 observers that are both moving with the Hubble flow, does not change with time, as comoving distance accounts for the expansion of the universe.Comoving distance is obtained by integrating the proper distances of nearby fundamental observers along the line of sight (LOS), where the proper distance is what a measurement at constant cosmic time would yield.In standard cosmology, comoving distance and proper distance are two closely related distance measures used by cosmologists to measure distances between objects; the comoving distance is the proper distance at the present time.