The Everything of Theory: Galaxies and Beyond

[Brian O'Donnell]

This post looks at the spiral galaxy rotation problem and goes on to speculate about resonant behaviour on a grand scale.

SPIRAL GALAXIES
Spiral galaxies are observed to rotate too fast in their outer regions, that is in the arms. The conventional approach is to posit some kind of new physics such as dark matter or a modification of Newton's laws to make it all work.
There is, however a hidden assumption in this approach which is that the matter in the galaxy can be regarded as a fairly uniform distribution. A more subtle version of this is to assume that a common centre of mass is an adequate approximation to the mass distribution. As part of the conventional idea, the spirals are regarded as stars being ignited by a compression wave in a relatively uniform disc.
Although the concept of a centre of mass is a good approximation for inter-galactic distances, it becomes less accurate as the distribution of matter becomes more uneven and as the distance from the central point becomes less, especially within the galaxy itself. Wikipedia's page on 'center of mass' contains several caveats on the use of this idea.
If you assume an even distribution then a Newtonian solution to the rotation problem becomes impossible.
But what if what you see is what you get? Just suppose that matter actually is concentrated in the spiral arms. The problem now becomes how the arms stay stable enough. Imagine a section through the plane of the galaxy represented as a stretched rubber membrane with a large depression representing the central bulge and curved valleys representing the arms. A test mass released at zero initial velocity at the edge of the galaxy would roll down the curve of one arm. Instead of travelling in a straight line towards the centre, it would be attracted firstly to the nearest arm with a forward component to its acceleration and secondly towards the centre of mass. So it would accelerate to keep up with the stars in the spiral arm.
If you want to see some figures, try http://www.mb-soft.com/public/galaxy.html. This site looks at the sun's path through our own galaxy and features the same idea. Where I beg to differ, however, is that I would substitute an orbit around the axis of the local spiral arm for their proposal of a simple harmonic to and fro motion. If each star is attracted principally to the axis of a spiral arm as well as, on a larger time scale, to the galactic centre then there is a plausible solution to the galaxy rotation using conventional Newtonian physics.

EMERGENCE OF SPIRAL ARMS
To set the previous argument into a possible context, I propose the following scenario. If the stars in the outer regions are orbiting the rings as well as orbiting the centre, each of these orbits will precess and also vary between circular and elliptical. The various periods taken for each of these oscillations will form a highly complex pattern with several harmonic overtones and undertones. The best analogy I can think of is hitting a cymbal and listening to the combination of sounds it makes. It is just possible that the spiral arms are an emergent phenomenon arising from a particular resonant vibration.
If this were to be the case, semi-stable spiral arms would form in a galaxy and would wind up over a period of time until they were absorbed into the disc. In this scenario, elliptical and spiral galaxies would be the same phenomenon at different stages of a cycle. a survey of galaxies would give an indication of what percentage of the time a galaxy spent in the spiral stage.
One question that springs to mind is whether entropy is considered to be preserved for such a cyclic system.

VIBRATING WALL
The largest known structure in the universe consists of an enormous wall of galaxies in space. If the principle of harmonic motion is applied here, the wall might resonate in various modes over very long time periods indeed.
There is an interesting parallel here with the idea of resonance and branes in superstring theory.

CYCLIC UNIVERSE
To step up in levels of scale and of speculation, let us look at the whole universe. The idea of a pulsating or cyclic universe has gone out of fashion in favour of the big bang theory but has never quite gone away.
The observable universe is seen to expand at an accelerating rate and the hopes of pulsating theorists from about 50 years ago seemed to vanish at an accelerating rate as the point of inflection when the expansion was expected to slow down never materialised. If the universe is cyclic, we must be at the low point of a sine wave of expansion. It is difficult at this stage to know whether the expansion will continue forever or whether some unknown factor will slow it down. After all, we don't know what causes the expansion in the first place, other than to label it 'dark energy'.
If the whole cosmos is resonating with waves of compression and rarefaction travelling in all directions, the visible part of the universe could currently be in a rarefaction stage, causing it to expand. As the wave passes in so many trillion years, it will be replaced by a compression phase and our corner of the universe would collapse in on itself.
There need not be a collapse to a single point but there would be a minimum level from which a new expansion phase would start.
This might explain why the furthest and therefore youngest galaxies look so much like the well established ones closer to us.
It is very difficult to calculate the masses and energies involved in a bounded universe but if the energy required for expansion comes from the long term vibration of a far greater mass there is a possible candidate for dark energy.

