Listening to the radio last month, I heard the film Gravity – which recently snapped up seven Oscars – described as “science fiction”. A quick check on IMDB shows that the ultimate movie directory also puts Gravity in the science fiction category. Is it, though?

Science fiction is notoriously difficult to define, but it’s usually speculative fiction, often inspired by possible scientific advancements we imagine the future will hold. It can involve settlements in other galaxies or extraterrestrial beings we have yet to discover, but even a dystopian Earth or an alternate version of Earth could be the setting for science fiction. In all cases, though, the setting is different from the reality we live in.

Gravity, on the other hand, is set in orbit around Earth, in the present day, and references technology we know and use. It features a telescope and two space stations that are far from fictional. Gravity doesn’t fit the classical description of science fiction, but the story does include both science and fictional elements. I’m going to talk about those now, so consider this your spoiler alert.

The film opens with medical engineer Ryan Stone (Sandra Bullock) repairing a broken panel on the Hubble Space Telescope. This is part of a shuttle mission she’s on with Matt Kowalski (George Clooney) and others. In the opening scene, the mission gets a call from Houston, warning them that, elsewhere above Earth, a missile impact on a satellite has caused debris. This space debris soon embarks on a trip around the planet, and is on course to hit Hubble and the shuttle. Stone and Kowalski are the only shuttle passengers to escape on time, and spend the rest of the film trying to get back to Earth.

If you ignored the previous spoiler alert, the real big spoilers are coming now.

Their plan involves spacewalking their way to the International Space Station, visible in the distance, and taking a small shuttle from there back to Earth. Just as they reach the ISS, the space debris has come around again, and knocks them about. Kowalski can’t seem to reel himself in on the cables he’s holding and, to save Stone, cuts himself free and gets swept into space. He drifts off all alone, out of radio contact.

The scientific accuracy of this sad scene is hotly contested. One view is that, since they are in space, there are no forces pulling Kowalski away, and Stone should be able to easily tug the cable and pull him in. However, the film’s science advisor, former NASA engineer Kevin Grazier, maintains that the physics is correct, and that Kowalski would indeed drift off.

After Kowalski’s departure, Stone makes it to the ISS, and via a detour about which I’ll spare you the details, to a second space station, Tiangong-1, from where she finally finds a shuttle to take her back to Earth.

The biggest inaccuracy in the film has to do with this journey between The Hubble Space Telescope, the International Space Station, and Tiangong-1. All three are real, all three are currently in space, but it’s impossible to casually travel between them without extensive prior calculations, because they aren’t in the same orbit, and not even at the same distance from Earth.

Is the assumption that Hubble, the ISS, and Tiangong-1 are all in the same orbit fictional enough to be considered a setting for “science fiction” though? I think not, and at least one film reviewer agrees with me. The film is set in our world and in our time. The film’s science advisor has tried to make the physics as accurate as possible. The main liberty that Gravity takes concerns the distance between three locations. This kind of deviation from reality is comparable to showing people in a film taking a direct train between two cities that aren’t connected by train – which is far from uncommon at the cinema. Gravity is an unrealistic journey that happens to be set in space, but that doesn’t make it science fiction.