In media you’ll occasionally see someone stranded in freefall in space use a gun, or fire extinguisher, or thrown object, or something to try to alter their trajectory. Hell, pop a bottle of champagne and rechristen the ship!
Would this actually work though? I know you don’t have to deal with friction, but would these tiny amounts of thrust be enough to significantly effect a much more massive object?
Will firing a 125 gram 9mm round have a noticeable effect on a 80,000 gram astronaut drifting away from his ship?
It seems hard to believe,but then I’ve heard of stuff like solar sails which can apparently move an entire ship using just photons? So I don’t know.
In: 9
You can run the maths to find out.
Momentum must be conserved, so if you fire a 100g bullet at 500m/s, (numbers made up) it has 50kgm/s of momentum in one direction, meaning the astronaut that fired it has 50kgm/s of momentum in the other direction (if we assume none of it was turned into angular momentum by firing off-center of mass).
For a human (and equipment) weighing 100kg total, this would mean they have been accelerated to 0.5m/s, which isn’t much, but if you were next to a relatively stationary object you would be able to notice the motion.
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