Inertia and Gravitation

Scientific Paper
Title	Inertia and Gravitation
Read in full	Link to paper
Author(s)	Felix F Gorbatsevich
Keywords	Inertia, Gravitation, Inertness, Ether, Mass, Speed of Light
Published	2011
Journal	Unpublished
No. of pages	13

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Abstract

There are quite a lot of works dedicated to revelation of the physical essence of the body inertia [1-4]. They present the historical development of the concept of "inertia", various kinds of the body inertia manifestation and practical use of inertia in operating mechanisms. The notions of inertia and inertness are introduced. Some authors use the inertia and inertness notions designating one and the same body property by them. By inertia is most often meant the attempt of the body to preserve its state invariable in relation to the inertial (motionless) reference system. The most advanced formulation of the inertia properties is given in [5]: "Every body offers resistance in attempting to put it in motion or to change the modulus or direction of its movement". Otherwise, if no external forces act on a body from other bodies or the environment, or these forces balance each other, the body preserves the state of rest or steady rectilinear motion. This expression is, in essence, Newton's first law...

Overview

Felix F Gorbatsevich's essay is an attempt to clear up what he regards as a persistent terminological confusion at the base of mechanics, and then to use the cleaned-up vocabulary to argue for an ether medium. His claim is that two distinct properties have been run together under one word. Inertness is a body's resistance to having its state changed — a property of mass, present whether the body moves or not, and in his view simply a synonym for mass. Inertia is a property of motion: it is the kinetic energy a body carries relative to another body, and it exists only relative to that other body and manifests only in collision. Once these are separated, he argues, several long-standing puzzles dissolve.

The second half of the paper is the constructive part. Gorbatsevich argues that gravitation cannot be a force applied to a body at a point or surface, as contact forces are, because all bodies — large, small, or divided down to atoms — fall with the same acceleration. It must therefore be a gradient pressure applied individually to every elementary particle constituting a body. But a distributed pressure of that kind requires a medium that penetrates freely into all matter, and that medium is the ether. From this he draws his account of weight, of weightlessness, of the equality of inertial and gravitational mass, and a direct challenge to Einstein's equivalence principle — supported by a specific thought experiment with two dynamometers.

The argument

Inertia is relative and manifests only in collision

Gorbatsevich begins from Newton's first law and notes that it can hold only under abstract conditions free of gravitational fields, since every region of space is permeated by gravitation and the paths of comets, planets and stars are correspondingly curved. The Sun itself carries the planets around the galactic centre at about 250 km/s. "Straight motion" and "uniform motion" are therefore usable only as approximations over short paths.

To quantify inertia he considers collisions. Writing the kinetic energies of two balls before and after a perfectly inelastic central impact, the absorbed energy is a term proportional to (V₁ − V₂)² and to the product of the masses over their sum. In the limiting case of a small mass m striking a much larger one initially at rest, and neglecting second-order effects, the energy released is E_k = ½mV² — a formula he attributes to Oliver Heaviside and, independently, to William Thomson. Because the small body ends with zero speed, it has lost all its inertia with respect to the large one. Gorbatsevich concludes that "the body inertia can be set equal to the amount of kinetic energy accumulated in its mass and speed."

The consequence he presses is relational. A body has no inertia with respect to another body relative to which it does not move; two bodies moving together at the same speed have no inertia relative to each other, but do relative to a third. "Therefore the inertia (potential) measure of every specific body moving independently has a great number of values depending on the fact in relation to which other body it is estimated." Since some external object is needed for it to be manifested at all, he calls this external inertia.

Internal inertia and a combined law

Rotating bodies, by contrast, possess what Gorbatsevich calls internal inertia, which does not depend on any external body and has a single definite value. It is accompanied by real internal stresses and strains from centrifugal forces, and by the gyroscopic effect, and is measured by the moment of inertia J = mR² for a point mass, with rotational energy E_r = ½Jω². Because rotation can be detected experimentally within an isolated space, he concludes that "Galilean relativity principle is inapplicable for rotating bodies", and that strictly speaking it cannot be followed under terrestrial conditions at all. His examples of the Earth's own internal inertia are the equatorial bulge of the geoid, the Coriolis deflection of streams, and the Foucault pendulum.

Since Newton's first law describes only external inertia, Gorbatsevich proposes a formulation covering both: "a body set in motion that is free from external relations will move indefinitely long conserving the motion energy." He offers this as a fuller law of inertia.

Inertness equals mass equals gravitational mass

Turning to the equality of inertial and gravitational mass, Gorbatsevich notes the long series of precision null results — Eötvös, Pekár and Fekete; Roll, Krotkov and Dicke; Braginsky — and argues that the difference "must not exist since inertness and mass are adequate categories." The same body accelerated by a contact force or by gravity may experience different forces and accelerations, but the mass cannot differ; Eötvös's experiments prove only that bodies of any physical composition move alike in a gravitational field.

