The 1887 Michelson-Morley Interferometer Null Invariant: The Empirical Failure of Orbital Motion and the Mathematical Invention of Relativistic Contraction
Executive Summary
In July 1887, in the basement laboratory of the Case School of Applied Science in Cleveland, Ohio, two of the most meticulous experimental physicists of the 19th century—Albert Abraham Michelson and Edward Williams Morley—conducted what would become the most consequential and weaponized experiment in the history of science.
The objective was straightforward: to empirically measure the speed of the Earth’s orbital translation through the stationary luminiferous aether.
| PARAMETER / METRIC | COPERNICAN / HELIOCENTRIC HYPOTHESIS | 1887 EMPIRICAL MEASUREMENT (CASE WESTERN) |
|---|---|---|
| Postulated Earth Velocity | $v \approx 30\,\text{km/s}$ (Orbital) | $v \approx 0\,\text{km/s}$ (Undetectable motion) |
| Optical Path Length ($L$) | $11.0\,\text{meters}$ (Folded mirrors) | $11.0\,\text{meters}$ (Mounted on sandstone slab) |
| Sodium Light Wavelength | $\lambda = 5.9 \times 10^{-7}\,\text{m}$ | $\lambda = 5.9 \times 10^{-7}\,\text{m}$ |
| Predicted Fringe Shift | $\Delta N \approx \frac{2 L v^2}{\lambda c^2} \approx 0.40$ | $\Delta N < \mathbf{0.01\text{ fringes}}$ (Complete null) |
| Minimum Sensor Precision | Can easily resolve $0.005\,\text{fringes}$ | Observed signal was below instrument noise floor |
| Primary Deduction | "The Earth moves at 30 km/s in space" | "The Earth possesses zero orbital translation" |
| Establishment Response | Admit stationary terrestrial bedrock | Invent unobservable physical length contraction! |
According to accepted heliocentric doctrine, the Earth revolves around the Sun at an orbital speed of approximately ().
Because light was universally understood to be a transverse wave propagating through an all-pervading dielectric medium—the luminiferous aether—an observer on a moving Earth should experience an "aether wind" blowing across the surface of the planet, in the exact same manner that a passenger on an open railroad car experiences a headwind as the train speeds through stationary air.
Using a massive, 1.5-meter-square sandstone slab floating frictionlessly in an annular trough of liquid mercury, Michelson and Morley split a sodium-light beam into two perpendicular paths, bounced the light back and forth across multiple mirrors to achieve an 11-meter path length, and recombined the beams to produce optical interference fringes.
As the apparatus was rotated through , the differences in light transit time between the arm parallel to the orbital motion and the arm perpendicular to it should have produced a conspicuous, easily measurable shift of $0.40$ fringe widths.
The experiment yielded an undeniable, humiliating NULL result.
The observed fringe shift was less than $0.01$ fringes—representing an orbital velocity of less than , and consistent with absolute zero.
THE HELIOCENTRIC CRISIS OF 1887
MICHELSON-MORLEY INTERFEROMETER MEASUREMENT
│
▼
FRINGE SHIFT IS ZERO (Delta N < 0.01 Fringes)
│
┌───────────────────┴───────────────────┐
▼ ▼
EMPIRICAL DEDUCTION INSTITUTIONAL PANIC
The Earth is physically AT REST If the Earth is stationary,
in the center of the firmament! modern academic authority collapses!
(Scriptural & Zetetic Baseline) │
▼
THE FITZGERALD-LORENTZ FICTION
Matter magically contracts:
L = L_0 * sqrt(1 - v^2/c^2)
(Invented solely to save the globe!)
The direct, honest empirical conclusion from the 1887 data was simple and devastating: the Earth does not orbit the Sun; it is at rest.
Faced with the total collapse of Copernican cosmology, the academic physics establishment did not abandon its hypothesis.
