Observations from a scientific team at the Harvard-Smithsonian Center for Astrophysics have revealed that an incredibly dense star cluster known as 47 Tucanae includes many binary stars. Most of the binary star systems in 47 Tucanae are systems in which a normal, Sun-like companion orbits a collapsed star, either a white dwarf or a neutron star. 47 Tucanae is about 12 billion years old, making it one of the oldest structures in our own Milky Way galaxy. The observations, made with NASA’s Chandra X-ray Observatory, and using data from the Hubble Space Telescope and ground-based radio data, may help to explain how this ancient cluster of stars evolved. NASA’s Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. The Smithsonian’s Chandra X-ray Center controls science and flight operations from Cambridge, MA.