How do rockets move in space when theres nothing to push against?

>>7709765
the exhaust gases push against the rocket

gas goes one direction, rocket goes in the opposite direction

>>7709765
The combustion of the fuel itself pushes the rocket away from the burning point. The engine does not push on anything, it is the push.

>>7709765
>reaction mass

>>7709773

fuck off tripfag

It doesn't need to push against anything. If you stood on a small boat on a lake and threw a heavy object in one direction, the boat will move in the opposite direction.

Newton's third law.

>>7709875
the boat is pushing against the water

>>7709944
No. The boat is not "pushing against the water" not when it comes to the initial movement.
It's you who's pushing against the rock to throw it. The rock "pushes back" with it's weight.
The rock moves and you move, the rock gets thrown overboard and you push against the boat itself, which then starts moving.

Only when the boat starts moving does it "push against the water".

>>7709765
Actual top scientists trashed Goddard's rocket work for this exact same reason. /sci/ could learn a lesson from this.

The earth can slingshot you at high speeds due to how fast it spins. Once your in space there is no friction to slow the rocket so they can maintain that speed for a while. New Horizons travels at 15.73 km/s

>>7709961

It would be easy to test using a small rocket-like device in a vacuum container though. You don't have to actually go to outer space to prove it.

>>7709961

Pretty much every major innovation has been poopoo'd by sideline blowhards.

>>7709765
A rocket doesn't "push against something" to move. Neither does a jet engine, or a jet ski.

The propulsion of a rocket is based on the application of Newton's 3rd Law of Gravity - every action has an equal but opposite reaction. In simple terms, a force acting in one direction produces a reaction of the same amount in the other direction.

So in the case of a rocket, when the fuel is burned the force of the hot gasses escaping through the rocket's exhaust creates an equal force acting in the opposite direction. If the gasses escape to the rear, the reaction force acts in the forward direction and the rocket moves forwards.

It's the same action that causes guns to recoil when fired - as a bullet leaves the gun, the force of the bullet creates an equal force acting in the opposite direction and this is felt as a recoil.

>>7709788
>tripfag

>>7710011
It actually pushes against the rocket fuel, and thus ends up moving in the opposite direction.

>>7709983
No because some virgin will say it pushed against the container wall.

>>7710011
Well, actually, a rocket *does* push off something to move. It pushes off the rocket fuel, also known as "reaction mass".

There's no difference between pushing off of the Earth, pushing off of a bowling ball, and pushing off of a hydrogen molecule, except that you have to push the lighter ones a lot harder.

Recoil is the gun pushing off of the bullet.

I'm not actually substantiatively disagreeing with anything you said, just pointing out that *all* applications of Newton's Third Law are "things pushing off of other things." And it's the Third Law of Motion, not of Gravity; you may be able to figure this out by noticing it has nothing to do with gravity.

The combustion pushes against the rocket.

/thread