A Generalized MOND Paradigm For Weak Gravitational Fields And Experimental Confirmation Of GR In Strong Gravitational Fields

This new (published) paper is a provocative generalization of the MOND paradigm, although still not a true "FundaMOND" in the sense of providing a rigorous, fundamental physical explanation for why the phenomenological MOND paradigm is observed in Nature. 

Notably, MOND addresses gravity in the extremely weak gravitational field regime.

The primary author, Robin Eappen, who is a doctoral student in astrophysics, is not well know. But Pavel Kroupa is one of the leading MOND proponents (and is perhaps a little less mainstream in his scientific positions and his manner of advocating for them, than either Mordehai Milgrom who devised MOND in 1983, his now deceased colleague in astrophysics, Jacob Bekenstein, or Stacey McGaugh, one of MOND's leading proponents in the current generation of astrophysicists).

Mass discrepancies in galaxies are empirically known to appear only below a characteristic acceleration scale a(0). 

Here we show that this behaviour is not limited to galaxies: it extends continuously across the full hierarchy of self-gravitating stellar systems, from gas-rich dwarfs and spirals to massive early-type galaxies, and further down to compact stellar clusters. 

We introduce the Milgromian dynamics (MOND) depth index DM, together with dynamical maturity index T = t(cross)/t(H), dynamical collisionality index T(1) = t(cross)/t(relax), with t(cross) being the crossing time, t(H) the Hubble time and t(relax) the median two-body relaxation time, and the MOND acceleration index A = a(bar)/a(0). 

We uncover a well-defined two-dimensional dividing surface in dynamical space. The "dark matter phenomenon" is found only in systems that are both in the deep-MOND regime (a(bar) < a(0)) and collisionless (t(relax) > t(H)), while high-acceleration, collisional systems (a(bar) > a(0), t(relax) << t(H)), including globular clusters and UCDs, show no evidence for a mass discrepancy. 

This clean dynamical separation defines a new, physically motivated classification scheme for stellar systems, unifying galaxies and clusters under one framework. The observed division emerges naturally within the MOND framework and provides a useful diagnostic for examining how different gravitational paradigms account for the origin of the mass discrepancy.

Robin Eappen, Pavel Kroupa, "The MOND Depth Index and Dynamical Maturity Clock: Toward a Universal Classification of Galaxies and Star Clusters" arXiv:2603.18135 (March 18, 2026) (published in 14(2) Galaxies 22 (2026)).

* * *

In other gravity news, a series of three papers (one, two and three) look at gravitational wave observations of extremely strong gravitational fields created by black holes and/or neutron star binary systems to test General Relativity (GR) in this regime in various ways. 

All of this evidence is consistent with GR and more tightly constrains deviations from GR in this strong field context than prior tests of GR.

Nailing Neutrino-Nucleus Interaction Rates

An experimental test of how frequently neutrinos interact with atomic nuclei has a best fit value of the Standard Model expectation and an uncertainty of less than ± 15%, which is impressive given how slight the interaction is, fit 10^22 trials yielding just 124 observed interactions.

The COHERENT collaboration reports the most precise measurement of the coherent elastic neutrino-nucleus scattering cross section to date. This measurement was performed with COHERENT's germanium detector array, Ge-Mini, at the Spallation Neutron Source at Oak Ridge National Laboratory. 

A cumulative exposure of 4.68 × 10^22 protons on target yielded a total number of observed counts of 124 + 14 −12 and a flux-averaged cross section of 1.00 ± 0.10 (statistical) ± 0.10 (systematic) relative to the standard-model expectation of 5.9 × 10^−39 cm^2. 

The well-understood energy and timing distributions of the neutrino source allow for independent measurements of muon- and electron-neutrino scattering rates. This information is used to improve constraints on non-standard neutrino interactions mediated by heavy particles.

M. Adhikari, et al., "Measurement of coherent elastic neutrino nucleus scattering on germanium by COHERENT" arXiv:2603.17951 (March 18, 2026).

