Started July 10, 2000
(Supplements to essays The Nature of Light and Lorentz and the Aether)
Why do I think light is essentially a longitudinal wave?
How do I explain the "angular momentum" of light?
Can the aether be used to define absolute space and time?
How does the photoelectric effect work?
The answer comes in several parts:
1. Various properties of light, such as interference effects, indicate that it is a wave, so it requires a medium in which to propagate. Let us call this the aether.
2. The Michelson-Morley experiments and similar seem to show that the aether is not static. If it had been they would have detected a stronger "aether wind" as the Earth moved through it in its passage around the Sun.
3. Both this evidence and our intuitive impression that the aether poses no resistance to motion seem to indicate that it is some kind of fluid. It seems to be an "ultra-perfect" fluid (except when it "condenses" to form the standing-wave systems we know as "solid matter"!).
4. Such a fluid would not be able to support transverse waves, so light must be intrinsically longitudinal, despite the fact that it can be polarised..
5. Does this make sense? Well, think of large-scale waves: long-wave radio. Modern systems may be different, but the original idea was that you had a tall mast and the electric potential was different at top and bottom. The potential difference oscillated. The radio wave is caused by the effect of this oscillating pattern flowing out (as a longitudinal wave) in all directions. In order to detect it you require a long receiving antenna. The aether pattern that represents high potential reaches the top out of phase with the bottom. You get the strongest reception if the receiving mast is vertical, and deduce that the incoming radio wave must have been "vertically polarised".
But it was formed from longitudinal waves! What you are detecting is effectively the interference pattern between simple longitudinal patterns flowing out from top and bottom of the emitter. Interference patterns, when caused by an oscillating source, carry some information about the motion of that source. The "charge" in the emitter is oscillating up and down and the effect of this is being detected. The information becomes more and more difficult to retrieve the further you are from the source, unless you have a very large receiving antenna. This explains why you need antennae that spread across the whole globe to study the polarisation properties of radio waves from outer space.
6. The above explains (plane) polarisation at moderate distances or with large antennae, but what about other cases? I suspect that not all light is "polarised". The term "unpolarised light" may sometimes mean just that: the light has no pattern to its transverse oscillations and it best regarded as purely longitudinal.
Again, the answer comes in several parts:
1. Are we sure that all light has "angular momentum"? I think that only light with an element of circular polarisation does.
2. That circular polarisation can be associated with real angular momentum seems to me well illustrated by the phenomenon of the "optical spanner". If you read how this works, e.g. in Miles Padget and Les Allen's article, "Optical Tweezers and Spanners", Physics World, Sept 1997, p35, it will also give you some insight into what I think circularly polarised light really is.
3. The mechanism is the same as for plane polarisation (see above) except that the source is moving in a circle, so some kind of circular pattern propagates outwards. The pattern is a pattern of phase differences in a longitudinal wave. (The article referred to above illustrates how a phase difference can be imposed artificially, increasing the angular information carried and hence the resultant turning force.)
4. The wave itself does not turn! If you try and visualise a focussed parallel beam, think of a helical wire spring that moves parallel to its length but without turning. It will look as if it is turning, and an object placed in its path will react to a real turning force, but each part of the wire is moving in a straight line.
5. Whether or not the quantum theory belief that a fixed unit of angular momentum is associated with each frequency is correct I do not know. I doubt it. In any case, plane polarised light has no angular momentum. QT explains this by saying that it is composed of two parts, of opposite momenta, and these cancel. Think of those radio waves, though (see above). Is this likely to be universally true?
These are my idea of real aether waves. Today's (20:11:00) ideas are as follows:
They are basic oscillations in the aether, which is a featureless kind of perfect fluid, probably not composed of any kind of particle. It's just a smooth medium - after all, in its raw form it is just "the vacuum" - but it manages to have some amazing properties. In raw form, possibly all it can do is transport waves of oscillation of its "state", phi. Quite whether phi is distinct from aether density I'm not sure. I think it can only take positive values. All the different forms of force are the result of different patterns of phi-waves. The intensity of the force is governed by the rate of change of intensity of the relevant phi-wave pattern, so that phi-wave intensity (or some specific component thereof) corresponds to "potential".
The aether is able to change state when the phi-waves get too violent. It in effect solidifies by setting up stationary (or at least not travelling at speed c) "wave centres" that pulsate at some almost fixed standard rate, generating new phi-waves. The wave centres jiggle around a bit so as to try and get into the most advantageous position to absorb other phi-waves. The whole universe is governed by this need of wave-centres to get into resonance with incoming waves whenever possible. The macroscopic effect of their jiggling is what we attribute to "force". (When they jiggle they have a slight preference for going towards the source of the pattern of interest -- except when things are already too violent!)
In the neighbourhood of wave centres, the phases of the waves become important. Far away, it is only the intensities. This must be so or the tiniest bit of heat would be enough to destroy all solid matter. Where the phases match and there is interference the effective force is very much stronger, i.e. we have explained the strong nuclear forces.
In a nucleus, different rules might apply, though. My separate wave centres might not exist at all!
I know this is wildly speculative and quite complicated, but for me it is easier than thinking of separate electric, magnetic and gravitational fields. I can't hope to relate it very directly to real lab-scale physics. I tend to think at this very small level of the individual phi-wave, and at this level NONE of the macroscopic variables -- mass, charge, energy etc -- are properly defined. They all emerge as the
net effects of the collective behaviour of groups of wave-centres. I have no intention of ever trying to mathematicise all this! I think it is enough to feel that something of the kind is happening, and be no more definite about it than the Greeks were.
