We all collect photographs, souvenirs, or even just our own memories to mark important life events. Each album is like a miniature time capsule, a Pandora’s box of emotions. Prospect Theater Company has opened a musical time capsule and brought forth a daring new show, Myths and Hymns, which focuses on themes of remembrance and reexamination. This work by established composer Adam Guettel (The Light in the Piazza; Floyd Collins) entered the theatrical vault in 1998, after it appeared as a concert version of songs under the title Saturn Returns at the Public Theater.