The German astronomer William Herschel (1738–1822), who lived and worked in England, mapped out 848 pairs of binary stars, showing that the force of gravity acts between stars, as theorized by Isaac Newton. He hypothesized that stars originally were randomly scattered throughout the universe, and that over time they came together in pairs and clusters.
The Kepler-47 system was the first binary system with planets identified by NASA. It is now thought that many binary star systems could have large habitable zones that make life possible on the planets that orbit them. (NASA/JPL-Caltech/T. Pyle)