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Modified Newtonian dynamics (MOND)

Mordehai MilgromStacy McGaughKyu-Hyun ChaeIndranil Banik

This page delivers no verdict; it presents claims and evidence with their sources. No theory in science is absolute. Method

For everyone

In 1983 Mordehai Milgrom proposed that the rotation speeds of galaxies could be explained not by invisible matter but by a law of gravity that works differently at very weak accelerations. MOND predicts galaxy rotation curves from the visible matter alone with striking success. By contrast it struggles with galaxy clusters and the cosmic microwave background. Recent tests with wide binary stars have given opposing results.

For specialists

In MOND, at accelerations well below a₀ ≈ 1.2 × 10⁻¹⁰ m/s² the effective gravitational acceleration becomes √(a₀·g_N). This directly gives flat rotation curves and the baryonic Tully–Fisher relation (M ∝ v⁴). Non-relativistic versions such as AQUAL and relativistic extensions such as TeVeS have been proposed; the 2017 observation that gravitational waves travel at the speed of light ruled out some relativistic versions. It is known that in galaxy clusters even MOND needs additional unseen mass.

Claims

Evidence

Supporting

Observation

In 153 galaxies the observed acceleration was found to follow a single, tight relation with the acceleration computed from visible matter alone, of the form MOND predicts.[2]

Observation

An analysis of wide binary stars with Gaia data reported orbital speeds higher than Newton predicts at very low accelerations.[3]

Challenging

Observation

A detailed statistical analysis of 8,611 wide binaries in Gaia data preferred Newtonian dynamics over MOND with very high confidence.[4]

Observation

In the Bullet Cluster the mass lies apart from the visible gas, which is hard to explain by changing the law of gravity alone.[5]

Connections

Parent

Dark matter

Builds on

Newton's Principia

Argues against

Cold dark matter (the ΛCDM model)

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Sources

  1. ArticleMilgrom, M. (1983). A modification of the Newtonian dynamics as a possible alternative to the hidden mass hypothesis. The Astrophysical Journal 270, 365–370DOI 10.1086/161130archive
  2. ArticleMcGaugh, S. S.; Lelli, F.; Schombert, J. M. (2016). Radial acceleration relation in rotationally supported galaxies. Physical Review Letters 117, 201101DOI 10.1103/PhysRevLett.117.201101archive
  3. ArticleChae, K.-H. (2023). Breakdown of the Newton–Einstein standard gravity at low acceleration in internal dynamics of wide binary stars. The Astrophysical Journal 952, 128DOI 10.3847/1538-4357/ace101archive
  4. ArticleBanik, I.; Pittordis, C.; Sutherland, W.; Famaey, B.; Ibata, R.; Mieske, S.; Zhao, H. (2024). Strong constraints on the gravitational law from Gaia DR3 wide binaries. Monthly Notices of the Royal Astronomical Society 527(3), 4573–4615DOI 10.1093/mnras/stad3393archive
  5. ArticleClowe, D. et al. (2006). A direct empirical proof of the existence of dark matter. The Astrophysical Journal 648, L109–L113DOI 10.1086/508162archive

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Cite this page

APA

Athena contributors. (2026). Modified Newtonian dynamics (MOND). Athena: The tree of human knowledge. Retrieved November 1, 2026, from https://latifkedi.github.io/athena/en/d/mond/

BibTeX
@misc{athena_mond,
  title        = {Modified Newtonian dynamics (MOND)},
  author       = {{Athena contributors}},
  year         = {2026},
  howpublished = {\url{https://latifkedi.github.io/athena/en/d/mond/}},
  note         = {Athena: The tree of human knowledge. Accessed: 2026-11-01}
}

Added: September 28, 2026 · Last changed: September 28, 2026 · Page history

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