Smithsonian Astrophysical Observatory

Science Updates


There are now about 1750 confirmed exoplanets, and several thousand candidates awaiting followup measurements. Most of them have been discovered by the Kepler satellite which looks for planetary transits: the slight dimming of starlight when an exoplanet crosses the face of the star as seen from Earth.


Galaxies are often found in groups or clusters, the largest known aggregations of matter and dark matter. The Milky Way, for example, is a member of the "Local Group" of about three dozen galaxies, including the Andromeda Galaxy located about 2 million light-years away.

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.