Smithsonian Astrophysical Observatory

Science Updates


The path of a light beam is bent by the presence of mass, as explained by General Relativity. A massive body can therefore act like a lens - a so called "gravitational lens" – to distort the image of an object seen behind it.


Astronomers have long realized that the process of making new stars is very inefficient. In the Milky Way the overall efficiency is only about 5% as measured by the mass in stars compared to the total mass of the galaxy.

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.