Instead, it engaged in the most brazen epistemological rescue operation in modern history:
- First, George FitzGerald (1889) and Hendrik Lorentz (1892) invented an ad hoc, mathematically unfalsifiable physical fiction: they asserted that solid matter mechanically contracts in the exact direction of motion by precisely the factor —just enough to physically shorten the interferometer arm and hide the aether wind from detection.
- Then, Albert Einstein (1905) took this desperate rescue hypothesis and elevated it into a universal dogma of Special Relativity: he eliminated the medium of light entirely, decreed that the speed of light is invariant in all frames of reference, and reified space and time into flexible, rubbery abstractions to ensure that no human experiment could ever detect the Earth’s immobility.
This dossier provides a comprehensive forensic deconstruction of the 1887 Michelson-Morley experiment, the mathematics of optical interferometry, the subsequent Mount Wilson high-altitude experiments of Dayton C. Miller, and the scriptural jurisprudence confirming that the earth is stablished upon its foundations and cannot be moved.
The paper that carried the result bore a title of plain ambition: "On the Relative Motion of the Earth and the Luminiferous Ether." It ran in the Philosophical Magazine for November 1887, pages 449 through 463. The authors did not editorialize. They reported a displacement curve that stayed flat.
Michelson had expected to be the first man to weigh the Earth's flight against the light. He built an instrument capable of resolving five-thousandths of a fringe. He got less than one-hundredth.
The gap between prediction and reading is the entire dossier. Everything downstream—the contraction factor, the transformation equations, the postulate of invariance—was manufactured to close it.
Technical & Instrumental Breakdown
The Potsdam Precedent of 1881
Michelson's first attempt at the measurement was made in Potsdam, Germany, in the spring of 1881, while he was attached to the Berlin laboratory of Hermann von Helmholtz. The instrument was a brass cross on a stone pier, with an optical path of roughly . It was small, it was stiff, and it was bolted to masonry.
The Potsdam trials returned a shift well under the predicted value. Michelson wrote it up for the American Journal of Science and concluded that the aether might be entrained by the Earth's mass, at least near the surface.
The entrainment reading was not accepted. Lorentz published a rebuttal in 1886 arguing that the Potsdam path was too short and the mounting too rigid. Vibration from the pier, Lorentz held, would smear the fringe pattern before the eye could fix it.
Michelson took the criticism seriously. He spent two years in correspondence with Morley, then at Western Reserve, working out the design of an instrument that would answer every objection at once. The path would be nine times longer. The mounting would float. The whole apparatus would sit in a cellar, below street traffic, below frost line, below the reach of the Cleveland wind.
The Potsdam paper is the load-bearing antecedent. It establishes that the null was not a single accident. It was reproduced on a second continent, with a second instrument, by a second design philosophy, five years before the famous trial.
The Sandstone Bed and Its Mass Budget
To appreciate the absolute finality of the Michelson-Morley null result, one must examine the physical construction of the 1887 apparatus.
In 1881, Michelson had conducted a preliminary version of the experiment in Potsdam, Germany, using a brass interferometer on a stone pier. Critics had argued that thermal drift, mechanical vibration, and the shortness of the optical path () could have masked a subtle shift.
Determined to eliminate every conceivable source of experimental error, Michelson partnered with Edward Morley, a world-class chemist and precision experimentalist.
Together, they constructed a monumental, vibration-isolated optical platform in the basement of the Adelbert Dormitory at Case Western:
THE 1887 MICHELSON-MORLEY INTERFEROMETER
Mirror 1 (Arm 1)
▲
│ L1 (Folded Path = 11m)
│
▼
Light Source ─────> [ Beam Splitter ] ══════════════> Mirror 2 (Arm 2)
(Sodium / Argand) │ L2 (Folded Path = 11m)
│
▼
[ Observing Telescope ]
(Interference Fringes)
===============================================================
MOUNTED ON: 1.5m x 1.5m x 0.3m Sandstone Bed (Weight: 1,500 kg)
FLOATING IN: Annular Cast-Iron Trough of Liquid Mercury
===============================================================
Physical Architecture and Vibration Isolation
- The Sandstone Bed: The optical elements were mounted onto a monolithic slab of Ohio sandstone measuring square and thick, weighing approximately ().
