Three Wise Men
| Scientific Paper | |
|---|---|
| Title | Three Wise Men |
| Read in full | Link to paper |
| Author(s) | Salvatore E Iaquinta |
| Keywords | light, aether, Galilean relativity, absolute motion, aberration |
| Published | 2007 |
| No. of pages | 13 |
Read the full paper here
Abstract
For the field of physics, the great theoretical triumph of James Clerk Maxwell in the 1860's had seemed to wrap up electricity and magnetism so neatly that there was talk that perhaps all of nature's secrets had been laid bare and there may soon be nothing left to discover.
Overview
Three Wise Men is a thirteen-page illustrated dialogue in which Salvatore E Iaquinta stages an argument between Albert Einstein, "Isaac" (Isaac Newton) and Galileo about the light-clock thought experiment. Einstein presents the familiar train-and-mirror derivation of time dilation; Newton and Galileo then dismantle it, and the greater part of the document is theirs. The style is deliberately informal — cartoon figures, a running score of numbered diagrams, and closing lines about God providing man with a "magnetic compass to navigate the seas" and a "light compass to navigate the heavens".
The substantive claim is a single one, repeated in several settings. Iaquinta argues that a light pulse, once it has been emitted, carries no component of the source's velocity, because it did not exist until the moment of emission. In a vehicle moving at v with a laser on the ceiling aimed at a target on the floor, the pulse should therefore travel straight down in the ground frame and diagonally in the vehicle frame — the exact reverse of the standard picture — and should miss the target by an amount proportional to v/c. Since the observer riding with the apparatus can see that miss, absolute motion is detectable and special relativity's premise fails. This puts the paper firmly against emission theory (the "bullet mentality", as the dialogue calls it) as well as against Einstein, and squarely on the side of a stationary or Earth-attached medium.
The argument
The historical setup
The opening section is a conventional narrative: Maxwell's equations unify electricity and magnetism; Heinrich Hertz confirms electromagnetic waves in 1887; the wave speed follows from the permittivity and permeability of free space as 1/√(εμ), quantities measured with pith balls and current-carrying wires; and the letter c comes from celeritas. The conundrum is stated crisply: Maxwell's equations give a speed "without reference to a marker", which is what Galilean relativity forbids. Iaquinta's Einstein resolves it by keeping both Maxwell and Galilean relativity and discarding the velocity addition theorem — a theorem, the text says, resting "not on a large body of evidence but on ancient common wisdom".
The light-pulse objection
The core objection is put by Galileo against Einstein's Figure 6. The vehicle, observer and laser are all moving at 0.5c at t1 and t2, "but the light pulse does not yet exist. The light pulse does not exist until t3 when the LASER is activated." At that instant it moves away from the source at c, independent of the source, and therefore "possesses no horizontal velocity". Consequently it will not strike the target, and Galilean relativity simply does not apply to it. The diagonal, longer light path that Einstein's diagram requires is, in the dialogue's word, "an ILLUSION".
Newton reinforces this with a point about the source rather than the pulse: in Maxwell's theory electromagnetic waves are produced by accelerating charges, so the emitter "is not in any inertial frame other than instantaneously", and to speak of the wave having speed c in the source's inertial frame overlooks that there is no such frame. Newton also notes, correctly, that cosmic rays entering the atmosphere faster than light travels in air emit an electromagnetic "sonic boom" — Cherenkov radiation.
Aberration and the deflection formula
From the same premise the dialogue extracts a quantitative prediction. When the source moves at v, the angle θ between the emitted beam and the normal satisfies
- tan θ = v/c
and this, the text says, "should clear up the paradoxes relating to 'Stellar Aberration' and star-light bending in the presence of a gravitational field" (see Gravitational Lensing). Applied to the Earth, four consequences are listed: (1) the null result of the Michelson–Morley experiment is explained by an aether — "or the geomagnetic field" — attached to the Earth, so that the interferometer never moved relative to the signal, since "for a shift to be detected the source must move relative to the signal"; (2) Galilean relativity does not apply to electromagnetic fields any more than it applies to sound in air, and trapping the aether inside the moving laboratory is not a plausible fix; (3) a laboratory beam aimed perpendicular to the Earth's orbital motion should tilt away from the normal by tan θ = v/c, a beam aimed along the motion should redshift and one aimed against it should blueshift, giving a "light compass"; and (4) red shift and blue shift arise from motion of the target relative to the light, so that motion of a star relative to the target "will not cause a red, or a blue shift".