Palau Is An Oceania Outlier

This is a further refinement of an already pretty well worked out story of Oceanian origins. 

The ultimate source of Oceanian and Austronesian seafaring people was one of the indigenous tribes of what is now called Taiwan (we have identified which of them it was based upon linguistic evidence), via island Southeast Asia.  

Before expanding very far east, however, these Formosan origin Lapita people admixed with Papuan people (in an encounter that amounted to a hostile conquest).

This "graphical abstract" really sums up a new paper on the topic. 

Note that the dates in this image are "before present", i.e. before 1950 by archeological convention, and not BCE. The initial settlement of Palau was roughly contemporaneous with the Greek "dark ages" after Bronze Age collapse, for example, while the admixture of the people who settled Palau was contemporaneous with the Late Bronze Age in Europe.

An educated layman's explanation of the paper explains: 

About 3200 years ago, Southeast Asian seafarers known as the Lapita pushed east into the tropical islands of the Pacific Ocean, hitting nearly every habitable isle in that corner of the globe from New Guinea to Fiji and Tonga. As they did so, they left behind artifacts of their culture, including pottery stamped with distinctive geometric patterns.

But on Palau, there’s not a single shard of Lapita pottery—and the island’s inhabitants speak a language that’s distinct from the tongues spoken on other Pacific islands. So who were the first Palauans, and where did they come from?

A new study published last week in Cell suggests an answer. Genetic evidence confirms Palau’s first settlers descended from Southeast Asians who had intermingled with the Papuans, Indigenous peoples who settled the island of New Guinea some 50,000 years ago.

“It’s lovely to see a piece of Pacific history—which we’ve traditionally been at a bit of a loss to explain—finally start to come together into a more understandable story,” says Murray Cox, a computational biologist at Massey University of New Zealand who wasn’t involved in the new work.

The discovery builds on previous ancient DNA research into the origins of the Lapita themselves. That work, led by evolutionary biologist David Reich at Harvard University and his colleagues, showed that Lapita were essentially pure Southeast Asians of Taiwanese roots—but that modern populations on Pacific islands showed Papuan ancestry, too. The studies suggested this Papuan ancestry came in about 2500 years ago, as Papuans began to join the same canoe voyages that had earlier carried Lapita settlers into the region.

From Science.

The underlying paper in Cell is as follows:

Highlights

• Ancient DNA of 21 individuals from Palau spans around 2,400 years

• Papuan-East Asian admixture in Palauans predates initial settlement

• Over 2,900 years of genetic continuity in Palau

• Shared East Asian-Papuan admixture in Palau and eastern Indonesia 

Summary 

The first people reached Remote Oceania 3,000 years before present (BP), arriving roughly simultaneously in the southwest Pacific, the Marianas Archipelago, and Palau. However, no genome-wide ancient DNA data have been available from Palau, a gap we address by reporting 21 individuals from four archaeological sites dating between 2,900 and 500 BP. 

All had approximately 60% ancestry related to East Asians and 40% to Papuans, similar to present-day Palauans, the longest stretch of population continuity anywhere in Remote Oceania. The lengths of contiguous Papuan ancestry segments in the oldest individuals show that major admixture between Papuans and East Asians in the ancestors of all sampled Palauans began prior to first settlement. This differs from the pattern in the southwest Pacific, where sampled individuals of the Lapita archaeological culture from three different islands had almost entirely East Asian ancestry, with large amounts of Papuan admixture observed only hundreds of years later. 

Yue-Chen Liu, et al., "Papuan admixture predated the settlement of Palau" (March 10, 2026).

A System With Three Galaxies Showing No Dark Matter-Like Phenomena

This is also consistent with the MONDian External Field Effect explanation.

