More On Wide Binaries

A paper claims to see MOND in a reanalysis of wide-binary star data. I'm still on the fence.

Wide binary stars provide natural laboratories for directly probing gravity in the low-acceleration regime, as dark matter inferred from any viable gravity has negligible effects on their internal dynamics. Various recent studies including Bayesian 3D analyses have shown that wide binaries with separations greater than several thousand astronomical units experience MOND-type gravity with a boost factor of γ≈1.3−1.6. However, results claiming preference for, or no deviation from, standard gravity have also been published during the same period, particularly highlighting the roles of data quality control and realistic modeling of multiple-star (i.e., triple and higher-order) systems that host hidden companion stars. 

Here we carefully reexamine the issues of data quality control and modeling multiple-star systems in statistical gravity tests based on sky-projected 2D velocities of wide binary stars. Through extensive tests including the acceleration-plane test, the ṽ -distribution test, and the median-ṽ -profile test (where ṽ is the sky-plane 2D relative velocity normalized by the Newtonian circular velocity between the two stars), we show that proper data quality control or reasonable variation in multiple-star modeling cannot remove the low-acceleration gravitational anomaly but confirms the MOND-type gravitational anomaly, particularly consistent with recent realistic MOND solutions of wide binary orbits. 

We find that studies claiming no evidence for the low-acceleration gravitational anomaly are consequences of bypassed calibration of the fraction of multiple-star systems using the Newtonian-regime data, bias-introduction in data quality control that is not taken into account in gravity tests, or insufficient statistics in the low-acceleration regime.

Kyu-Hyun Chae, Youngsub Yoon, "Revisiting Data Quality Control and Multiple-star Modeling in Wide Binary Gravity Tests: Confirmation of MOND-type Gravitational Anomaly at Low Acceleration" arXiv:2607.14450 (July 16, 2026) (submitted to the AAS journals).

The Latest Global Electroweak Fits Of Standard Model Physical Constants

A global electroweak fit combines experimentally measured values of Standard Model physical constants with the theoretical relationships between those constants in the electroweak sector of the Standard Model to determine where, within the range of uncertainties in the experimental measurements the true value of those physical constants is most likely to be. Basically, it uses theory to eke out a bit more precision in our determination of these constants than the measurements make possible in isolation.

The fact that it is possible with experimentally measured value of Standard Model physical constants without serious tensions (which it is) also provides a global test of the consistency of the Standard Model with reality.

The latest paper using up to date experimental data to make a global electroweak fit of Standard Model physical constants can be found here. The discussion of how the input values are chosen (basically, an educated best summary of the data to date) in the paper is also noteworthy.

The global fit of the Z boson mass is 91.1882 ± 0.0019 GeV and the global fit of the Z boson width is 2.4945 ± 0.0006 GeV.

The global fit of the W boson mass is 80.3584 ± 0.0048 GeV and the global fit of the W boson width is 2.090 ± 0.001 GeV.

The Higgs boson mass is 125.13 ± 0.11 GeV. The Standard Model expectation for the Higgs boson width is 4.10 ± 0.06 MeV; a complete global electroweak fit of the data produces 3.78 + 0.30 − 0.27 MeV, which is consistent with the Standard Model expectation. The couplings of the Higgs boson in an electroweak global fit are within roughly 1% ± 1% of the Standard Model expectation. 

The global fit of the charm quark pole mass (in the MS scheme) is 1.273 ± 0.003 GeV.

The global fit of the bottom quark pole mass (in the MS scheme) is 4.183 ± 0.004 GeV.

The global fit of the top quark pole mass is 172.67 ± 0.56 GeV.

The global fit of the strong force coupling constant at the Z boson squared energy scale is 0.1179 ± 0.0009.

The global fit of the effective leptonic weak mixing angle is sin^2(theta) = 0.23149 ± 0.00005.

Can We Measure The External Field Effect On Earth?

Color me skeptical. 

The External Field Effect can be understood as basically a swamping of a second order MOND effect by first order Newtonian effects, so I'm very doubtful that it could be measured experimentally in the solar system anywhere near Earth. Also, a 0.1 fm precision measurement, i.e. a fraction of the size of a proton or neutron, starts to run into definitional issues about what the object your measuring even is due to quantum mechanics and the parton makeup of hadrons. And, the uncertainty regarding the functional form of a MOND interpolating function further muddies the waters and makes any measurement model dependent.

Despite compelling evidence, the absence of a confirmed dark matter particle has sustained interest in modified gravity as an alternative explanation for the observed phenomenology. One prominent example is Modified Newtonian Dynamics (MOND), which predicts that the internal dynamics of a system depends on the external gravitational field in which it is embedded. This so-called External Field Effect violates the strong equivalence principle (SEP) and is absent in canonical mechanics, making it a promising avenue for experimental tests of modified gravity. 

Motivated by this, we investigate the dynamics of two spherical masses arranged such that their symmetry axis is either parallel or orthogonal to the local gravitational field. We derive solutions describing the internal dynamics of such systems in both strong uniform and radial external fields. In particular, for a radial external field, if the non-relativistic gravitational field is free to have non-vanishing curl, we find that the mutual attraction of the masses in the perpendicular configuration is not strictly aligned with their symmetry axis. It acquires a small transverse component, even when the external gravitational field is everywhere balanced by non-gravitational forces. 

Using these solutions, we determine the spatial and temporal sensitivities required to distinguish the two configurations and systematically assess experimentally relevant effects, including air drag, object size, and surface interactions. As an example, detecting the prediction of the simple MOND interpolating function requires a spatial sensitivity of order 0.1 fm for sub-millimeter masses evolving over approximately 30 minutes. Such times may be achievable with levitated particles or in space-based environments. Experiments operating at lower resolutions are also interesting as independent tests of SEP and place constraints on modified-gravity theories.

Ankit Kumar, et al., "Probing the Strong Equivalence Principle through the External Field Effect. How Do Two Masses Fall?" arXiv:2607.10247 (July 11, 2026).