Science Fiction History: 1963 Heinlein Orphans of the Sky

About the 1963 sci-fi novel Orphans of the Sky by Robert A. Heinlein.

--1963. Orphans of the Sky by Robert A. Heinlein was the 1st book to tackle the still-unsolved paradox of space travel: If other solar systems lay millions of light-years away, how could humans survive the journey there? His answer was a spaceship--immense and self-operating--which was a miniature universe; it even contained farms, and had its own gravitation. With the passage of time, however, its passengers forgot that they were "in passage" and interpreted their records and textbooks as religious allegories. Arrival at a habitable planet in a universe infinitely larger than the only one they knew was an immense psychological shock, but they survived.