16. Avatar (2009)
Forget the “Dances with Smurfs” jokes; if anything, Avatar is riffing on pulp sci-fi classics like John Carter of Mars – in which a human soldier is transported via astral projection to another planet, gains superpowers and falls in love with a local girl. Sound familiar?
Inspired by his interest in deep-sea exploration and environmentalism, director James Cameron conjured up the alien world of Pandora – where strange alien creatures live in harmony with the native Na’vi. When humanity turns up to destroy everything with a dose of corporate greed, it’s left to hero Jake Sully to turn his back on the humans and save the Na’vi.
The plot may be so predictable that you can see its twists coming a mile off, but where Avatar truly shines is in creating a living, breathing 3D world, peopling it with characters realised through performance capture. At times, you’d be hard-pressed to believe that what you’re seeing on-screen isn’t real – it’s a triumph, heralding a new age of 3D and believable computer-generated characters.
17. Forbidden Planet (1956)
It looks rather quaint and dated now, but this 1950s film was spectacular in its day. Previously, the sci-fi genre had been the preserve of B-pictures and Saturday matinee serials, but Forbidden Planet was a big-budget picture with big ideas – based on no less a source than Shakespeare’s The Tempest.
From the matte paintings and spectacular sets that opened up the film’s scope, to its electronic score, the film pushed the boundaries of what was possible on screen at the time. And, in the Monster from the Id – animated by Disney artist Joshua Meador – it explored themes of the subconsicious and the work of Carl Jung.
It deserves to be remembered for far more than Leslie Nielsen playing it straight and a star turn from Robbie The Robot. An all-time great.
18. Gravity (2013)
It may be set in outer space, but Alfonso Cuarón’s thriller is remarkably contained; grounded, even. There are no flying saucers or little green men here, just a worryingly feasible disaster in orbit that leaves astronaut Ryan Stone stranded miles above the Earth. It’s heavy on spectacle, but for much of the film, the only person on screen is Sandra Bullock – giving a career-best performance as Dr Stone.
To achieve the film’s extraordinary long takes in zero gravity, Cuarón used innovative visual effects trickery – the actors stood inside a box delivering their lines, while lights moved around them to simulate the lighting sources shifting as their characters moved. Then their faces were composited into CGI spacesuits for the final shot – in many sequences, the only real thing in the frame is Sandra Bullock’s face.
19. Dark Star (1974)
Possibly the strangest premise ever for a sci-fi movie: a crew of planet demolitionists, with a dead captain who can be awoken from deep freeze to offer advice, is struggling with one of their bombs becoming sentient and thinking it's God. Oh, and there's an alien that looks suspiciously like a beach ball.
John Carpenter’s directorial debut was originally intended as a short student film; when it was picked up for theatrical distribution, he shot extra footage and re-edited it. Although it kickstarted his film career, Carpenter was never entirely happy with the theatrical cut, feeling that it worked better as a short film, where its budgetary shortcomings were more easily overlooked.
Screenwriter Dan O’Bannon subsequently took one of the film’s comedy subplots – a hunt for an alien aboard the spaceship – and refashioned it into a horror film: Ridley Scott’s Alien.
20. Serenity (2005)
When Fox axed Joss Whedon's 2002 sci-fi series Firefly after just one season, the outrage from his fanbase was predictably rabid. To be fair, they had a point – in the show's 14 episodes, Whedon had sketched out a universe that begged to be explored further.
In 2005, he got that opportunity, reuniting the show's cast for a movie sequel that wrapped up most of the show's dangling plotlines. For Firefly fans, it's a must-see – but it's also a fine sci-fi film in its own right, a space western with some big ideas packed in there. The film's opening shot is worthy of note, too; it's a masterclass in film-making, with Whedon (re)introducing the ensemble cast and the titular spaceship in a single long take.