The idea for the film was derived from research by California Institute of Technology (Caltech) physicist Kip S. Thorne, who is an expert on relativity.
Thorne is most famous for his controversial theory that wormholes not only exist, but can be accessed and used as portals for time travel.
The director was so enamored with Thorne’s theories that he attended a Caltech workshop with the physicist and other scientists.
Spielberg also brought his 89-year-old father, Arnold, who is a retired engineer, to the workshop.