Smithsonian Astrophysical Observatory

Science Updates


The universe was created 13.7 billion years ago in a blaze of light: the big bang. Roughly 380,000 years later, after matter (mostly hydrogen) had cooled enough for neutral atoms to form, light was able to traverse space freely.


Astronomers have known for decades that the merger of two normal stars is a frequent and astronomically important phenomenon. In globular clusters, for example, with as many as several million stars gravitationally bound together, collisions often occur between stars, producing stars that are more massive, hotter, and bluer than usual.

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.