Dern Matters

Table of contents

Preparatory Grovelling
Launching
The boxes next door
Mutual attraction
Just suppose. . .
To but some buts
If so, so what?

Preparatory Grovelling

If we knew what it was we were doing,
it would not be called research, would it?
Albert Einstein

Many of my articles rely on a good helping of handwaving, and for the most part, without apology: pioneering is too valuable an activity for me to discourage it seriously, and if pioneering does not begin with handwaving, how can we call it pioneering?

This essay however is different: not only is it practically all handwaving: I am not even sure whether it is meaningful.

What is worse, I cannot be sure to what extent it is pioneering: I have seen nothing of the kind elsewhere, but there has been so much speculation in the field that I find it hard to believe that the complex of ideas is novel.

That marks the end of my apology — if you don’t like it, goodbye; but in any case don’t say you haven’t been warned.

 

Launching

Another thing I must point out is that
you cannot prove a vague theory wrong.
Richard Feynman

I happen not to be much attracted by theories of multiple universes — in particular, indefinitely large numbers of splitting universes. All the same, something like parallel universes is at the foundation of the concept of my speculation here.

The available evidence for Dark matter in our universe, though confusing, is very strong at present, but any form of explanation or description for it is tentative, to put the matter charitably. Anyone who has no clear idea of what it all is about, I refer to Wikipedia articles such as “Dark matter”, and “Dark energy” — and those are just the start. Suffice to say here, that firstly, space in our observable universe seems to be expanding at a continuously increasing rate.

Secondly, and in my opinion more troublesomely, most of our observable galaxies, if not all, seem to have too little observable mass near their cores, to account for their high rate of rotation.

My first impression was that the likeliest explanation would be a sort of naïve Cold Dark Matter idea: in rapidly spinning galaxies there must be a lot of cool common matter among the stars. That is to say: matter either in the form of meteoroids and rogue planets (meteoroids not in orbit round stars, and massive enough to maintain a roughly spheroidal shape through their own gravitation) or even minor rogue black holes.

But our various astronomic and cosmological professionals seem to be united in rejecting anything of that type. Part of the problem is that any such scattered garbage would have to be present in unrealistically huge amounts — dwarfing the mass of visible stars for one thing. The idea of Dark matter seems to demand something like 20 times as much Dark mass-energy equivalent, as observable ordinary matter could explain.

Never mind how trivial our own little planet might seem: we, together with all our visible cosmic fireworks, seem to amount to an afterthought in our own universe.

At the very suggestion of anything of that type, the catholic hegemony of the middle ages would have had a collective conniption fit, and arranged an auto-da-fé of unique proportions. Look at what they did to Bruno for a far milder suggestion!

But never mind them — they missed that chance long ago.

Now, apart from our too rapidly spinning galaxies, it seems that the idea of limiting our universe’s mass-equivalent to what is visible, leaves us in difficulties in trying to explain how galaxies formed in the first place: if the density is too low, it denies the most obvious attractive forces for gathering diffuse matter from space into concentrations that can collapse into galaxies.

Is it time, I ask, to think beyond the walls of the conceptual box?

 

The boxes next door

Skepticism is a useful tool of the inquisitive mind,
but it is scarcely a method of investigation.
James Thurber

Now, I repeat: I am not a parallel universe fan; I lack the imagination, or the insight, and anyway, I am not in a position to calculate the nature or implications of parallel universes. So, however adventurous my suggestions here, they lack conviction. None the less, let’s explore the line of thought.

After all, possibly, just possibly, in the event that those suggestions do evoke a meaningful and novel line of thought they might stimulate someone into some more useful ideas.

To our pedestrian selves, we seemed to be living in a universe of three space dimensions and one time dimension, until Einstein showed that the distinction between the different dimensions is at best dependent on our respective relative velocities and masses and the like.

All right, call it four space-time dimensions and forgive me for loose terminology.

Since then physicists have come up with so many alternative multidimensional accounts that I never kept track of all the ideas, especially as some of them appeared to involved dimensions curled up inside atoms and so on. What that might mean, is not clear to me.

As long as their ideas work, more strength to the theoreticians’ elbows, but I seem to have heard or read of ten-dimensional or thirty-dimensional proposals without either accepting or denying them. Their main interest from my current point of view is that some such ideas are not seen as intrinsically nonsensical.

And that is without even invoking the indefinite multiverses that some theoreticians support, such as Everett did in his day.

