Recently we praised the latest sci-fi blockbuster Iron Man for including so many real-world technologies.
It makes a change, since all too often Hollywood's use of science involves shocking blunders: including spaceships making whooshing noises in Star Wars to the journey to the center of the Earth in The Core.
So, to give credit where it's due, we have picked out five more sci-fi films that go against the grain, and contain some accurate, plausible science. They may not be completely realistic, but they get it right when it matters most.
Be warned: this article inevitably contains a number of spoilers.
2001: A Space Odyssey (1968)
"Open the pod-bay doors, HAL."
Despite being made before the first moon landing, Stanley Kubrick and Arthur C Clarke's masterpiece is a strikingly realistic depiction of space travel.
It envisions interplanetary spaceships that use a variety of techniques to allow people to exist in zero gravity – some sections rotate to generate artificial gravity, others have walls covered in Velcro (or something similar) so that crewmembers wearing suitable shoes can walk across them.
Among the film's neater details:
All scenes in outer space are silent – sound does not travel in a vacuum The stars do not move past the ship – for there to be a visible motion of the star field, the ship would have to be travelling at close to the speed of light The crew eat paste-like food and only drink liquids through straws.
Additionally, crew members are shown coping with the boredom and routine of a long, straightforward trek across empty space.
Newtonian physics is strictly obeyed in the behaviour of the ship and little "pods" that the astronauts use to travel outside it. Trouble only starts when a carefully-aligned radio transmitter, the crew's lifeline to Earth, begins to drift out of position.
Eternal Sunshine of the Spotless Mind (2004)
"I walked out the door. There's no memory left."
The central character, Joel, discovers that his girlfriend Clementine has erased her memories of their relationship. Heartbroken and embittered, he goes to the company that performed the procedure and asks them to erase his memories as well.
However, as the procedure gets underway, he realises that he wants to keep the memories after all, and begins to resist.
This sort of selective memory erasure is well beyond our current technology, but there are good reasons to think it may not be impossible. Several forms of dementia affect particular types of memory – for instance semantic dementia, which targets only factual knowledge about the world, and not "personal" life memories.
Sensibly, the film depicts memory as essentially a network of links. In its frenetic second half, Joel is asleep while the technicians "operate" on his mind. We follow as he careens from recent memories of his relationship to those of his earliest childhood.
As he encounters each memory, it is identified by the technicians and erased, leading to spectacular sequences of him running through bookshops while books disappear from the shelves and escaping from a house that is disappearing one wall at a time.
"I can't lie to you about your chances, but you have my sympathies."
This sci-fi horror has a number of realistic touches, such as the use of suspended animation to keep the spaceship's crew alive during decades-long interstellar travel (no implausible faster-than-light travel for these astronauts).
It makes the list, though, for the vicious creature the crew encounters, in particular for the finer details of its life cycle.
The alien goes through three stages over the course of the film. It begins as an egg, which produces a kind of head-sized spider, equipped with a strong tail and a vaguely reptilian appearance. This attaches itself to the nearest living body and, while clamped over the face, implants an embryo into its victim's stomach. It then falls off and dies. The embryo survives by feeding on the victim's digested food. Eventually it breaks out (in the least pleasant way possible) and runs amok on the ship.
Every element of the life cycle can be found in nature, variously in parasites, robber wasps and social insects. Much of the film's suspense comes from the filmmakers' decision to let events unfold without too much explanation – the viewer has to piece the life cycle together for themselves.
Unfortunately, there are a couple of pretty dubious points. First, the adult somehow manages to grow from about 30 centimetres to 2 metres in a matter of hours. The alien is also equipped, throughout its life, with very strong acid for blood. For that to work, the rest of it must be made of Teflon, as conventional organic tissue would obviously be destroyed.
"We now have discrimination down to a science."
Andrew Niccol's film is noteworthy for its grimly plausible vision of a society dominated by genetic prejudice.
The majority of babies are conceived using IVF, following a process of preimplantation genetic diagnosis that weeds out all genetic imperfections. As a friendly geneticist explains to worried parents, "This child is still you, simply the best of you." Everyone's identities, and their genetic status, are also continuously monitored by biometric ID systems.
The central character, Vincent, is an "in-Valid" – he was conceived naturally, and consequently is short-sighted and has a heart defect. Debarred from all but the most menial jobs, he pays a crippled "Valid" to lend him his genetic identity – in the form of urine samples and the like – so he can pursue his dream of becoming an astronaut.
The society depicted in Gattaca is intentionally dystopic, sometimes to the point of parody. Most notably, Vincent's job interview at the Gattaca Aerospace Corporation consists entirely of a urine sample. However, genetics can only give statistical predictions, and rarely delivers 100% certainty. So the company would be well-advised to put him through a real interview as well.
Nevertheless, it is one of the few films to tackle the issue of genetic determinism: how much are we really controlled by our genes? Vincent out-competes genetically-superior characters mostly through sheer strength of will. Does that mean that genetic testing really cannot predict how people will perform – or does it just mean we haven't found the genes for willpower yet?
Solaris (1972 and 2002)
"I was haunted by the idea that I remembered her wrong, and somehow I was wrong about everything."
This Russian classic makes the list not so much for the specific science it portrays, as for its portrayal of the limits of science and of human understanding.
Psychologist Chris Kelvin is dispatched to a space station orbiting the mysterious planet Solaris, to find out why the crew has stopped responding to messages from Earth. He discovers them in a state of emotional breakdown, and is soon in the same condition himself. After falling asleep on the station for the first time, he wakes to find his wife Rheya, who committed suicide years before, next to him.
Somehow, and for no reason ever made clear, Solaris has brought Rheya back, constructing her using her husband's memories. But is she really Rheya, or is she just Chris's flawed recollection of her, seen through his own preconceived ideas and limited understanding? Solaris itself is equally inexplicable, creating bizarre geometric shapes across its surface that may or may not be alive.
Stanislaw Lem, who wrote the original novel, was convinced that extraterrestrial life would be so strange that humans would be unable to understand it. Solaris gets right to the heart of this idea.
Despite being a trained psychologist and an educated man, Chris cannot even understand his wife. How then, the film asks, could he possibly understand something as alien as Solaris? Devotees of quantum mechanics and the consciousness problem will no doubt sympathise.