HUGE blow for alternate theory of gravity MOND

originally posted by: kwaka
This theory has been out for a while, Laniakea.

Laniakea is not a theory, it's a supercluster. The title of the video you posted even says so: "Laniakea: Our home supercluster". You don't know the difference between a theory and a supercluster?

a reply to: NoOneButMeAgain
Good point!
I don't know if we can ever control gravity, but we already use it to our advantage in gravitational slingshot maneuvers which reduce fuel requirements! The more we understand it, the better our chances of using it even more to our advantage, and I admire your thinking beyond your own personal needs.

We should be thinking about future generations, and the survival of our species, which is certainly doomed when the oceans boil away, maybe in a billion years, unless we can make some settlements off this planet before then.

a reply to: Arbitrageur

Laniakea is not a theory, it's a supercluster.

It looks like a great start to define how things are moving in the universe. As for what exactly is going on with the great attractor still looks like a work in progress.

Sabine Hossenfelder mentioned the latest findings by Banik et al in her November 15 Science News video. If you watched the Dr. Becky youtube video embedded in the opening post, Dr Hossenfelder doesn't add anything technically, but just gives an overview of why the Banik et al results are so significant. What she does add that Dr. Becky didn't mention, is that she knows someone who is investigating whether "MOND is a systematic artifact coming from data interpretation" and she expects we will see papers looking into this in the future. She says she doesn't want to jump to conclusions, but something like that is already suggested by what she says in the first paragraph here, from the Science News video transcript:

3:20
The published paper contains an extensive discussion about why the two groups find so wildly different results. To make a long story short, it’s because they use different samples of the data. The paper that finds evidence for MOND uses pretty much the entire available data. The paper that finds evidence against it throws out data with high uncertainty. They show in the new paper that including this high uncertainty data brings back the evidence for MOND.

I’ve found that to be very interesting because we’ve seen the same thing in data from galaxy rotation curves, that the higher the uncertainty of the data, the better MOND seems to work. This raises the very real possibility that MOND is a systematic artifact coming from data interpretation. I don’t want to jump to conclusions here, but I am sure there’ll be more papers about this in the near future because I know someone who’s working on it, so stay tuned.

4:19
For now, little Albert is pleased that he’s been right, once again.

We can look forward to seeing those papers in the future, which hopefully will add some clarity to what is going on here. Here's the full video, where she also discusses other science news topics:

New Data Spell Trouble for Dark Matter's Biggest Competitor

Today we have an update on the biggest astrophysics drama of the year, that’s an observation which seems to be ruling out the most popular alternative to dark matter...

originally posted by: Arbitrageur
a reply to: quintessentone
But that theory is completely silent so far on dark matter; does it need dark matter, or doesn't it? The authors don't even seem to know. If you read my quote you cited, I mentioned dark matter, or alternatives to dark matter and we can't even say where that theory falls because the authors of the theory apparently have no idea! So I'm not sure how that adds to the discussion about dark matter or alternatives, and doesn't it seem odd to you that they haven't even considered the dark matter question and how it does or doesn't fit into their model? They are going to look into it apparently, but that doesn't tell us anything now.

I do not think it odd that they haven't considered the dark matter question when they don't know what is dark matter, so including it or not including it in various theories seems a logical path forward for developing new theories.

The theories being put forward, from the few I have seen, are looking elsewhere. Some are looking to baryons while others are pointing to electromagnetism...so as my mind wanders and I go down many rabbit holes all I can see with these two MOND theories is that we are all on the outside looking in, but we don't know what we are looking at, still.

Again, this video confirms the same problem that we do not know what dark matter/energy is but we can hypothesize and imagine what it may be. Didn't Einstein say 'Imagination is more important that knowledge. Knowledge is limited. Imagination encircles the world".



Anyway, this is where I'm at right now with this extremely interesting and mind blowing topic and thank you for posting it for me to exercise my mind and imagination. And if you feel anything I post veers away from MOND, I feel it really doesn't because even those most qualified to speak for or against MOND continue to ask further questions or seek elsewhere for answers.

Rabbit hole #1A: MOND Paradigm of Modified Dynamics.

We do not know if MOND is only relevant to gravitational phenomena, or should also affect in some way other phenomena, such as electromagnetism.

www.scholarpedia.org...

