Does Light Exist Between Events?
by Jim Walker
originated 28 Dec. 1998
- "One might still like to ask: 'How does it work? What is the machinery behind the law?' No one has found any machinery behind the law. . . We have no ideas about a more basic mechanism from which these results can be deduced."
- -Richard Feynman
Perhaps we cannot find a basic mechanism of light for the simple possibility that it may not exist. Whether it exists or not between events, I cannot imagine a more wonderfully perplexing and yet seemingly ubiquitous phenomenon as that of light. I use the term "light" in its general sense as that energy which allegedly pervades our existence and which physicist's call the electromagnetic force or electromagnetism (EM). It encompasses the entire spectrum from low frequency (long-wavelength) radio waves, heat (infrared), visible light, X-rays, and to the most energetic gamma rays. Quantum physicists today describe electromagnetism as one of the four elemental forces of the universe (the other three consist of the weak force, strong force, and gravity).
Almost everything we sense, see, touch and feel comes as a result of this force; it holds atoms together, creates the properties of chemistry and of every element in the periodic chart. Our every thought consists of electrochemical patterns. We cannot exist and, in fact, we consist of the reactions of the electromagnetic force within matter. Yet this most common "thing" remains completely inexplicable. We know nothing at all about its physical mechanism.
By inexplicable, I mean it in its philosophical sense rather than the scientific. Scientifically, light has received the most scrutiny of any other force and provided physicists with its most acclaimed successes, with predictions within one part in millions. Newton, Maxwell and Einstein have produced theories and mathematical descriptions that, through their understanding, have emerged technological achievements such as radio, television and lasers. Yet the success of these scientific theories have thrown virtually no light (pun intended) on the nature of the mechanism of light. How does it actually exist in nature? How can it travel through space? If it exists in space, what describes its shape, size, and boundary limits within space-time? How does this mysterious "action-at-a-distance" occur? No one has yet come close to accurately describing the alleged corporal substance of this ethereal phenomenon, and certainly not without also producing insurmountable paradoxes. Needless to say, the inconsistent descriptions present epistemological problems as well as ontological. Can we actually know anything about sole photons? Perhaps, even in principle, there occurs a quantum barrier to forever prevent knowledge of them. Or perhaps there exists nothing for us to know about; maybe light does not exist at all between emission and detection!
In this treatise I have no intention to show that the phenomenon of light does not exist. On the contrary the vast experimental data provides ample evidence that something occurs at the events. By "event" I mean something happening. For example the source (emission) of light and the detection of light act as measurable events. But where else does it occur? Our descriptions of light forces us to think of light as traveling through space, either as wave, particle or a union of both. But in doing so, we come up against insurmountable logical problems when we try to apply these descriptions to the double-slit experiment or the three polarizer problem. Can we describe light in another way that upholds the data yet eliminates the paradoxes without contradicting the mathematical models?
I will attempt to show that part of the problem may come, not from the nature of light, but in our unexamined use of language, the way in which we try to describe light, and of the philosophical beliefs held by scientists in their attempt to explain the properties of light. Because of the impreciseness of our spoken language, paradoxes and fallacies emerge that tend to confuse rather than to reveal. So also do scientists have their favorite beliefs, perhaps unconsciously born into them from Aristotelean beliefs, learned from rote teachings that appear absolute and unforgiving. I intend to show that perhaps many of the properties of light do not occur "out there" but only in our heads. Indeed, the phenomenon of a discrete packet of energy traveling through space might not exist at all, but rather the idea of its existence comes about through an incorrect way of thinking that derived from the Ancient Greeks and passed onto the 19th century physicists who created the scientific vocabulary we use today.
THE INVENTION OF PHOTONS
There appears only two ways to avoid action-at-a-distance. Either you propose a wave traveling through a medium, (like water and sound) or your propose an independent body that moves from point to point (like baseballs). The idea that light consisted of corpuscles actually began with Isaac Newton, but the mathematical description of quanta began in the early 1900s when Planck proposed the quantum of measured energy. He did not, however, believe in the corporal existence of light. Rather, he thought of light as traveling through a luminiferous ether in accordance with Maxwell's light theory, but measured in discrete lumps which he called quanta (Planck, 1909). The idea of light existing independently as discrete quanta came from Albert Einstein:
"Only the conception of a luminiferous ether as the carrier of the electric and magnetic forces does not fit into the theory described here; for electromagnetic forces appear here not as states of some substance, but rather as independently existing things that are similar to ponderable matter and share with it the feature of inertia." (Einstein, 1907)
Thus Spoke Zarathustra.
