Galaxy Curve Plotter

Failed — published equation, γ = 2 at ρ_crit = 0.029·V_flat²Reparametrization — the stand-in that matched MOND

Tool type: Model Explainer (the Interactive Tools index grouping — shows how the equation works, not a verdict) · Claim status: the two badges above. The label says what kind of tool this is; the badges say how its claims stand.

What this tool is for: seeing the dark-matter problem itself — pick a real galaxy and watch the gray line (what visible matter predicts) sag below the dots (what telescopes measure). That gap is the puzzle. As of 2026-07-08 this page also renders the framework's actual failure instead of narrating it: the solid violet curve is the real C(ρ) evaluated on a disk density profile — it hugs the baryon line and never fills the gap, because C never gets anywhere near its knee. The dotted amber curve is the hand-tuned stand-in this page used to show (recolored from violet 2026-07-23 so the theory and the illustration can't be confused). The green curve is now MOND's real simple-ν interpolating function on a toy mass model whose only inputs (Vflat, disk scale length) are observed quantities — nothing is fitted to the dots. Why a second (amber) curve? The dotted one is what a curve would need to look like to fit the data — drawn by hand, not computed. The solid one is what the equation actually produces. Showing both is the point: the gap between them is the failure.
Read “real” on this page as “as published” — the violet curve is the framework's equation at a calibration this site refutes three separate ways (named here 2026-09-10, after three of four visitor personas flagged this one page). The curve is honestly computed — nothing is fitted to the dots — but every parameter in it is one the site elsewhere marks as failed:
• γ = 2 — the pin refuted on the RAR at ΔBIC = +184 (Honest Assessment).
• ρcrit = 0.029·Vflat+2— an a₀-tracking knee would need ρcrit ∝ V−2, and the knee measured on SPARC has no velocity dependence at all (V−0.16 ± 0.19, median 0.161 M☉/pc³), so V+2 is a wrong exponent, excluded at ~11σ (Parameter Derivations). The “240–300,000×” magnitude this line used to quote was withdrawn 2026-08-28: it applied the V² law to a coefficient derived for V0.5.
• Per-system normalization — keying the knee to Vflat makes it a function of the very observable being predicted; the site names that move disqualifying, and MOND by contrast uses one global a₀ for all galaxies.
Which wiring (added 2026-09-24): the violet curve adds the coherence term in quadrature, v² = vb² + (Vflat·C)². That display wiring takes the observed Vflat as an input, and with C ≈ 0.001 it does nothing. It is also circular by construction: if C ever approached 1, the “prediction” would simply hand back the observed Vflat (extended 2026-09-25 after a graduate-physics visitor flagged it). The ledger's tests use the division wiring, g = gbar/C, which at the same C fails the other way: about 10³× too much gravity, roughly 30× in velocity, far off the top of this plot. So the tool shows one failure mode (inertness), and the tested law has the opposite one (over-boost).
So the tool is best read not as “the theory's prediction” but as a working demonstration that the equation is inert at its published calibration — which is exactly what the DDO 154 annotation on this page says in one line (max C on this disk: 0.001 — the equation never switches on here: this galaxy is too spread out; this read “inert by construction” until 2026-09-25). At Vflat = 47 km/s that calibration puts the knee at 64 M☉/pc³ against disc densities of order 10−2: no galaxy in the dropdown can lift off the Newtonian baseline, for any of them.
One more cross-link the plot owes you: the green MOND reference uses the simple-ν function — the RAR-preferred choice, and also precisely the function TEST-25 reports Cassini excluding at +17.95σ. The benchmark drawn here is a function this site refutes in the Solar System; that is a real tension in the comparison and not a drafting slip.

The dark matter puzzle in one picture: Physics predicts that galaxies should rotate more slowly at their outer edges (like planets in the solar system — the further out, the slower). They don't. The outer stars rotate just as fast as the inner ones. Something invisible is adding gravity. Most physicists call it dark matter — a proposed invisible substance that has never been directly detected; we infer it only from its gravitational pull (whether it's real stuff or a placeholder for missing physics is exactly what's being debated). MOND (Modified Newtonian Dynamics) explains the same curves by changing the gravity law. Synchronism proposed a third interpretation: the coherence function C(ρ) would mimic the extra gravity via density-dependent coupling. Only the first two fit the observations: dark-matter halos and MOND both reproduce these curves (MOND with one global constant, a₀, for every galaxy). The framework's own equation, as published, does not — the violet curve below stays on the visible-matter line. What matched MOND was either the hand-drawn amber stand-in or, in the archive's SPARC work, a fit that re-tunes ρcrit for each galaxy (one extra free parameter per galaxy). The violet curve is not a fit of any kind: nothing in it is adjusted to the dots. (Corrected 2026-09-15: this paragraph said “all three fit the observations” and described the violet curve as refitting ρcrit; the chart beside it shows neither.)

