Smithsonian Astrophysical Observatory

Science Updates


A globular cluster is a roughly spherical ensemble of stars, as many as several million of them, gravitationally bound together in groups whose diameters can be as small as only tens of light-years.


Our Milky Way galaxy is a barred spiral galaxy, a flattened disk of stars, gas and dust about 100,000 light-years in diameter containing several hundred billion stars.

The Smithsonian Astrophysical Observatory (SAO) is a "research institute" of the Smithsonian Institution. It is joined with the Harvard College Observatory (HCO) to form the Harvard-Smithsonian Center for Astrophysics (CfA). Because these research activities share Harvard and Smithsonian staff and resources, the links at this website will take you to information posted on the "CfA" pages.