While most dwarf galaxies are strongly dark matter dominated, two remarkable objects in the NGC 1052 field, DF2 and DF4, appear to lack dark matter. DF2 and DF4 were recently found to be part of a trail of low luminosity galaxies that follow a linear relation between their position on the trail and their radial velocity. If the other galaxies on this trail formed together with DF2 and DF4, e.g., from gas that was separated from dark matter through a 'bullet dwarf' collision, they may lack dark matter as well. 

Here we constrain the dark matter content of DF9, the galaxy on the trail that most closely resembles DF2 and DF4. Using Keck/KCWI absorption line spectroscopy we find that DF9's stellar velocity dispersion is 6.4 + 4.0 − 4.3 km/s. This is consistent with the 8.3 + 0.9 − 1.4 km/s dispersion that is expected from DF9's 1.4 × 10^8 M⊙ stellar mass alone, and we conclude that -- like DF2 and DF4 -- dark matter is not required to explain the kinematics of DF9. The dispersion is far below the 27 ± 3 km/s expected if DF9 fell on the stellar mass--halo mass relation. Our results are further evidence that the trail of low mass galaxies in the NGC 1052 field formed together in a unique galaxy formation channel, and are consistent with the prediction of the bullet dwarf scenario that other trail galaxies should show the same lack of dark matter as DF2 and DF4.

Michael A. Keim, Pieter van Dokkum, Zili Shen, Shany Danieli, Imad Pasha, "A Third Galaxy Missing Dark Matter along a Trail of Galaxies in the NGC 1052 Field" arXiv:2603.15860 (March 16, 2026) (Submitted to ApJL).

Yet Another Observational Problem With The ΛCDM Model

The ΛCDM model is contradicted by a host of independent observational tests (dozens of them). 

The luminosity-temperature relation for galaxy clusters is independent of any of these previous tests and doesn't share significant sources of systemic error with it. And, the ΛCDM, again, is not a good fit to this data, while one of the more well-studied modified gravity theories, f(R) gravity, does significantly better.

We investigate the luminosity-temperature (L-T) relation of galaxy clusters as a probe for testing modified gravity (MG) theories, focusing on f(R) gravity and symmetron models. Using an improved semi-analytic framework that incorporates angular momentum acquisition, dynamical friction, and shock heating within the modified punctuated equilibrium model, we compare predictions against hydrodynamical simulations and observational data. 

While massive clusters remain largely screened and follow standard ΛCDM predictions, low-mass systems (kT ≲ 1−2 keV) exhibit systematic deviations characterized by steeper L-T slopes in MG scenarios. 

Crucially, we demonstrate that these signatures cannot be mimicked by conventional astrophysical processes such as feedback or angular momentum effects, which primarily affect normalization rather than curvature. Our results establish the L-T relation as a robust diagnostic tool for distinguishing general relativity from screened MG theories, with the strongest discriminatory power emerging at group scales accessible to current and future X-ray surveys. Moreover, a normalized reduced χ2 analysis of the L-T relation shows that MG models provide significantly better agreement with observational data than ΛCDM, with several realizations achieving excellent fits while the ΛCDM model consistently performs worst.

Antonino Del Popolo, Saeed Fakhry, David F. Mota, "Luminosity-Temperature Relation as a Probe for Modified Gravity" arXiv:2603.15077 (March 16, 2026).

See also this paper, which finds fault with the NFW halo distribution which is mathematically implied in any collisionless dark matter particle model, yet clearly time and again, does not reflect real world observations.

We investigate how reliably the global properties of Milky Way-mass dark matter haloes can be recovered from dynamical data over a limited radial range, particularly ≲30 kpc where observations are most sensitive but baryonic processes modify the halo structure. 

Using the ARTEMIS simulations, which produce varying degrees of baryon-induced contraction, we fit dark matter profiles over restricted radial ranges using commonly adopted parametric models. Assuming negligible observational uncertainties allows the systematic errors from these choices to be isolated. 

When fits are confined to inner radii, an NFW profile underestimates the virial mass by a factor of ≈2 on average (≈4 for some systems), and the concentration by a factor of ≈2. Einasto and generalised-NFW models provide excellent local fits but retain similar global biases. 

