eli5: If space is a vacuum, how can rockets work? What are the thrusters pushing *against* if there is nothing out there?

543 views

I’ve never really understood the physics of this. Obviously it works somehow — I’m not a moonlanding denier or anything — but my (admittedly primitive) brain continues to insist that a rocket thruster needs something to push *against* in order to work.

So what is it pushing against if space is essentially a void?

In: 7157

31 Answers

Anonymous 0 Comments

To push is to give something a shove into another object. With helicopters it is air being shoved into the ground. The helicopter would generate equally as much lift if it was flipped upside down in our atmosphere

Now with rockets you are throwing a shit ton of hot gas out the back. In space this hot gas will not slow down. who knows if it will eventually hit a planet, asteroid or just get slowed down by colliding with particles in space.

Either way you threw mass away from you and that’s what makes you go in the opposite direction.

You are viewing 1 out of 31 answers, click here to view all answers.