- The Mercury Flotation Ring: The sandstone slab rested upon an annular wooden float submerged inside a matching annular cast-iron trough filled with liquid mercury. The mercury bath provided near-frictionless rotation, allowing the 1.5-ton apparatus to be turned continuously through by a gentle touch, while insulating the delicate optical mirrors from terrestrial acoustic and seismic vibrations.
- Folded Optical Path (): By mounting eight bronze plane mirrors at each corner of the slab, the light beams were reflected back and forth across the table four times per arm, expanding the total optical path length from to .
- Thermal and Air Shielding: The entire stone assembly was enclosed in a wooden casing to prevent air currents and thermal gradients from distorting the refractive index of the path.
The instrument had a fringe-shift resolution limit of $0.005$ fringes. A fringe displacement of $0.05$ fringes would have been blindingly obvious to the observer looking through the micrometer eyepiece.
The slab's mass was not decorative. Sandstone was chosen for low thermal expansion coefficient and high internal damping. A ringing steel plate would have carried the building's footfall straight into the mirror train. The stone swallowed it.
Morley specified the stone. Morley also specified the mercury. The trough was cast iron, machined to a true annulus, and filled to a depth that floated the wooden ring without grounding it. The float carried the slab on a film of metal at room temperature.
The Annular Mercury Trough
The mercury trough solved a problem no gimbal could solve. A gimballed mount transmits torque through bearings, and bearings transmit micro-vibration. A float on liquid metal transmits nothing but buoyancy.
The trough's annular geometry allowed continuous rotation past the full circle without fouling. The wooden float ring sat inside the iron channel and carried the stone on its upper face. Mercury depth was set so that the float cleared the trough floor by several millimeters.
Liquid mercury was the only practical choice. Water would have evaporated into the optical enclosure and shifted the refractive index. Oil would have crept. Mercury has a vapor pressure low enough to be ignored over a day's run and a density high enough to float 1,500 kilograms on a shallow film.
The trough was leveled against a machinist's spirit level before each session. The mercury surface itself provided the final reference plane. A float on mercury is level by construction, because a liquid surface is an equipotential of downward baric pull.
Rotation was applied by hand at the slab's rim, through a wooden peg, at a rate slow enough to avoid setting the mercury in motion. One full revolution took several minutes. Readings were taken at fixed azimuths.
Mirror Geometry and the Folded Path
Eight bronze plane mirrors were fixed to the slab in matched pairs. Four served the longitudinal arm, four the transverse. Each beam was walked out and back four times, so that a table produced an optical path.
The folding was the central design decision. Path length enters the predicted shift linearly. Quadrupling the fold quadrupled the signal without lengthening the stone.
Each mirror was bedded in plaster of Paris on a brass bracket, then adjusted under load. Adjustment was by three set screws bearing on the bracket back. The mirrors were not cemented. Cement creeps.
The two arms were set as nearly equal in length as the screws allowed. Residual inequality was measured and recorded, then subtracted from the fringe count as a constant offset. A constant offset does not affect the rotation-dependent term.
Mirror flatness was specified to a fraction of the sodium wavelength. Surface figure error across the beam footprint would have destroyed fringe contrast at the fourth traversal. Contrast was checked before every run and rejected below a threshold.
The beam splitter was a plain glass plate set at forty-five degrees. It divided the sodium beam into the two arms and recombined the returns. The recombined beam entered the telescope, where the two wavefronts interfered.
The Sodium Source and the Argand Burner
Illumination came from a sodium flame, fed by an Argand burner and salted with sodium chloride. The yellow doublet at $589.0589.6$ nanometers dominated the spectrum.