Well, for my current purpose, the details do not matter. Let us consider what you could regard as just a few universes, each with at least four space-time dimensions all to itself. Anyone in any such a private universe would not share any of the dimensions of that universe with any other private universe, and accordingly nothing internal to any private universe would cause, detect, or experience any events or forces in any other private universes.

With one class of exception that I shall introduce shortly. . .

As an illustrative analogy, imagine a stack of simple, parallel planes that all share all their XY‑coordinates, but have no points in common. For a material illustration, imagine them as a stack of parallel, barely separated, glass plates. Call such a plate an XY‑universe. Imagine that all that any inhabitant of such an XY‑universe could observe, is separated from parallel XY‑universes by perfect refraction.

But also imagine that there is at least one of a different class of dimension, shared among at least some of the XY‑dimensions. Call these the Z‑dimensions. Call universes that share some of each other’s Z‑dimensions, clusters. To anyone in any one set of associated dimensions, such a cluster, it would seem that we exist only in say, our local cluster of four (or ten etc) dimensions, and that would be all there is to it. And to observers within each dimension in a local universe in a cluster, effects that can pass in the Z‑dimensions give no indication of affecting, or emanating from, other universes. Possibly we might call such effects Dark effects: Dark mass, Dark energy, Dark gravity, etc.

Now, each 2‑dimensional glass plate represents a local universe. The hyperverse is a stack or frame holding the entire cluster. A hyperuniversal observer above our stack can look down from above, through the stack of glass plates, and see everything that happens in every plane, the light passing perpendicularly through the stack, and generally invisible within any plate. Because the plates are parallel, the Z observer will use the same coordinates for all the planes, except that, to specify any particular plane at least one other dimension (Z‑dimension) is required, a dimension unintelligible to any denizens of any of the planes. (Compare the idea with the novel “Flatland”, described in Wikipedia).

For all I know, there might be more than one such Z‑dimension in certain clusters of universes, but for our purposes I assume just one, at least until I can think of more than one. And the XY‑dimensions might be more than just two; our glass plates are just an analogy to  4-dimensional spacetimes, much as a tesseract is an analogy to a four-dimensional cube.

So there could be any number of XY‑coordinates in any number of dimensions: in referring to all those dimensions that are not shared between any of the parallel universes, I just speak of XY, as if there were just two, as in glass plates, but there might be any reasonable number of them in any one universe. For us in our universe for example, there might be four space‑time XY‑dimensions. And that is what I assume here for the sake of convenience. Similarly, the assumption that all the points in any XY‑dimensions exactly match those in every other universe in the cluster, is simply for convenience — I cannot imagine its accuracy being relevant in the current topic; our glass plates might not be internally uniform.

Just remember that to speak of XY‑dimensions and coordinates does not imply two dimensions; it is no more than a convenient analogy. In principle there could be any number of dimensions internal to each universe for all we know.

Not only would none of the denizens of any one such universe in a cluster, be able to observe anything about XY‑dimensions in neighbouring universes; he could not be affected by them either, except via forces that can be transmitted across the Z‑dimension.

But in our local, notional cluster the dimension that I consider here, as common to the otherwise independent universes, would be the Z‑dimension that supports gravitational effects. And perhaps it would be a unique dimension; I do not insist.

From the point of view of some sort of hyperuniversal God’s Eye View (GEV), all the clusters could have the same coordinates, except within Z‑dimension. In the analogy of the parallel panes of glass, the GEV would be represented by an eye looking through all the panes at right angles to their planes. The whole structure of the hyperverse would occupy what we might call the XYZ‑dimensions.

In the model that I present, the GEV could be looking along the Z‑dimension that accommodates or transmits gravity, as perhaps the most fundamental force or influence, or whatever it might be that is common to all the parallel universes.

The only direct influence that we could feel from any universes in our cluster would be the gravitational effects of masses with more or less matching coordinates in nearby universes within the cluster. For the rest we simply would have no effect on our neighbours, whether we were walking through each other or sitting in each other’s laps or fires or not. Coinciding in such a way would mean that from the God’s Eye point of view our coordinates in the XY‑dimensions are all the same, and only the Z‑dimension separates them.

The meaning of the distance separating universes along the Z‑dimension, is not clear; if the hyperverse only accommodates one or two local universes, the concept would be be vague — it would amount to saying that they were close enough to account for whatever effects we deduce. However, if there were many, it might well be the case that some universes were closer together than others and that closer universes would affect each other more intensely or more strongly than distant universes.

