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Updated: May 22, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
What do gas-rich galaxies actually tell us about modified Newtonian dynamics?
1Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T 1Z1 Canada. sfore@stanford.edu
Abstract:
It has recently been claimed that measurements of the baryonic Tully-Fisher relation (BTFR), a power-law relationship between the observed baryonic masses and outer rotation velocities of galaxies, support the predictions of modified Newtonian dynamics for the slope and scatter in the relation, while challenging the cold dark matter (CDM) paradigm. We investigate these claims, and find that (1) the scatter in the data used to determine the BTFR is in conflict with observational uncertainties on the data, (2) these data do not make strong distinctions regarding the best-fit BTFR parameters, (3) the literature contains a wide variety of measurements of the BTFR, many of which are discrepant with the recent results, and (4) the claimed CDM "prediction" for the BTFR is a gross oversimplification of the complex galaxy-scale physics involved. We conclude that the BTFR is currently untrustworthy as a test of CDM.
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