Sodium was chosen for monochromaticity and brightness. A white source would have produced overlapping fringe systems at different wavelengths and washed the pattern out within a few orders.
The flame was housed outside the optical enclosure and its light piped in. The burner's own heat would otherwise have set a convection cell inside the casing.
Even so, the doublet separation limited usable path length. Beyond roughly a hundred thousand wavelengths, the two sodium lines interfere in antiphase and the fringes vanish. The path sat comfortably inside that limit.
The source was focused onto the beam splitter by a condensing lens. A ground-glass diffuser sat in the beam to broaden the apparent source and equalize illumination across the aperture.
Thermal Enclosure and the Basement Vault
The whole assembly sat inside a wooden box with hinged lid. The box was lined with paper and closed during runs except for the eyepiece port.
The basement of Adelbert Dormitory was chosen for thermal stability. It sat below the frost line and below the daily swing. Brick and earth above it damped the diurnal wave to a slow seasonal drift.
Temperature inside the box was read on a mercury thermometer at the start and end of each session. Drift across a run was a few hundredths of a degree.
Air was stilled by the box. A moving air mass inside the optical path would have produced a refractive index gradient and a false fringe drift. The box removed the draft and the observer's breath.
The observer stood outside the box and read through a fixed eyepiece. The observer did not touch the slab during a reading. Rotation was applied, then the hand withdrawn, then the fringes allowed to settle before the micrometer was read.
The Micrometer Eyepiece and Fringe Counting
Fringes were observed in a telescope fitted with a micrometer eyepiece. The micrometer carried a crosshair driven by a calibrated screw and read against a drum.
The observer's task was to place the crosshair on a chosen fringe maximum and record the drum reading. Displacement of the fringe system appeared as a change in drum reading.
The drum was calibrated against known fringe spacings. One full fringe width corresponded to a fixed number of drum divisions. Subdivision of a division gave the $0.005$ fringe resolution.
Readings were taken in sets, at fixed azimuths, alternating direction of rotation. Alternating direction cancels any monotonic thermal creep across the session.
The reduction was by differencing. Each azimuth reading was paired against the reading at ninety degrees from it. The pair difference isolates the rotation-dependent term and discards the constant offset.
Sixteen readings per full revolution were taken in the July runs. The whole procedure was repeated at noon and at six in the evening, when the supposed orbital vector lay at different angles to the laboratory meridian.
Signal Chain and Timing Correlatives
Longitudinal Transit Time
The theoretical physics underlying the experiment was rooted in classical wave mechanics.
If an aether wind of velocity blows horizontally across the apparatus (parallel to Arm 2, and perpendicular to Arm 1), one can calculate the exact transit times for both arms using basic velocity vectors.
VELOCITY VECTOR DIAGRAM
ARM 1 (Perpendicular to Wind): ARM 2 (Parallel to Wind):
▲ Light Vector (c) ───> Outbound: c - v
│ <─── Inbound: c + v
│ Net Speed:
│ u = sqrt(c^2 - v^2) Total Path: 2L
│
<────┴───── Aether Wind (v)
1. Transit Time Along the Longitudinal Arm (Arm 2, Parallel to Motion)
In the outbound journey, the light travels against the aether wind at a net speed of .
In the return journey, the light travels with the aether wind at a net speed of :
Factoring out from the denominator:
Applying the binomial expansion (for ):
The longitudinal arm is the slow arm. The wind assists one leg and retards the other, and the retardation outruns the assistance because the retard leg takes longer to complete. The net is a delay that grows as the square of the wind speed.
Transverse Transit Time
2. Transit Time Along the Transverse Arm (Arm 1, Perpendicular to Motion)
To travel straight across the moving aether and strike the transverse mirror, the light must angle slightly into the wind.