I don't mean to chastise Einstein, but rather the leagues of followers (read, believers) who have transmitted his concept in hundreds of scientific papers and placed it upon an untouchable pedestal of Truth. Yet few people realize that Einstein gave a heuristic description of light, not one that he thought of as absolute or as a requirement for his theories:
"For the time being the most natural interpretation seems to me to be that the occurrence of electromagnetic fields of light is associated with singular points just like the occurrence of electrostatic fields according to the electric theory. It is not out of the question that in such a theory the entire energy of the electromagnetic field might be viewed as localized in these singularities, exactly like in the old theory of action at a distance. I more or less imagine each such singular point as being surrounded by a field of force which has essentially the character of a plane wave and whose amplitude decreases with the distance from the singular point. . . I am sure it need not be particularly emphasized that no importance should be attached to such a picture as long as it has not led to an exact theory. All I wanted is briefly to indicate with its help that the two structural properties (the undulatory structure and the quantum structure) simultaneously displayed by radiation according to the Planck formula should not be considered as mutually incompatible." (Einstein, 1909) [bold characters, mine]
Compton's work in the 1920s with X-rays and electrons appeared correlated with Einstein's idea of discrete particles, and this convinced many physicists. And although Einstein invented the concept of a discrete quantum of energy, the idea of a "quantum" does not necessary impart indepenent existence. The believers of the reality of light needed a more concrete word. That word came in 1926 from a proposal by the chemist, Gilbert N. Lewis in a letter to the editor of Nature magazine. Just as had the electrons and protons, a unit of light (phot) got promoted with the suffix "on" to become a concrete description of energy as a particle of existence. Physicists could now regard the photon as real and as fundamental as all the other "on" particles that have the ability to putt about in free space.
"I therefore take the liberty of proposing for this hypothetical new atom, which is not light but plays an essential part in every process of radiation, the name photon." (Lewis, 1926)
From then on, the idea of the independent existence of light, with the blessing of the great scientist, Einstein, had firmly cemented itself into the lexicon and literature of science. How could one not think of light as a particle any more? Like the little man in this children's poem:
- I saw a man upon the stair
- A little man who wasn't there.
- He wasn't there again today--
- Gee, I wish he'd go away!
Have we hypnotized ourselves into a grand reification fallacy where we have mistakenly treated our abstractions as a physical reality? (see the "List of common fallacies")
THE PROPERTIES OF LIGHT
Scientists throughout history have called this mysterious energy by various names: rays, waves, light, beams, lumiferious ether, electromagetic radiation, quanta, photons, wavefunction, state vector, and who knows what else. All of the descriptors assume an existence in space-time.
Below lists just some of claims for this elusive force:
Now I ask the reader to try to assimilate these features and attempt a simple understanding of light. Mind you, this alleged fundamental particle, which has no mass and has no size, appears to have so many parts and features that a complex carburetor pales by comparison and with the elusive magic of a Houdini! I submit that something has gone awry here.
The illustration below describes a typical vector diagram that agrees with Maxwell's classical wave threory of light. Many high school and college text books use this version to this day:
This vector diagram shows light as a composite of an electric and magnetic field traveling through space as a sinosodal transverse wave. The electric wave always travels at 90° to magnetic wave, so the theory goes.
The illustration below shows a particularly creative attempt that seems to solve the wave particle duality in accordance with de Broglie's wavicle theory:
Note how this thread loop (the wave) appears within a discrete volume (the particle). I must admit, however, that I do not understand this model when you apply it to polarizers and double slit experiments (and I suspect the inventor had doubts too).
Perhaps the most successful and most abstract view of the photon came from Feynman in his diagrams that show interactions between mass particles by virtual photons. The Feynman diagram below shows an interaction between two electrons by a virtual photon:
But even in a virtual sense, the squiggly line imparts the idea of something with frequency traveling in space from point 6 to point 5. Of course no one has ever seen these photons; they exist virtually so they tell us. So do spirits, I hear tell.
"Photons are responsible for transmitting electromagnetic forces. The electric forces that hold atoms together are in effect 'carried' by photons'." (Close, 1987)
None of the above illustrations show the carrier/force model that agrees with Gilbert Lewis' and modern day descriptions. Therefore I humbly propose the following model which I think best describes how the photon carries the electromagnetic force. I haven't yet worked out the exact shape of the carrier but I think it looks something like this:
Notice the fine streamlined shape for fast traveling through atmospheres (it does slow down a little bit).
Of course all of these descriptions appear as abstractions and no physicist would dare make the claim that they describe an absolute description of light. But make no mistake about it; one thing that most physicists agree with: that in all of their abstractions, they believe the contention that light (whatever their description) exist as discrete packets of energy traveling through space, completely separated from matter.
Do you suppose that, perhaps, a simpler model might work without imparting so much baggage and paradoxes?
A BETTER MODEL?
Imagine that the phenomenon of light occurs only at the time of emission, reflection, defraction, and detection in matter, at the electron level, and nowhere else. Immediately, we eliminate the concept of light as discrete particles or waves traveling through space. Once you eliminate the concept of particles, waves and trajectories, the paradoxes, except for one (I'll explain later), completely disappear!
The equation for electromagnetic energy, e=hv imparts a quantum unit of energy with a frequency. Yet nowhere in the equation does it say where the energy occurs. Could not the entire phenomen occur as a function of electron events? Could not an electron transfer a part of its energy to another electron, not through a trajectory in space, but in delayed time?
