A Swiss-based team at the University of Geneva, searching for exoplanets (i.e., planets that exist outside our solar system), has detected an Earth-mass planet orbiting the star Alpha Centauri B. The idea that one or more planets might orbit the star system closest to Earth has been a favorite subject of science-fiction writers for decades. It is no surprise then that the possibility of an Earth-mass planet orbiting Alpha Centauri B has piqued substantial interest among astronomers and the general public.