The concept of time travel—travelling backwards and forwards through time—has always been a popular staple of science fiction film and science fiction television series. Time travel usually involves the use of some type of advanced technology, such as H. G. Wells' classic The Time Machine, or the commercially successful 1980s-era Back to the Future trilogy. Other movies, such as the Planet of the Apes series, explained their depictions of time travel by drawing on physics concepts such as the Special relativity phenomenon of time dilation (which could occur if a spaceship was travelling near the speed of light). Some films show time travel not being attained from advanced technology, but rather from an inner source or personal power, such as the 2000s-era films Donnie Darko and Mr. Nobody.
More conventional time travel movies use technology to bring the past to life in the present, or in a present that lies in our future. The film Iceman (1984) told the story of the reanimation of a frozen Neanderthal. The film Freejack (1992) shows time travel used to pull victims of horrible deaths forward in time a split-second before their demise, and then use their bodies for spare parts.
A common theme in time travel film is the paradoxical nature of travelling through time. In the French New Wave film La jetée (1962), director Chris Marker depicts the self-fulfilling aspect of a person being able to see their future by showing a child who witnesses the death of his future self. La Jetée was the inspiration for 12 Monkeys, (1995) director Terry Gilliam's film about time travel, memory, and madness. The Back to the Future series goes one step further and explores the result of altering the past, while in Star Trek: First Contact (1996) the crew must rescue the Earth from having its past altered by time-travelling cyborgs.
H. G. Wells novels The Invisible Man, Things to Come and The Island of Doctor Moreau were all adapted into films during his lifetime while The War of the Worlds was updated in 1953 and again in 2005, adapted to film at least four times altogether. The Time Machine has had two film versions (1961 and 2002) while Sleeper in part is a pastiche of Wells' 1910 novel The Sleeper Awakes.
With the drop-off in interest in science fiction films during the 1940s, few of the 'golden age' science fiction authors made it to the screen. A novella by John W. Campbell provided the basis for The Thing from Another World (1951). Robert A. Heinlein contributed to the screenplay for Destination Moon in 1950, but none of his major works were adapted for the screen until the 1990s: The Puppet Masters in 1994 and Starship Troopers in 1997. Isaac Asimov's fiction influenced the Star Wars and Star Trek films, but it was not until 1988 that a film version of one of his short stories (Nightfall) was produced. The first major motion picture adaptation of a full-length Asimov work was Bicentennial Man (1999) (based on the short stories "Bicentennial Man" and "The Positronic Man", the latter co-written with Robert Silverberg), although 2004's I, Robot, a film loosely based on Asimov's book of short stories by the same name, drew more attention.
The adaptation of science fiction author Arthur C. Clarke's novel as 2001: A Space Odyssey won the Academy Award for Visual Effects and offered thematic complexity not typically associated with the science fiction genre at the time. Its sequel, 2010, was commercially successful but less highly regarded by critics. Reflecting the times, two earlier science fiction works by Ray Bradbury were adapted for cinema in the 1960s with Fahrenheit 451 and The Illustrated Man. Kurt Vonnegut's Slaughterhouse-Five was filmed in 1971 and Breakfast of Champions in 1998.
