Can the "Dark Energy" concept be wrong?

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jeffinbath
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With virtual particles now thought to be popping in and out of existence, can this affect light in the very long term?
With the latest view that free space has virtual particles constantly popping in and out of existence, is it now rational to argue that light can electromagnetically travel through free space for ever and ever without the slightest energy loss? Edwin Hubble found that the general red shift of galaxies far more distant than the Andromeda galaxy, indicated through the Doppler effect that they are apparently accelerating away from us at an increasing rate which seemed to be proportional to their distance from us.

It has become conventional cosmology to explain this perplexing observation as being caused by “dark energy”. But there is no independent evidence that such an entity exists. Why can we not more reasonably say that there is an energy drop factor per billion years in those ancient photons which is perhaps too small to show up in the case of photons from Andromeda whose light is thought to be “only” around 2 to 3 million light years away (and has a blue shift indicating it is approaching us)?

While most of the red shift from galaxies tens of billions of light years away must be due to the Doppler effect, why can we not say also that that increasing red shift with distance (known as the Hubble constant) is actually caused by a drop in photon energy as the light ploughs it way through those virtual particles that are going in and out of existence?

At the moment I am thinking that the only reason this explanation cannot be entertained is because it would throw a gigantic spanner into the modern cosmology works.
 
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Motore
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Orodruin
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That’s not how virtual particles work. They are not actual particles and their effects on light propagation are known and accounted for (they do not affect the ability of light to propagate indefinitely).

Apart from that, theories of so-called tired light have been considered as an alternative to dark energy but do not fit the data as well.
Other alternatives include dust models where intergalactic dust would down-scatter the light. Again, not as good fit to data.
 
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  • #4
jeffinbath
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This is effectively another tired light model, which were debunked:
https://astro.ucla.edu/~wright/tiredlit.htm

You will get similar responses as in your other thread:
https://www.physicsforums.com/threads/is-there-more-to-the-red-shift-than-we-think.977895/

In this one you also included your misunderstanding of virtual particles.
https://www.physicsforums.com/insights/misconceptions-virtual-particles/
The tired light model does not deal with it as a small proportion of the red shift which is indisputably mainly caused by the Doppler effect.
 
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PeroK
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At the moment I am thinking that the only reason this explanation cannot be entertained is because it would throw a gigantic spanner into the modern cosmology works.
I can think of other explanations. Is that really the only explanation you can think of? That cosmologists are too stupid, stubborn and/or reactionary to consider alternative ideas?
 
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  • #6
Bandersnatch
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Are you sure you have the basis for your argument straight? There seems to be some mixing up of various concepts that in the end make it hard to figure out what it is you're actually thinking of.
Edwin Hubble found that the general red shift of galaxies far more distant than the Andromeda galaxy, indicated through the Doppler effect that they are apparently accelerating away from us at an increasing rate which seemed to be proportional to their distance from us. It has become conventional cosmology to explain this perplexing observation as being caused by “dark energy”.
Hubble's observation was not (and the law named after him isn't) showing accelerating expansion. That discovery is from 1990s. Hubble's observation shows expansion, period. That velocities increase with distance might suggest otherwise at first glance, but it would be a misunderstanding.
Each point on the graph is a galaxy captured at (with some caveats) the same moment in time. They are not showing the changing state of motion of any single galaxy over cosmic time.
In a uniformly expanding universe galaxies further out will have higher recessional velocities just by the virtue of being more distant, not because they were accelerated.
In fact, even in a universe where all galaxies are monotonously decelerating since the dawn of time, as was thought to be the case until relatively recently, the Hubble's law would largely hold. The deceleration would show up as a particular deviation of the observed curve of redshift vs distance, as one looks further out and further back into the past.
This was not and is not what dark energy attempts to explain. Dark energy came into play once the improved observations allowed the shape of the aforementioned curve to be better measured. It was found to deviate the wrong way - but only for relatively low redshifts. For the very far objects the curve shows deceleration as previously expected. This indicates a switch from deceleration to acceleration.

If what you're saying here is that you don't doubt expansion, but feel that the added effect of accelerated expansion, specifically, can be explained by a form of tired light (which is what this is in anything but name), then this is immediately distinguishable as not a good fit for observations because of that switch from deceleration to acceleration. I.e. with tired light you have the proposed effects grow proportionally to distance covered as there is more interactions to degrade the energy of an incoming photon. Here, we have the effect gradually disappear and then reverse the farther you look.


So, it's not dogma keeping the proposal from being entertained - the competing hypotheses can be validated or discarded by confronting them with observations. This is to the credit of tired light, mind you - a good hypothesis can be falsified. Dark energy is a staple of modern cosmology simply because it is so far the only one that has survived the gauntlet.
 
