Pale Blue is a tribute to an iconic photograph and an iconic figure, astronomer Carl Sagan. This photograph shows planet Earth, taken on February 14, 1990, by the Voyager 1 space probe at a record distance of approximately 6 billion kilometers. It is part of the Family Portrait (a series of photographs of the solar system taken that day). It is called A Pale Blue Dot, after the title of a book inspired by this photograph, written in 1994 by Carl Sagan, because the Earth appears in it as a tiny blue dot. Albarrán Cabrera's book Pale Blue is a symbolic journey that begins with the origins of planet Earth. The different layers of this Earth help humanity better understand its origins and evolution, and this "memory" seems to tell them that their destinies are inseparable, but that it is humanity's responsibility to "preserve and cherish that pale blue dot, the only home it has ever known."