The 81018 Model

A Discrete Base-2 Geometric Framework from Planck Scale to Cosmological Scales

Authors: Bruce E. Camber and AI-assisted editing-and-review by (alphabetically)
ChatGPTClaudeDeepSeekGeminiGrokMetaMistral, and Perplexity

Abstract

The 81018 model presents a toy, discrete geometric framework that spans from Planck-scale structure to cosmological scales using a base-2 notation system. Beginning with a tetrahedral-octahedral geometric seed, successive edge bisections generate nested refinement layers indexed by an integer notation n, where n=0 anchors at Planck length/time and positive n correspond to binary doublings: L_n = 2^n L_P, T_n = 2^n t_P. Extending this chain to n≈200 naturally produces length/time scales comparable to the observable universe’s radius (~10^26 m) and age (~ 13.8 billion years). The model functions as a combinatorial laboratory for exploring discrete scale hierarchies, making no claim to derive cosmic dynamics from first principles. We detail the geometric construction, scaling relations, and numerical mapping to cosmological milestones, positioning 81018 as a heuristic tool for relating Planck discreteness to large-scale expansion within a unified binary framework.

1. Introduction

Contemporary cosmology describes the large-scale universe with remarkable precision using general relativity and ΛCDM, yet the Planck regime and the ultraviolet completion of gravity remain open questions. Discrete geometric frameworks offer one approach to exploring scale hierarchies that bridge quantum and cosmological domains. The 81018 model adopts this perspective through a simple base-2 construction rooted in tetrahedral-octahedral geometry.

This paper presents 81018 as a toy model, a combinatorial system, not a physical theory. Beginning at Planck scales (n=0), successive binary doublings generate a notation chain that reaches cosmological scales near n=200. The model serves as a discrete analog to logarithmic cosmological plotting, providing a geometric template for thinking about scale separation from Planck discreteness to large-scale homogeneity. Yet, unlike conventional logarithmic plots, this construction provides a discretized, integer-indexed template where each step corresponds to a doubling of geometric complexity, offering a new combinatorial perspective on the Planck-to-cosmos scale hierarchy.

Sections 2–4 develop the construction, scaling relations, and cosmological mapping. The construction makes no dynamical claims and is intended as a heuristic laboratory for scale hierarchy questions.

1.1 Model specifications (v1.0)

Four defining rules:

  1. Geometric seed: Tetrahedron-octahedron pair, unit edge length (Fig. 1).
  2. Notation indexnZn=0 at Planck scale, Ln=2nLPtn=2ntP​.
  3. Binary process: Edge bisection (inward), edge doubling (outward).
  4. Domain: ~202 notations spanning Planck to cosmological scales.

Core parameters (CODATA 2018):

SymbolValue
LP1.616×1035
tP5.391×1044

1.2 Toy Model: Again, we use ‘toy model’ in the combinatorial sense: a simplified, discrete framework for organizing scales and exploring logical consequences, not a candidate for fundamental dynamics. It does not propose new forces, particles, or modifications to general relativity.


2. Geometric construction

The 81018 model begins with a tetrahedral-octahedral geometric seed, chosen for its duality and space-filling properties. A regular tetrahedron and its dual octahedron form a natural pair: the face centers of a tetrahedron define vertices of another tetrahedron, while octahedron vertices lie at cube face centers.

An educational image displaying a geometric arrangement of tetrahedrons and octahedrons, with yellow lines outlining the shapes. There are exercises for schoolchildren to count and observe the figures.

Figure 1. Geometric seed: (a) unit-edge tetrahedron, (b) dual octahedron, (c) first edge-bisection step. Midpoints on each edge generate 4 smaller tetrahedra + 1 central octahedron.

The refinement process follows three explicit steps:

  1. Start with a tetrahedron (or octahedron) of unit edge length a0=1.
  2. Edge bisection: Place vertices at midpoints of all edges. For a tetrahedron (6 edges), this yields 6 new vertices. Connect to form:
    • 4 corner tetrahedra (edge a1=1/2)
    • 1 central octahedron (edge a1=1/2)
  3. Iterate: At step k, bisect all edges from step k1. Edge lengths scale as ak=2kgenerating nested layers indexed by notation n=k (inward).
Diagram showing geometric concepts including spheres, tetrahedrons, and octahedrons, illustrating scaling, close-packing geometry, and edge bisection.

