published on 17 December 2015 in space
The infinite space that lies beyond the Earth’s atmosphere is not easy to reconstruct in the cinema, not so much for technical reasons – nowadays, in fact, special effects are increasingly surprising – but because respecting the laws of physics while making a compelling film is not easy! One of the films that has, and still does, kept us glued to the screen is Star Wars: let’s see together some of the most unlikely scenes from a scientific point of view of one of the film sagas with the highest audience… in the hope that after reading them we will not have ruined your viewing of the “The Force Awakens”, released yesterday in cinemas throughout Italy.
Sounds in space
George Lucas with his Star Wars created a universe of unforgettable sounds, including the breathing of Darth Vader, the sound of the Laser Blasters and the Lightsabers while the Jedi are fighting and many others.
The sounds you normally hear are vibrations that are transmitted through the air that reach our ear: they need a material medium (air, in our case) to propagate, otherwise they cannot be heard. In empty space, therefore, noise cannot be propagated and it becomes impossible to hear the explosion of a spaceship or the noise of a weapon as in science fiction films. So, from now on, when in Star Wars the rebel forces destroy the Death Star, with a loud explosion, you should know that, in reality, no one has heard a pin drop.
Faster than light!
Who has not dreamed as a child of being able to travel at the speed of light on board the Millennium Falcon with Han, Luke and Leia? In reality, as we know, you cannot reach the speed of light (300,000 km/sec). But let’s assume for a moment that this hypothesis was to come true: what we would see from the “windshield” of our ship? Certainly not what George Lucas has shown us in the films of the Star Wars saga. The spaceship crew, in fact, would not see an endless trail of stars, but simply a very bright disk of light, as if the stars had melted.
In science fiction films there is always a certain amount of asteroids on a collision course with the spaceships of our heroes, such as in the case of Star Wars. Once we thought that asteroids moved around in space and constantly crashed against the body of the spacecraft; the most exuberant writers even imagined them struggling with dense clouds of asteroids to be avoided through the rings of Saturn. In reality, even in the asteroid belts, these objects are situated at an average distance of hundreds of thousands of kilometres one from another.
There cannot be so many explosions!
Fire is due to a chemical reaction, combustion. Combustion involves the oxidation of a fuel by a combustive agent (which is typically represented by the oxygen present in the air), with the generation of heat and electromagnetic radiation. Without these conditions, lighting a fire or even just a spark would be impossible. So all those films that have accustomed us to loud explosions in space are assuming that in space there are the conditions for lighting a fire… We know very well, however, that in reality there is no oxygen in space!