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Tensioni del modello a materia oscura sulla scala delle galassie


Dark matter tensions on the scale of galaxies


Academic year 2022/2023

Teaching staff
Antonaldo Diaferio (Lecturer)
Luisa Ostorero (Lecturer)
Degree course
PhD in Physics
Teaching period
Second semester
Distinctive Related or integrative
Course disciplinary sector (SSD)
FIS/05 - astronomy and astrophysics
Type of examination

Sommario del corso


Course objectives

The course provides the students with some basic elements of modern epistemology. As a working example, the course illustrates how modern epistemology largely favours Modified Newtonian Dynamics (MOND), a theory that does not requires dark matter, over the standard model that requires dark matter to interpret the dynamics of galaxies. Indeed, some properties of galaxies, that represent a tension in the standard model, were actually predictions of MOND.


Results of learning outcomes

The students will be able to distinguish between a progressive and a degenerating problemshift of a scientific theory. The students will also be able to develop their critical thinking.


Course delivery

The course is taught in a traditional way: all the equations, the calculations, and the plots that are useful to understand a topic are hand-written and drawn on the board.


Learning assessment methods

As final exam, the student delivers a 20-30 min presentation on a specific topic of his/her choice related to the course program. The student prepares his/her presentation based on the lecture notes and one or more scientific papers suggested by the teachers. A following discussion examines the preparation of the student on the presented topic. The exam outcome is either passed or failed.



In the first part of the course, we illustrate some kinematic properties of disk and dwarf galaxies, including the acceleration scale, the baryonic Tully-Fisher relation, and the galaxy disk stability, that hardly fit within the currently standard Cold Dark Matter model. Over the years, a number of ad hoc modifications to this model have been proposed to solve some of these tensions.

In the second part of the course, we show that, in epistemology, this approach is called degenerating problemshift. This condition might prelude to a substantial scientific revolution. In fact, most of these tensions are actually novel predictions in a different theory proposed in 1983, called Modified Newtonian Dynamics (MOND). The observed kinematic properties were indeed predicted by this model years in advance of their discovery, as expected in a sound progressive theory.

Suggested readings and bibliography



- David Merritt, A Philosophical Approach to MOND, Cambridge University Press

- Robert H. Sanders, The Dark matter Problem: A Historical Perspective, Cambridge University Press


Review papers:

- Ivan De Martino et al. 2020, Dark Matters on the scale of galaxies, Universe, 6, 107

- Stacy McGaugh, 2020, Predictions and outcomes for the dynamics of rotating galaxies, Galaxies, 8, 35


Class schedule

Lessons: from 21/05/2024 to 31/05/2024

Notes: The starting and ending dates shown above are tentative. The course is expected to be delivered in two weeks, with 8 lectures of 2 hours each, during Spring 2024 (March to June 2024). The exact period of delivery is flexible and can be arranged depending on the schedules of the interested students. Interested students are encouraged to contact the teachers.



The students who wish to attend the course are invited to register by using the register flag below at their earliest convenience.

The language of the course can be English on request.


Last update: 17/10/2023 16:42
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