as everyone with a fucking brain knows, a rocket engine works by throwing really fucking hot gasses at really fucking high speeds
But user, that's not how a rocket works. A rocket works because gases exert their average pressure equally on all sides of their container. The combustion chamber of a rocket is their container. And the act of combustion is what creates the pressure. When a nozzle is opened at one of of the container, the pressurized gases exit the chamber without exerting force on that area of the container, which creates a net positive force on the opposite side of the container.
When a rocket is activated, the force isn't being applied by the flaming fumes coming out the ass end. The force is being applied on the opposite side of the combustion chamber.
Now if you stood behind a rocket, and got hit by the hot gases moving at high speeds, they would inflict a force upon you. And the force they would inflict upon you, is the exact amount of force they DIDN'T inflict upon the ass end of the chamber, which is why the front end of the chamber was able to scoot the rocket away.
To illustrate this, imagine there are only two particles bouncing back and forth in a rocket between the front, and the nozzle door, hitting each end of the rocket at precisely the same time. Every time one of them hits the nozzle door it is saying "I really want to make the ship go backwards!" but at the same time, the other particle is hitting the front of the rocket saying "I really want to make the ship go forwards!" They cancel out.
But as soon as the nozzle door is open, the one moving backwards leaves the ship without exerting it's force. At the precise same time the one moving forwards hits the front of the rocket and says, "I want to make the ship go forwards!"
Well now, it pushes the ship forwards because his little buddy fell out the open door into space and can't provide an equal force upon the other side of the rocket.
Now you just have to scale this up to an incomprehensible numbers of particles, and instead of going back and forth perfectly front to back, they are moving in random directions all over the place. Mathematically speaking, we can assume that every particle that flies out the open nozzle door in the back has a corresponding partner going the exact opposite direction towards the front. More often that not, their vectors aren't completely forwards and backwards but exist and contact at angles that simple over time provide an average movement as though they moved precisely front to back.
Or to sum it up, a rocket doesn't work by throwing flaming super fast gases out it's ass end. That is an unfortunate side of effect of trying to maintain a pressure differential in the chamber. If we could maintain a pressure differential in the chamber without throwing shit out, that would be ideal.
You may already know this. But I want to get this out there before the morons who show up and claim that rockets don't work in space show up. They fundamentally believe the particles leaving the ass end are pushing against other particles in order to move the rocket forwards, and therefore declare that rockets don't work in space because the shit leaving the ass end has nothing to push off against in the vacuum of space.