By the Pythagorean theorem, the transverse velocity component is:
The round-trip transit time is:
Applying the binomial expansion :
The transverse arm is the fast arm. Its delay grows only half as fast as the longitudinal delay, because the wind lengthens the diagonal path without adding a differential along the direction of travel.
The Second-Order Difference
3. The Time Difference and Predicted Fringe Shift
The time difference between the two arms is:
When the entire apparatus is rotated by , the roles of the two arms are reversed.
Arm 1 becomes longitudinal, and Arm 2 becomes transverse. The total change in time delay between the two optical paths is therefore doubled:
The resulting fringe shift () observed in the telescope is given by the total path difference divided by the wavelength of light ():
The shift is second order in . At orbital speed the ratio is one part in ten thousand, and its square is one part in a hundred million. The experiment is therefore a measurement of a hundred-millionth, converted into a fringe count by the path-to-wavelength ratio.
Numerical Prediction
+======================================================================================================================+
| NUMERICAL PREDICTION FOR 1887 CASE WESTERN TRIAL |
+===========================+=======================================+==================================================+
| Path Length ($L$) | $11.0\,\text{meters}$ | Effective folded path |
| Light Wavelength ($\lambda$)| $5.9 \times 10^{-7}\,\text{meters}$ | Sodium yellow D-line |
| Postulated Speed ($v$) | $30,000\,\text{m/s}$ ($30\,\text{km/s}$)| Heliocentric orbital velocity |
| Speed of Light ($c$) | $3.0 \times 10^8\,\text{m/s}$ | Measured speed of radiant propagation |
| Ratio $(v/c)^2$ | $(10^{-4})^2 = 1.0 \times 10^{-8}$ | Second-order velocity factor |
+===========================+=======================================+==================================================+
| PREDICTED FRINGE SHIFT | $\Delta N = \frac{2(11)}{5.9\times 10^{-7}} \times 10^{-8} = \mathbf{0.373 \approx 0.40}$ fringes |
+======================================================================================================================+
A shift of $0.40$ fringe widths is enormous in optical interferometry. It represents nearly half a full wavelength displacement—a shift that would sweep cleanly and unmistakably across the micrometer crosshairs as the sandstone slab turned.
The path-to-wavelength ratio is . Multiply by the velocity-squared factor and the answer is a fraction of a fringe that any competent observer can see, count, and record without strain.
The Rotation Schedule and the Observed Curve
The experiment was executed over multiple days in July 1887, taking readings at noon and at 6:00 PM (when the Earth’s supposed orbital velocity vector was aligned with different geographic orientations).
The results were recorded with meticulous precision.
The observed curve did not trace a sinusoidal wave of amplitude $0.40$. It traced an almost completely flat line:
THE 1887 INTERFEROMETER READINGS
Fringe Shift (Delta N)
▲
+0.40│- - - - - - - - - - - - - - - - - - - - - - - - - - - EXPECTED SHIFT
│ (30 km/s Orbital Velocity)
+0.20│
│
0.00├───/\
The observed amplitude was under $0.015,\text{km/s}$. The measurement could not distinguish the result from zero.
The runs were repeated at different hours and different days. The flatness persisted. The apparatus was rotated through the full circle, in both directions, at every session.
Michelson and Morley reported the mean displacement as roughly one-hundredth of the predicted value. They noted a small systematic drift of thermal origin and corrected for it. The corrected curve stayed flat.
The Contraction Term
The 1887 paper offered no rescue. Michelson and Morley closed with a statement that the result seemed to show the aether to be at rest relative to the Earth, or that the Earth's motion produced no measurable effect.
Two years later, George FitzGerald wrote a short letter to Science. He proposed that the arm of an interferometer shortens in the direction of its motion through the aether, by a factor depending on the velocity.
The shortening was tailored. It had to be exactly to cancel the predicted second-order delay. Any other exponent would leave a residual.
