Toy-Model Derivation of the Hubble Constant

by ChatGPT building upon Grok4.

Overview & Assumptions
This is a global discrete-creation toy model that imagines the universe producing one “Planck sphere” per Planck time (tP) across all of space. It’s not one sphere per Planck volume, but a single global event per tick. The goal is to translate that playful-but-ginormous rate into conventional Hubble units (km s-1 Mpc-1) to test whether it is anywhere near observations.

This file: https://81018.com/toy-model-derivation-of-the-hubble-constant/
Date posted: 6 October 2025

Remarkably it is. The final calculation yields a present-day expansion rate numerically close to Hubble’s.


1. Raw “thrust” frequency at the Planck scale

The Planck time is: tP = 5.391 × 10-44 so the raw creation frequency is: fraw = 1 / tP ≈ 1.85 × 1043 s-1 This is the foundational “drive” of the toy model — far larger than any observed expansion rate.


2. Converting frequency to Hubble units

The Hubble constant H0 is typically expressed in km s-1 Mpc-1. To convert a rate in s-1 (call it Hs) to those units: Hkm = Hs × (1 Mpc in km).

Since 1 Mpc ≈ 3.086 × 1019 km, a direct (naïve) substitution gives:

Hkmnaïve = (1.85 × 1043) × (3.086 × 1019) ≈ 5.7 × 1062 km s-1 Mpc-1

— an absurdly large value that makes clear a dilution factor is needed.


3. Dilution by cosmic accumulation

Take the current cosmic age as: t ≈ 4.35 × 1017 s (≈ 13.8 billion years)

The number of Planck intervals that have elapsed is: N = t / tP ≈ 8.1 × 1060

We treat the effective expansion rate as the raw frequency diluted over those N accumulated events:

Hseff = fraw / N = (1 / tP) / (t / tP) = 1 / t

Numerically: Hseff ≈ 2.30 × 10-18 s-1


4. Conversion to km s-1 Mpc-1

Hkmeff = (2.30 × 10-18) × (3.086 × 1019) ≈ 71 km s-1 Mpc-1

That value happens to fall right within the observed range (≈ 67–73 km s-1 Mpc-1).

Summary (at a glance)
fraw = 1 / tP → Hseff = 1 / t → H0 = Hseff × 3.086 × 1019 ≈ 71 km s-1 Mpc-1


5. Caveats and context

  • This is a purely dimensional toy argument, not a physical derivation.
  • The “one sphere per Planck time” rule is a speculative assumption.
  • Cosmic expansion in standard cosmology refers to metric stretching, not literal creation of new spheres.
  • Results depend directly on the assumed age of the universe: a 5–10 % change in age shifts the derived value similarly.

Still, the dimensional coincidence is intriguing: a Planck-time process diluted over cosmic history yields a present-day expansion rate numerically close to Hubble’s.

Graph illustrating cosmic expansion, showing the relationship between Planck time, age of the universe, and present-day Hubble constant. A blue curve indicates the expansion trend.

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Mathematics and geometries to expand upon the toy model:

  1. Base-2 notation from the Planck base units to the cosmic scale: https://81018.com/chart/
  2. Stabilizing geometries: The Four Primary Irrational Numbers Stabilizes Spheres from the Planck to the cosmological scale: https://81018.com/planck-polyhedral-core/ https://81018.com/ross/
  3. Perfect Domains: Notations-0 to Notation-50: https://81018.com/starts-8/
  4. A Lagrangian is slowly emerging.