Reading The Martian and thinking about things like depressurisation – why does air from a higher concentration feel the need to rush through a small leak with enough force to rip or blow things apart instead of staying put?
What calls it from the vacuum for it to be so obsessed in doing so?
In: Planetary Science
Air particles are moving around very fast, bouncing off each other at the speed of sound. Though affected by gravity (if present), this energy and bouncing will cause them to spread themselves out fairly evenly. With gravity the pressure at the bottom is higher than the pressure at the top, but it’s a small difference most of the time. Eventually, air pressure reaches its consistent point and it feels like nothing’s moving at all.
At least, until your hole forms in your spaceship or whatever. Now the air that happens to find its way into the hole goes out… and let’s be honest, is never coming back again. So now there’s fewer molecules in that area bouncing around, so the bouncing around of other molecules wins the war of numbers and pushes themselves towards that hole… But that just means more air heads for the hole and slowly (or quickly) escapes, never to return again.
Over time, pressure keeps dropping and dropping until it’s so low it might as well be zero. 1% air pressure to a human might as well be 0%.
A vacuum is not a force. But in general, “balance” is what forces want and a vacuum will be filled by the force, if it can.
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