Thinking of light as a function of matter events places the wave-particle duality entirely upon the experimental set up. If you want waves, your detector must behave in wave-like fashion. If you want particles, the detector must react as if it detects particles. Instead of imparting all the myriad of impossible feature to the virtual photons, why not attribute them to the very material from the emitters, reflectors, and detectors? Quantum philosophers will note the similarity to Wheeler's "observer creates reality" hypothesis (Wheeler, 1983). But in this model, either the observer or the contingencies from nature supply the materials of reality. (conscious observers need not exist for the reality of matter).
To explain it by way of a classical analogy, think of throwing a stone into a pool of water. You will see concentric waves emanating outwards (wave measurement). If you throw the stone into a bed of soft sand, you will observe an impact crater (particle measurement). Now imagine that (for whatever reason) something always prevents you from seeing the stone. You can only analyse the water and the sand (the stuff of your detector). Should you impart wave-like and particle-like properties to the stone? Clearly, imparting the wave or particle-like hit onto the stone would create unexplainable paradoxes.
The difference in the analogy from the classical model comes with eliminating the concept of discrete particle entirely. In other words, light does not exist between events, but only at the events.
A matter-measurement model of light not only does not contradict any known physical laws but, in effect, tends to support quantum mechanics. Just as electrons jump from atomic orbital to another in the Bohr model of the atom, so also can we think of electromagnetic events that jump from event to event.
Ah, but what of the solid evidence for photons? So much research, so many experiments; surely there exists mounds of evidence to throw against this view.
EXAMINING THE CLAIMED EVIDENCE
The challenge may seem incredulous but until someone can provide evidence, I will have to stand by it, lest I stand among the faithful believers. It amounts to this: no one, throughout the history of science has ever seen or detected a photon in space! To this day, there has never existed a single scientific evidential experiment that has shown the existence of a wave or a particle of light between emission and detection. So on what evidence do the believers rely on to justify their alleged photons?
The reason might appear obvious for the quantum philosopher. Since it requires some material means to detect a photon, we can never observe the alleged photon in its solitary state. Our emitters and detectors, themselves consist of matter. Therefore, whenever we detect light, we must do it at some instrument, whether it consists of a photometer or a biological eye. We simply have no way to look at the alleged photons in its pristine state without matter getting in the way. (Quantum philosophers might see in this Bohr's insistence of the importance of the measuring instrument in determining the outcome [Copenhagen Interpretation]). This, of course, did not occur to the first experimenters of light, and thus we get left with their Classical interpretations. The following briefly describes why the experiments seemed to confirm the photon's existence.
The Compton effect
Although Einstein believed in the independence of light particles, most physicists held on to the classical view of light. But Arthur Compton's experiments in the 1920s showed that X-rays can knock electrons about like billiard balls. This finally convinced the majority of physicists of the alleged particulate nature of light. The Compton effect, as we now call it, shows the path of deflected electrons in free space when "bombarded" by X-rays. But Compton's photos never showed the X-rays (Compton, 1926). The photos only show deflected electrons! Compton inferred that particles of X-rays traveled through space simply because the electrons behaved as if particles had hit them. And although the results of Compton's experiments correlated with Einstein's abstract definition of discrete quanta, correlations do not prove causation.
Along with all the instruments of detection such as the Wilson cloud chamber, and bubble chambers, physicists can detect many of the strange sub-atomic particles by looking at the tracks of these particles. But even by using these precise instuments, we cannot detect photons between events. Since the alleged photons have no charge, they never appear in particle track photos. Only the massive particles that have charge (electrons, protons, muons, pions, etc.) appear in them. Thus we can only use inference, without any direct evidence whatsoever to support the notion of discrete light particles moving through space.
"Invisible gamma ray photons produce pairs of electrons (green) and positrons (red) in a bubble chamber at the Lawrence Berkeley Laboratory. The photons come in at the top of the picture. In the upper pair, some of the photon's energy is taken up in displacing an atomic electron, which shoots off towards bottom left. In the lower example, all the photon's energy goes into the production of the electron-positron pair." (Close, 1987)
"Invisible gamma ray photons." "They come in at the top of the picture." I also have it on the authority of several people, in the know, that poltergeists indicate their existence by slamming doors, and moving small objects. Maybe I just don't get it but I just cannot detect the photons anywhere in the picture, coming or going. Nor do I see any squiggly lines. Oh, I can certainly imagine it, but I cannot detect them and I have not yet submitted myself to let my imagination serve as a form of existence outside my body.
The illusion above demonstrates how the mind can get fooled. I challenge anyone to look at it with without seeing a square. Perhaps a similar kind of illusion occurs with our imagining the trajectory of photons coupled with the classical existential description of light.
As animals we humans have evolved a way of gaining knowledge about the world so that we can survive and make use of our knowledge. However, we evolved in a macroscopic world where everything seems to have a cause and effect. The patterns we think we see corespond to patterns we find in nature but we have a difficult time trying to understand things not of our world (the subatomic world). As the biologist Richard Dawkins observed, "We are not the only animals to seek statistical patterns of non-randomness in nature." (Dawkins, 1998)
The Faraday effect
Many a scientist has fooled himself into believing that a magnetic field can change the polarization angle of photons. This shouldn't surprise anyone, considering the unexamined language of their definitions. For example, a definition from the Handbook of Chemistry and Physics, the Faraday effect describes "the rotation of the plane of polarization produced when plane-polarized light is passed through a substance in a magnetic field. . . the rotation is proportional to the thickness traversed by the light and to the magnetic field."