In contrast, the contracted halo prescription from Cautun et al. (2020) yields stable extrapolations and recovers unbiased halo mass estimates over all radii. 

The inferred mass improves systematically with increasing radial coverage, and tracers beyond ≳50 kpc largely eliminate the mean bias for all models. The local dark matter density at the Solar radius is recovered to within ≲5% for all profiles other than NFW. These biases are sufficient to reconcile recent low Milky Way mass estimates derived from inner rotation-curve analyses with the canonical ≈ 10^12 M⊙. 

We additionally find a halo-to-halo scatter of ≳0.1 dex (≈25%) persists even under idealised conditions, setting a likely lower limit for the precision of halo mass estimates.

Diego Dado, Shaun T. Brown, Azadeh Fattahi, Andreea S. Font, Ian G. McCarthy, "Implications of a contracted dark matter halo for the Milky Way's inferred virial mass" arXiv:2603.13516 (March 13, 2026) (submitted to MNRAS).

Some analysis of the measurement issues for galactic rotation curve of the Milky Way are discussed here.

Predicting Heavy Hadron Masses

This paper makes mass predictions for a huge number of three and five valence quark hadrons (in both ground states and excited states) made by both traditional methods from the literature and AI models, producing multiple estimates by different methods for each hadron considered. It is mostly a pattern recognition exercise, rather than a set of calculations from QCD first principles. It predicts several hundred composite particle masses.

This is easier for baryons (i.e. half-integer spin fermions) than for mesons (i.e. integer spin bosons) because baryons have far fewer quirky exceptions to general rules that flow, in part, from different mesons blending into each other, which is something that baryons don't do.

One observation is that these several hundred heavy baryons (in the broad sense of half integer spin hadrons, rather than the narrow sense of three valence quark hadrons) fill a pretty narrow range of masses, with the lightest having a mass of about 1.5 GeV, the heaviest having a mass of 11.4 GeV, and most of the predicted masses bunching up in the middle, with more than 4 GeV and less than 10 GeV. The lightest pentaquarks are a bit over 4 GeV.

Given that there are only a handful of possible quantum numbers for each hadron, the experimental task of distinguishing one heavy baryon from another would be challenging, with many possibilities near any given mass. 

While experimental mass measurement of heavy baryons typically have uncertainties of a few MeV, the uncertainties in the theoretical mass predictions are much greater. The theoretical uncertainties of the predictions range from about 100 to 2000 MeV, with most in the range of about 450 to 1200 MeV. The differences between theoretical mass predictions methods for the same hadron also frequently exceed the combined claimed uncertainties in the predictions, however, so the uncertainties are probably underestimated.

Since it is easy to make predictions if they are vague enough, which makes it easy for the predictions to be consistent with the experimentally observed values, the significance of these models shouldn't be exaggerated. They are making very ballpark estimates based upon very general considerations. 

But because it is so comprehensive, this is still somewhat useful in winnowing down candidates for a particular observed resonance with a particular observed mass from several hundred possibilities to perhaps a few dozen likely candidates of similar mass, which can be narrowed down further with measurements of the resonances spin, charge, and other quantum numbers to perhaps a dozen or fewer candidates.

In this article, we use two different methods for studying the mass spectra of fully-heavy baryons and pentaquarks. 

In the first section, we use state-of-the-art machine learning methods, such as deep neural networks and the Particle Transformer model architecture, to predict baryon masses directly from their quantum numbers, based on experimental information on hadrons from the Particle Data Group (PDG). We use this data-driven approach for the case of fully heavy baryons, and a large number of exotic pentaquark states, going much beyond the well-known P+c(4380) and $ P_c^+(4457) candidates. Subsequently, we extend the Gürsey-Radicati mass formula to incorporate the contributions of charm and bottom quarks, enabling analytical calculations for both ground and radially excited states of baryons and pentaquarks. 

