An Ancient Universe: How Astronomers Know the Vast Scale of Cosmic Time
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.
You are free to print and distribute the booklet. You will need a PDF viewer such as Adobe Reader.