It says nothing explicitly about a magnetic field causing an effect on light itself, yet it does describe light as "plane-polarized". From such language many scientists think that a magnetic field has the ability to shift the polarization angle of light while in flight. This simply does not happen. For an example of how some scientists can get fooled into thinking this, see Scientific American, July 1977, "Science and the Citizen," where you will find this amazing statement:
"Polarized light often twists as it propagates through space, as a result of its encounters with electromagnetic fields; this well-understood phenomenon is called the Faraday effect."
Apparently they do not understand this phenomenon as well as they think. If light, indeed, can twist in a magnetic field, we should have a way to measure it. The experimental setup below illustrates how one can easily confirm or overthrow this view:
By aiming a polarized laser toward a polarizer filter and a photo detector, a voltmeter indicates a reading whenever the detector "sees" light when both the laser and the polarizer have the same alignment. If a magnetic field can twist the polarization angle of the alleged light beam, the voltmeter should indicate a lower reading when the magnet approaches the beam at location B. It does not! Nothing twists. No change of polarization angle. However, if the magnet approaches the detector or the laser (at location A or C) a dramatic polarization shift occurs. This happens because, as the definition states, the rotation occurs when "passed through a substance." Note the key word "substance." But the deceptive part of the language describes light as "passed through" as if light actually traverses through it. Just this kind of language can easily lead to misinterpretation. Since magnets can affect charged particles, it can affect the electrons in the substance, thus creating the Faraday effect. Magnets never affect the alleged light rays in free space, perhaps, because they do not exist.
If light does not exist, then why do people see light beams?
If you shine a light or a laser through a cloudy atmosphere, you can clearly see what looks like a beam of light. But note that the illusion of the beam requires some material substance for its apparition. The beam consists of millions of particle events that occur at the electron level of the atoms in the clouded atmosphere. Taken individually, we have an event at the light source, an event at an atom in the air, and an event at your eyeball. When taken in total, it gives the appearance of a trajectory. Again, the only things we can detect amount to electron events (the measurement points).
To give another example of a similar illusion in a different media, think of dots moving across a computer screen. Does anything actually move? No, because all that happens involves turning on and off pixels. It just seems as if something moves through a trajectory. You cannot scientifically say that just because it seems to move, that it does.
REMOVING THE PARADOXES
There occurs a paradox when trying to explain a wave model of light when using three polarizers. The problem begins by understanding the implications of polarized waves or photons. The following illustrates a typical description:
"A sheet of polarizing film transmits all light incident on it at a right angle if the light is linearly polarized along a certain direction in the film called the transmission axis (hatching). This polarization state of the photon is represented by the wavy colored line at the top [red]. The film blocks all light incident on it at a right angle if the light is linearly polarized perpendicular to the transmission axis (wavy gray line at top). Now suppose a photon is linearly polarized at some angle to the transmission axis between zero and 90 degrees (bottom). Then whether or not the photon will be transmitted is indefinite; the probability of transmission is a number between zero and 1 (the square of the cosine of the angles)." [description taken from Sci. Am., Jan. 1988, p. 48]
Notice the contradiction of the language"polarization state of the photon" but represented as a classical Maxwellian wave.
The following illustrates what happens when using two polarizers:
Any individual light wave coming from an ordinary light source (sun, or light bulb) can travel in any possible polarization angle at right angles to the line of propagation. The total mixture of light rays constitutes unpolarized light. When a light wave hits the first polarizer, it will either go through or not, depending on the wave's alignment with the polarizer transmisstion axis. If the light waves get through, they all proceed at the same polarized angle to the next polarizer material. Depending on the second polarizer's transmission axis, some may get through or get absorbed. In an idealized state, polarizers at the left give us a probability of 1. The polarizers at the right give us a probability of 0. Eveything works fine with the classical wave theory of light so far, but what if we introduce a third polariszer?
The three polarizer problem
If you add a third polarizer in-between two polarizers, the classical wave concept falls apart:
Note that the example above describes the same experiment as the two polarizers aligned at 90° except that here we introduce a third polarizer between the other two, aligned at 45°. As unbelievable as it may seem, some light still gets transmitted through all three. How can this happen if the two outside polarizers (according to the classical model) blocks all waves?
This clearly demonstrates a paradox and shows why a transverse wave or photon model (or any existential model) simply cannot account for the results.
However, if there occurs no waves and no particles, the paradox goes away. Imagine that instead of propagating light, we have vibration events occurring at the light source, the polarizers, and at the detector, and nowhere else. Nothing at all occurs between the measuable events, no trajectories, no particles, no waves-- nothing. The illustration belows shows what happens:
The "vibrations" occur only at the electron level in matter (marked in the illustration as an x). Note that in order to have polarized light, you must have a polarizing material. Instead of imparting polarization and transverse waves to light, why not attribute it to the very polarizer material from where it occurs?
