 Dr. Arroway hypothesizes that the message could be an "Encyclopaedia  Galactica", a concept envisioned by Carl Sagan (qv) as well,  featured prominently in the TV series _"Cosmos" (1980)_ (qv) and  meant to be an planetary database for all the worlds within the  Milky Way Galaxy. The term originates from Isaac Asimov (qv)s  science fiction novel, Foundation.