Rabbit hole #1B: Baryons with a half-interger spin - Rabbit Hole #1C: Pauli's Exclusion Principle

en.wikipedia.org...

originally posted by: quintessentone
I do not think it odd that they haven't considered the dark matter question when they don't know what is dark matter, so including it or not including it in various theories seems a logical path forward for developing new theories.

Well we know what some dark matter is, like some small fraction is objects like the earth, and another small fraction is neutrinos, but the majority of dark matter has to be something else. The fact is, nobody knows what the rest is, but that doesn't stop mainstream scientists from including it in their models, and in fact attempts to model the universe without it fail.

It's also odd that you don't find that article odd, so I'll explain to you why I think it's odd. Here are some passages from the article you posted:

www.advancedsciencenews.com...

"the findings of the current study may be substantial as it explains the observed expansion rate of the Universe without the need to introduce any type of unobservable energy."

Although the results are encouraging, the scientists indicate they still have a lot of work to do to confirm whether their theory of gravity is indeed more accurate than general relativity. To do this, precise predictions about the dynamics of the expansion of space and other processes that took place are necessary.

The authors also hope that their modified gravity will be able to solve the mystery of dark matter, which, like dark energy, has not yet been detected in any experimental study, and was discovered only through its gravitational effect on other fields and particles.

The team say they are planning to analyze this interaction in their theory, and, hopefully, will be able to explain the observational data.

To say that ""the findings of the current study may be substantial as it explains the observed expansion rate of the Universe" implies they have a model that matches the observed expansion rate, but they they say "precise predictions about the dynamics of the expansion of space and other processes that took place are necessary", implying it can be more precise. But when you keep reading, here's the odd part, they don't know if their theory includes dark matter which according to current mainstream models is about 85% of the mass of the universe.

So first it sounds like they just need to do some more work to improve the "precision", but then they admit they don't know if the 85% of the universe known as "dark matter" is part of their model or not. Removing 85% of the mass of the universe, or not, is not a matter of "precision", it's a gaping hole which confirms that their model is vastly incomplete. One of the problems with models that try to remove the dark matter, like MOND, and maybe also this model, if it removes dark matter, is that simulations of those models don't produce a universe anything like the one we live in.

If it does include dark matter, like the current mainstream model, lambda-CDM, then simulations can approximate something like the universe we live in. There are probably better simulations now, but this is an older simulation done with older supercomputers years ago by George Smoot:

The design of the universe | George Smoot

10:23
And we had to add one more thing to make the universe come out right. It's called dark matter.
That is matter that doesn't interact with light the typical way that ordinary matter does, the way the light's shining on me or on the stage.

The dark matter has to be there to run a simulation of the formation of the universe like this. I have yet to see any model without dark matter in it that can show how the universe evolves like this simulation.

The problem with the model you posted is so large that it's not just that they haven't run any simulation of how the universe could evolve to its present state, but they wouldn't even know what parameters to plug into the simulation if they wanted to run it. Like does their model have dark matter, or not?

I know some people think dark matter is just "made up" to make things work, but indirect observation is still observation. We have even used gravitational lensing observations to map the location of the dark matter, in maps like this one:



More information about dark matter maps here:
Scientists release best-ever dark matter map
I have yet to see how alternative models to dark matter explain those maps of dark matter, I don't think they do, or if any do, please show them.

Anyway the debate between MOND and dark matter has been one of the hottest astrophysics topics of the year, and it's the topic of this thread. When you post a link to a "model" that doesn't know whether it's a dark matter model, or an alternative model, don't you understand how that adds nothing to this hot debate? Moreover, the model must be incredibly incomplete to not have even a hint of a resolution to that issue of whether it's a dark matter model or not.

Again, this video confirms the same problem that we do not know what dark matter/energy is but we can hypothesize and imagine what it may be. Didn't Einstein say 'Imagination is more important that knowledge. Knowledge is limited. Imagination encircles the world".

Yes, and don't forget we can map dark matter, and show where it is. That doesn't require imagination, just an application of general relativity combined with telescope observations.

I heard three voices in that video. The narrator at the beginning, another voice at 36 seconds, and then Neil DeGrasse Tyson later in the video. Who is speaking at 36 seconds? I had to exit the ATS embed to see if the 3rd voice is identified and I can't find it. They really shouldn't use someone's voice like that without giving any credit, so I put that channel on my bad list, though I've found far worse channels. However I didn't have any disagreement with the video content, though maybe the title is a bit misleading, because it didn't really address the question in the video title, "does dark matter even exist?" For example, it didn't explore any alternate theories which suppose that dark matter doesn't exist, like MOND. So that misleading title is another reason to not like that title/channel.