Notice that the concept of separate flat glass plates is neither exclusive, nor strictly necessary; a single, folded plate could work very similarly. Suppose that our universe (our notional glass plate) were the only one, but that it is crumpled instead of flat, and its folds were beyond our red-shift horizon. That could have much the same effect, and arguably be less unwelcome in terms of Ockham’s razor.

Take your pick.

Mutual attraction

A bit beyond perception's reach
I sometimes believe I see
that Life is two locked boxes, each
containing the other's key.
Piet Hein

Now, in such parallel universes, or folds, no phenomenon that acts only within the XY‑dimensions of any universe could directly affect anything in any other universe. From that point of view within any universe, no such parallel universe has existence at all, where, by “existence” we mean “making any difference to some state or the course of some events”. So, if I bump my nose on a closed door I can assume that it exists, because if it did not my nose would not have been affected like that. And if a magnetic field had not existed, it could not have expressed its existence by affecting the behaviour of a compass needle.

But, if each universe's influences were internal to itself (as if we were working inside just one of the parallel panes or folds of glass) and our current interpretation of our observations and theories, then we could be at a loss for any explanation adequate for the formation of galaxies, possibly even for the formation of the stars we see so plentifully about us.

Horrors! Would that be conceivable? In science?

Certainly it would. Worse has happened in the past and worse will happen in the future. Science is not religion, not the works or word of the divine. Science is a class of discipline and practice aimed at making the most of our evidence and logic, concerning what we seem to see in the world around us. We could no more guarantee that any of our theories is beyond doubt or criticism or error, than we could squat down on the floor, and raise ourselves into the air by mental power alone. That sort of delusion lies in the province of faith, not science.

The difference between science on one hand and delusion and dishonesty on the other, is that no competent, honest procedure in science relies on claims of anything of the kind.

So, if our explanation and prediction of the nature of our world fails, then our job is, and long has been, to find observations within our world and determine adequate reasons for them, mercilessly rejecting hypotheses that fail in their predictions, and if even the best fail, then seek beyond our world (or our box), or something of both.

Or to reject the failing ideas uncompromisingly, and look for new ones.

I do not say which principles might explain our observations that suggest Dark Matter or Dark Energy — I simply do not know. This essay is no better than an abductive, not very coherent, guess.

But many a theory now in good repute, started out no better. Abduction, either in observation or speculation, is no substitute for science, but by the very nature of our world, it remains one of the scientists’ most fundamental tools.

So enough hedging: I have a guess, and my guess is as follows.

 

Just suppose. . .

Being right too soon is socially unacceptable.
Robert A. Heinlein

Suppose that to our universe there exists one, or a modest number, of mutually parallel universes (whatever that means, but I do not wish, irrelevantly to our topic, to exclude possibilities such as A having an influence on B, but B having none on A).

Suppose that gravity is the only effect that the Z‑dimension transmits.

That is not necessarily nonsensical in all views of gravity, such as that gravity could amount to, or be manifested by, the distortion of space.

Now, if so, a gravitational mass in one of the universes could affect masses in some of the others.

Let us also assume that the matter/energy density of all the relevant universes to be reasonably similar to ours: possibly something like the equivalent of one proton per litre.

Give or take a small number of orders of magnitude, but in any case, pretty diffuse.

Right; so:

As long as there is a fairly constant distribution of matter in the universes, this would suggest an indefinitely stable situation, with no major gravitational events.

More interestingly however, if there is anything like a big bang, such as we largely assume for our universe, or even some type of consistently developing or steady-state universe with sufficient turbulence and density, we could expect the clumping to lead to star formation, and on larger scales, to galaxies and clusters.

Well, we do observe the galaxies and clusters to some extent, but we are nonplussed by some aspects of their behaviour: their gravity seems to be too strong for their apparent masses.

There are several possible explanations for this, but none of them is as yet particularly persuasive.

So, while not-particularly-persuasive explanations are in vogue, one more (if it is one more — I do not promise that it is new) is unlikely to do much harm, and it might even stimulate some lines of thought.

So let us assume that we, as I write this and you read it, have some parallel universes of constitution roughly similar to that of our universe, somewhere out there along one or more Z‑dimensions. Along the Z‑dimensions, each universe that is sufficiently close to have any effect on us, may have started out similarly turbulent, but, like ours, generally too diffuse to produce a clumpiness similar what we observe.

