Galactic mass refers to the total mass of a galaxy, which includes all of its stars, gas, and dark matter. Measuring the mass of a galaxy is important for understanding its structure, dynamics, and evolution. Scientists use various methods, such as analyzing the gravitational effects on surrounding objects or studying the motion of stars within the galaxy, to estimate the mass of galaxies. By studying galactic mass, researchers can gain insights into the formation and evolution of galaxies, as well as the distribution and properties of dark matter in the universe.