If, instead of describing the polarization angle of the alleged photon, and we limit ourselves to only what we can examine (the molecule alignment in the polarizer which describe the transmission axis, and an electron events) we need not think of a wave traveling through space at all. We only need to describe what happens with our test set-up. If we have an unpolarized light source, three polarizers and a detector, there will occur a probability that the detector will sense an event between 0 and 1. And the probability depends entirely on the properties of the materials in the experiment and the alignment of the polarizers. In short, we simply do not need an independent wave/particle model to predict what happens!
The Double Slit Experiment
Because of the length necessary to describe the double slit experiment, I won't go into the details but you can find an excellent description of the paradox in The Feynman Lectures on Physics (Feynman, 1963) (seeVol. 1, Chapter 37).
Briefly, the experiment describes an emitter, a wall with two slits, and a detector screen. The thought experiment shows that a subatomic particle (photon or electron) seems to behave particle-like when it passes through only one slit open, but wave-like with both slits open. The paradox occurs when imagining what would happen if the experimenter closed one of the slits as the photon (or electron) "flew" through space before it passed through a slit. How can the particle "know" beforehand if it should act wave-like or particle-like? It seems as if the particle has to know the future.
However, if you think of a measurement-only, non-trajectory model, the problem goes away:
If light does not exist between matter events, then we have no paradox simply because nothing passes through the slits. Instead, we can explain it as the source vibrating (jiggling electrons) which in turn causes the electrons in the wall to jiggle, which in turn cause the detection screen to jiggle its electrons (each sequence of event gets delayed through time). The wave and interference properties occur entirely within matter at the electron level (think of millions of electrons vibrating, like a 'wave' in a crowded football stadium). If we had only one slit open, then the detector would behave as if it received particle-like hits.
This model also works for individual photon events, excited one at a time and accumulated over a long period of time.
Why do electrons behave like photons in the double slit experiment?
Electrons may behave similarly to photons but they do not behave identically. Textbook descriptions attempt to confuse this issue by attempting to show identity through scaled up defraction photos so that they appear the same. You will find electron microscope defraction photos compared with X-Ray defraction photos (Wichmann, 1967). But if you look closely at the experimental setups (which rarely get mentioned in the textbooks), you cannot substitute an electron for a photon in either a defraction experiment or a double-slit experiment and get the same results. Although experiments with electrons have shown interference effects, the scales of the setup for an electron experiment must occur at magnitudes smaller than setups for light.
We can detect electrons in free space because they have mass and charge. We know they exist in free space because we can change their direction with magnetic fields. Electron tubes in TV sets would not work if we could not do this. Because they have mass, they add their mass to atoms, which we can weigh. Bubble chambers indirectly detect them by ionizing the gas in the chamber. You cannot do these things with light. Electrons also differ in their apparent slower velocity.
Speaking in quantum mechanical terms, however, electrons do not travel or move through space either, although they can exist in space for short periods of time while quantum jumping, or tunneling from one location in space to another. These quantum jumps give the illusion of a trajectory (like pixels turned on across a screen).
Although electrons do not exhibit identity to photons, they appear exactly identical to each other. Unfortunately we have no way of tagging an electron. Unlike macroscopic objects, we cannot mark one with a pen, or attach a tag, or tie a ribbon to one. In short, we cannot tell the difference between one electron and another, and according to quantum theory, not even in principle.
By using electrons in a double slit experiment, one might at first say that this has to prove that an electron (which we admit can exist in space) must pass through a slit. However, one can equally say that it does not pass through but rather "tunnels" from one location to another. Since electrons appear exactly identical to another, no one can tell the difference between an electron at location A from one at location B. I have no right to choose only one frame of reference. I can just as well say that a different electron at location B replaces the one at location A. Moreover, we have no way of finding out whether it jumps directly from A to B or from a staccato of events in-between.
In the double slit experiment, light and electrons behave similarly but with the added ability that an electron can sometimes jump at locations between events.
Thus, even in a quantum description of electrons in a double-slit experiment does not invalidate the measurement-only model.
Interestingly, if a light quanta occurs as nothing but a feature, or a vibration of an electron (a soliton?), then one might say that a gamma event (classically called a gamma ray) occurs as an electron, quantum jumping (with a delay equal to light speed), from one location to another. Interestingly, the energy equivalence of a gamma quanta equals the rest mass of an electron.
Does light gravitate?
Clearly, if gravity pulls on light, this would seem to prove the existence of discrete electromagnetism. But does gravity attract light like everyday objects?
According to Einstein's thought experiment on gravity, he imagined himself in an elevator feeling its acceleration upward. Einstein thought that since you cannot see outside the elevator, you cannot tell the difference between the force of gravity or an acceleration force (imagine the elevator in free space). Einstein proposed that the two forces appear equal. Furthermore, if a "ray" of light entered the elevator parallel to the floor, the light beam would appear to bend downward. This meant that light, if traveled across a gravitational field, would looked curved to the observer.
In 1919, the astronomer Sir Arthur Eddington photographed stars whose field of vision appeared close to the sun during an eclipse. He compared the photos with those of the same stars taken with the sun removed. Eddington found the apparent location of the stars had shifted, just as Einstein predicted and confirmed one of the predictions of the general theory of relativity.