Figure 2. Refinement sequence: four spheres, centers connect, first tetrahedron. Green tetrahedra actualized. Each edge halved edges, four tetrahedron in corner, one octahedron in center. One octahedron, each edge haleed for eight tetrahedrons and six octahedrons in the corners.

Outward construction reverses the process: from n=0 (Planck scale), edge doubling (an+1=2an​) generates the cosmological sequence. This bidirectional refinement produces the full notation chain:

nZ,Ln=2nLP,edge length scales with 2n.

The tetrahedron-octahedron pair provides both visual intuition and combinatorial structure for the base-2 hierarchy. Section 3 maps this geometric progression to physical scales.

3. Base-2 scaling and 202 notations

The 81018 model indexes refinement levels by an integer notation nZ, where n=0 corresponds to Planck‑scale quantities and positive n represent successive doublings of characteristic scales. If this nested bisection process is extended to its logical limit, the edge length of the smallest tetrahedron is determined by the Planck length (L_P). Setting this as the base unit (n=0), each outward doubling step (n=1,2,3,…) defines a discrete scale. The time associated with each scale follows identically from the Planck time (t_P), assuming the speed of light c = L_P/t_P. The length and time associated with notation n are defined by

Ln=2nLP,Tn=2ntP,(1)

where LP=1.616×1035m and tP=5.391×1044s are the Planck length and time, respectively. These basic equations, simple rules, provide a discrete logarithmic bridge between Planck-scale structure and much larger physical scales.

Table 1 lists selected notations depths, showing how n202 produces T20213.8 billion years and L202​ on the order of the observable universe radius (1026 m), up to factors of order unity.

Table 1. Selected notations in the 81018 base‑2 chain.

Notation nLength Ln​ (m)Time Tn​ (s)Physical Reference
01.616×10355.391×1044Planck scale
84~3 × 10⁻¹⁰~∼10−19Bohr radius / atomic scale
143∼10−9∼10−18Near the first second of the universe
202~10²⁶~4.4 × 1017Observable universe radius/age

Notes: Numerical values use CODATA 2018 Planck constants. Cosmological/ scales from Planck 2018 ΛCDM fits.

The key point is that a notation depth on the order of n200 spans the gap from Planck units to cosmological scales with a compact binary indexing rule. In that sense, the model provides a discrete analogue of logarithmic scale separation: lower notations describe refined geometric structure, while higher notations organize macroscopic length and time scales. The numerical coincidence at n=202 is not presented as a dynamical derivation of cosmic expansion, but as a scale-matching feature of the base-2 hierarchy.

This scaling section will support the later cosmological interpretation without claiming that the model replaces ΛCDM or general relativity. Instead, it frames the observed hierarchy of scales as a finite depth within a binary refinement structure rooted in Planck units.

Figure 3. Base-2 notation chain spanning Planck scale (n=0) to cosmological scales (n202). Logarithmic plot of Ln=2nLP​ (solid) and Tn=2ntP​ (dashed) against notation depth n. Dotted lines mark standard cosmological scales for reference.

4. Cosmological interpretation

The base-2 notation chain (Table 1, Fig. 3) naturally spans from Planck scales to cosmological scales over approximately 200 steps. At notation depth n=202, the characteristic length L2021026m approximates the radius of the observable universe, while T2024.4×1017s (approximately 13.8 billion years) matches the Planck 2018 age estimate.

This numerical correspondence arises because ~60 orders of magnitude (base 10) separate Planck units from cosmological scales, requiring n ≈ 202 binary doublings (base 2) to bridge that gap: log₂(10⁶⁰) ≈ 200. Notation n200 thus demarcates discrete geometric refinement of lower notations and the effective continuum descriptions for large-scale cosmology.