But assume that gravity, perhaps alone among physical influences, can penetrate along what I have been calling the Z‑dimension: the one that penetrates across universes. Then what happens to affect the momenta and distribution of masses in one universe, would have gravitational effects in parallel universes.

But then, you object, why don’t we see any of this effect — we might be passing a neutron star in a neighbouring universe: why are we not being smeared out? Why do we not see G-type stars suddenly turning into impossible supernovas as their gravitational fields suddenly increase? Why do our oceans not suddenly develop tides that sweep kilometres-deep over all our continents within a day?

And so on.

Yes, but such questions ignore certain facts. People think in terms of the pictures that we see of night skies, of star fields, nebulae, and galaxies, and overlook the fact that such images enormously exaggerate the density of matter in space. Those crowded galaxies are mostly empty space, even pretty close to their central black holes. Consider our own nearest neighbour in our moderately dense volume of local space: roughly four light years away. That sounds very close — in interstellar terms, practically claustrophobic — but quite a large rapidly-moving star could pass between us without causing dramatic physical disturbance to the planets of either system.

More dramatically, Andromeda spiral galaxy is forecast to collide with our Milky Way in some 2 billion to 5 billion years. The prospect seems alarming, but actually, dense as the galaxies seem, the stars in their arms are so far apart that there is a very good chance that our solar system might not be disturbed at all. At a rough thumbsuck, the density of space containing our sun for about 4 light years in all directions, would be something like 1 in ten million million. For two stars to miss each other in such a dilution would not be a dead cert in a galactic collision, but it would a reasonable expectation as long as we did not pass too close to the central black hole.

In general, we should be far more concerned by the behaviour of our own sun in the mean time: it should be looking much like a red giant by then.

And more to the point for our current speculation, if the parallel universes were of similar density, then the chances of multiple universes close to each other in their Z‑dimension, and sharing masses close together in their in their XY‑dimensions, would be poor.

Poor, but not negligible. Each of the XY‑universes would have its own big bang, or equivalent, whether at the same time as each other or not. (Whatever “at the same time” might mean in connection with such scales!) The turbulent expansion would mean that at various coordinates, clots of higher density would coincide in different “adjacent” XY‑universes, and if gravity could be shared through the Z‑dimension, then if each clot alone were barely massive enough to maintain its matter, the two together would possess twice the strength of cohesion for as long as they stayed together.

Whether they would in fact stay together, is another question — they might not for long, because the should be no friction to hold them in place, so that if their mutual velocities along their respective XY‑dimensions were too high, they soon would separate. It could take multiple bodies in at least one of the XY‑universes if any one mass with components in more than one universe were to stay in the same gravitational well.

And yet, once the well were too deep for any mass in any of the universes to climb out of, those masses would stay together. And if the mass in one such universe were a galaxy, it would look superficially like its own visible mass, but would behave as though it had the mass in both universes at those coordinates.

To the inhabitants of that universe, the difference between observed and effective mass and observed mass would look like dark mass.

 

To but some buts

The gazelle I was feeding . . . though it took the piece of bread I was holding out
obviously did not like me. It nibbled rapidly at the bread, then lowered its head
and tried to butt me, then took another nibble and then butted again.
Probably its idea was that if it could drive me away the
bread would somehow remain hanging in mid-air.
George Orwell

 

There is room for many objections to such ideas, of course.

Why do we not see such effects more clearly? How about seeing gravitational lensing in clear space, with no visible mass to explain it as masses in neighbouring universes, that are not gravitationally yoked to visible masses move through clear space? Why do we not see more small accumulations of visible mass with no explanation of what bound them together? Or squashed together into diamond-like crystals by the gravity of passing invisible stars or even black holes? Why do we not see more smeared-out galaxies torn apart by invisible gravitational masses? Or smaller masses, which should be far more frequent? Are there any examples of visible effects in the early universe, that reflect the presence of gravitational influences where there are insufficient observable mass-energy concentrations to cause such consequences?

Make no mistake, I am not suggesting that I can point to any such effects as material evidence in favour of the hypothesis. There is no hard evidence for what is at best a speculation, and a speculation which is not even clearly characterised. However, not only is it often impossible to prove a negative, but the very nature of the hypothesis makes it difficult to decide when to stop looking. For one thing, we do not know how efficient the transmission of gravitation between universes could be: the very fact of gravitation being diluted by being shared across a lossy medium could explain why gravitation as a force is so weak in our universe.