Lorentz arrived at the same factor independently in 1892, by way of his electron theory and a set of coordinate substitutions. The factor became the contraction hypothesis.
The hypothesis is not derivable from the 1887 data. It is fitted to it. The data give a null; the hypothesis is the smallest addition that converts the null into a hidden confirmation.
The contraction is also unobservable in isolation. A shortened arm cannot be compared against an unshortened one, because every ruler is shortened in the same proportion. The effect is defined as undetectable.
Miller at Mount Wilson
Dayton C. Miller took up the question at the Case laboratory in 1902 and continued it for two decades. He rebuilt the interferometer with steel instead of stone and with a lighter frame.
From 1921 onward Miller ran the apparatus at the Mount Wilson Observatory, at an elevation of roughly . He took data over four years, in a shielded concrete hut, with a path of .
Miller reported a positive drift, not a null. The amplitude was small, on the order of a tenth of a fringe, but it varied with sidereal hour in a repeatable way.
Converted to velocity, Miller's amplitudes corresponded to something near $8$ to . That is well below the orbital figure and well above the 1887 null.
Miller also reported a seasonal modulation and a sidereal period. He read the period as evidence of motion against a cosmic aether frame rather than an orbital one.
The Altitude Gradient
Miller's data carried a second feature. The amplitude was larger at Mount Wilson than it had been in the Cleveland cellar. The drift grew with elevation.
Miller ran comparison runs at lower altitude and at sea level. The amplitude fell as he descended. At the Case basement the effect was near the noise floor.
The gradient suggests the aether is not uniformly entrained. Near the ground, the lower atmosphere may carry the medium along with the Earth's surface. At altitude, the entrainment thins and the underlying drift reappears.
The reading is consistent with a boundary layer. It is not consistent with the pure kinematic picture, in which altitude should make no difference to a velocity measured against a medium that the whole planet is supposed to be plowing through.
The Administrative Cover-Story
FitzGerald's 1889 Letter
FitzGerald's letter to Science ran to a few hundred words. It was titled "The Ether and the Earth's Atmosphere" and appeared in volume 13, page 390.
The argument was that an electric charge in motion sets up a magnetic field, that the field stores energy, and that the energy must come from somewhere. FitzGerald reasoned that the molecular forces holding a body together would be affected by motion and the body would shorten.
The shortening was given as a function of velocity and direction. It was offered without derivation from first principles and without an independent test.
The letter's brevity is instructive. It is a note, not a paper. It proposes a mechanism in outline and leaves the working-out to others.
Lorentz's 1892 Transformation
Lorentz published his version in the Verslagen of the Amsterdam Academy in 1892. He had the electron theory behind him and a set of substitutions that made Maxwell's equations hold in the moving frame.
The substitutions included a contraction of lengths along the motion and a change of the time variable. The time change later became known as local time.
Lorentz treated the aether as real and the contraction as a physical effect of motion through it. The aether stayed at rest in his system. The Earth moved through it and shrank.
The 1895 revision and the 1904 revision extended the scheme. By 1904 the transformations were complete and symmetric. The physical interpretation of the contraction remained.
Einstein's 1905 Postulate
Einstein's paper of June 1905, in Annalen der Physik volume 17, dispensed with the medium. It opened with a statement about the electrodynamics of moving bodies and the asymmetry in the existing treatment.
The paper set two postulates. The first is that the laws of physics are the same in all inertial frames. The second is that light in vacuum propagates at regardless of the motion of the source.
From the two postulates the Lorentz transformations follow. The contraction is then a consequence of the kinematics rather than a mechanical effect on matter.
The aether is not refuted. It is declared unnecessary. The null of 1887 becomes a postulate rather than a finding.
The move is administrative. A result that had been an anomaly becomes a starting axiom. Once it is an axiom, it can no longer be tested against the theory it was used to build.
Textbook Absorption
The 1905 paper was slow to enter the curriculum. The 1887 experiment entered faster, and usually as a demonstration of relativity rather than as a problem in aether physics.
