The Hubble Space Telescope has conducted a comprehensive survey of the Andromeda galaxy, revealing over 200 million stars, though the galaxy's total population is estimated at 1 trillion stars. This survey, combining data from the PHAT and PHAST programs, covers the entire disk of Andromeda and provides insights into its evolutionary history, which differs significantly from the Milky Way. Andromeda appears to have undergone recent star formation and interactions, possibly due to a past collision with another galaxy. These findings will aid future observations by the James Webb and Nancy Grace Roman Space Telescopes.
