Uncertainty in the Newtonian Gravitational Constant

A cautionary tale in fitting galaxy rotation curves with Bayesian techniques: does Newton's constant vary from galaxy to galaxy?

We present an analysis in which the newtonian constant is allowed to vary from galaxy to galaxy when fitting rotation curves from the sparc database, in analogy to in the recently debated bayesian analyses.When imposing flat priors on weobtain a wide distribution of which, taken at face value, would rule out as a universal constant with high statistical confidence.However, imposing an empirically motivated log-normal prior returns a virtually constant with no sacrifice in fit quality.This implies that the inference of a variable (or is the result of the combined effect of the combined effect of parameter parameter degeneracies and unavoidable uncertainties in the error model) is the result of the combined effect of parameter degeneracies and unavoidable uncertainties in the error model.