Select a SPARC galaxy. The plot shows five things: what visible matter predicts (dashed gray), what we observe (dots), what Synchronism's equation as published gives (violet solid — it fails, at a calibration refuted three ways; see the red box above), the hand-tuned stand-in formerly shown (amber dotted — illustration only), and what MOND gives (green). Notice that the stand-in and MOND nearly overlap — the framework's own Honest Assessment labels this a reparametrization — plain words: the same curve wearing a different costume; fitting a known curve isn't discovering anything new. Plain verdict for casual readers: MOND and dark-matter (NFW) halos (not plotted here) both fit these curves; the framework's own equation, as published, does not (solid violet); only the hand-tuned stand-in (dotted amber) does, and it was drawn to. (Corrected 2026-09-15: this verdict used to say all three models fit about equally well, which the chart beside it contradicts.) Fitting alone would not settle much anyway — what matters is whether a model makes a different, testable prediction, and the ensemble test (SPARC RAR, ΔBIC=+184 — a fit in acceleration, MOND's own variable, not in the density this plotter uses; see Honest Assessment for which test kills which version) shows Synchronism collapses to MOND when γ is freed — curve-equivalence at fitted γ only, not theory-equivalence. (Corrected 2026-08-09: this read “the framework has no action, no Lagrangian, and no dynamics.” It has all three, postulated in Appendix D of the archive since 2025-12-01 — but the version stated there is eliminated a priori, and writing down the surviving one changes none of the refutations. See Honest Assessment.) The curve on this plotter is built from a quadrature stand-in, not from any field equation — see the formula box below. See what the tests actually say →

Parsimony note: MOND fits all 175 SPARC galaxies with a single global constant (a₀). Synchronism refits one free ρcrit per galaxy — an extra free parameter for each galaxy. By parsimony (BIC), the Synchronism per-galaxy fit is strictly dominated, not equivalent. Additionally, the scale A in ρcrit = A·Vflat² is itself Audited-Negative (chain-of-custody failure: stated derivation gives A ≈ 4.6×10⁻⁵, 600× off the claimed 0.029 — the number outlived its computation). Is the formula-consistent A ≈ 4.6×10⁻⁵ an untested branch? No, not on SPARC (answered 2026-09-23 for a researcher persona who asked). The explorer's head-to-head fit left A and γ free in ρcrit = A·Vflat² (division wiring gobs = gbar/C, no floor) on 2,438 points in 122 galaxies, and still lost to the acceleration-keyed compander by ΔBIC +3309 (+2843 with one global ρcrit). Any fixed A, including 4.6×10⁻⁵ at γ = 2, is a point inside that search, so its likelihood can only be worse. The two fixed parameters save about 16 BIC units, which does not change the verdict. What the fit did not cover is the field-equation wiring with a floor; that is the separate knee-grid result on Honest Assessment. Source: explorer/findings/the-argument-of-C-three-functions-each-killed-by-its-own-distinguishing-feature.md, Result 3. Vflat is taken from existing SPARC/MOND fits, not independently predicted. See parameter derivations for full accounting.

