 This team included Annie Jump Cannon, who developed the stellar classification system, and Henrietta Swan Leavitt, who discovered the means to measure the distance from a star to the Earth by its spectra, later used to identify other galaxies in the universe.Later, this team included Cecilia Payne, who would develop a good friendship with Cannon; Payne's thesis based on her work with Cannon was able to determine the composition and temperature of the stars, collaborating with Cannon's classification system.Tyson then explains the lifecycle of stars from their birth from interstellar clouds.