Where the two cases do differ, he argues, is in how the force is applied. A body resting on a support is under internal load: divide it into parts and the lower parts bear the weight of the upper ones. "Our soles undergo the pressure equal to the body weight. The pressure perception in our body is the ponderability perception." The same is true of a body accelerated by contact, where the greatest strains are near the surface of application. Gravity is different, and the proof is Galileo's: a lead pellet and a feather fall alike in an evacuated tube, and dividing a body into ever smaller pieces changes nothing, down to atoms. "Hence it follows that a gravitational field is applied to every elementary particle possessing mass and constituting a physical body." Weightlessness in free fall then has a mechanical explanation: because every particle receives the same acceleration, no stresses arise between the parts, and "weightlessness is exactly the state when internal stresses between the body parts are missing."

Why this requires an ether

The key inference follows immediately. A gradient pressure that reaches every elementary particle individually requires "a medium freely penetrating into all physical bodies without exception" — only then is close-range interaction preserved rather than action at a distance. That medium is the ether. On a support, the ether's gradient pressure acts on each particle and the forces sum to the body's weight on the support, with deformations increasing toward the support; in free fall the same pressure acts, unchanged in magnitude, but produces no differential stress.

For this to work the ether's constituents must be far smaller than the particles they pass among. Gorbatsevich cites A.A. Potapov's analysis of the effective polarisability of ether particles, which gives their size as the Planck length, built from the Planck constant, the gravitational constant and the speed of light — of order 10^-35 m. He contrasts this with atomic sizes of about 10^-10 m, nuclear sizes around 10^-14 m, and the classical electron radius of 2.818×10^-15 m, concluding that ether particles "can easily penetrate and take places among atoms in the intra-atomic space." A physical body is then "a kind of a space 'lattice'" of nuclei and electrons with the ether inside it, and the gradient pressure of that ether on the lattice is the gravitational force. He supports the picture by noting that light passes through transparent bodies as well as vacuum, which he takes as evidence that the same substrate oscillates in both. Newton's letter rejecting action at a distance through a vacuum without a mediator, and Maxwell's remarks that the ether cannot be the air and that interstellar space is "filled with a material substance or body that is the vastest and most homogenous known body", are quoted in support.

Against the equivalence principle

Gorbatsevich then attacks the equivalence principle directly with a thought experiment. Build a body from two masses joined by bars, with a dynamometer D₁ in the horizontal bar. Accelerate it by a contact force F at acceleration g in a region free of gravity. Build an identical body with dynamometer D₂ and let it sit in equilibrium in a gravitational field of the same acceleration. He argues D₁ will read more than D₂, "since the body masses in Fig. 1b will be attracted together", and calls this a clear demonstration of "the inconsistency of the equivalence principle". His diagnosis is that when gravitation is imitated by an accelerating lift, "the distributed gravitational field is absent."

The same framework handles orbital weightlessness. For a body on a circular orbit the required centripetal force is supplied by gravity, so g = V²/R, and the centrifugal inertia force — analogous to Euler's transportable force — balances the gravitational force particle by particle throughout the body. No internal stress arises, and every body reaching circular velocity becomes weightless regardless of its mass.

Motion in the ether, and near-light speeds

At speeds well below c a body scarcely interacts with the ether, which "resembles an ideal medium displaying no friction effects" — Gorbatsevich invokes d'Alembert's observation that uniform straight motion in an ideal liquid meets no resistance — while also having "certain characteristics like a specific solid body." He cites E.I. Styrkov's Earth–geostationary satellite observations as showing that the electromagnetic wave velocity in free space is set only by the ether's properties, and that the Earth's motion affects the aberration of waves from a satellite, yielding an orbital velocity component of 29.4 km/s and an apex at right ascension 270°, declination 89.5°, in agreement with observational astronomy — which he takes as direct proof that the ether medium can serve as an independent coordinate system.

At near-light speeds the picture changes. He reviews the Cherenkov effect — light emitted when a particle exceeds the phase velocity c/n(ω) in a medium, within a cone of half-angle given by arccos(V_f/V) — and Ginzburg's remark on the value of analogies, noting the parallel with the Mach cone of a supersonic shock. He cites Tyapkin's report of Cherenkov radiation from a lead-ion beam at speeds quoted as 1.00006–1.0047 c, and Sommerfeld's 1904–5 result that a charge moving superluminally in vacuum must radiate. Since such a particle radiates, it loses energy and inertia, so superluminal travel is short-lived.