[Graybeard]

If the universe is cyclic, we must be at the low point of a sine wave of expansion.

Hi Brian ... I don't get this part, could you explain a bit more. Why would the cycle include a full sine-wave. What part of the Universe's evolution would be characterized by the X axis ?

cool bananas ... greg

[Farsight]

Brian: re my post on your other thread, I also cover dark energy and dark matter. I get into the relationship between space and energy, but that's too much to go into here. Suffice to say space has been expanding since the big bang, but in some regions this expansion is constrained, and the result is non-homogeneous space. This means gravity can't follow the inverse square rule to the letter of the law, and hence we see flat galactic rotation curves. It's a little like MOND in that you don't need large quantities of dark matter.

[Brian O'Donnell]

Hi Brian ... I don't get this part, could you explain a bit more. Why would the cycle include a full sine-wave. What part of the Universe's evolution would be characterized by the X axis ?

cool bananas ... greg

What I mean is the following. Imagine plotting the size of the universe (or at least the size of a defined region of space) on the y-axis and the time on the x-axis. Assume that time=0 represents the big bang or big bounce or a more gentle type of turnaround. Let us set the minimum point of a sine/cosine wave at a point above the time axis (x-axis). The size is always +ve.
With a cyclic universe theory, the size as measured on the y-axis goes up at an increasing rate for the first quarter of the cycle until it hits a point of inflection. At present we are well within the first quarter. For the next quarter, the size goes up at a decreasing rate until it reaches a maximum. As it goes through several cycles it might continue indefinitely or be damped down. There is no way of telling.
If conventional theory is correct, we would see the same concave curve between time=0 and the present day but in the future, the universe would continue to grow at an accelerating rate without limit.
If the big bang theory is correct, the lower part of the curve would continue down to the origin at a steeper angle hitting a point where size and time are both zero.
Sorry, but my efforts at turning the universe inside out exceed my ability to post graphics in the reply template.

[Graybeard]

What I mean is the following. Imagine plotting the size of the universe (or at least the size of a defined region of space) on the y-axis and the time on the x-axis. Assume that time=0 represents the big bang or big bounce or a more gentle type of turnaround. Let us set the minimum point of a sine/cosine wave at a point above the time axis (x-axis). The size is always +ve.
With a cyclic universe theory, the size as measured on the y-axis goes up at an increasing rate for the first quarter of the cycle until it hits a point of inflection. At present we are well within the first quarter. For the next quarter, the size goes up at a decreasing rate until it reaches a maximum. As it goes through several cycles it might continue indefinitely or be damped down. There is no way of telling.

I'm still not sure if I get you right. How about this ... which one are you picturing ? I can't see how it could enter the negative region of the Sine Wave.



Click on the pic to make it bigger !

cool bananas ... greg

[Brian O'Donnell]

Oh dear, Greybeard - I'm not explaining myself clearly enough!
The lower of your graphs represents a proper sine wave with the x-axis along the neutral line of the curve. What I was trying to explain was a sine wave which is always positive and where the x-axis lies beneath the minimum value in the troughs of the graph.
The vertical y-axis is taken through one of these troughs.
So at time=0 the diameter of the universe would be at a minimum value (but not necessarily zero) and it would then start to increase, sweeping upwards for the first quarter cycle of the wave. This part of the curve corresponds to observations.
If there were a repeating grander scale cycle of rarefaction and compression operating on the observable part of the universe, the diameter of our little bit would increase and decrease following a broadly sine wave pattern, repeating itself from the distant past and into the distant future. Under this scenario the push to expand our universe would come from a compression in a region just beyond the visible horizon. As the adjacent region started on an inflationary part of the cycle, ours would stop growing and start to shrink. Each part of the larger universe would affect every other part and the wave of expansion and contraction would continue, perhaps forever.
This idea might not solve all the problems and is not directly testable but I hope it is an overview which is worth looking at.

