Smithsonian Astrophysical Observatory

Science Updates


The solar corona, the hot outer layer of the Sun, has a temperature of over a million degrees Kelvin and powers a wind of charged particles, some of which bombard the Earth producing auroral glows and often disrupting global communications.


About seven and one-half billion years from now our sun will have converted most of its hydrogen fuel into helium through fusion, and then burned most of that helium into carbon and oxygen. It will have swollen to a size large enough to fill the solar system nearly to the current orbit of Mars, and lost almost half of its mass in winds.

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.