) a tired light effect, or 4) Compton scattering.

Hubble's law is based on the hypothesis of the ‘Redshift-distance law” in that an object’s distance from us is proportional to its redshift value (the usual interpretation of Hubble’s Law).

Hubble's Law and Hubble's constant H0 is are based on a rather complex set of equations involving the Doppler shift Z and the relative Luminosity of the light source.

Shu, F., The Physics of Astrophysics, Vol. 1, II: University Science Books, 1992.

I disagree with Shao.

“Tired light” made for good sci-fi stories in the 1940s. But it’s no more viable than Phlogiston, or the presence of luminiferous aether.

Compton scattering is easily determined. The plasma effect is a guess, a hypothesis, at best.

It’s easy to dismiss Hubble’s work as theory, but in the 100 years since that theory was espoused, it has been borne out by observation.

The only people arguing against Hubble’s theory are people who are trying to explain cosmological phenomena via “outside the box” ideas. But none of those ideas have any substantive evidentiary support. They’re guesses at best.