An Ancient Universe

The booklet, An Ancient Universe: How Astronomers Know the Vast Scale of Cosmic Time, is a guide for teachers, students and the public. The booklet was written by a subcommittee of the American Astronomical Society’s Astronomy Education Board, and was published in 2004 by the American Astronomical Society with the Astronomical Society of the Pacific.

Click here for the electronic version of the booklet. You will need a PDF viewer such as Adobe Acrobat.

For information on how to order additional copies of the booklet, please contact the AAS by email at or by telephone at 202-328-2010.