But notice that even though Einstein believed in the discrete existence of quantum light, his description does not explicitly state that light gravitates. In his paper on The Foundation of the General Theory of Relativity he states: "We easily recognize that the course of the light-rays must be bent with regard to the system of co-ordinates..." (Einstein, 1916) . But to an observer at rest, the light beam would appear straight. In other words, Einstein gives a relativistic description, not a gravitating mechanism. The description further gets exacerbated by illustrations that show the Einstein bend in an exagerated way:
This typical diagram shows the light bending in a dramatic but inaccurate way. Eddington measured a deflection of 1.75 seconds of arc (Einstein actually predicted .83 seconds of arc, but the measurement came close enough to confirm the theory). We can forgive the artist's exaggeration, however, because one cannot draw the actual arc and see it. The tiny angle, would result in, for all appearances, a straight line. Eddington's photos also had to capture stars at the closest periphery to the sun.
I do not pretend to have a solution for how light gives this bending illusion, but I can speculate:
Since Einstein's theory predicts a gravitational influence on the measurement of clocks, perhaps electrons at the solar edge, shift their spin orientation accordingly when acting as a reflector or defractor. How else can we think of curved space except for how matter behaves in it? Physicists also know that electrons can pop in and out of existence, even in a vacuum. In short, in order to observe this bend, you must have a mass to cause the deflection.
Note also, that a pixel moving across a screen while you watched from a gravitational well would also appear to bend even though we know the pixel does not actually move. (In Einstein's thought experiment, imagine looking outside the elevator at a large TV screen with a pixel trajectory instead of a beam of light).
Gravitational lensing can occur which can make stellar objects, (such as galaxies and quasars), appear doubled, magnified or focused. This seemingly odd phenomon actually implies a special case of Einstein bend, as described above, except that the deflection occurs on both sides of a mass. For an illustration, see: http://scruffy.phast.umass.edu/a114/lectures/lec24/node2.html
Again, in order observe an Einstein shift or a gravitational lens effect, there must exist some material body to influence its relative observed position.
In describing the effects of a black hole, Stephen Hawking writes that, "light cannot escape, neither can anything else; everything is dragged back by the gravitational field." (Hawking, 1988) [bold characters, mine].
But wait! If nothing can escape, if everything gets dragged back, how can the gravitational force, itself, escape to influence other stars and matter? Gravity, according to quantum physicists also comes in the form of discrete particles called "gravitons" which can create waves and ripples through space at the speed of light. How do gravitons manage to escape black holes? Do you see the problem the language creates? Perhaps we should question the existential claims of gravitons as well (please note that no one has yet detected gravitons either).
Black holes describe, in effect, a dramatic case of the Einstein's theory of relativity. In principle, it differs only in magnitude from the Einstein's relativity "bending" of light. But this again must agree with either the relativistic effects, or with a mass-to-matter influence, or both.
Since electromagnetic energy requires a mass particle event, we can speculate on the mass particles themselves. Visible light requires an occurrence of an electron event (we cannot deny the discrete existence of this mass particle). Could then a black hole influence electrons in such a way as to either prevent their transmission of light or by redirecting their influence inward, toward the center of the black hole, instead of outward?
Again, I cannot answer these questions, but I can create concept models just as workable as those who believe in the existence of light as a discrete particles. No one has yet proved that light can gravitate, regardless of how many descriptions say that it does. Beliefs, regardless of how many believers, do not equal proofs.
EVOLUTION THROUGH HISTORY
Looking back through the history of science, we can see how the evolution of the understanding of light came about, the conceptual confusions that arose, and how the information got transferred from brain to brain (a classic meme transfer, that with the vast documented history might appeal to those interested in memetics). From various empirical experiments from Huygens and Faraday, it seemed clear that light behaved like waves. And like all waves known to human comprehension, light needed a medium to vibrate in. The scientists could not accept the idea of action-at-a-distance, so they borrowed Aristotle's ancient concept called an "ether" to account for a hypothetical medium that filled the void of space. They spent years searching for it but they could not detect it. Later, Einstein showed that, through the principle of relativity, the concept of an ether contributed nothing to the physics, and therefore we need not spend time thinking about it. Physicists did not like the idea of losing the ether because it introduced the idea that subatomic events do not behave like ordinary classical objects. But this they had to do, if they wished to advance the state of physics.
Unfortunately for the believers of classical reality, things got worse. Not only did light not require a medium to travel in, but some atomic particles, like the electron, seemed to jump from one atomic orbital, in discrete steps, without anything occurring between. The idea of sub-atomic trajectories made no sense in the quantum world, and the physicists had to abandon classical trajectory motion.