The results obtained from both approaches demonstrate strong agreement with experimental data where available and make predictions for a number of unobserved states, including higher radial excitations. By addressing the question through both data-driven prediction and analytical modeling in different frameworks, this study offers complementary insights into the mass spectrum of conventional and exotic hadrons, guiding future experimental searches.

S. Rostami, A. R. Olamaei, M. Malekhosseini, K. Azizi, "Comprehensive Mass Predictions: From Triply Heavy Baryons to Pentaquarks" arXiv:2603.11259 (March 11, 2026).

An Unreview

What makes this paper especially notable is not its content per se but the concept of an "unreview", which potentially has broad interdisciplinary applications.

Accreting white dwarfs (AWDs) are among the best natural laboratories for understanding disk accretion. Their proximity, brightness, and purely classical nature make them ideal systems in which to probe the fundamental physics that governs the transport of angular momentum, the generation of outflows, and the coupling between disks, magnetospheres, and accretors. Yet despite decades of study, many critical questions remain unresolved. 

In this ``unreview'', we therefore focus not on what is known, but on what is unknown. 

What drives viscosity and sustains accretion in largely neutral disks? How are powerful winds launched, and how do they feed back on the disk and binary evolution? Why do so many systems show persistent retrograde precession, and what drives bursts in magnetic AWDs? 

By identifying these open problems -- and suggesting ways to resolve them -- we aim to motivate new observational, numerical, and theoretical efforts that will advance our understanding of accretion physics across all mass scales, from white dwarfs to black holes.

Simone Scaringi, Christian Knigge, Domitilla de Martino, "Accreting White Dwarfs: An Unreview" arXiv:2603.10150 (March 10, 2026) (Accepted in Space Science Reviews).

Also notable is a paper demonstrating that a twenty times faster method of computing big data in cosmology is indistinguishable in its results from a more conventional method of doing so, despite the fact that the faster method isn't obviously theoretically rigorous and sound (because it uses linear rather than non-linear mathematical methods).

There is also a new paper replicating a result of a 2026 paper finding MOND-like effects in wide binaries using a modestly different analysis method.

Variations On Tully-Fischer

The Baryonic Tully-Fischer relation (a tight correlation between ordinary matter and inferred total mass) holds much more tightly than a parallel correlation considering only ordinary matter in stars.

We combine data for extragalactic systems to quantify a relation between the observed baryonic mass Mb and the enclosed dynamical mass M200 inferred from kinematics or gravitational lensing. Our sample covers nine orders of magnitude in baryonic mass, including galaxies with kinematic or weak gravitational lensing data and groups and clusters of galaxies with new gravitational lensing data. 

For rich clusters with M(b)>10^14M⊙, the observed baryon fraction is consistent with the cosmic value, f(b)=0.157. 

For lower masses, the baryon fraction decreases systematically with mass. The variation is well described by M(b)/M(200)=f(b) tanh(M(b)/M(0))^1/4 with M(0) ≈ 5 × 10^13 M⊙. 

This relation is qualitatively similar to stellar mass-halo mass relations derived from abundance matching, but exhibits less scatter.

Stacy McGaugh, Tobias Mistele, Francis Duey, Konstantin Haubner, Federico Lelli, Jim Schombert, Pengfei Li, "The Baryonic Mass-Halo Mass Relation of Extragalactic Systems" arXiv:2603.06479 (March 6, 2026) (Accepted for publication in the Astrophysical Journal).

A Muon g-2 Recap

Ref. [8] is R. Aliberti et al., The anomalous magnetic moment of the muon in the Standard Model: an update, Phys. Rept. 1143 (2025) 1 [arXiv:2505.21476].

A paper on the latest developments of calculating muon g-2 (the anomalous magnetic moment of the muon which can be calculated in the Standard Model from first principles) in the latest BMW group calculation not only updates their calculation to be more precise (and consistent with the high precision experimental results), but also provide excellent background for the entire enterprise of calculating muon g-2 and comparing it to the experimental results.

