Two physicists propose different explanations for the anomalous rotation curves of spiral galaxies. Physicist 1 suggests that an unseen form of matter, 'dark matter,' permeates galactic halos and provides additional gravitational pull. Physicist 2 argues that our current understanding of gravity (General Relativity) is incomplete at galactic scales, and a modification of gravity is needed (Modified Newtonian Dynamics, or MOND).
If future observations reveal direct evidence of particles that interact weakly with ordinary matter and light, but possess significant mass, this would most strongly support which viewpoint?
Correct: A
Physicist 1's hypothesis relies on the existence of 'dark matter,' an unseen form of matter that provides gravitational pull. Direct evidence of particles that fit the description of dark matter (weakly interacting but massive, Choice A) would provide substantial empirical support for Physicist 1's core idea, as it identifies a specific candidate for the 'unseen matter' posited. This would make the modification of gravity (Physicist 2) less necessary to explain the observations.