γ note: the violet curve pins γ=2, which via γ=2/√Ncorr implies Ncorr=1 — stars treated as uncorrelated. No galaxy satisfies that; the data-preferred fit (γ≈0.49, ΔBIC=+7 vs +184 for γ=2) implies Ncorr≈17, still not a physical correlated-star count. See Galaxy Rotation for the full both-directions contradiction.
Related environment result (corrected 2026-07-24): This card previously reported “TEST-03: R² = 0.14 triggered as Failed against the 20% kill threshold.” That statistic was never a valid TEST-03 measurement — archive tracing (2026-07-09) shows 0.14 is a Hubble-type/morphology term at SPARC scale (N ≈ 171), not an environment-density result, and 0.14 does not even exceed the 0.20 threshold it was said to fire. The registered environment test has since been run as registered (2026-07-14: SPARC RAR offsets vs Cosmicflows-4 ambient densities): r² = 0.0001 against the framework's >20% claim — the environment prediction is refuted by execution, not by the old conflated statistic. See Tier 1: TEST-03/TEST-05 for the full trace →
Why the stand-in misled (kept for the record): (Precision 2026-09-15: the drawn stand-in, now dotted amber, contains no γ and no ρcrit — see the formula box. The argument below is about the per-galaxy SPARC fits that stand-in was imitating.) Those per-galaxy fits use the same parametrization (γ=2) that the RAR ensemble test rejected at ΔBIC=+184. They still overlap MOND per-galaxy because ρcrit = A·Vflat² is refit to each galaxy's own flat velocity — that degree of freedom absorbs the shape mismatch one galaxy at a time. The ensemble RAR (all 2,807 SPARC data points — 175 galaxies — plotted together in acceleration space) is where γ=2 dies: free-γ converges to γ≈0.49 with RMS identical to McGaugh-MOND to four digits. Per-galaxy shape recovery is not the same test as ensemble shape rejection. Cross-system failure (locality no-go): a single global ρcrit(Vflat) — no per-galaxy refit — exposes a ~1.7 dex offset between the local volumetric density ρ(r) and the observed gbar that MOND tracks. That cross-system gap is the reason local-density frameworks fail where MOND succeeds; the per-galaxy overlap you see here hides it by refitting ρcrit independently for each galaxy.
Reading this plot: In plain terms: the gray line sagging below the dots is the dark matter puzzle. The solid violet line — the framework's real equation — fails to fix it. The dotted amber line that used to be shown here was drawn to fit, not computed from the theory.
  • Dashed gray — Newtonian prediction using visible matter only (toy exponential disk). Drops off at the edges; this is the puzzle.
  • Dots — observed rotation velocities. Flat at large radius; doesn't drop like Newtonian says it should.
  • Violet solid — Synchronism's real C(ρ) at γ=2 with the framework's asserted ρcrit = 0.029·V². The disk's density is thousands of times below ρcrit, so C stays near zero and the curve sits on the baryon line. This is the 2026-07-02 audit result, rendered. Caveat (2026-08-05, revised same day): that “thousands of times below” is conditional on A = 0.029, since ρ/ρcrit ∝ 1/A — at A = 4.6×10−5 the ratio for NGC 3198 is 0.60 and the curve would lift off the baryon line. But the 635× between them is a law swap, not a scale choice: universal A with ρcrit ∝ V² versus per-galaxy A ∝ Rhalf−2 with ρcrit ∝ V0.5 — the two-law fork parameter derivations item 1 has documented since 2026-06-07. An earlier version of this caveat attributed the gap to an unstated coarse-graining length ℓ; that is withdrawn — a self-consistent ℓ smooths ρ and ρcrit alike and cancels, leaving ρ/ρcrit ≲ 0.019βJ² in every sector at every ℓ. This plot shows the framework under its own stated law.
  • Amber dotted — shown only to illustrate what a working boost would look like; not a prediction of any theory. It is the hand-tuned tanh(radius) stand-in previously displayed, and it fits because it was drawn to fit; no ρ, ρcrit, or γ enters it. (Recolored from violet 2026-07-23: it is an illustration, not the theory.)
  • Green dashed — MOND's real simple-ν function on a BTFR-assigned mass (one global a₀, zero per-galaxy knobs). It lands close to the dots — expect ~10% mismatches from the toy mass model, not from tuning.
Which MOND, and why it matters: the green curve here uses the simple-ν function (ν = ½ + √(¼ + 1/y)). The Galaxy Rotation page's RAR/ΔBIC test uses McGaugh's RAR function ν = 1/(1−e−√y). Both are called “MOND” on this site, and they are different functions. Neither survives the Solar System as a QUMOND interpolating function. Cassini bounds the quadrupole the Galactic field induces around the Sun, and that quadrupole is set near 7,000 AU, where the Sun's own field is about a₀. There the two functions are close. Run through TEST-25's own instrument, McGaugh's function fails Cassini by +15.9σ to +20.9σ and the simple function by +15.3σ to +20.1σ. The framework's compander at the SPARC fit fails by +17.95σ on the same instrument. Desmond, Hees & Famaey (2024) report 8.7σ after marginalizing.
Revision noteThis note used to call McGaugh's exponential-return function “Cassini-safe” and say only the simple function fails. That reasoning used the high-acceleration tail at Saturn, but Cassini constrains the quadrupole set in the transition region. A visitor persona (graduate physics) caught it. The numbers above come from a pre-registered run: maintainer/scripts/cassini_q2_mond_interpolating_functions.py.
The actual formulas plotted (disclosure, updated 2026-07-08): for a page badged Reparametrization, the formulas are the argument — so here they are, exactly as coded:
Toy mass model: M_b = 47·V_flat⁴ M☉ (empirical BTFR, McGaugh 2011), exponential disk with each galaxy's observed scale length R_d, h = 0.3 kpc
Gray “Newtonian”: v_b(r) = √(G·M(<r)/r), M(<r) = M_disk·[1 − e^(−r/R_d)(1+r/R_d)]
Violet SOLID “C(ρ), quadrature wiring (a display branch, not the ledger's gbar/C law)”: v(r) = √(v_b² + [V_flat·C(ρ(r))]²), C(ρ) = tanh(2·ln(ρ/ρcrit+1)), ρ(r) = Σ(r)/2h, ρcrit = 0.029·V_flat²
Amber DOTTED (old illustrative stand-in — what this page showed before 2026-07-08, kept for comparison): v(r) = √(v_toy² + [V_flat·tanh(0.4·r/2.5)]²), v_toy = 0.6·V_flat·√(1−e^(−r/2.5))
Green “MOND”: v(r) = v_b·√ν(y), ν(y) = ½ + √(¼ + 1/y), y = g_N/a₀, g_N = v_b²/r (real simple-ν)
This figure and the ledger run different force laws — the fork, stated (2026-08-08). The violet curve above couples C in quadrature: v² = v_b² + [V_flat·C]², so C → 0 means no boost. But Tier 1 derives the boost ceiling behind TEST-09/TEST-10 from fDM = 1−C, i.e. from reading the coupling as gobs = gbar/C, where C → 0 means an infinite boost. Same symbol, opposite orientation. The legend's “max C on this disk: 0.001 — boost never turns on” would read “fDM = 0.999, a 1000× acceleration boost” under the ledger's law. Every σ on Honest Assessment is conditional on this choice, and the site has not made it — the fork is what currently blocks registering EFE = 0 as a numbered test.