"The motion of a particle cannot be described in the familiar terms of classical mechanics, and both its position and its velocity are subject to a certain indefiniteness (Heisenberg's uncertainty relations and Bohr's complementarity principle)." (Gamow, 1961)
"Classical physics is played out before an all-seeing eye. It has trajectories. We can follow the motion of particles from moment to moment as they interact with each other. We have to give that up in the quantum world. There are no longer trajectories." (Polkinghorne, 1984)
To make matters worse, single particle events occur at random intervals. This randomness does not happen like the randomness of a coin toss. In principle, if one knew every physical property of the coin, a physicist could determine the outcome. In other words, classical randomness has an absolute deterministic outcome. In quantum randomness, no one can figure it out, not even in principle. Many physicists, especially those trained in classical physics, could not accept the idea of indeterminate randomness. Unfortunately, Albert Einstein could not accept quantum randomness either and his intransigent beliefs outlined his barrier to further understanding. Along with his fame and influence, so also went his classical reality descriptions of light.
Although Einstein helped advance the first steps of the quantum theory, he could not entirely let go of the classical world, and this, I think, gives reason why he could not have postulated light in a non-trajectory way. His form of reality corresponded to classical physics, just as his education taught him. Yet Einstein did understand the problems of language when he wrote:
"When language becomes thus partially independent from the background of impressions a greater inner coherence is gained. Only at this further development where frequent use is made of so-called abstract concepts, language becomes an instrument of reasoning in the true sense of the word. But it is also this development which turns language into a dangerous source of error and deception. Everything depends on the degree to which words and word combinations correspond to the world of impression." (Einstein, 1950b)
For this reason, I think Einstein, even though he understood the problems of description, must have had such a deep belief in classical reality that it never occurred to him to think of light in any other way. In arguments with Neils Bohr, he stated his famous line about a god not playing dice. Also in a letter to Max Born, he states his belief clearly:
Unfortunately, physicists, as all human beings, can fall prey to beliefs and faiths. Isaac Newton had postulated the first ideas of relativity, but he could not advance the theory as long as he held the belief of absolute time. And Einstein could not let go of his classical descriptions to understand the implications of quantum mechanics, even in the light of the success of the new science.
Most physicists do not concern themselves with the epistemological questions of science. And as J. C. Polkinghorne put it, "Your average quantum mechanic is about as philosophically minded as your average mechanic." (Polkinghorne, 1984). In the language of quantum mathematics, the paradoxes do not appear. Physicists aim for useful reliable predictions, and if their physics does not agree with common sense, then it doesn't matter. But in ignoring the consequences of describing physical events in an inaccurate way, it can lead the layperson and, indeed, other scientists, to wrong conclusions. Who can calculate how many research dollars and wasted time came about because of false beliefs?
To this day, we see descriptions of light that carry a mix-match of classical and quantum descriptions which produce the very paradoxes that support an industry of new-age books that get preached to the naive. Even the mathematical proofs of non-locality by John Bell have him implying the existence of wave-packets and photons where he predicts: "the signal involved must propagate instantaneously, so that such a theory could not be Lorentz invariant." (Bell, 1987) That implication out of the English language (not out of the math), produced new ghosts, and along with it, a generation of believers who use science as a kind of religion. Alain Aspect and his colleagues tested Bell's theory and showed that, indeed, Einstein's classical view fails and the quantum mechanical description holds (Shimony, 1988). But included in the quantum descriptions remained Einstein's discrete quantum of existence with Lewis' verbal invention of photon (the ghost), all to avoid the Aristotelean abhorrence of action-at-a-distance.
We now have a plethora of books that describe the "collapse of the wave function," "superposition of states," and Schrödinger's cats, all of which depend on some kind of reality of energy existing between events. From collapsing wave functions, some people see a "Consciousness creates reality" view of the universe.
If the phenomenon of light, indeed, acts like action-at-a-distance, then we have no collapsing wave function! The wave function would simply occur only as the detection itself. Period. Nor does it produce a nonreality universe, for we can measure things and make use of them. Nor does it produce a necessity for a consciousness required reality (unconscious instruments can measure things while we look elsewhere).
A MYSTERY REMAINS
If we gave a scientific description of only what we can measure in the quantum world, we need not introduce unnecessary concepts. But even if we do so, we do not escape a puzzle: If light does not exist between events, how does an electron event influence another electron? Physicists have no problem describing quantum jumps at the scale of atomic nuclei. But what about an electron event that occurs in a star, millions of miles away, one that occurred millions of years ago, which influences an electron in the eye of an earthly beholder?
The implications appear staggering, and I do not pretend to have an answer. It certainly does not conform to common sense. Regardless, we have not introduced a new mystery but have only have eliminated the forest of other paradoxes so that we can see the remainder which already occurs for quantum jumping particles. For even if we maintain the idea that energy exists as a particle of existence, we have added problems such as: How can a particle remain in a pristine state over such long distances? Why do these particles not interfere with themselves in free space? And we would still have the paradoxes of the double-slit and the three polarizers.
Perhaps our human nature bars us from understanding. We evolved as pattern recognition animals. If we cannot see a pattern, we invent one to account for the phenomenon. But if the quantum world acts through randomness, we will never see a pattern (no-pattern = randomness). For even if we detect an electron event, we cannot help but think of a determined actuality-- a reality. But by eliminating the old classical way of describing causal events, and conform to the quantum description for all quantum events, including light, we drop the useless paradoxes, so we can attempt to solve the problems relevant to the best physics.
