The science of SCI-FI

We love a good sci-fi film, but do they get the science right? Amy Arthur picks six of the big mistakes made in space films

- Amy Arthur

Hollywood's greatest sci-fi blockbusters have taken us to the stars, introduced alien worlds and imagined humanity's future in the cosmos. But how often do they get the science right? In the rush to thrill and entertain, filmmakers often sacrifice realism for dramatic effect.

From explosive sound in the vacuum of space to impossibly fast interstellar travel, these cinematic liberties stretch - and sometimes break - the boundaries of actual science.

Here we take a look at six common mistakes that Hollywood makes about space science, unravelling the truth behind the fiction. What would really happen if there was a fire in space? Is warp speed actually possible? And could you have a punch-up in zero gravity? Get ready for science to set the record straight, proving that reality can be just as fascinating as fiction.

Fire in microgravity

Flames in space shouldn't behave like they do at home

Fire can't start in the vacuum of space, as there is no oxygen available for combustion. They can, however, start inside a spacecraft or space station that has oxygenated air for passengers. Any fire in space would look and behave differently than the lit candles on your birthday cake back at home, though, and that's down to gravity.

The typical teardrop shape of a burning candle on Earth is caused by the effects of gravity: hotter air is less dense, so it rises to the top of a flame in a peak. This also pulls in cooler, more oxygenated air, keeping the fire going.