the420code · galaxy-rotation · mond-nbody

Our SPARC/MOND rendering, held against the public record

What our engines actually measure — live, this run — beside the physicists' own published benchmarks and the datasets we can legally re-render. Every number below is computed from vendored data, not asserted. Where a claim is consistency rather than proof, it says so.

a₀ = C_S²·cH₀/2π ≈ 1.192×10⁻¹⁰ m/s² SPARC 175 galaxies (Lelli+ 2016) run green · 2026-07-22

Comparison 1 — The Radial Acceleration Relationg_obs vs g_bar

◆ Ours — galaxy-rotation/demo.py

RAR scatter over the full SPARC surveymeasured live · fixed unfitted M/L · G's parameter-free a₀

Primary scatter (e_V/V < 10% cut)0.144 dex
Raw scatter (no cuts, 3389 pts)0.199 dex
Robust σ (16–84 span, cut)0.122 dex
a₀ vs canonical MOND a₀0.7 %
Galaxies · gate175 · PASS
Honesty: consistency, not proof. G's a₀ — derived with no galaxy data — is the same acceleration floor MOND already fits. 33/175 noisy dwarfs flagged, not cherry-picked out.
Published benchmark

McGaugh, Lelli & Schombert 2016PRL 117, 201101 · arXiv:1609.05917

Published RAR scatter (after cuts)0.11–0.13 dex
Points · galaxies (their cuts)2693 · 153
Canonical a₀ (fitted to galaxies)1.20×10⁻¹⁰
The famous g_obs–g_bar figure© APS
License: the canonical figure is cite-and-link only (pre-2021 APS copyright, not CC-BY). We land inside their band once measured their way — but render our own plot beside theirs; don't republish the original.

Comparison 2 — QUMOND rotation curve & disk renderv(r), self-gravity

◆ Ours — mond-nbody/qumond.py

From-scratch QUMOND particle-mesh, one idealized disk2M particles · isolated BCs · measured v(r)

Flat speed (measured from field)119.9 km/s
QUMOND curve flatness (RMS)3.5 %
Newton same disk (declines)−0.64 slope
BTFR normalization ratio1.30
Disk survives settle98% in 8R_d
Honesty: a solver-correctness demo, not astronomy. One idealized disk, fixed baryons, ν-family choice stated. NOT a fit to any real galaxy.
Published benchmark · same method

Phantom of Ramses (PoR / QUMOND)Nagesh+ 2021 · arXiv:2101.11011 · CJP

MethodQUMOND-on-grid
Code lineageRAMSES patch
Scopehydro + adaptive
Disk / interacting rendersmany, high-res
LicenseCC-BY 4.0 ✓
License: genuinely reusable with attribution — and it's the same QUMOND method as ours, so it's the truest apples-to-apples visual companion. Their renders are the rigorous "one click away."

The honesty HUD — what's real, what's artSkyLab law

Exact

The MOND gravity integration and the rotation curve measured from live particle motion. This is the load-bearing physics. Newton (a₀→0) never flattens — the falsification is shown as a strength.

Approximate

Algebraic-MOND-on-a-disk is not the full QUMOND field — the sandbox says so in its own copy and links the rigorous offline solve. ν-function family is a stated modelling choice.

Illustrative

Any nebula / gas glow in a zoom view is art, not physics — nebulae carry radiative & hydro physics we don't simulate. The stars stay real; the HUD must draw that line.

Reusable comparison sources — ranked by license clarityscout result

TierSourceWhat it gives usLicense
1 Unified HI Rotation Curve Corpus v7.0zenodo 10.5281/zenodo.19563417 438 galaxies — SPARC + THINGS + LITTLE THINGS + WALLABY DR2 in one CSV/JSON schema, built for renderers. SPARC slice matches ours exactly (175 / 3391). CC-BY 4.0 ✓
1 Phantom of Ramses user guidearXiv:2101.11011 · CJP 2021 QUMOND disk & interacting-galaxy renders — same method as our sim. The rigorous visual companion. CC-BY 4.0 ✓
1 Banik & Zhao 2022Symmetry 14, 1331 (MDPI) N-body disk/bar snapshots, rotation curves, RAR — review with reusable figures. CC-BY 4.0 ✓
2 SPARC RAR & BTFR tablesVizieR J/ApJ/836/152 · J/AJ/152/157 Renders an RAR panel directly + a Baryonic Tully-Fisher panel we don't currently have. VizieR · cite ✓
2 LITTLE THINGS · THINGSVizieR J/AJ/149/180 · J/AJ/136/2648 Dwarf & nearby-galaxy curves (also embedded in the Tier-1 Zenodo corpus). VizieR · cite ✓
3 McGaugh/Lelli 2016 RAR figurePRL 117, 201101 · arXiv:1609.05917 THE canonical scatter plot — but a figure, not a free asset. Link it; render our own beside it. cite / link only
3 Wittenburg 2020 — exponential disks in MONDApJ 890, 173 · arXiv:2002.01941 Closest subject match to our idealized disk — but ApJ-closed, arXiv license ≠ reuse grant. cite / link only

Two honest flags before anyone builds on thiswith salt

"On arXiv" ≠ reusable. The physicists' own famous figures (McGaugh/Lelli, the SPARC site) are the hardest to reuse — arXiv's license is a distribution grant to arXiv, not a reuse grant to us, and these papers predate the 2021 CC-BY switch. The genuinely free material is the CC-BY Zenodo corpus (data) and the CC-BY PoR / Banik-Zhao figures (renders).
No clean modern declining-MW curve exists as a table. Ou/Eilers/Rix 2024 and Jiao/Hammer 2023 (the ~230→170 km/s decline) publish no machine-readable v(R) — "on request" / journal-supplement only. Our Eilers 2019 curve stays the cleanest tabulated Milky Way option we hold. And a stray correction from the scout: the PoR code paper is arXiv:1405.5963, not …5769.
Sources — galaxy-rotation & mond-nbody proofs (the420code, CI-green) · SPARC: Lelli, McGaugh & Schombert 2016, AJ 152, 157 · RAR: McGaugh, Lelli & Schombert 2016, PRL 117, 201101 · PoR: Nagesh et al. 2021, CJP 99, 607 · Zenodo Unified HI Corpus DOI 10.5281/zenodo.19563417 · Banik & Zhao 2022, Symmetry 14, 1331.
Consistency, not proof. Claim only what runs. State the boundary. — with love, and with salt 🐐