What evidence suggests that most of the mass of the Milky Way is in dark matter?

The most compelling evidence for the existence of dark matter in the Milky Way comes from the observation of orbital speeds of stars that are located far from the galactic center. According to Newtonian dynamics and gravitational theory, we would expect stars further from the center of the galaxy to move at lower speeds because they are under the influence of less gravitational pull from the central mass. However, measurements show that these stars maintain surprisingly high orbital speeds, which implies that there is considerably more mass present than what is visible in stars and gas alone.

This phenomenon suggests that a significant amount of mass must be located in an unseen form, which we characterize as dark matter. The gravitational influence of this mass is necessary to account for the high velocities of stars located in the outer regions of the galaxy. Since dark matter does not emit or interact with electromagnetic radiation, it cannot be observed directly, but its existence is inferred through its gravitational effects on visible matter.

The other options, while they may contribute to our understanding of the galaxy, do not provide as direct evidence for dark matter as the observed orbital speeds. Neutron stars and globular clusters are both part of the visible mass and do not themselves imply the existence of dark matter. The abundance of gas clouds in the halo