A blog explaining science and technology through the movies ... or explaining the movies through science and technology, depending on the point of view. English is not my first language, so I apologize for the mistakes you are likely to find in the posts

Friday, October 27, 2006

Total recall: Schwarzenegger under pressure

Living on another planet is quite complicated for any animal on Earth, man included. Evolution has provided us with bodies fully adapted to the Earth, actually to very definate and restricted habitats (the sea, rivers, jungles, the pole, …). The idea of human beings living in another planet is like thinking of a fish living on the mainland or a polar bear living on the tropics.

Apart from the gravity problem we dealt with a couple of posts ago, which must be taken into account seriously, we have the atmosphere matter. Our bodies are machines which work by burning food with oxygen in a chemical reaction of combustion, quite similar to the one that takes place inside a car’s engine. We need an atmosphere that allows us to breathe oxygen in order to live. In addition to that, it protects us from ultraviolet rays coming from the sun, and, in the third place, it allows blood to run through our veins.

As with any other fluid moving, blood flows through our body under a certain pressure, and the same is true for the air on our lungs. If we were out on the void with no atmosphere, blood and air pressure would swell our skin and take our eyes out of their orbits, among other things. It is thought, though, that our skin is strong enough to take this without breaking, or without bursting at least. In normal life the atmospheric pressure on the outside makes up for pressure inside our bodies; not always in a perfect way, though, and that’s why some people have high or low blood pressure. On the void, nevertheless, the very low pressure would evaporate the water inside the cells, causing death in less than one minute.

This phenomenon was shown in a rather harsh way in the 1990 movie Total recall. Harsh but probably exaggerate, as we have said the body is believed not to burst on the void. This film, though, hits the nail on the head at explaining what a human colony on other planet would be: a bunker or a bubble with an artificial atmosphere inside with the same quantity of oxygen and the same pressure that there are on the Earth.

Lack of oxygen can cause malformations on pregnant women’s fetus, which produced all sort of mutants in the movie. On the other hand, too much oxygen would raise the risk of fire and turn the planet into a powder magazine. And in case someone pierces the artificial atmosphere bubble, like Arnold Schwarzenegger and his girlfriend do at the beginning of the movie (in a premonitory dream) and also in the end, he would find himself exposed to radiation and with his head on the verge of exploding. Therefore, thinking of human beings walking peacefully over the surface or remote planets with no need of a spacesuit is nothing but a beautiful dream.


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