Now There Is More
Why it is hard sci-fi
Soft on physics, careful about contact protocols. The film is built around the idea that first contact would be slow, scientific, and based on signal exchange. The five-note tone sequence used by the visitors is a real musical phrase the team derives, and the response system uses synthesisers to match pitch and rhythm. The military lockdown of the landing zone follows real disaster-response logic.
Science inside it
SETI-style signal correspondence. Mapping a tonal sequence to coordinates using solfege. Spielberg also treats the abductees as a control group whose memories return on a schedule, which is closer to a clinical model than a mystical one.