Stars orbit the galactic bulge at the same velocity, independently of their distance from the bulge, due to the presence of dark matter.
Scientists attribute this phenomenon to the gravitational influence of dark matter. Dark matter, an invisible and mysterious substance, exerts gravitational forces that affect the motion of stars. Unlike normal matter, dark matter doesn't emit, absorb, or reflect light, making it challenging to directly observe. However, its gravitational effects on visible matter, such as stars, provide evidence for its existence.
Dark matter distributes more uniformly throughout the galaxy, creating a gravitational field that keeps stars orbiting at consistent velocities. This differs from expectations based solely on visible matter, where orbital velocities would typically decrease with distance from the galactic bulge.
In summary, the uniform orbital velocities of stars around the galactic bulge, irrespective of their distance, are attributed to the gravitational influence of dark matter, an elusive component that significantly shapes the dynamics of galaxies.