Perhaps the answer will come with a better description of probability events. The quantum world shows us that events occur out of pure randomness. There seems no clear cut way to say that an electron at one point influences an electron at another point. It occurs only in a probable sense. We assign a causal relationship only after we have made our measurements, not before or during its randomness. In the language of probability math, the mystery does not occur; but perhaps, yet again, our spoken and written language creates unnecessary spooks and creates a barrier to our understanding.
1. In this paper, I have addressed primarily the electromagnetic force because it represents the best known force and the most viable link to human affairs. But the same treatment can apply for any alleged massless particle, including the hypothetical gravitons of the gravitational force and the gluons of the strong force.
2. In no manner do I mean to show that light cannot exist between events (I cannot prove non-existence), only that the evidence of its discrete existence has not yet arrived. I use a variant of "Occam's Razor" approach to the problem: the simplest description the better, as long as it describes the phenomenon equally or more thoroughly.
3. Anyone can easily test the 3 polarizer problem by using 3 ordinary plastic polarizers. You can order polarizing material from Edumd Scientific or get and old pair of polarized sun glasses and cut the plastic lens into three pieces.
4. The children's poem derives from a William Hughes Mearns rhyme in Antagonize, 1899: "Yesterday upon the stair, I met a man who wasn't there. He wasn't there again today, I wish that man would go away." Many other derivations of the rhyme exist. The version I used came from Robert Anton Wilson.
- Aspect, Alain (1976), "Proposed experiment to test the nonseparability of quantum mechanics," Physical Review D, Vol 14, No. 8, p. 1944
- Bell, John S., (1987), Speakable and unspeakable in quantum mechanics, Cambridge University Press
- Born, Max, (1971), The Correspondence Between Albert Einstein and Max and Hedwig Born, 1916-1955, Walker and Company
- Bostick, Winston H., (1961), The Gravitationally-Stabilized Hydromagnetic Model of the Elementary Particle, published by the Gravity Research Foundation, New Boston, N.H.
- Close, Frank, et al, (1987), The Particle Explosion, Oxford University Press
- Compton, Arthur H. (1923), Physical Review, 21, 483 (Compton's original paper on X-rays)
- Compton, Arthur H., (1926), X-rays and electrons; an outline of recent X-ray theory, D. Van Nostrand Co.
- Dawkins, Richard, (1998), Unweaving the Rainbow, Houghton Mifflin Company
- De Broglie, Louis, (1937), Matter and Light: The New Physics, W.W. Norton & Co.
- Dolbear, A.E., (1894), Matter, Ether, and Motion, Lee and Shepard Publishers
- Einstein, Albert, (1905), "On a heuristic point of view concerning the production and transformation of light," Annalen der Physik 17, 1905, (translated by Anna Beck, published by Princeton University Press, 1989)
- Einstein, Albert, (1907), "On the inertia of energy required by the relativity principle," Annalen der Physik 23, 1907, (translated by Anna Beck, published by Princeton University Press, 1989)
- Einstein, Albert, (1909), "On the development of our views concerning the nature and constitution of radiation," Deutsche Physikalische Gesellschaft, Verhandlugen 7, 1909: 482-500 (translated by Anna Beck, published by Princeton University Press, 1989)
- Einstein, Albert, (1916), "The Foundations of the General Theory of Relativity," Annalen der Physik, 49, 1916, (translated by W. Perrett and G.B. Veffery in, The Principle of Relativity, Dover Publications, Inc., 1923)
- Einstein, Albert, (1950a), Essays in Physics, Chapter 4: "The Fundamental of Theoretical Physics," Philosophical Library, New York
- Einstein, Albert, (1950b), Essays in Physics, Chapter 5: "The Common Language of Science," Philosophical Library, New York
- Feynman, Richard P., (1963), The Feynman Lectures on Physics, Vol. 1, Addison-Wesley Publishing Company
- Gamow, George, (1961) One Two Three...Infinity, Bantom Books
- Gibbins, Peter, (1987), Particles and Paradoxes:The Limits of Quantum Logic, Cambridge University Press
- Hawking, Stephen W. (1988), A brief History of Time, Bantam Books
- Herbert, NIck, (1985), Quantum Reality: Beyond the New Physics, Doubleday
- Lewis, Gilbert N., Nature, 18 December, 1926 (Letters to the Editor, "The Conservation of Photons," p. 874)
- Planck, Max, (1909), Discussion following lecture version of "On the Development of our Views Concerning the Nature and Constitution of Radiation," (translated by Anna Beck, published by Princeton University Press, 1989)
- Polkinghorne, John C., (1984), The Quantum World, Princeton University Press
- Shimony, Abner (1988), "The Reality of the Quantum World," Scientific American, January 1988
- Weast, Robert C. Ed., (1986), Handbook of Chemistry and Physics,CRC Press, Inc.
- Wheeler, John Archibald, et al, (1983) Quantum Theory and Measurement, Princeton University Press
- Wichmann, Eyvind H., (1967) Quantum Physics, Berkeley Physics Course, Vol. 4