[analog]

Hi Brian,

I think I understand what you are describing, and I view the manifestation of our current universe from a physical fundamental substance (i.e. material Aether) as one cycle of your sine wave. I don't discredit continuing cycles and they would help in explaining an initial event/bang/collision which could allow for the chain reaction of events that would eventually lead to our current asymmetrical arrangement of substance we know as our universe, but to my understanding the major problem would be conserving the mechanism within the framework which allowed for the next cycle.

Some of us here use a framework derived of a malleable fundamental substance from which all physical things are manifest (e.g. matter, anti-matter, space, etc.) with properties (i.e. absolute motion and self-affinity) which set the parameters by which the chain reaction of existence occurs. Our recognition of a volume, whether it be matter or space, is dependent upon its density, determined by the state of motion (random or uniform) within that volume defining its mass and also dictating the self-affinity's ability to further direct the motion; thus governing spatial condensation towards material formations (e.g. atomic structures, galaxies, stars, planets, compounds, structures, life, etc.), or expansion towards a less dense spatial arrangement (i.e. space). Energy thus becomes the measurable interactions manifest through the redistribution/changes of density throughout the whole (i.e. universe); therefore unifying the 'forces' by identifying the absolute scale at which they act upon. Thus, when applying an absolute velocity to the motion, the linear velocity of our entire universe (i.e. fundamental substance), along with any definable internal volume, would become the reciprocal to spatial expansion (with the only other factor being the angular momentum at the micro atomic scale which allows for an internal volume to become autonomous to its spatial medium) as absolute time (i.e. total elapsed motion) would be the product of both.

This means that all motion is positive to the arrow of time, and the start and end of a cycle would be at a universal configuration of maximum linear velocity through the void; thus also an absolutely condensed diameter; thus in a state of absolute symmetry/absolute zero temperature. I view this condensation as being perpendicular to the direction of travel thus causing a minimum diameter in that direction with a trailing length proportional to the amount of fundamental substance, but that's just my interpretation.

I say all this to explain that from this perspective, the problem therefore becomes that at this stage, the fundamental substance is now at an arrangement of absolute solidity and mass, whereby according to the physical parameters by which it operates, dictated by its properties, nothing less than a head-on collision with a similar volume of fundamental substance (i.e. another universe in its initial absolute state) would be able to ever start the progressive algorithmic cycle (symmetrical chain reaction) of inflation/expansion, which is redirected back to the initial state by means of its properties; thus completing one cycle; having manifest all that we know (us included) purely by physical interactions of emergence and evolution of structure.

It is for this reason that I am undecided about such an event or cycle, and I'm curious how you would address this problem as it is fundamentally incorporated within the parameters of a framework and the properties which define them, if we hold true to the conservation laws, which I believe in.

Regards,

Tim

B.T.W. Due to my perspective, I don't believe in the dark matter and dark energy needed to make the current galactic calculations work.

[Brian O'Donnell]

Hi Analog. One or two questions for you.
I don't know what you mean by 'self-affinity'. Do you explain this elsewhere?
How do you measure 'the linear velocity of our entire universe' and in relation to what? Or do you mean velocity through space-time?
I can see that my 'Time = 0' point is causing some problems. I intended this expression as an arbitrary fixed point at one of the minima in a time continuum. Compare it to the BC/AD division in our calendar. In my proposed model, the cycle was always there, befrore any arbitrary zero point in time. So you don't need any event to kick off the cycle.
This cyclic theory is an extrapolation of the concept of harmonic oscillations to the grandest of scales. An analogy is the tensile energy of a plucked guitar string being tranformed into kinetic energy as it passes the unstressed neutral axis and through to maximum tensile energy and zero velocity at the other side. On a more abstract level, the cyclic shift between stressed electrical and magnetic fields keeps light vibrating at a set frequency. In a system of orbitting masses, rotation and precession continue on different time scales, conserving energy throughout.
It is not possible to devise a test for whether such an extrapolation to the scale of the entire universe is justified or not but it does provide a model for the current expansion phase where the energy comes from within and is conserved.

[AntonioLao]

Spiral galaxies are observed to rotate too fast in their outer regions, that is in the arms.

These could be the effect of a process of solidification similar to a flywheel that as a solid object the outer rim must rotates faster in order to keep up with the rotation of the inner rings.

[mkirkpatrick]

The driver of galaxies and beyond are vortexes,without them life could not exist.




regards michael.