THE EQUIVALENCE PRINCIPLE
Einstein used the equivalence principle to develop a geometric description of gravitation. In a local freely falling frame, nongravitational physics takes the form described by special relativity. Over an extended region, tidal effects reveal spacetime curvature.1 Measurement Quantization (MQ) approaches the subject through a narrower question. Under what conditions do relative inertial motion and gravitational escape give the same dimensionless speed ratio?
Foundations of the Count Description
MQ begins with one axiom. Measure is discrete. Starting from discrete count relationships, MQ uses a geometric construction to anchor an expanding frame of information that describes a universe. In its reconstruction of the fundamental measures and constants, four physical inputs select and normalize the realized universe. The fine-structure constant selects the dimensionless coefficient for our universe, the speed of light anchors the relation between realized length and time, and the electron mass and Bohr radius provide the cross-dimensional normalization. The exact SI value of the speed of light is a unit convention. The temperature of the cosmic microwave background serves separately as an epoch selector in the cosmological construction. See Fundamental Measures for the underlying scales.
The Internal Frame is the discrete configuration domain, where relationships are encoded in integer counts. It has no continuous geometry of its own. The Frames mapping is the kinematic transformation that relates those configurations to continuous relational structure in the System Frame. Observable quantities are defined in the System Frame, which has no independent fundamental measure. See Physical Significance of Measure for the distinction between count structure and physical realization.
Inertial Motion in Count Form
The fundamental measures of length and time are and . For the inertial comparison, counts fundamental lengths traversed by the object relative to the observer, and counts those traversed by light relative to the same observer over the same elapsed interval. For positive motion and light-reference counts, the normalized count geometry used here also includes , the count associated with the observed realized separation.
The squared separation ratio is the complement of the squared motion-count ratio. The latter has a direct interpretation. The object and light displacements use the same fundamental length and elapsed time, so both factors cancel in the ratio of the relative speed to the speed of light .2
Gravitation in the Same Count Language
The gravitational calculation starts from the classical escape-speed law for a point mass. Here denotes the escape speed, is the source-mass count, and is the fundamental mass. In this calculation is the positive radial length count from the source. The same symbol thus denotes a motion count in the inertial calculation and a radial count in the gravitational calculation.
Writing the source mass as and the radius as gives . The upright G denotes the upper-count gravitational coupling in MQ. Using and , the fundamental length and mass factors cancel. Normalizing by gives the following result.3
Equivalence as a Count Identity
For the comparison in which the relative inertial speed equals the escape speed, the two expressions have the same squared speed ratio. Equating them gives the MQ count identity.4
For the broader MQ treatment, see Gravity and The Gravitational Constant.
Source Notes
- Albert Einstein, Die Grundlage der allgemeinen Relativitätstheorie, Annalen der Physik 354(7), 769–822 (1916), §§2–4 and §§11–14.
- Jody A. Geiger, Discrete Approach to Deriving the Equivalence Principle as a Predicted Outcome, author-posted manuscript, §2, Eq. (15). The displayed triangle above uses the normalization adopted on this page. The manuscript’s Eq. (12) writes a separate reference count in the second denominator.
- Geiger, Discrete Approach to Deriving the Equivalence Principle as a Predicted Outcome, §2, Eqs. (16)–(19). These steps apply the escape-speed expression and the upper-count coupling.
- Geiger, Discrete Approach to Deriving the Equivalence Principle as a Predicted Outcome, §2, Eq. (20). The historical radial subscript is rendered with current MQ notation. The radial and motion roles are identified in the text.