The standard textbook sequence presents the null, then the postulates, then the transformations. The null is read as the experimental motivation for the postulates.
The sequence hides the order of events. The contraction was published sixteen years before the postulate. The postulate absorbed the contraction and renamed it.
Later editions compress the history further. The 1887 trial becomes a clean confirmation of a theory that did not yet exist when it was run.
The Falsifiability Problem
The contraction hypothesis is difficult to falsify by interferometry alone. Any null can be accommodated by adjusting the contraction factor to match.
A positive result would falsify it, but only if the positive result exceeded the fitted factor. Miller's amplitudes were small enough to be argued away.
Miller's work was reexamined in the 1920s by others and reported as inconclusive. The Mount Wilson runs were criticized for thermal and mechanical artifacts. The criticisms were partly valid and partly circular.
The 1929 repetition by Michelson, Pease, and Pearson at Mount Wilson used a rigid steel frame in a vacuum tank and a path. It returned a small positive drift, again well under the orbital figure.
The Miller Suppression
Miller's 1933 summary in Reviews of Modern Physics ran to forty pages and included the full data tables. It is the most complete record of the altitude series.
The summary did not overturn the consensus. The consensus had already settled. Miller's amplitudes were folded into the noise budget and the null was retained as the headline.
The dossier's position is that the suppression was not conspiratorial but procedural. A result that does not fit the framework is filed as a residual and the framework stands.
The residual is where the evidence lives. The 1887 null, the Miller gradient, and the 1929 partial return are three readings of the same instrument family, and they do not agree with each other under the orbital hypothesis.
What It Implies for the Created Architecture
The Foundation Texts
The scriptural record does not describe a body in flight. It describes a body founded.
Psalm 104:5 states that the earth is laid upon its foundations, that it should not be removed for ever. Psalm 93:1 states that the world also is stablished, that it cannot be moved. 1 Chronicles 16:30 repeats the stablishing.
The vocabulary is architectural. Foundation, stablish, not be removed. The terms belong to a builder's specification, not to a poet's ornament.
Job 38:4-6 puts the question in the same register. Where wast thou when I laid the foundations of the earth? Whereupon are the foundations thereof fastened? Or who laid the corner stone thereof?
The questions assume a foundation and a fastener. They assume a corner stone. The earth of the text is a built thing on a set base.
Ecclesiastes and the Circuit
Ecclesiastes 1:5 gives the one apparent exception. The sun also ariseth, and the sun goeth down, and hasteth to his place where he arose.
The verse describes solar motion, not terrestrial motion. The sun runs a circuit and returns to its place. The earth is not said to run.
The Hebrew of the passage carries the sense of panting or eager pursuit. The sun hastens. The hastening is the sun's, and the place it returns to is its own.
Taken with the foundation texts, the picture is a fixed platform and a moving luminary. The 1887 null is a measurement of the platform.
Entrainment as a Boundary Condition
The Miller altitude gradient fits the architectural reading better than the kinematic one. A medium that is entrained near the ground and free at altitude implies a boundary.
A boundary implies a container. A container implies a defined region with a floor and a ceiling, which is the firmament of the text and not the infinite void of the convention.
The gradient also explains the 1887 null without any contraction. The Case basement sat inside the entrained layer. The interferometer was measuring the medium it was sitting in.
The contraction hypothesis becomes unnecessary under this reading. It is retained in the convention because the convention has no boundary to appeal to.
The Instrument as Tribunal
The interferometer is a differential device. It compares two paths in the same room at the same time. Whatever the medium does, it does to both arms.
A differential device inside a co-moving layer returns a null. A differential device at the top of a mountain, above the layer, returns a residual. The instrument reports its own elevation.
The 1887 trial was not a failed experiment. It was a correctly executed experiment at the wrong height, read as a universal verdict.