PARIS, France (AFP) — The Milky Way’s neighboring galaxy, Andromeda, was formed in a colossal crash between two smaller star systems no more than three billion years ago when Earth already existed, researchers said Wednesday. Calculating the birth date of the galaxy has been a major challenge for astrophysicists given the vast age gap between the different stars it is made up of. For the latest study, French and Chinese researchers led by Paris Observatory […]