Harvard University astronomers and Smithsonian Institution astronomers explore the cosmos together. The combination of the Harvard College Observatory (HCO) and the Smithsonian Astrophysical Observatory (SAO) is known as the Harvard-Smithsonian Center for Astrophysics (CfA).

News Releases

November 13, 2018

A new discovery reported in the Astrophysical Journal Letters might lay claim to title of the most unusual extreme class of astronomical object: very high energy (VHE) gamma-ray emitting, neutron star-massive star binary pairs.

October 17, 2018

The single most important puzzle in today's cosmology (the study of the universe as a whole) can be summarized in one question: How old is it? For nearly a century -- since the discoveries by Einstein, Hubble, LeMaitre and others led to the big bang model of creation -- we have known the answer.

Latest Science Update

November 9, 2018

Most galaxies lie in clusters containing from a few to thousands of other galaxies. Our Milky Way, for example, belongs to the Local Group cluster of about fifty galaxies whose other large member, the Andromeda galaxy, is about 2.3 million light-years away.

SI Specific Information

SI-specific information regarding the government shutdown may be found at alerts.si.edu. SAO staff are encouraged to review the website for updated information