The overview of the paper is as follows:

Almost twenty years ago, physicists at Brookhaven National Laboratory measured the magnetic moment of the muon with a remarkable precision of 0.54 parts per million (ppm) [20]. Since that time, the reference Standard Model prediction forth is quantity has exhibited a persistent discrepancy with experiment of more than three sigma [9]. This raises the tantalising possibility of undiscovered forces or elementary particles. The attention of the world was drawn to this discrepancy when Fermilab presented a brilliant confirmation of Brookhaven’s measurement, which brought the discrepancy to 4.2 sigma [21]. In the meantime a very large-scale lattice QCD calculation of a key theoretical contribution was performed by the Budapest-Marseille-Wuppertal (BMW) collaboration [3], as seen in Fig. 1. This result significantly reduces the difference between theory and experiment, suggesting that new physics may not be needed to explain the experimental results. However, it simultaneously introduces a new discrepancy with the existing data-driven determination of this contribution. 

Since then, the experimental [2] results have been updated with significantly improved precision, and the lattice result has been independently confirmed by other lattice collaborations. At the same time, new developments in the data-driven inputs that the lattice calculations replace [17–19] lead to a significant spread in the results depending on what inputs are taken. This has culminated in an updated theory prediction based on the lattice results instead of the data-driven determinations, as seen in Fig. 1. 

In these proceedings, I present a new hybrid calculation that combines an update to the most precise lattice results with data-driven inputs in a low-energy region where the observed discrepancies are not present. This new result leads to aprediction that differs from the experimental measurement by only 0.5𝜎, providing a remarkable validation of the Standard Model to 0.31 ppm.

As Table 1 shows, the main problem is how to more precisely measure the Hadronic Vacuum Polarization (HVP) component more precisely.

According to the abstract: 

The latest results from the Budapest-Marseille-Wuppertal (BMW) and DMZ collaborations, . . . [make] a determination of the hadronic vacuum polarisation contribution to a precision of 0.45%. [i.e. from ± 6.1 to ± 3.2.]

This new calculation is about twice as precise as the previous HVP calculation. 

The conclusion of the paper states that:

Recent lattice QCD results have surpassed the precision of all other theoretical predictions of the hadronic vacuum polarisation contribution to the muon magnetic moment. When taken together with the latest theory consensus for the other contributions [8], these results show excellent agreement with the latest experimental measurements [2]. This a remarkable success for quantum field theory, bringing together diverse computational tools to include all aspects of the Standard Model in a single calculation that validates the Standard Model to 0.31 ppm.

As a practical matter, this further tightens global constrains on low to medium energy deviations from the Standard Model. 

Mirror Universes And Dark Energy?

An interesting idea, coupled to one of the most plausible explanations for baryon asymmetry and what came before the Big Bang, even if it may not actually be provable.

We investigate a possible resolution of the dark energy problem within a pair-universe framework, in which the Universe emerges as an entangled pair of time-reversed sectors. 

In this setting, a global zero-energy condition allows vacuum energy contributions from the two sectors to cancel, alleviating the need for extreme fine-tuning. We propose that the observed dark energy does not originate from vacuum fluctuations but instead arises as an effective entanglement energy between the visible universe and its mirror counterpart. 

Treating the cosmological constant as an integration constant fixed by boundary conditions rather than a fundamental parameter, we show that the cosmological equations can be formulated without explicitly introducing vacuum energy. By imposing physically motivated boundary conditions at the cosmological event horizon, we obtain an integration constant consistent with the observed dark energy density. The parallel mirror world scenario thus provides a unified framework that may simultaneously explain the origins of dark energy and dark matter.

Merab Gogberashvili, Tinatin Tsiskaridze, "Dark Energy from Entanglements with Mirror Universe" arXiv:2603.03385 (March 3, 2026) (published at 8 Physics 29 (2026)).