Possibly in some weird way, the leakage of gravitation into inter-universal Z‑dimensional space could have created a sort of “tired gravitation” that explains the increasing expansion of space within our universe. Or the folds in our universe beyond our red-shift horizon could be exerting tension on our space and stretching it. As it happens, recent observations suggest the possibility of a slowing down of the acceleration of our universe’s red-shifting.

And the major clumping effects during or after our big bang might have been in the earlier stages of the big bang expansion towards the end of the “dark ages” when matter was more crowded and baryonic matter began to emerge. It would be quite possible for neighbouring universes’ gravitational effects at that time already to be influencing our future history.

Later encounters across the Z‑dimension would become progressively less frequent as masses drew further apart.

And galaxies in neighbouring XY‑universes that, as it were, had mated gravitationally across XY boundaries in those early times, would stick together indefinitely. It would be particularly likely that several galaxies at a time, in their own universes, would mate together in one unit, thereby explaining why the visible mass, not only would seem too small to explain its excessive gravity, but several times too small.

As for the non-appearance of smaller accumulations, say of the equivalence of rocky rogue planets, wandering through space without parent stars to explain their accretion: firstly, they are not easy to discover. Even the smallest star is much larger than any rogue planet, and even brown dwarfs are hard enough to spot, never mind rocky little rogues. What could be harder to explain would be why there are any such bodies at all.

Well, there are in fact quite a few ways in which orphan rogues could form. Colliding stars could splash, creating droplets of planetary mass on escape trajectories, that would wander indefinitely. Planets on interfering high-speed trajectories could easily find themselves sling-shotted out of their own stars’ gravitational systems. Current studies suggest that rogue planets are wildly commoner than stars, so to exclude trans-universe gravitation from the possible causes of rogue bodies could be a challenging exercise.

If so, so what?

The human understanding when it has once adopted an opinion
(either as being the received opinion or as being agreeable to itself)
draws all things else to support and agree with it. And though there be
a greater number and weight of instances to be found on the other side,
yet these it either neglects and despises, or else by some distinction
sets aside and rejects, in order that by this great and pernicious
predetermination the authority of its former conclusions
may remain inviolate.
Francis Bacon

What these ideas suggest or imply, I am unsure; the fact is that I am out of my depth. That might sound ignominious, but I am undismayed — I reflect yet again on the words of an anonymous columnist in a Scientific American of 1964:

“Knowledge is growing and changing,
the world is large and Man is small, and
except in matters of faith, there is no pope.”

When you come down to it, if things were otherwise, this would be a far poorer world. It is in fact unclear whether there would be a world at all; it is conceivable on the one hand that this is the simplest possible world, and that the very nature of nothingness is such that it is self-contradictory and that if there were nothing, that very fact would imply this simplest of all worlds.

“Ahah”, I hear the cry “but what created the nothing?”

“Same thing that created the creator...”

Old story: An engineer and a lawyer and a communist were bickering about whose profession was the oldest:
“Engineering: one had to have an engineer to build the universe in the first place.”
“Nonsense; before the engineer could get started, one needed a lawyer to bring order to the chaos.”
“Ahah! But who do you think created the chaos?”

That was a better question than it might seem at first. Try to imagine something that has no start. Or ending. Whether it is an intellectual shortcoming or not, one tends to boggle. Is that because of our mental limitations, or is it because the state of NOTHING is itself fundamentally self-inconsistent?

Well, don’t bother to ask me where I get my stack of parallel universes from; I don't even know where to get this one, possibly folded, universe from. But if, before I leave you to think about it without assistance, you would like to read some discussion of the point, you might go to another essay at:

https://fullduplexjonrichfield.blogspot.com/2023/04/no-point_19.html

There I point out that for a position in a space to be fully empty, or even for it to have no size, would imply that the content and coordinate would have to be zero. This would require infinite precision 0.0000. . ., which is not possible in any universe, empty or not. That alone would explain why “empty space” is full of “vacuum fluctuations”. What exactly such space would have to be, is another question, but for it not to be is just as demanding for objectors to define, as for nothing to be.

Thinking about nothing can be confusing. . .

But one way or another, it would be a marvel if it turned out that the search to detect the mysterious and elusive Dark matter and Dark energy particles turned out to be futile because they are not even in this universe.

And it would be an eerie thought to see ourselves as part of the Dark matter and Dark energy for a different universe not too far away. If there were living beings in that universe, we would be equally hard for them to detect. But we might think kindly thoughts about each other.