More than three decades ago Ridley Scott's sci-fi horror classic Alien introduced moviegoers to a menacing, insectlike, parasitoid extraterrestrial species. The film's sequels and spinoffs over time created a rich mythology of a universe in which the films' predatory antagonists and doomed heroes coexist, complete with terraformed colonies, interstellar mining and commerce, and a recurring role for the fictional Weyland Corp., whose relentless efforts to capture and control the alien species set in motion much of the film franchise's narrative.

Scott returns to this universe on June 8 with the opening of Prometheus, a movie set in the same cosmos as the Alien films but several years earlier than the original. Although the moviemakers are keeping many plot details confidential in advance of the film's release, Scott has made clear that Prometheus is not a prequel to Alien. Instead, the new movie centers on scientific exploration—sponsored by Weyland, naturally—on board a spacefaring vessel named for the Titan in Greek mythology who stole fire from the gods and gave it to humans—and paid a terrible price for doing so.

The Prometheus is following a star map found at various unrelated archeological sites on Earth. The commonality of these images leads the scientists to believe that the map may help them discover humanity's origins.

Scientific American spoke with Prometheus co-screenwriter Jon Spaihts about the film's scientific pursuits, its portrayal of late 21st-century technology and the dangers faced by humans in such a hostile cosmos.

[An edited transcript of the interview follows.]

Prometheus is not a prequel to Alien but both films are set in the same universe. What does this mean exactly?
If a prequel is a story that presets the conditions for another story—gives you everyone's back story and so forth—and is mated to a specific set of characters and a specific tale, then this is not that. This is a story that shares a storytelling universe with the Alien films, in particular the first film. There are also some scientific notions and some storytelling archetypes that we inherit, but we are really not telling the same story at all. We're opening up a whole new branch of science fiction mythology.

What storytelling archetypes did you inherit, and how did you weave the old and new mythologies together?
One of the things I was very aware of in composing the story is that in the Alien universe there are a number of dualities that leap to the fore. There's a core duality between humanity and the alien species, obviously. The Xenomorph [as the alien came to be known] wasn't just something dangerous but something demonic in the perfection of its adaptation to destroy us. And it made Ripley—the female protagonist of Alien and its sequels—feel that much more innocent, vulnerable, human, real. This conflict between human and alien is central to these films.

A secondary duality is between the human and the artificial person. Whether we're talking about Ash in the first film, Bishop in Aliens or David in the new movie, an android is always there, and there's always a tension between the human and artificial characters that seems intrinsic to these stories. And then there's also a duality between the humans and "the Company," an implacable and self-serving interest, a heartless force. Although these movies are science fiction, we can relate [because of] similar tensions in day-to-day life. People feel uneasy about our dependence on artificial intelligence and robotic appendages as machines get closer and closer to us. And there's certainly a widespread tension between us and the corporate forces in our lives. All of these forces become concrete representations in the universe where Prometheus and the Alien movies take place.

The Alien films never fully explained the origin of the Xenomorph creatures, even though the first movie presents the audience with a derelict ship filled with alien eggs that have seemingly been abandoned on a hostile planet. What approach does Prometheus take to exploring the origins of life?

One of the things that distinguishes the original Alien movie is the extent to which it doesn't even attempt to explain the alien phenomena its protagonists encounter. It's almost devoid of pseudoscience talk. If you've seen the original Alien, you've seen the remains of the enigmatic giant—whom the fan community calls the "space jockey"—who has died in the derelict wreck. This character is the great, unopened door of that original film—the great mystery. Who is that? Where did that derelict ship come from? How did that giant die?

And it's in that mystery that the story seed of Prometheus takes root. There is some inevitable kinship between the two stories in terms of xenobiology. But the titular creature of Alien is very much confined to the shadows and is not at all the focus of Prometheus, which is driving in a new direction. With Prometheus, the origin of the menace and forces that our heroes encounter is essentially the central mystery of the tale itself. So the story is very much about people prying into the shadows and trying to shed light on these mysteries.

As with any science fiction film, technology sets the tone by establishing the film's look and to a large extent determining what the film's characters can (and cannot) do. What was your vision for the technology in this film?
That it should look real. One of the things that Ridley Scott has done as a director is pioneer for us a grungy vision of the future. His films Alien and Blade Runner plus the original Star Wars directed by George Lucas taken all together showed us a future in which everything was well used, rusted and battered. And that was a real leap from the gleaming and spotless future of Buck Rogers and Flash Gordon. Prometheus likewise wants to feel like reality. So the vessels, vehicles and tools in the movie are designed to be things that are somewhat familiar to us while also representing an optimistic vision of future technology.

Given that Prometheus is set prior to Alien, how did you devise a set of technologies that would appeal to an audience in 2012 without making Alien's 1979 vision of the future seem outdated?
There's an inevitable trickiness around the chronology just because technology in the real world and technology in filmmaking have come so far in the years since the original Alien. But for me a lot of that is easily rationalized by virtue of the fact that the Nostromo, the original ship in Alien, is an industrial tug. It's a rust bucket that itself might be 150 or 200 years old at the time that we see it. The Prometheus is a state-of-the-art scientific exploratory vessel. So it's only reasonable that it be sleeker and technically vibrant.

Along those lines, how did you invent David, the android in Prometheus? Did you take into account that he would not be as advanced a piece of technology as the robots from the Alien movies?
As with any archetype that's been touched on in previous films, you need both to honor its place in the canon and at the same time find some new insight, some new approach to it. The exciting thing about David is that perhaps there isn't yet a habitual place in society for machines like this at the time Prometheus takes place. In the sequels to Alien it's more normal to have an android on a starship crew as a matter of corporate protocol. But perhaps that's not the case in the new film. Perhaps David doesn't quite know his place in the universe, how humans will interact with androids and what's expected of these robots. And perhaps the human members of the crew are not yet accustomed to working and living with a crew member who is artificially intelligent.