MOND-like Behavior Within The Milky Way In Milky Way Subsystems

The radial acceleration relation and baryonic Tully-Fischer relation, while not perfect, work far too well to be consistent with almost any dark matter particle theories (ultra-light bosonic dark matter still might be possible to make work).

We test whether parsec-scale stellar systems in the Milky Way follow the galactic radial acceleration relation (RAR) or the baryonic TullyFisher relation (BTFR). 

We analyse 5646 Gaia DR3 open clusters from the Hunt & Reffert catalogue. Observed accelerations are derived from velocity dispersions and characteristic radii, and baryonic accelerations from stellar masses and characterisitc radii. The clusters are placed on the RAR and BTFR planes and compared with Newtonian and MOND expectations. Approximately 90 per cent of open clusters (those with N⋆≤250) lie close to the RAR, albeit with significant scatter. In a first-of-its-kind test, a smaller fiducial sample is consistent with a best-fitting acceleration scale g†≈1.2×10−10 ms−2±0.5 dex, compatible with canonical MOND values. 

More massive clusters approach the Newtonian virial expectation. No correlations are found between RAR residuals and galactocentric radii, distance to the Galactic disk midplane, age, or morphology. Tidal effects and unresolved binaries are insufficient to reproduce the observations without fine-tuning. 

Interpreted within a MOND framework, the alignment of most open clusters with the RAR and BTFR suggests that low-acceleration dynamics operate on parsec scales within the Milky Way. This implies that the Galactic gravitational field is not smooth on these scales and may include regions where the total gravitational acceleration falls below a0, partially mitigating the external field effect, thereby motivating higher-resolution modelling of the Galactic potential and informing other small-scale gravity tests within the Galaxy.

Mark D. Huisjes, X. Hernandez, "Most open clusters follow the radial acceleration relation (RAR) and the baryonic Tully-Fisher relation (BTFR)" arXiv:2603.03522 (March 3, 2026).

The Wide Binary Wars Continue

Neither the astrophysicists who say that there is evidence of MOND in wide binaries, nor those who say there is not, are relenting, and I currently rate the debate as inconclusive.

If this paper is right, it is bad for MOND, but good for Deur, who reproduces MOND behavior in galaxies by another formula and mechanism.

Wide binaries (WBs) offer a unique opportunity to test gravity in the low-acceleration regime, where modifications such as Milgromian dynamics (MOND) predict measurable deviations from Newtonian gravity. 

We construct a rigorous framework for conducting the wide binary test (WBT), emphasizing high quality sample selection, filtering of poor astrometric solutions, contamination mitigation, and uncertainty propagation. We show that undetected close binaries, chance alignments, and improper treatment of projection effects can mimic MOND-like signals. We introduce a checklist of best practices to identify and avoid these pitfalls. Applying this framework to Gaia DR3 data, we compile a high-purity sample of WBs within 130 pc with projected separations of 1 - 30 kAU, spanning the transition between the Newtonian and MOND regimes. 

We find that the scaled relative velocity distribution of wide binaries does not exhibit the 20% enhancement expected from MOND and is consistent with Newtonian gravity across all separations. A meta-analysis of previous WBTs shows that apparent MOND signals diminish as methodological rigour improves. We conclude that when stringent quality controls are applied, there is no observational evidence for MOND-induced velocity boosts in wide binaries. 

Our results place strong empirical constraints on modified gravity theories operating between a0/10 and 200 a0, where a0 is the MOND acceleration scale. Across this range of internal accelerations, Newtonian gravity is up to 1500x more likely than MOND for our cleanest sample.

Stephen A. Cookson, Indranil Banik, Kareem El-Badry, Will Sutherland, Zephyr Penoyre, Charalambos Pittordis, Cathie J. Clarke, "A Quality Framework for Testing Gravity with Wide Binaries: No Evidence for MOND" arXiv:2602.24035 (February 27, 2026) (published in MNRAS).