For rotation curves specifically, though, the fork does not block the verdict — it doubles it. Take a gas-rich dwarf like DDO 154, which needs a boost of B ≈ 10 in acceleration to explain its outer curve (SPARC's most DM-dominated systems reach fDM = 0.927, i.e. B ≥ 13.7 — see TEST-10). At max C = 0.001 the quadrature branch delivers B ≈ 1 — a factor ~10 under. The division branch delivers B = 1/C ≈ 1000 — a factor ~100 over. Both branches are refuted by the same galaxy, from opposite sides. Registering a canonical coupling is still required for the EFE and cluster sectors; it is not required to conclude that the galaxy sector fails. (Raised independently by two expert visitor passes, 2026-08-08.)
The solid violet curve and the dotted one differ in exactly one ingredient: the coherence factor. The stand-in used tanh(radius) with hand-tuned constants; the real curve uses C(ρ) on the disk's density profile. With the framework's asserted ρcrit = 0.029·V², the disk midplane density sits orders of magnitude below ρcrit everywhere (the legend shows this galaxy's maximum C), so the boost never turns on and the real curve stays on the baryon line — the knee is never crossed, exactly as the 2026-07-02 audit found by computation (its more charitable density estimates reach at most C ≈ 0.28; no estimate reaches the knee). What you see is the difference between a mechanism and a costume. The 2026-07-02 audit also showed the ρcrit = A·V² scaling itself is sign-inverted: MOND-matching forces the knee density to fall as V−2 (BTFR envelope), while the framework makes it rise as V+2 — see Parameter Derivations. The stand-in is forced, not incidental: C(ρ) is a function of local density, while the rotation curve it needs to reproduce is organized by gbar, a non-localenclosed-mass acceleration — see the local-vs-non-local structural no-go for why a pointwise density map cannot in general reproduce an acceleration-space relation without per-galaxy calibration. And the “local” side of that contrast is not local either (added 2026-09-07): ρcrit = 0.029·Vflat² keys the threshold to the asymptotic rotation speed — an r → ∞ quantity fixed by the galaxy's total baryonic mass — so what this curve evaluates is C(ρ(r), Mtotal), not C(ρ(r)). That is an MRH violation by the framework's own definition and it needs no data at all; see MRH → Does the framework respect its own horizon?

