For 50 years, dark matter explained why galaxies spin too fast. MOND explained the same thing with no new particles at all. Gaia just measured a billion stars in our own galaxy. Alessandro Melchiorri & Ruchika say both of them may have predicted the wrong curve.

2/ Kepler's rule: the farther out you orbit, the slower you go. Speed falls as 1 over the square root of radius. Galaxies refused. Their outer curves stayed flat. That refusal is the clearest single reason dark matter became central to astrophysics.

3/ A flat curve means the enclosed mass keeps growing with radius. The light fades. The gravity does not. So we wrapped the disc in a halo that contributes almost no light and plenty of mass. It worked. For decades.

4/ Then Gaia DR3. Jiao et al. fit a power law to the Milky Way beyond 19 kpc. Index: 0.47 ± 0.15. Keplerian is 0.5. A flat curve is excluded at 3 sigma.

5/ Now the awkward part for the other camp. MOND's deep-regime prediction: v⁴ = G·M_baryonic·a₀ Look at what's missing. There is no radius in it. That's why MOND gives a flat curve for an isolated galaxy. It was the theory's best feature. It may now be the problem.

6/ Both frameworks reach flat outer curves through completely different physics. Dark matter adds gravitating mass. MOND changes the dynamics themselves. A real Keplerian decline strains both. The question is not which camp lost. It's why both were expecting the wrong curve.

7/ Before anyone celebrates: we are inside the galaxy we are trying to measure. The disc is warped. Sagittarius has crossed it. The LMC is massive and nearby. FIRE-2 simulations show Jeans-pipeline biases of 10 to 40 km/s at 20-25 kpc. That is the size of the entire decline.

8/ Three scenarios survive: 1. Real decline, lighter halo 2. Real but exaggerated by systematics 3. Artefact of an outer disc too disturbed to model One pattern. Three stories. The evidence does not pick between them.

9/ The sharpest problem is not in the error budget. Run the same slope-fitting pipeline across all 175 SPARC galaxies: no Keplerian taper anywhere. Run it on the Milky Way: unmistakable. Either our galaxy is exceptional, or we measure it in a way that doesn't transfer.

10/ Full breakdown, Kepler to Vera Rubin to Gaia DR3, and why flaws lead to new laws: Paper: Melchiorri & Ruchika, arXiv:2608.10189 SPARC test: Bariego-Quintana & Llanes-Estrada

@alemelk Peratt. Alfven.

@alemelk Dark matter was always complete BS to me

@alemelk It’s not that acceleration changes, it’s that mass of particles changes.

Thanks, Brian, for this post! Very timely, since an updated version of our review is out on arXiv today. Here’s a plot with the current data: it doesn’t look flat…

If you had to bet an espresso, what is causing this? Does 21cm data help?

@alemelk No, “dark matter” is a placeholder for something scientists haven’t a damn clue of.

@alemelk I suspect dark matter would be easier to tweak.

@alemelk Please have a chat with @memcculloch; then DM me and I’ll send you a paper on quantum substrate gravity (QSG). Mike’s amazing work and this paper explain it… Mike just doesn’t know it yet :). He’s busy making insanely good videos.

Brian, in the Morphic Block Universe, both Dark Matter and MOND are trying to fix a broken map by either adding invisible ink or redrawing the lines. They miss the actual mechanism: affordability economics. Galaxies do not spin too fast because there is missing mass. They appear to spin that way because we are measuring velocity using continuum assumptions in a discrete lattice. What we call Dark Matter is actually regions of high transmissivity corridor density T_ij that have low visible lock fraction. These are basins where coherence persists with minimal routing tax P_ent, creating gravitational influence without emitting light. It is not a particle; it is unpaid geometry. MOND fails because it tries to tweak the force law without accounting for the sparsity cap P_max. Gaia’s data showing both models miss the curve confirms that the problem is not the amount of mass or the shape of gravity, but the underlying sorting dynamics. The galaxy is not a smooth fluid; it is a collection of earned locks. When you average them out, you get artifacts that look like missing mass or modified gravity. The correct curve emerges when you model the galaxy as a discrete sorting event where each star’s position is determined by its ability to afford persistence in the local T_ij landscape. The halo is not dark matter; it is the proto-coherence reservoir that has not yet been sorted into visible stars but still exerts economic pressure on the system. Rest in Lattice. Stop looking for ghosts. Start balancing the ledger.

@alemelk Пространство квантовано!

@alemelk Or, we live in a highly accelerated world, and we experience time slower that that galaxy. In the twin experiment, we are the twin moving away, and watching the galaxy move seemingly faster than it should, because time is slowed down for us.

@alemelk How can MOND predict the wrong curve if it is basically a curve fit over the measured curves🤔

@alemelk @grok can you simplify and separate the new data from interpretations. what is MOND and what data lead to the index change, why is keplerian 0.5

@alemelk Wait, I thought you retired from cosmology hype after that BICEP2 dust burger?

@alemelk Janus model can do it too,with ordinary, on the" other side" aka negative matter.

@alemelk Somebody here either didn't take seriously what a pretty big group of scientist already discovered a long time ago or he doesn't know yet?

@alemelk It turns out BTDG also claims that Dark Matter isn’t necessary after all. 🌌⚛️ #Science #Physics #Cosmology #BTDG

@alemelk So many observations, experiments and models converging on the long overdue Copernican shift of paradigm/ontology. Soon, the mechanism of gravity will be understood and this conundrum will be as trivial as understanding why planets go retrograde.

@alemelk This article describes the Milky Way galaxy as observed by Gia and predicts it's mass within the observed values including the quasi Keplerian rotation curves

@alemelk We could just explain it with electromagnetism. Thoughts?

@alemelk Oops! Left out Dr. Mike McCulloch's Quantised Inertia, a step beyond MOND...

@alemelk Dark matter is 50 years old? I didn’t think we were that stupid. How long did it take to disprove aether?

@alemelk Quantized inertia is the answer. It explains galaxy rotation and many other anomalies. I wish more mainstream guys like you would explore this.

@alemelk > dark matter explained why A question explained why?