Regarding your "rabbit holes", even the "MOND supporter for years" scientist, who wrote the latest paper appearing to rule out MOND to 16 sigma, apparently hasn't given up completely on MOND. It sounds like he thinks modifying it somehow might be able to salvage it, so he's saying he really only falsified MOND in its current form if I interpret his writing correctly. There have been numerous ideas on how to modify MOND, but as far as I can tell, they all run into a common set of problems, like not explaining gravitational lensing, and not being able to simulate the formation of the universe without the dark matter. Now there's the newer problem they can't seem to explain, of how a modified gravity model can explain galaxies which don't appear to have any significant dark matter. A modified gravity model should affect all galaxies the same way, so finding galaxies without dark matter creates a big problem for those models! I made a separate thread about this topic.

a reply to: Arbitrageur

I understand what you are saying but I just watched yet another video questioning whether or not dark matter exists or not, which I won't post because it is just another 'we don't really know' MOND rabbit hole. Anyway, I find both theories interesting in as far as I can understand them. However, that original source I posted was discussing dark energy not dark matter and I was on a quest to see whether or not all this MOND speculation was not worth it if we got the whole Big Bang wrong anyway. It's all speculation.

This is why the findings of the current study may be substantial as it explains the observed expansion rate of the Universe without the need to introduce any type of unobservable energy.

a reply to: quintessentone
Theories like big bang involving an expanding universe have always been dreamed. We think some of the barred spiral galaxy stone drawings at Newgrange Ireland may have been such an expression chiseled 5000 years ago by a lonely priestess.

A lifetime of gravitational data observations would have occurred in a picosecond at a time of history closer to the big bang if that theory is correct.

As Arbitrageur hinted the Hubble constant appears to vary depending on the age of the stars used in its calculation which lends support for variations in classic time measurement. Frames of reference for time measurement confuses many people. And even when its explained there are things like gravitational lensing that distort what we record in the night sky. Nothing was where it appears today.

Dark matter theory is not intuitive for me and there may be evidence that phenomena like the Hubble constant were known long ago(as an average) but that would have been unverifiable. Verifiable theories more easily pass the peer review process and there are so many unverifiable Dark Matter explanations out there that its hardly worth posting.

originally posted by: Skinnerbot
a reply to: quintessentone
Theories like big bang involving an expanding universe have always been dreamed. We think some of the barred spiral galaxy stone drawings at Newgrange Ireland may have been such an expression chiseled 5000 years ago by a lonely priestess.

A lifetime of gravitational data observations would have occurred in a picosecond at a time of history closer to the big bang if that theory is correct.

As Arbitrageur hinted the Hubble constant appears to vary depending on the age of the stars used in its calculation which lends support for variations in classic time measurement. Frames of reference for time measurement confuses many people. And even when its explained there are things like gravitational lensing that distort what we record in the night sky. Nothing was where it appears today.

Dark matter theory is not intuitive for me and there may be evidence that phenomena like the Hubble constant were known long ago(as an average) but that would have been unverifiable. Verifiable theories more easily pass the peer review process and there are so many unverifiable Dark Matter explanations out there that its hardly worth posting.

I think it's wonderful that we reach for the stars and understanding of our place in the universe.

originally posted by: Skinnerbot
Dark matter theory is not intuitive for me...

Dark matter is not a theory, as this physicist explains.

dark matter is not a theory

You could watch the first minute where she says dark matter is not a theory, and just take her word for it, or you can watch as much of the 43 minute explanation as you want for why it's not a theory, but either way, I hope you will realize that dark matter is not a theory.

Now, we do have a standard model of big bang cosmology, called ΛCDM, where the CDM stands for "Cold Dark Matter", and one might think that must include a theory of dark matter, but it really doesn't. As explained in the wikipedia article, it just incorporates the dark matter observations, without having a specific theory or explanation for dark matter:

Lambda-CDM model

ΛCDM has no explicit physical theory for the origin or physical nature of dark matter or dark energy

So even though dark matter is in that model, it's not a dark matter theory, since it has no explicit theory for the origin or physical nature of dark matter. I would say all we have are hypotheses for what might explain the dark matter observations, and hypotheses are not theories, at least not in scientific vernacular, though the distinction may be blurred in laymen's terminology. A number of the hypotheses are shown in this illustration:

a reply to: Arbitrageur

Her strongest argument is that gravitational lensing of the 3.8 billion year old light from the Bullet Cluster produces observational data that is more easily explained with dark matter.

