Christopher Nolan’s Interstellar is a lot to process. That's not only because of the plot, stuffed as it is with relativity theories and quantum data and time as a physical dimension. As a film in and of itself, Interstellar is fascinating as a next step in the space-travel subgenre as well as in Nolan’s own personal development as a filmmaker. Film is a referential medium, and even the most innovative, forward-thinking movies are advancing the works that came before them. Interstellar gets exponentially more interesting the more you think about it in the context of its predecessors—particularly these following five films, all of which influenced Nolan’s journey through the stars.

2001: A Space Odyssey

Here’s a natural starting point, since 2001 remains the space-travel movie by which all others are judged (or at least all others that appear to have some degree of ambition or seriousness about them). Released in 1968 and directed by Stanley Kubrick, it is an epic in every sense of the word. The film also falls between the satirical Dr. Strangelove and the dystopic A Clockwork Orange in a three-film run that certainly serves as the high point of Kubrick’s filmography.

While any comparison of Interstellar to 2001—the greatest space film of all time—is certainly a compliment, there’s almost no way Interstellar can measure up. The most prominent common thread is the idea that space travel is inextricably tied to evolution. 2001 makes this claim outright, setting its entire first act at the “Dawn of Man.” The black rectangular “monoliths” that appear to nudge mankind along its evolutionary path appear to be alien in nature, but no one knows for sure. This is reflected back in Interstellar with the wormhole that takes Cooper and his crew from our solar system to the system, along with the fifth-dimensional space that occurs in the final act. The focus on this evolutionary take on space travel makes Interstellar itself something of a next link in cinema’s sci-fi chain, fittingly one where the next evolutionary leap is revealed to be love.

Of course, anybody who has seen both 2001 and Interstellar knows that the similarities between the films comprise a fairly short list. If Interstellar is obsessed with explaining, however briefly, concepts of relativity, wormholes, black holes, and the like, 2001 feels just as adamant about explaining nothing. What are the monoliths? Who sent them? What makes the HAL system go bad? What’s with the starchild? Kubrick offers answers in the form of visual cues and metaphors, but what he mostly provides is the space to figure it out yourself. Whether a movie marketed to a mainstream audience in 2014 can afford to give its audience that much room to ponder is a question we may never get answered.

Contact

Robert Zemeckis’s 1997 adaptation of the Carl Sagan novel is probably the closest analogue of any film to Interstellar, to the point where their climactic scenes play like mirror images of one another. The connections range from cosmetic to more fundamental. For one thing, both films star Matthew McConaughey. For another, Contact’s recurrence of Occam’s razor as a rhetorical device is pretty easily compared to Interstellar repeatedly evoking “Murphy’s Law.” That both films ultimately hinge on the dimensions-spanning bonds of love between a father and his daughter is no small thing.

Contact sends Jodie Foster through a wormhole (just like our Interstellar heroes) to encounter an alien civilization. But rather than seeking salvation for the human race, Foster is merely on a fact-finding mission. She is purely a pioneer. In many ways, Contact behaves like an earthbound scientist craning its neck to get a glimpse at the infinite. Ninety percent of the movie is about the political and personal struggles that Foster goes through just to get to be humankind’s first experimental interstellar traveler. Even once Foster does enter that wormhole and emerges on the other side in the Vega star-system, the gooey beachfront scene with her “father” is very quickly sussed out by Foster as a façade—a way for the alien race to get on her level, so to speak.

Interstellar, meanwhile, sets up camp right inside that gooey familial space and lives there. McConaughey’s bond with his daughter, the oft-mentioned Murph, is not only the key to unlocking the film’s plot—it’s the saving grace of all mankind. The final scenes of Contact, in which Foster’s character tries in vain to convince a Congressional subcommittee of the veracity of her experience despite no hard evidence of it, are hugely frustrating from an audience perspective. While Interstellar takes up a lot of time explaining, and re-explaining, its concepts to the audience, the government skeptics in Contact could use some remedial lessons in relativity.

Sunshine

Danny Boyle’s 2007 film was hugely divisive but faded out of view when the director’s career took a leap the next year with Slumdog Millionaire. It’s tempting to use this space simply to compare the scores for both Sunshine and Interstellar: Hans Zimmer’s much-debated music for Nolan's film is testing the limits of how loud and insistent a piece of music can get before you can no longer describe it as “twinkly.” John Murphy and Underworld collaborated on the Sunshine score and subsequently changed the way audiences think of movie-trailer music forever.

The non-musical aspects of Interstellar that recall Sunshine lie in the ideas of sacrifice, of missions to space without concrete plans for return. The life of a handful of space crusaders is ultimately worth so little when stacked up against the survival of all mankind, but that’s a whole lot easier to say in the abstract. The mission in Sunshine is simple: Pilot a craft out to the steadily dying sun, set off a nuclear device inside the sun, and reignite the sun. The minute things start to go wrong (oh, they always go wrong) is the minute that it starts looking less and less likely that this mission is going to include a return trip. Almost every decision the Icarus II crew (including Rose Byrne, Chris Evans, and Cillian Murpy) makes is judged along one axis: what’s good for us vs. what’s good for humanity. As Interstellar progresses, decisions have to be made in the same way. On a long enough timeline, in both movies, enough things will go wrong that self-sacrifice becomes necessary for the survival of the species. Which is pretty convenient, since self-sacrifice is a nifty dramatic device.