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  • #7
jeffinbath
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I can think of other explanations. Is that really the only explanation you can think of? That cosmologists are too stupid, stubborn and/or reactionary to consider alternative ideas?
No, I certainly do not think that. The band-waggon effect like the ancient's idea of sun going around the Earth is the prime example, where the brightest minds did not doubt it for many hundreds of years.
 
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weirdoguy
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where the brightest minds did not doubt it for many hundreds of years.

You REALLY should check out how modern science works, because it's not what you think.
 
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berkeman
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Thread closed temporarily for Moderation...

Thread is reopened for now, but may end up being closed at some point.
 
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  • #10
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You cannot explain the data with the data. That is circular.
What would you base physical theories on, if not observations? All of physics has to be made based on experimental data. We find minimal sets of rules that describe as many observations as possible. That's all we can do. There is no way to do physics for our universe without learning from experimental results.
Dark energy (or equivalent descriptions) is by far the best theory we have to describe our observations.
rather than to entertain the many many other ways people are seriously considering this problem.
People studied tons of different models. They are either very similar to dark energy, or they don't fit to experimental results. If something cannot agree with experimental results it's time to stop entertaining this model. Only cranks won't give up in that case.
 
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  • #11
artis
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Since I am not an expert in the field but an interested person much like the OP seems to be @jeffinbath, I would welcome comments from members with more expertise in the field, that being said let me introduce certain aspects that the OP @jeffinbath might find interesting and that are more plausible than the ideas put forth so far.

To start answering the question , yes Dark energy and matter concept can be wrong , but at the moment we don't know, we simply try to explain what we see and so call it "dark" in the meantime.
As to understand the dark matter part, @jeffinbath please see this article
https://www.space.com/20930-dark-matter.html
Astronomers examining spiral galaxies in the 1970s expected to see material in the center moving faster than at the outer edges. Instead, they found the stars in both locations traveled at the same velocity, indicating the galaxies contained more mass than could be seen.
Motions of the stars tell you how much matter there is," Pieter van Dokkum, a researcher at Yale University, said in a statement. "They don't care what form the matter is, they just tell you that it's there.
So by our observations it seems the distant stars and their rotation suggest there should be more mass because of how they behave , yet we can't find the mass/matter so that's why it's "dark"

For one the WIMP's of dark matter are yet to be found and dark matter itself has other competing hypothesis that don't involve new hypothesized elementary particles.
The competing hypothesis is MOND ,
https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics
https://arxiv.org/pdf/astro-ph/0605322.pdf

Some recent news with regards to MOND
https://physics.aps.org/articles/v14/143


As for dark energy which is the supposed phenomena that causes the accelerated expansion of the universe in it's later stages up until the current time , according to standard model of cosmology. There is the recent work and evidence that it seems we are located at or near the center of a rather large local underdensity or more commonly known as "void". It is called the "KBC Void"
https://en.wikipedia.org/wiki/KBC_Void

Here is a paper describing the KBC Void and claiming such a structure falsifies the predictions of Lambda CDM model , because a universe that at some early point existed as a homogeneous plasma could not have formed structures that deviate from homogeneity by that much, judge for yourself.
https://arxiv.org/pdf/2009.11292.pdf

Here is a blog on the subject by one of the authors of the paper above
https://darkmattercrisis.wordpress....a-way-out-of-the-current-cosmological-crisis/



There are attempts made to explain what @Bandersnatch said here

Dark energy came into play once the improved observations allowed the shape of the aforementioned curve to be better measured. It was found to deviate the wrong way - but only for relatively low redshifts. For the very far objects the curve shows deceleration as previously expected. This indicates a switch from deceleration to acceleration.

So low redshifts means objects (stars) that are younger and closer to us recede from us faster than they should if we compare them to the far away distant/old stars from the early cosmos. What I understand about the Void idea is that unlike the traditional idea that this acceleration once started happens everywhere the same (driven by dark energy) instead the void hypothesis says that it is the gravity of the more dense outer cosmos pulling "stuff" outwards from our local underdensity region. Now I don't have the data at the moment to know whether this KBC Void diameter coincides with the furthest stars (from earth) that show increased redshift due to accelerated expansion but maybe someone else can come in with this information.

Apart from these hypothesis @jeffinbath I suggest read these two links below , they simply state the problem of dark energy and show the multiple different solutions that have been put forth in order to explain it.
This one is simple and good from NASA
https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy

http://www.flatuniversesociety.com/accelerating-expansion.html
 
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berkeman
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Thread closed temporarily for Moderation...
 
  • #13
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Moderator's note: A speculative post has been deleted. Please keep the discussion based on the published peer-reviewed literature.

Thread reopened.
 
  • #14
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After reconsideration, this thread is closed. The links provided in post #11 are a good basis for further reading. Further questions can be posted in a new thread provided they are based on the peer-reviewed literature.
 

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