@essrt/physics

The physics core of ESSRT — the Expanding Solar System Resonance Theory — as implemented by the Holistic Universe Model (source, AGPL-3.0). Pure computation: no I/O, no globals, no DOM, constants injected. The package ships the complete model, including the fitted coefficients, so an installed copy reproduces the hosted simulator bit-for-bit on the shared golden masters.

Versioning — two axes, deliberately

• Package semver (this package's version) tracks the API axis — what import gives you.
• Model identity rides inside every published version: the essrt.modelVersion field in package.json plus CONSTANTS_HASH and COEFFICIENTS_HASH in src/constants/. A refit or structural model change always lands as a new package version — npm's immutability then guarantees a pinned version's results never change.

Cite results as model vX.Y (package A.B.C).

Usage

import { DEFAULT_CONSTANTS, FITTED_COEFFICIENTS, createEpochPrimitives } from '@essrt/physics';

Domain modules are CJS subpath exports, each a create* factory taking its dependencies explicitly (the injectable-constants design — counterfactual runs are first-class):

const { createEclipseFinders } = require('@essrt/physics/eclipse/finders');
const { createPredictivePrecession } = require('@essrt/physics/planets/predict');

See the exports map in package.json for the full surface: moon (arguments/series/apparent/ecc-channel/month-chain), planets (geometry, corrections, predict, model, fibonacci-laws, …), deltat (cycles, deep-time, historical), cardinal points, phase, chain-cycles, sun, climate, eclipse finders, and the published reference curves.

For rendered display values (day/year lengths, precession rates, orbital elements as preformatted strings), see @essrt/model-values — generated from this engine at the same model version.

The assembled model — createModel()

The canonical assembly, wired once inside the package:

import { createModel, DEFAULT_CONSTANTS } from '@essrt/physics';

const model = createModel();
model.identity.modelVersion;          // the shipped model identity (e.g. 'v11.0') + both content hashes
model.epoch.hAtYear(2000 - 380e6);    // 306189 — Devonian H (the Wells 1963 match)
model.earth.obliquityDeg(2000);       // 23.4393
model.cardinal.jd(2000, 'SS');        // 2451716.575 — June solstice 2000 (USNO)
model.lengths.tropicalYearDays(2000); // 365.24219

// Counterfactual (§2d): inject different constants, get a different solar
// system — self-identifying, with its own constants hash.
const cf = createModel({
  ...DEFAULT_CONSTANTS,
  foundational: { ...DEFAULT_CONSTANTS.foundational, holisticyearLength: 400000 },
});
cf.epoch.hAtYear(2000);               // 400000
cf.identity.counterfactual;           // true

The surface groups: time (exact JD ↔ model-year conversion on the SI axis the fits were anchored on — callers holding a JD convert here, never with their own formula), identity (version + hashes + citation DOI), epoch (H, LOD, α, ΔT, deep-time quantities at any year ±500 Myr), earth (obliquity, eccentricity, inclination, perihelion), lengths (year and day lengths), cardinal (solstice/equinox JD, RA, year length), moon (distance and months at epoch, plus the apparent-position chain on the JD(UT) axis — ecliptic longitude, latitude and distance from the shared Meeus series over framework-native arguments), eclipse (geocentric solar/lunar eclipse search over a JD window, greatest-eclipse convention), climate (the L1 orbital-forcing formula) and planets (the Fibonacci-law records and orientation at epoch). Validation targets are refused as inputs — a counterfactual cannot move the goalposts it is judged by.

Underneath: a parts library

createModel() is assembly over unassembled factories. Each factory receives everything through one deps object — plain numbers plus functions — and no module imports another; that is what makes counterfactuals first-class and lets the same core run in Node and the browser. For custom wiring (different α channel, subset assembly), use the factories directly: the reference adapter is tools/lib/ in the public repository — the hosted simulator and the project's verification gates run on it. A service surface over createModel() lives in the same repository (packages/api, an OpenAPI 3.1 handler with zero runtime dependencies) — build-only until the hosting decision.

Provenance

Every value derives from the model parameters and fitted coefficients in this package; the fitting pipeline, verification gates, dataset manifest and documentation live in the public repository. Preprint: https://doi.org/10.21203/rs.3.rs-8758810/v4.

Licence

AGPL-3.0-or-later. Commercial licensing: [email protected].