Approximation note (added 2026-07-17, flagged by an expert reader): the gray Newtonian curve uses spherical enclosed mass for what is physically a thin exponential disk. The exact thin-disk result (Freeman 1970: v² = 4πGΣ₀Rd·y²[I₀K₀ − I₁K₁], modified Bessel functions) runs ~15–20% higher near the peak (r ≈ 2Rd), so the plotted Newtonian baseline understates the baryonic prediction there and the visual “dark matter gap” — this page's pedagogical centerpiece — is modestly exaggerated near the peak. The gap itself is real and much larger than this correction at large radius (where the discrepancy actually lives), so no conclusion flips; a Bessel-function implementation is queued for a future pass rather than rushed here.

What to notice in the chart below: the solid violet line is the framework's density law with ρcrit = 0.029·Vflat². It barely moves off the dashed gray Newtonian line. The green MOND line does follow the dots. That gap between violet and green is the failure this tool shows.
Two assumptions behind that picture:
  • “The equation never switches on here” is a property of the calibration A = 0.029, not of the equation's form. Parameter Derivations records that A = 0.029 does not follow from its own stated formula, which gives A ≈ 4.6×10−5. At that value the knee sits inside dwarf-disc densities: a visitor's estimate puts C ≈ 0.5 near the DDO 154 midplane (an estimate, not a computation this page performs). The chart draws only A = 0.029.
  • The violet law, v² = vb² + [Vflat·C]², takes the observed Vflat as an input, so even a match would not count as evidence. It is also a different law from the g = gN/C used in the site's refutations (see the wiring note inside the chart card). The failure verdicts rest on those refutations, not on this picture.
DDO 154Dwarf irregular
Vflat = 47 km/s (observed input) — taken from SPARC for this galaxy and fed into the curves, not predicted by them. It enters the violet curve twice: through ρcrit = 0.029·Vflat² (here 64 M☉/pc³) and through the Vflat·C boost term. A curve built from Vflat cannot be a prediction of Vflat. Units: the code compares ρcrit with a disk density in M☉/pc³ with Vflat in km/s, so the 0.029 carries units of M☉ pc−3 (km/s)−2; the archive ledger states units only for the V0.5 law that coefficient was originally derived under, not for the V² law drawn here. The green MOND curve uses Vflat too (BTFR mass 47·Vflat4), so its flat outer level is also largely set by construction: deep-MOND V4 = G·Mb·a₀ returns 0.93·Vflat for every galaxy here. Why 0.93 and not 1: the BTFR normalization A = 47 M☉ km−4 s4 is empirical, and in the flat deep-MOND limit it corresponds to a₀ ≈ 1.6×10−10 m/s², while the curve uses a₀ = 1.2×10−10 (where 1/(G·a₀) ≈ 63 M☉ km−4 s4; (47/63)1/4 ≈ 0.93). Because the mass is set from Vflat, MOND's agreement at large radius is partly circular too; the non-circular version would use SPARC's per-galaxy mass models (public) instead of a BTFR mass. What the green curve adds is the shape on the way up, with no per-galaxy knob. See Honest Assessment.

Which wiring this chart draws (2026-09-15): the violet curve couples C in quadrature, v² = vb² + [Vflat·C]², so C → 0 means no boost. The ledger's kills (TEST-09/TEST-10) use the division wiring gobs = gbar/C — but with a different C (see the box below), not this one clipped at a floor. Applying a floor to this chart's C would give a boost of 1/C ≈ 1275× unfloored, or a flat 3.17× floored. For DDO 154 (needs ≈ 10×) that is quadrature ≈ 1× (under), floored division ≈ 3× (under), unfloored division ≈ 1000× (over) — every wiring fails; the fork box above has the detail. Radius is in kpc (kiloparsecs): 1 kpc = 1,000 parsecs ≈ 3,260 light-years.

