The 25 best sci-fi movies that are out of this world

15. Avatar (2009)

The movie: Visually spectacular and one of the few actually really good uses of 3D, Avatar dazzles with its vibrant jungle planet and ambitious mo-capped performances. Despite the liberal use of cgi, the gigantic blue cat-like aliens with their ability to tame the local wildlife via psychic links, feel surprisingly real. Though the humans who want to destroy a giant tree to mine what's beneath feel like pantomime villains rather than real people. James Cameron knows what he's doing; the movie is the biggest grossing of all time and currently has several sequels in development.  

Most iconic moment: It sure is a long one, but nevertheless, the lengthy air-strike fight between the humans and the Navi is breathtaking.  

14. Close Encounters Of The Third Kind (1977)

The movie: An average working man played by Richard Dreyfuss becomes obsessed with UFOs after one appears right over his truck. As strange occurrences follow shortly thereafter - such as power outages and planes reappearing after 30 years - his behaviour becomes more erratic. As is later revealed, something more is at work here and the answer is in five musical notes. Spielberg's hymn to cinematic awe transforms us all into young Roy Nearys, slack-jawed and wonder-struck by the infinite possibilities of the universe.  

Most iconic moment: Hearing those five notes for the first time - chilling, eerie and beautiful.  

13. Donnie Darko (2001)

The movie: A troubled teen has visions of a giant bunny called Frank who tells him the world is going to end in 28 days. Frank draws Donnie away from his bedroom the night a jet engine crashes into it so he is unharmed, but he doesn't always have Donnie's best interests at heart. Is Frank just a hallucination or is there something more to it? It's a tantalising Mobius-strip of a movie that spins off questions and never stops for answers.

Most iconic moment: Donnie takes Gretchen to a double-bill at his local cinema, where Frank the Rabbit decides to turn up and show Donnie a wormhole.  

12. Back To The Future (1985)

The movie: The most famous tale of time-travel in film history, Back to the Future remains a classic to this day. After accidentally being sent back in time time to the 1950s, Marty McFly (Michael J Fox) must make sure his parents fall in love so that he can still exist in the future and help mad scientist Doc Brown (Christopher Lloyd)... so he can send him back to the 1950s. Okay, there's some time loop stuff going on that's always the case when temporal logic enters into things, but who cares? With iconic quotable moments galore, this is a fun ride from start to finish. 

Most iconic moment: The first time the Delorean reaches 88mph in the Twin Pines mall parking lot.  

11. Blade Runner 2049 (2017) 

The movie: Blade Runner 2049 is that rarest of beasts; a sequel to a beloved classic that not only lives up to the impossibly high expectations, but exceeds them. 30 years after the events of the original Blade Runner, LAPD officer K (Ryan Gosling) stumbles onto a secret from the past that could reshape the course of the future. His trail leads him to none other than an older, grumpier Deckard, and that's where things get really interesting. 

Most iconic moment: K and Deckard meet for the first time, neither of whom are fully acute to the significance of their encounter. 

10. The Terminator (1984) 

The movie: Sometime after he directed Pirahna Part II: The Spawning, James Cameron awoke one night from a terrible nightmare where he saw a metal torso rise up from the debris of an explosion. That delightful visual stayed with him, serving as inspiration for The Terminator. His full debut is the perfect sci-fi thriller: glinting black wit, fatalist tech-noir visuals, phenomenally visceral action. While its sequel splurged on expensive set pieces, the first film is more concerned with the horror and suspense of being pursued by an unstoppable killer. It also marks the birth place for Arnold Schwarzenegger's most iconic role as the Terminator himself.  

Most iconic moment: "Come with me if you want to live!"  

9. The Matrix (1999) 

The movie: Is real life really real life? Turns out it's not in The Matrix and we're all plugged into a simulation of what Earth once was so that robots can harvest us for electrical energy. Lovely. But once you know that? The world, sorry The Matrix, is your oyster. At least that's the case for Keanu Reeves' Neo who chooses to learn the truth about the machines and his own fate as The One. This makes it easier for him to manipulate the matrix and bend it to his will. It makes for some impressive slow-motion bullet fights.  

Most iconic moment: Neo and Trinity getting trigger happy during the lobby sequence, blasting the crap out of dozens of agents. Hands down.

8. Inception (2010)

The movie: This film takes the idea of being able to control your actions in lucid dreams and runs with it in some stunningly inventive ways. Dom Cobb (Leonardo DiCaprio) is a thief usually charged with stealing secrets from people by navigating their dreams, but is tasked with something much bigger - actually implanting an idea within someone else's head. To do so they must plant a dream within a dream within a dream, a feat that's incredibly difficult to pull off. It's a colossal concept played out on a multi-layered mental battlefield homaging the best Hollywood blockbusters. 

Most iconic moment: Joseph Gordon Levitt, uhhh, levitt-ating (ahem) in a hallway while fighting a whole bunch of bad guys.  

7. Aliens (1986) 

The movie: What's scarier than one Alien? A million of the slobbering, acid-for-blood xenomorphs, slowly picking off a mining colony that's what. Ripley returns, albeit reluctantly, as she aids a group of space marines to establish what happened to the citizens of a colony on LV-426 after all communication is lost. That planetoid happens to be the very same one from the first movie, so it's no surprise that Ripley's a bit reticent to join the mission. It's an incredibly tense sequel, packed with some of James Cameron's best action sequences and finest characterizations.   

Most iconic moment: The doors to the elevator open, Ripley steps out to greet the snarling alien queen. The power loader clunks across the floor as she spits "Get away from her you BITCH!"  

6. ET: The Extra-Terrestrial (1982)

The movie: A small alien gets left behind on Earth after his ship is chased away by a human force, but he soon makes friends with 10-year-old Elliot and his siblings. He gets homesick however and works on a way to build a device to get himself home. The connection they share has some incredibly heartfelt moments and Spielberg's touch has never, ever been more magical than in this wondrous family drama. 

Most iconic moment: Elliot and the gang fly their bicycles in the night sky.  With ET's help, of course.