The 81018 model makes no claim to derive cosmic expansion dynamics. Instead, it offers a combinatorial perspective: if spacetime admits a binary scale hierarchy from Planck units, the observable universe corresponds to finite depth n200 within that hierarchy. This provides a discrete geometric analog to standard logarithmic cosmological plotting.

The construction suggests three heuristic organizing principles:

  • Finite notation depth corresponds to finite cosmic age/size.
  • Binary refinement mirrors the hierarchical structure of physical scales.
  • Planck anchoring provides a natural ultraviolet boundary.

These principles position 81018 as a scale-separation framework rather than a dynamical theory, potentially useful for organizing cosmological data analysis or exploring effective descriptions across the Planck-to-cosmic hierarchy.

5. Limitations and outlook

The 81018 model is explicitly a toy combinatorial framework with well-defined limitations that merit discussion.

Primary limitations:

  1. No dynamics: The model specifies a static scale hierarchy but provides no equations of motion, field equations, or evolution laws. It cannot predict expansion rates, density parameters, or observables beyond order-of-magnitude scale matching.
  2. Geometric idealization: The tetrahedral-octahedral refinement assumes perfect regularity and infinite divisibility down to Planck scales. Real spacetime geometry involves quantum fluctuations, curvature, and topology changes not captured here.
  3. Numerological risk: The near-match at n=202 is suggestive but not predictive. Without independent physical input, the specific notation depth risks appearing as a tuned parameter rather than a derived result.
  4. No quantum gravity: The construction treats Planck units as fixed anchors without incorporating quantum gravitational effects, loop corrections, or ultraviolet completion.

Outlook and potential extensions:

Despite these limitations, the framework suggests several constructive directions:

  • Data organization: The fixed binary notation ladder provides a universal logarithmic coordinate system for tabulating physical scales across all regimes, potentially useful for multi-scale simulations or phenomenology.
  • Effective field theory interface: Notation depth n could serve as a natural renormalization group “flow parameter,” mapping ultraviolet (low n) to infrared (high n) physics within effective field theory constructions.
  • Geometric quantization: The discrete polyhedral lattice might provide a basis for geometric quantization or spin network-like structures, with notation depth encoding combinatorial complexity.
  • Scale-separation phenomenology: The clean separation between “discrete geometric” (low n) and “continuum cosmological” (high n) regimes suggests applications in understanding effective theories across the hierarchy.

The 81018 model thus occupies a niche as a scale catalog rather than a dynamical theory — a discrete geometric template for organizing the 60-decade span from Planck to cosmic scales within a single coherent framework. Future work might explore whether this combinatorial structure suggests novel organizing principles for multi-scale physics or provides useful heuristics for quantum gravity phenomenology.


References

[1] CODATA Recommended Values of the Fundamental Physical Constants: 2018.
E. Tiesinga *et al.*, Reviews of Modern Physics **93**, 025010 (2021).
[2] Planck 2018 results. VI. Cosmological parameters.
N. Aghanim *et al.* (Planck Collaboration), Astronomy & Astrophysics **641**, A6 (2020).
[3] Observable universe.
Wikipedia, accessed March 2026. [For radius/age estimates]
[4] Tetrahedral-octahedral honeycomb.
Wikipedia, accessed March 2026. [Space-filling properties]
[5] Dual polyhedra.
T. Banchoff, Brown University Geometry Center materials.
[6] Planck units.
Wikipedia + CODATA 2018 values.
[7] 81018 science education project.
81018.com, ongoing work 2011–2026.

Acknowledgements

The author thanks Perplexity AI for extensive assistance in clarifying, structuring, and refining this work through iterative synthetic peer review. Special thanks to the free tier of Perplexity and ChatGPT, which made this documentation of LLM-assisted research possible for an independent researcher without institutional support.

This work originated in a high school geometry class exploring tetrahedral-octahedral constructions, later formalized through the 81018 project (81018.com). The author acknowledges the patience of readers who engage with speculative frameworks developed outside traditional academic channels.

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This file is: https://81018.com/2026/03/25/81018-model/

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