Finally he interprets the relativistic mass increase m = m₀/√(1 − V²/c²) in ether terms: the particle's own mass is always m₀, and the excess m_e = m − m₀ is "the associated mass of the ether" carried along. The disanalogy with a body in a gas is stressed: gas flows around a body, whereas "the ether medium moves through the physical body", interacting with each constituent particle. Because infinite mass is barred by conservation of mass-energy, bodies cannot travel at c — from which he concludes that photons, which always do, "cannot have mass and consequently, they are the waves perturbing the ether medium and propagating in it."

The conclusion also rejects Mach's principle in its standard form: because a body's inertia has many values depending on which other body it is measured against, the claim that inertia is caused by gravitational interaction with all distant masses "becomes not obvious." What Gorbatsevich retains is that the gravitational force at any point is determined by all cosmic masses, visible and invisible, transmitted through the ether — every body distorting the ether in its vicinity, the attraction falling as the inverse square yet never wholly ceasing at any distance.

Assessment

The genuinely useful part of this paper is the terminological surgery. The distinction between inertness (a static property of mass) and inertia (a relational property of motion) is drawn carefully, and Gorbatsevich is right that ordinary usage slides between them. His observation that inertia in the second sense is frame-relative and manifests only in interaction is correct and worth stating plainly. The observation that rotation is detectable without reference to any external body — and that Galilean relativity therefore does not extend to rotating frames — is also sound, and the geoid, Coriolis and Foucault examples are well chosen. Best of all is the argument at the paper's core: that because bodies of any size and composition fall alike, and the subdivision can be carried to the atomic level, gravity cannot act at a surface but must act on each constituent particle, and that weightlessness is precisely the absence of internal differential stress. That is a genuinely illuminating mechanical reading of free fall, and it is stated more clearly here than in many textbooks.

The inference from that to an ether is where the argument becomes assertion. Gorbatsevich moves from "gravity acts on every particle" to "therefore a medium must penetrate every body" as though the second followed from the first, but a field acting locally at every point — which is what a field is — already does the job without any material carrier, and general relativity's account of free fall as geodesic motion produces exactly the stress-free condition he describes, for exactly his reason. His ether is asked to be simultaneously frictionless for uniform motion and solid-like for wave propagation, to be carried along as "associated mass" at high speed while offering no resistance at low speed, and no equation of state, density or coupling is given that would let any of this be tested. The Planck-length figure for ether particles is imported from a polarisability argument in a secondary source rather than derived, and the size comparison it supports would follow for any sub-nuclear scale whatever.

The attack on the equivalence principle rests on a misreading. Gorbatsevich's two-dynamometer comparison finds a difference between an accelerated frame and a gravitational field because the two masses in the gravitating case attract each other — that is, because of their mutual Newtonian attraction, which is a property of the apparatus, not of the external field. The equivalence principle has never claimed more than local equivalence, precisely to exclude effects of this kind along with tidal gradients; the modern statement restricts it to a region small enough that field inhomogeneity is negligible. His own dynamometer difference scales with the separation of the masses and vanishes as that separation goes to zero, which is the equivalence principle rather than a refutation of it. It is also striking that the paper affirms with great confidence the experimental equality of inertial and gravitational mass — Eötvös, Dicke, Braginsky — and then rejects the principle those experiments most directly support.

Two further claims are in conflict with established measurement. The Styrkov result cited as detecting the Earth's absolute motion through the ether at 29.4 km/s is a single conference report; the far more sensitive modern optical-cavity and Michelson-Morley-type experiments constrain any such anisotropy in the one-way speed of light to parts in 10¹⁷, many orders of magnitude below what a detectable ether wind would require, and the aberration signal Gorbatsevich points to is fully accounted for by the relative motion of source and receiver. The Tyapkin claim of lead ions at 1.00006–1.0047 c would, if real, be one of the largest results in physics; it appears here from a web reference, has never been reproduced, and stands against the entire body of accelerator data in which particle energies at fixed velocity follow the relativistic relation to high precision. Gorbatsevich's own use of m = m₀/√(1 − V²/c²) sits awkwardly beside it, since that formula makes V > c inaccessible; his reinterpretation of the excess as entrained ether mass is a relabelling that changes no prediction and is therefore untestable as stated. The final inference — that photons must be massless because massive bodies cannot reach c — happens to reach the right conclusion, but by a route that assumes what it needs.

Read as a conceptual essay on what "inertia" ought to mean, and on why free fall feels the way it does, the paper is clear and often instructive. Read as a demonstration that mechanics requires an ether, it substitutes a plausible mechanical picture for the argument that would be needed, and the observational supports it recruits are the weakest available.

See also

• Felix F Gorbatsevich
• Inertia
• Aether
• Mass
• Equivalence Principle
• Mach's Principle
• Ernst Mach
• Oliver Heaviside
• Speed of Light
• Photon
• Newton's Third Law
• Isaac Newton
• James Clerk Maxwell