How can a rocket and thrusters work in space when there is no atmosphere to push against? The space ship/rocket would stay still and all the thrust matter would just be ejected. - For example, If the rocket wants to turn left, it is always shown as firing a thruster from the right side that turns the rocket/ship to the left. But in a vacuum all that would happen is the matter that came out of the thruster would be sucked into the vacuum and spread out evenly. The ship would not move. 🤔 Nothing to push against.

Edit: I see now (from the more helpful replies) That it is not the rocket pushing back, but rather the combusting expanding fuel that is pushing the rocket forward. Which makes sense to me now.

Google says thrusters are similar, in that it is expanding steam etc.

[–] douglasg14b@programming.dev 15 points 1 month ago* (last edited 1 month ago) (1 children)

Equal and opposite reaction.

There's a law for this. The matter is "pushing" against the ship, it doesn't have to push against anything else.

In fact having an atmosphere to push against actually reduces the effectiveness of thrust due to atmospheric pressure, which must be overcome. Which is why different engines are designed to run in atmosphere versus out of atmosphere.

If you throw a baseball in space you have transferred momentum to that baseball, pushing you back. You will move in the opposite direction (likely spin because you just imparted angular momentum onto yourself since you didn't throw from center of mass)

[–] LustyArgonianMana@lemmy.world 5 points 1 month ago

Yes this is the conservation of momentum.

https://youtu.be/Fp7D5D8Bqjc?si=KyIr0doj2Pinf6U5

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