The short answer is "No!".
For me, "time" is best considered to be absolute anyway. We are free to define it as we wish but it's best if we all agree! In practice, even now when we can send signals all around the globe, we do manage this (see Tom Van Flandern: "What the Global Positioning System tells us about relativity": http://metaresearch.org/mrb/gps-relativity.htm).
But "space"? Although I do not think the aether itself moves very much - it is mostly waves in the aether that move, not the aether itself - I do not think that it remains stationary. Therefore if you want an absolute frame you can only have an approximate one, and you have to choose the one most appropriate for the scale of your problem. If you want to look within a solid body, it may well be that the "best" choice of frame, corresponding to the average aether state of rest, is the one moving with the body. If you want to plan a trip in space, you might be better advised to work in the frame of the fixed stars (though this is by no means certain, as possibly the aether swirls around a bit with the Solar System ...).
Not a particle, nor a wave! My thinking changes daily on this, but I currently (August 2000) think it likely that it does not exist except as a unit of "electrical energy".
Instead of trying to define the electron, let us think about its supposed effects: it is accompanied by a "coulomb field" that causes repulsion to other electrons and attraction to protons. But what do we actually see? We don't see isolated electrons doing this: we see "charged matter". The electron is always associated with "atoms". Could it be that the source of the coulomb field is an atom whose phi-waves (see my Nature of Light essay) are extra intense?
The atom is emitting phi-waves all the time, but when "charged" these increase in intensity. They propagate out in the aether in all directions, presumably at speed c.
But there is another side to the electron! Not only do those associated with matter generate coulomb fields, but it seems that the energy can take off and propagate as a free wave. Is this any different in fact from an extra intense sinusoidally modulated coulomb field, i.e concentrated phi-waves travelling in bunches? I'm not sure. I'd want to know more about how electron microscopes work, what the difference between and ordinary and a "field-effect" one is, and I'd want to know more about those "free-electron lasers" (FELs: see Peter Gwynne in Physics World, February 2000). Apparently you make a stream of electrons wiggle by passing it through alternating magnetic fields, and it radiates light. It looks as if the free wave - which I had hitherto thought of as composed of phi-waves travelling in just the one direction, is able to generate oscillating fields travelling in other directions. Does this mean that those beams really are "free electrons" and that they are pulsating? I don't know. It could be that the light is really a modulation of the magnetic fields that are causing the wiggling! (No simple answers in this FAQ I'm afraid!)
That light can be converted into electricity is now common knowledge, but does this mean that individual "photons" cause the ejection of individual "electrons"? Of course not! Before the "deification" of Einstein by the New York Times after the claimed confirmation of his General Theory of Relativity -- the 1919 eclipse data that confirmed his prediction of the bending of starlight -- Einstein was just about on his own in thinking the light could exist as localised "photons" (See Forgotten History). Moreover, in the real world there are many different variations on the effect, and it merges with "thermionic emission" and other known effects. Presumably the complete theory should also cover Compton scattering, in which light (gamma rays) causes the ejection of electrons but leaves spare energy which goes into the production of further gamma rays, of reduced energy. In my own model, there would also be continuity with the basic process whereby phi-waves can, when sufficiently intense, cause the creation of new electrons. Sometimes, I suspect, the light does not cause the ejection of complete electrons, only intensifies a field that can later cause other electrons to move more freely.
That the process cannot be a matter of individual photon-electron interactions is clear, one reason being simply that photons do not exist. Another reason is the scale of things: the wavelengths of the light are very much greater, in most cases, than the dimensions of an electron. In my view (shared by others such as Millikan) the light arrives as a complete wave, spreading over the entire receiving surface. In the case I have thought about most -- the application of the effect in "photomultipliers" of the type used by Alain Aspect in his Bell test experiments -- it influences the electric field throughout the material of the photocathode. The waves will suffer both self-interference and interactions with pre-existing oscillations of electrons. Where these two effects combine favourably, some threshold is exceeded and an electron gains enough energy to escape.
Thus a large wave-front gives rise to maybe a single electron emission, with any additional energy needed to make this process happen very fast (in a matter of femtoseconds) being obtained from that already present in the photocathode. In my view, this is typical of electron interactions with light. It is hardly ever (maybe never) a one-to-one relationship, whether we are talking about emission, absorption or any other interaction.
I suspect that the reason Einstein's interpretation caught on was largely that it was mathematically very neat. The real world, I fear, is untidy!
Could this be simply the amplitude of the phi-waves? An electric force is experienced when this amplitude varies - its magnitude is the gradient of the amplitude.
That's the biggest question of them all, and my ideas vary from day to day.
I have been known to say that the whole universe is formed of waves. The idea came from thinking about "particles" and what THEY were made of and how they interacted. If you dissect a "particle" it seems to me that you never come across anything actually "solid", so it must be "wave". Or is the most I can say that everything is made of aether?
Today's idea (12:07:00) is as follows: It may be necessary to assume that the aether itself changes state when subject to very high energy inputs. I don't see how the same pure waves that propagate in "open space" can ever form the standing waves of "solid matter" without some other assumptions. They may form vortices, but this seems beset with difficulties. I think it possible that the aether just suddenly changes to a state in which it pulsates. One "wave centre" helps generate others around it, in patterns that are influenced by another intrinsic property of the aether - it's natural tendency to oscillate at some preferred (very high) frequency. These properties must become more and more important as you get near solid matter.
That's not a complete answer but how can I say more? I doubt if we shall ever be able to say we really know.