The proposed experiment
Rather than argue further, "Galileo" proposes a test, invoking Ockham's razor in Latin. The apparatus (Figures 17 and 18) is a benchtop analogue of Michelson's interferometer: a laser fixed to a motor-driven assembly of two discs separated by a distance D, with an aperture a in the lower disc. At low RPM the beam passes straight through the aperture; at high RPM it should deviate from the normal by
- d = vD/c
where v is the disc velocity, D the disc separation, c the speed of light and d the displacement from the normal. This is simply D tan θ for small θ, so the experiment and the aberration formula are internally consistent. The document closes with a quotation on the natural philosopher's faith that "the universe exhibits order and is basically simple".
Assessment
The paper's virtue is its directness. It isolates one assumption — that a photon inherits nothing from the motion of the emitter at the instant of emission — states it in plain language, draws the consequence, and then proposes a falsifiable benchtop experiment with an explicit formula rather than leaving the matter at the level of debate. That is more than many critiques of relativity offer, and the disc apparatus is at least a well-posed measurement. The presentation is also honest about its own logic: the author does not smuggle in a preferred frame at the end, but has it present from the first page as an Earth-attached medium.
The difficulties are severe, and most of them can be checked with the paper's own equation. First, d = vD/c does not apply only to spinning discs. The Earth carries every laboratory through space at roughly 30 km/s in its orbit, so on Iaquinta's account a vertical laser beam with a 1 m path should land about vD/c = (3.0×104/3.0×108) × 1 m ≈ 0.1 mm off the normal, with the offset sweeping a full circle of ~0.2 mm diameter over the year as the Earth's velocity vector turns. Scale the baseline up and the prediction becomes enormous: for the 4 km arms of a gravitational-wave interferometer the same formula gives 10−4 × 4000 m = 0.4 m of annual beam wander, which such instruments — whose beams stay centred on their end mirrors to within millimetres — plainly do not exhibit. The formula is therefore already excluded by ordinary long-baseline optics, without building anything new.
Second, the proposed experiment is, by the same arithmetic, far less sensitive than the effect the author has already ruled out. A disc of 10 cm radius spinning at 10,000 RPM has a rim speed near 105 m/s, giving d ≈ 3.5×10−7 m over a 1 m separation — sub-micron, well below the width of the beam that must pass the aperture, and swamped by the ~0.1 mm terrestrial effect the same theory predicts. The paper gives no numbers for RPM, disc radius or separation, and no error budget, so this arithmetic has to be supplied by the reader; when it is, the apparatus cannot resolve what it was built to measure.
Third, the two escape routes offered are mutually incompatible. An aether "attached to the Earth" would indeed give a null Michelson–Morley result, but a fully entrained medium is precisely what the annual aberration of starlight — the 20.5 arcsecond ellipse traced by every star, known since Bradley in 1728 — excludes, since entrained aether would carry the incoming wavefronts along with the Earth and erase the aberration. Iaquinta invokes stellar aberration as something his picture explains, but the entrainment he uses to dispose of Michelson–Morley removes the very mechanism. Airy's 1871 water-filled telescope, which found the aberration angle unchanged when the light path was slowed inside the instrument, tightened the same knot.
Fourth, claim 4 conflicts directly with routine measurement. That a star's motion relative to the observer produces no Doppler shift is contradicted by the spectroscopic binaries, whose component lines oscillate in antiphase with the orbital period while the terrestrial spectrograph does nothing at all, and by the radial-velocity detection of extrasolar planets, where metre-per-second stellar wobbles are read out from line shifts. It is also inconsistent with the paper's own item 3, which grants that motion along the beam produces a shift — the paper does not explain why relative motion should count when the target moves and not when the source does.
Finally, the central premise is asserted rather than argued. "The light pulse does not exist until it is produced, [therefore] it possesses no horizontal velocity" does not follow: a wave's direction of propagation is fixed by the fields at the moment of emission, and those fields belong to a source that was already in motion. The paper never engages the momentum bookkeeping that this requires, nor with why the same reasoning would not apply to a sound pulse from a moving whistle. Taken as what it announces itself to be — a dialogue meant to provoke — Three Wise Men succeeds in putting a sharp question. Taken as a physical proposal, its own formula is its strongest objection.