The amounts and location of the necessary dark matter varies wildly with the observational method proposed and there are probably other theories to explain the gravitational phenomena that don't involve any hidden matter at all. Apparently there is a relativistic version of MOND.

Another study in 2006[18] cautions against "simple interpretations of the analysis of weak lensing in the bullet cluster", leaving it open that even in the non-symmetrical case of the Bullet Cluster, MOND, or rather its relativistic version TeVeS (tensor–vector–scalar gravity), could account for the observed gravitational lensing.

Professor Higgs was actively working on the existence of Dark Matter even after retirement.

He predicted the existence of his Boson long before it was proven at CERN and influences of Dark Matter were an important part of that work.

If we finally prove the nature of Dark Matter, I wonder if he will get A credit for it's discovery as well!

a reply to: Skinnerbot
Apparently, you're just ignoring the entire point of the opening post of this thread? Did you even read and try to understand the opening post?

a reply to: Arbitrageur

We are looking at radiation sources from distant objects.
I agree Proxima Centauri and Alpha Centauri are much closer to Earth than the Bullet Cluster.
Still due to the scale of the distance its like looking at a 2 dimensional event.

It takes light from the binary event over 4 years to reach Earth. If the extra gravitation attributed to dark matter mass also keeps the brakes on radiation traveling from the event for 4 years there might have been more conventional matter there to begin with?

They have not found dark matter locally in any accelerator (yet) although they may someday find high energy zero mass particles interacting with the Higgs field that (condense) out into lower energy particles with more mass than current theory. That cooling mass increase might even occur at an unexpected rate during the journey from the event which we are unable to record because it occurs light years away from Earth traveling in the direct observable to us.

a reply to: Skinnerbot

If there are external forces at play and those external forces are not uniform throughout the universe (NGC 1277 contains no more than five percent dark matter). MOND will never be able to correctly explain observation.

If those external forces prove to be electrogagnetic for example. General relativity will continue to be seen as correctly explaining gravitational forces.

a reply to: Skinnerbot
The point was you're bringing up some paper from 18 years ago about MOND, when the OP is about current research on MOND versus dark matter by a long-time supporter of MOND, who has published a study which rules out MOND to a very high confidence of 16 sigma. The same paper also explains the apparent contradictory results which claimed to support MOND quite satisfactorily by pointing out that study contained too many high uncertainty data points.

The binaries are just one small piece of the cosmic puzzle.

You also seem to have completely ignored the part of the "dark matter is not a theory" video which explains baryon acoustic oscillations.

MOND also fails to address other aspects of cosmology which dark matter addresses, such as gravitational lensing by dark matter, and the large scale structure of the universe, two huge problems with MOND that I didn't even get into in the opening post. The latter is discussed in this article:

Ask Ethan #94: Could dark matter not exist?

There’s the gravitational bending of starlight by mass, including strong and weak gravitational lensing. There’s the Shapiro time delay. There’s gravitational time dilation and gravitational redshift. There’s the framework of the Big Bang and the concept of the expanding Universe. There are the motions of galaxies within clusters and of the clustering of galaxies themselves on the largest scales...

For all of these — all of them — MOND fails spectacularly, either offering no predictions or predictions that woefully conflict with the available data. Perhaps if you argue that MOND was never intended to be a full theory, but rather a description of one phenomenon that might lead to a fuller theory, you can keep your hopes alive. There are many people working on extensions of MOND that could explain these observations, but there are no good successes so far, including TeVeS (Tensor-Vector-Scalar gravity by Bekenstein), MoG (Modified Gravity by John Moffatt), and others.

But if you keep Einstein’s law of gravity and simply add in a new ingredient, this collisionless, cold dark matter, you can explain it all, including some spectacular, novel nuances.

I find it strange that MOND supporters seem to ignore these rather spectacular failures of MOND, and write papers about MOND as if it's a competing theory for dark matter without even addressing them!

That article dates back to 2015 but I haven't really seen any improvement in those spectracular failures of MOND since then.