“max C = 0.001” and “the floor at Ωm” are two different C's. Measured and corrected 2026-09-18. A leading-edge visitor persona put the two numbers side by side on 2026-09-18 and concluded that the floor (0.315) must bind everywhere, since the computed C never exceeds 0.001 — so that the galaxy sector applies the constant 3.17, the tanh does no work, and TEST-09/TEST-10 are algebra rather than data. The persona flagged the inference as unverified and asked for a source check before publishing. It was run, on 123 real SPARC discs rather than this page's five-galaxy toy, and the inference does not hold — because the two numbers describe different functions.

• Cρ = tanh(γ·ln(1+ρ/ρcrit)), keyed on density — what this chart draws, and what “max C = 0.001” reports. It carries no floor. The 0.001 figure does generalise off the toy: over 123 SPARC discs the per-disc maximum has median 1.2×10−3 at γ = 2 (1.6×10−4to 4.9×10−2), and 0 of 123 reach Ωm anywhere.
• Ca = Ωm + (1−Ωm)·x/(1+x), x = (gbar/a₀)1/φ, keyed on acceleration — what the TEST-09 and TEST-10 scripts evaluate. Its floor is part of the functional form, not a clip. On the same 123 discs it runs 0.329 to 0.954 (median 0.515, IQR 0.235), and 0.00% of the 2,856 radii sit within 1% of the floor. The applied boost spans 1.05×–3.04×, and never reaches the 3.17 ceiling.

So the two corollaries the persona drew are refuted on the framework's own data: the predicted fDM is not a delta function at 0.685 (median 0.585, s.d. 0.062, and no galaxy within 0.01 of the cap), and TEST-09's slope is not ceiling-independent — it moves 0.62 across Bmax ∈ [2, 100]. What the sweep did find, and it is adverse: TEST-09's kill is convention-dependent, firing only under the site's own undefended ceiling. Pre-registered at site commit 89e0467; script maintainer/scripts/which_C_carries_the_floor.py (+ _output.txt), identity control reproduces TEST-09's published n = 3.35 ± 0.07 exactly.

The misreading is this page's defect, not the reader's. Both functions were written “C” and the sentence above this box put one function's output range next to the other function's floor. There are now three live objects behind the one symbol — Cρ, Ca, and the quadrature-vs-division wiring fork — and only the third was labelled.
015314661Radius (kpc; 1 kpc ≈ 3,260 light-years)V (km/s)ObservedSynchronism, quadrature branch: v² = vb² + (Vflat·C(ρ))², γ=2 (max C on this disk: 0.001 — the equation never switches on here: this galaxy is too spread out)NOT the theory — illustration stand-in: hand-drawn to show what a working boost would look likeMOND (real simple-ν, BTFR mass, no per-galaxy tuning)Newtonian (baryons only, toy disk)

What You're Seeing

The dashed line is what rotation curves should look like with only visible matter (stars + gas). The blue dots are what we actually observe. The gap is the “dark matter problem.”

The solid violet curve is Synchronism's real C(ρ) evaluated on the disk's density profile — and it fails to fill the gap: the disk never gets dense enough for the coherence boost to turn on (this galaxy's maximum C is 0.001; the knee needs C to approach 1). The dotted amber curve is the hand-tuned tanh(radius) stand-in this page displayed before 2026-07-08 — it fit because it was drawn to fit. Full disclosure of both formulas below the plot.

The green dashed curve is MOND (Modified Newtonian Dynamics) using its real simple-ν interpolating function and the acceleration scale a₀ ≈ 1.2×10⁻¹⁰ m/s², on a mass fixed by the baryonic Tully–Fisher relation — no per-galaxy tuning at all. The stand-in the framework needed to look like MOND is what the site labels a reparametrization; the real equation doesn't even manage the costume.

Note: Curves shown are simplified models for illustration. Actual SPARC fits use full surface brightness profiles and mass-to-light ratios. See the research data for precise fits.

Related Concepts

Galaxy Rotation CurvesSPARC (175) + ALFALFA-SDSS (14,435 galaxies after the quality cut)MOND Unificationa₀ = cH₀/(2π) is emergent, not fundamental