- Actor-Shared Background:
- California Doubling: Gros Morne National Park in Newfoundland doubles for Japan.
- Cue Card: Due to the complex scientific jargon, Jodie Foster needed cue cards.
- He Also Did: Carl Sagan, astronomer and famous for the scientific documentary Cosmos: A Personal Voyage, as well as essays and books of scientific and skeptical nature, writing a novel might sound alien for some. Indeed, it's possible to notice common points in this book which are later repeated (or are repeated from) his other works.
- Dyeing for Your Art: Jodie Foster has a massive bump on her head in the scene when Ellie and Kent first meet. That was from filming a scene when she gets in and out of a harrier jet, and she bumped her head three times.
- In Memoriam: "For Carl" before the closing credits. Carl Sagan, who wrote the novel and screenplay, passed away in December 1996, before the movie was released.
- Playing Against Type: David Morse as a character who isn't a hardass or a villain, but a loving father.
- Real-Life Relative: The Japanese home release had father-son seiyuu duo Chikao Ohtsuka and Akio Ōtsuka dubbing Hadden and Kitz.
- Science Marches On:
My fondest hope for this book is that it will be made obsolete by the pace of real scientific discovery.
- It is now thought that radio and TV signals are not capable of being detected much farther than a single light-year from Earth before they fade into nothingness, meaning the whole plot of Aliens Steal Cable is impossible.
- Sagan actually mentions this in the "Author's Note" section.
- Scully Box: In her DVD commentary, Jodie Foster admits she is standing on a box when Ellie and Palmer kiss, as she is shorter than Matthew McConaughey.
- Technology Marches On:
- At one point Ellie channel-surfs and finds a station offering onetime access to a downloadable fantasy RPG game; if you liked it, you could order the full game on a floppy disk.
- While leaving a museum with Palmer Joss, Ellie receives a message on her beeper. She has to get back to her office because she can't find a pay phone.
- The way space tech and travel is depicted didn't exactly play out in the real 1999.
- Averted in the last chapter, though. The Argus supercomputers calculated pi to 10^21 base-11 digits, whereas the real-world record stands at 22 trillion digits as of 2016.
- What Could Have Been: An earlier draft of the script portrays, in detail, a radio-signal relay station in orbit around Vega as it beams the first TV broadcast from Earth to the listening aliens far across space. The surface of their homeworld would have been seen in a flyover shot.
The pinball game:
- Follow the Leader: The success of Contact prompted many copycats by other manufacturers, and fostered the rapid use of solenoids, bells, and tilt.
- Throw It In!: The use of a bell started as a practical joke at Pacific Amusement. One of the employees wired a doorbell buzzer to the Contact Switch on a demo table, and every time it was hit, owner Fred McClellan thought his phone was ringing and tried to answer it. When the bell proved to be an attention-getting device, it was added to all subsequent machines.
The DS game:
- Science Marches On: The Green Rocks are supposedly made of element 117. Inevitably, the real element 117 was synthesized and recognized by IUPAC in the next decade or so, and naturally it has none of the properties displayed in the game.
- Unintentional Period Piece: The Professor's vocabulary and occasional meme reference are strikingly mid-2000s. "Weaksauce, as they say."