Ethan also shows the one graph that destroys MOND, again it's related to the baryon acoustic oscillations:

Why the Universe needs Dark Matter (and not MOND) in one graph

until those in favor of modifying gravity can successfully predict the large-scale structure of the Universe the way that a Universe full of dark matter does, it's not worth paying any mind to as a serious competitor. You cannot ignore physical cosmology in your attempts to decipher the cosmos, and the predictions of large-scale structure are some of the most basic and important predictions that come out of physical cosmology. And that's why the Universe needs dark matter -- and not MOND, MOG, TeVeS, or any other dark-matter-free alternative -- in one all-important graph!

a reply to: glend
That reminds me of another thread I made about how if modifying gravity is the answer as with MOND, then that should work in every galaxy. But it doesn't since some galaxies show no evidence of dark matter, and their rotation curves can be explained by an absence of dark matter but not by modified gravity, which is the point of this thread even though the title may sound a bit perplexing.

Does the Failure to Find Dark Matter Prove the Existence of Dark Matter?

Finally, the latest failure to detect dark matter may have actually proved its existence.

That's just another interesting observation but I think the spectacular failures of MOND discussed above are the biggest problems with MOND, including the relativistic version.

So the binaries discussed in the opening post I think are just the tip of a rather large iceberg, with MOND supporters seemingly ignoring or having no successful explanations for the majority of the iceberg.

a reply to: Arbitrageur

The point I'm intending to make is that trying to explain the observational anomalies of distant galaxies with dark matter is not intuitive and MOND descriptions comes in different flavors.

They didn't find dark matter locally at CERN and for accuracy you would intuitively seek out a nearby binary system such as Alpha Centauri that wasn't distorted as much by gravitational lensing.

Sure enough, the far star (Proxima Centauri) is orbiting far too fast to be bound by the visible matter of the other two, and yet it is definitely bound because it has the same motion through the sky and the same chemistry as the others.

physicsfromtheedge.blogspot.com...

One 'fix' that has been inevitably suggested is to increase the mass of the two central stars, by 3-sigma, a large increase over their mass uncertainty, so not ideal.

More conventional mass combined with MiHsC?

originally posted by: Skinnerbot
a reply to: Arbitrageur

The point I'm intending to make is that trying to explain the observational anomalies of distant galaxies with dark matter is not intuitive and MOND descriptions comes in different flavors.

The models are mased on mathematics, not intuition.

None of the flavors of MOND can explain away the things mentioned in my previous post, including MiHsC.

More conventional mass combined with MiHsC?

The best I could see McCullough doing is showing that maybe something else is going on besides dark matter, but his MiHsC model is not a viable alternative to dark matter for the same reason all other MOND variants are not viable alternatives. This article discusses some problems with McCullough's ideas:

Quantized Inertia, Dark Matter, The EMDrive And How To Do Science Wrong

The Unruh effect, Casimir effect and information theory are all well established in modern physics, but their hodge-podge combination in MiHsC is misapplied...

McCullogh then argues that MiHsC is inherently better than MoND, since MoND relies upon an adjustable parameter. Nevermind the fact that MiHsC violates established physics, while MoND is simply descriptive.

McCullough's MiHsC model doesn't really sound promising.

a reply to: Arbitrageur

Mathematics is the end game.
For example before you can apply any mathematical formula to adjust for relativistic frequency observations you need to expect that there may be mass in some distant galaxy moving other than in the two plane dimensions of the sky.
That takes intuition to model not math.

You can't beat the Nelson bot on Chess.com without at least that.
And Voyboy will call you a beast if you beat him.

originally posted by: Skinnerbot
a reply to: Arbitrageur

Mathematics is the end game.
For example before you can apply any mathematical formula to adjust for relativistic frequency observations you need to expect that there may be mass in some distant galaxy moving other than in the two plane dimensions of the sky.

With galaxy rotations, we can measure the galaxy rotations, and from that, calculate the gravitational mass of the galaxy. It's not an intuitive leap, it just uses actual measurements of the rotation and Newton's law of gravity which works almost perfectly in our own solar system (except the precession of Mercury, but we don't care about precession for the mass calculations).

After calculating the gravitational mass, you can then calculate the luminous mass. This site explains how to do both and gives measured data from a galaxy so you can do the calculations yourself, in fact it looks like a homework problem page:

Discovering Dark Matter

Part A: Finding the Gravitational Mass...

(Use observed rotation data and apply Newton's law of gravitation)

Part B: Finding the Luminous Mass
Now that we’ve found the gravitational mass of the galaxy, we wonder how much of that mass comes from stuff we can see (i.e. stars and gas). At right is a graph of the luminosity profile of NGC 2742. The x-axis is the distance from the center, the y-axis is the brightness contained within a circle of that radius.

