Smithsonian Astrophysical Observatory

Science Updates


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 universe contains some galaxies more than a thousand times brighter than our own Milky Way galaxy. Many of them are practically invisible at optical wavelengths because the star formation that powers their emission is buried deep inside obscuring clouds of dust, but at infrared wavelengths the starlight-heated dust glows brightly.

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.