“Are we alone in the universe?” Countless movies have asked that question, but few have given it more thought than this 1997 adaptation of Carl Sagan’s bestselling novel. Here are 10 things you might not have known about Contact.

1. ITS OPENING SHOT SET AN INDUSTRY RECORD. 

Contact begins with a close-up of our home planet. At first, a babel of '90s radio broadcasts nearly deafens the audience. But as the camera pulls back and Earth grows smaller, iconic audio clips that were recorded 20, 30, and even 100 years ago greet our ears—only to fade seconds later. By the time our galaxy recedes into an endless cosmic backdrop, there’s nothing left but silence.

This is one of the most ambitious sequences in cinema history. The completely digital intro lasted for 4170 uninterrupted frames, making it the longest computer-generated shot that had ever appeared in a live-action film at the time. Great pains were taken to capture the look of deep space. On the special edition DVD commentary, visual effects supervisor Stephen Rosenbaum recalls getting started by gathering “absolutely incredible” Hubble snapshots of “distant galaxies and stars and other interstellar phenomenon ... We laid out what we liked and said, 'Okay, how can we pass through some of this? How can we combine it together into something [that’s] visually stunning?’”

Brilliant as it is, however, the moment ignores physical law. Just ask Neil deGrasse Tyson. If one could really overtake the radio signals, he argued, “you would hear them in reverse.” Still, the good doctor acknowledges that—for artistry’s sake—everything needed to sound intelligible. “[They] couldn’t have gotten it right and still had the scene work,” deGrasse Tyson conceded, “so they had to do it the way they did.” 

2. THE NOVEL MADE CARL SAGAN $2 MILLION RICHER BEFORE HE'D WRITTEN A WORD OF IT. 

Sagan and his wife, Ann Druyan, originally envisioned Contact as a feature film. In 1980, they co-wrote the project’s first treatment. Frustrated with Hollywood’s glacial development process, the couple eventually chose to turn their story into a novel. Sagan hadn’t even begun working on the book when Simon & Schuster gave him a whopping $2 million advance for it. An instant hit, Contact sold almost 1.75 million copies within two years of its 1985 release. Sadly, we’ll never know what Sagan thought of Warner Bros.’ subsequent movie adaptation as he passed away several months before its release.

3. IN THE BOOK, AMERICA HAS A FEMALE PRESIDENT. 

Much to the White House’s annoyance, director Robert Zemeckis used footage of then-President Bill Clinton during key political scenes. He could’ve avoided the resultant controversy by following his source material a little more closely. In both the novel and an early screenplay, the Oval Office is occupied by Helen Lasker: a fictitious two-term commander-in-chief.

4. ASTRONOMER CAROLYN PORCO WAS ASKED TO HELP DEVELOP THE MAIN CHARACTER. 

Ellie Arroway, the film's star-gazing heroine, battles occupational sexism throughout the movie. Sagan knew that filming his tenacious, whip-smart protagonist wouldn’t be easy, so he recruited some help. “Carl called me up and said [that] out of all the female scientists he knew, I came closest to being like the character he wanted portrayed on the screen,” recalled planetary scientist Carolyn Porco, who collaborated with him on several occasions.

Decades later, the scientist still warmly remembers meeting with Sagan, Druyan, executive producer Linda Obst, and filmmaker George Miller—from whom Zemeckis would later take the director’s chair. “We spent a day sitting around a table in Santa Monica putting together the character of Ellie," said Porco. "They would ask me, ‘What kind of experiences have you had?’ ‘Why do you feel you’ve done well in a field dominated with men?’ I said ‘Well, I grew up with four brothers for god’s sakes. I’ve been fighting and spitting and kicking ever since I was a kid.’”

In her own words, Poroco was “brought on to lend authenticity to Ellie’s experiences in the movie.” Naturally, when Jodie Foster became Contact’s leading lady, Warner Bros. wanted the pair to meet. Though this never happened, Foster did touch base with Jill Tarter, an astronomer who—like Arroway—has spent her career scouring the universe for traces of intelligent life.

5. GEORGE MILLER WAS SET TO DIRECT THE FILM. 

The man who brought you Babe and Mad Max spent a year working with Sagan on Contact. He ultimately left the production when Warner Bros. decided to take the film in a “safer” new direction. “It was clear that [they] weren’t prepared to do the movie that I was interested in making,” Miller said.

What did he have in mind? In 2015, Miller told Collider that while he’s never actually seen Zemeckis’s version of the movie, he has read the script and feels like it needed “much, much less force-feeding exposition.” The filmmaker likened his own interpretation to Christopher Nolan’s Interstellar.

6. SAGAN'S WIDOW MAKES A BRIEF APPEARANCE. 

Skip ahead to 0:22 in this clip and look at the upper left-hand corner. You’ll see Druyan duking it out with a conservative politician (played by Rob Lowe) on CNN’s Crossfire

7. THE MOVIE PUT CNN IN AN AWKWARD POSITION. 

The cable news giant allowed 13 of its best-known reporters and anchors to play themselves in Contact. For then-CEO Tom Johnson, that was 13 cameos too many. “I don’t think having correspondents in the movies is a good idea,” he said in retrospect, arguing that the movie gave “the impression that we’re manipulated by Time Warner, and it blurs the line.” Today, CNN staffers need to clear potential off-network appearances with an ethics group. 

8. MATTHEW MCCONAUGHEY REFUSED TO DELIVER A CERTAIN LINE. 

Late in the final script, McConaughey's character—a self-described “man of the cloth without the cloth” named Palmer Joss—says “My God was too small.” Though Druyan really liked this line, McConaughey called it sacrilegious and wouldn't say it. Later on, the two talked at length about faith and became good friends (despite differences of opinion).

9. NASA FLATLY DENIES ONE OF THE FILM'S INSINUATIONS. 

In the movie's third act, a stunned Arroway receives a cyanide pill before entering the pod. According to Zemeckis, Sagan swore that this just-in-case practice was observed “on every single [NASA] mission.” However, Apollo 13 veteran James Lovell has dismissed the idea, writing “many people have asked me ‘Did you have suicide pills on board?’ We didn’t, and I never heard of such a thing in the 11 years I spent as an astronaut and a NASA executive.”

10. ELLIE CONDUCTS RESEARCH AT A FACILITY THAT'S ACTUALLY BEEN USED TO INITIATE CONTACT WITH ALIENS. 

Ellie and Palmer first meet near Puerto Rico’s world-famous Arecibo Observatory. In 1974, the site’s radio telescope aimed a Search for Extraterrestrial Life (SETI) message at a star cluster that resides some 21,000 light-years away. Using binary code, this powerful broadcast described DNA, the human body, and our solar system. Don’t expect a reply anytime soon, though—it won’t reach those heavenly bodies for another 25 millennia.