Both of those are rather straightforward mathematically and shouldn't take any intuition, just some simple knowledge of physics and math.

In the early history of Dark Matter observations, the amount of non-luminous mass was huge compared to the amount of luminous mass. It shouldn't be any surprise there's non-luminous mass, because we can see planets in our own solar system that don't vive off any visible light, like Jupiter, Saturn, even the Earth doesn't naturally emit visible light, so we live on a form of dark matter called baryonic dark matter. So of course baryonic dark matter exists, there's no question about this, it's also in the form of non-luminous gas clouds, and even black holes are classified as baryonic matter even though we don't really know their exact composition after the baryons fall inside.

So it's quite natural that we expect, and find, the gravitational mass of rotating galaxies is greater than the luminous mass, and maybe math isnt your thing but the math explained on that link is really quite simple.

The assumption of how much luminosity is hidden by gas clouds etc can certainly be questioned, but for the sake of this problem, the instructions are to assume actual luminosity is double the observed luminosity for the reasons explained:

Now that we've measured how much light is coming from NGC 2742, we need to estimate the mass of the stuff that produced that light. In order to take into account different brightnesses of stars, faint ones that are difficult to see, dust and gas that hides some stars, we will assume that there are two solar masses of stars for each solar luminosity of light.

Calculate the lumionous mass by counting 2 solar masses for each observed solar luminosity, and record the number in the “Radiation Mass” column of Table 1. (In other words, multiply the total luminosity by 2.)

Part C: What's Missing?
There's one last step to figuring out how much of the galaxy can be understood by things we know (luminous stuff like stars and gas), and how much of the galaxy can't be detected this way.

Divide the luminous mass by the gravitational mass at each radius, and enter this number in the last column on the table.
Answer the questions on the worksheet.

So, that's it, simple math, making calculations from observations, no intuition really.

You can go through the exercise and calculate the "missing mass" that way, it's just the difference between the gravitational mass and double the observed luminous mass.

Where it gets complicated, is how we have refined our observations over the decades. As we have done so, the amount of missing mass has been reduced a lot. We then try to account for the planets like Earth, Saturn, Jupiter, and countless other exoplanets that evidence suggests are likely to exist, black holes, gas clouds, and other things that have baryonic mass yet don't give off light. Yet all of the related observations trying to account for the missing mass suggest the baryonic dark matter like planets can only account for a fraction of the missing mass.

You can do other measurements too, that get more complicated than the galaxy rotation curves, but I focused on those to show how the missing mass in galaxies, comes right from observations of the rotation curves and luminosity measurements, and applying Newton's law of gravity.

This is how the "missing mass" can be a calculation, not an intuition. If you think it's intuition, you're missing something.
But of course there could be other reasons for the "missing mass" calculation besides missing mass, hence the MOND ideas and variants.

You said something about CERN not finding the missing mass. Some of the hypotheses CERN would be unable to find, for example primordial black holes are one possible component of dark matter and CERN wouldn't be able to find those, there are no primordial black holes at CERN. We don't know how many might be "out there", if any. For the particle searches, most are not done at CERN, they usually use underground facilities and have been searching through the parameter space so far without finding dark matter particles.

Keep in mind, we can barely detect neutrinos, and if dark matter is even harder to detect than neutrinos, we may not be able to detect it at all. Neutrinos are a fraction of the "missing mass" but we have reasons to think the known neutrinos can't be the majority of it, though some hypothesized neutrino types like sterile neutrinos are one candidate for the missing mass.

a reply to: Arbitrageur

I was very young back in the 60's when a friend showed me a map of the CMB, he was also one of the best players in our school chess club. Looking at the map was like walking in on a chess game late after many of the pieces were already missing from the board. We knew the universe was expanding and that the oldest cosmic background sources were moving away from us at the fastest rate but we didn't really know how much we could see. For example there may be a lot more mass in the universe outside our observable event horizon that contributes to gravitational lensing.



Speed of light C is only a constant if the second of time used for the measure is constant (like for the most part we find in the lab locally). Billions of light years ago and away extremely high energy low mass radiation may have traveled faster than our current value of C before cooling and continuing to expand at the current rate. Light from that early hidden mass might never catch up in that case but could account for some of the dark matter gravitation.

It is considered cheating to play blitz chess with a master and I haven't considered any theories that involve Baryonic mass other than maybe some of the Baryonic mass luminosity measurements arrived distorted.

I really enjoy your threads though, they are always thought provoking!