Mass-to-light ratios refer to the ratio of the total mass of a celestial object, such as a galaxy or a star cluster, to its visual or luminous brightness. This ratio provides insight into the distribution and nature of mass within these objects. By studying mass-to-light ratios, astronomers can better understand the amount and distribution of dark matter, as well as the overall dynamics and evolution of galaxies and other cosmic structures. These ratios are often used to infer the presence of dark matter, as the observed mass of a celestial object is often larger than what can be accounted for by visible matter alone. By comparing mass-to-light ratios across different celestial objects, researchers can also gain insights into the formation and evolution of galaxies and other astronomical structures.