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submitted 4 months ago by [email protected] to c/[email protected]

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[–] [email protected] 2 points 4 months ago (3 children)

You're on to something, I suppose, but the conservation of momentum does allow for travel in a vacuum. The matter ejected by the thruster pushes against the rocket.

[–] douglasg14b 10 points 4 months ago

They're not on to anything here. As further stated by your comment.

[–] [email protected] 1 points 4 months ago* (last edited 4 months ago) (1 children)

Yes I agree with you in that it would have the undisturbed momentum from pushing off from earth. But no way to slow down, or change course. I'm not sure mater ejected could push back. Surly the vacuum of space would just suck the rocket or thruster empty as fast as possible. . It just bugs me. Lol

[–] [email protected] 3 points 4 months ago* (last edited 4 months ago)

But no way to slow down, or change course.

It's very simple actually. If you want to change course or slow down you just eject mass in another direction. To slow down you just spin the rocket around and burn in the opposite direction (or you could have two engines in both directions if you wanted, but I don't think any rocket has that.)

I'm not sure mater ejected could push back.

Ejected in this case usually means very violently pushing fuel/gas in one direction. There isn't a small gnome sitting on the engine throwing blocks of fuel into space, even if they technically could have worked. Instead we use very powerful engines.

The ejection itself provides the push back, not the matter. Once the matter has been ejected it doesn't do jack shit.

Surly the vacuum of space would just suck the rocket or thruster empty as fast as possible. . It just bugs me. Lol

I'm sure they close the valves when they aren't actively using the engine. It's not like fuel injectors in cars just constantly spray out fuel, even when parked.

[–] [email protected] 1 points 4 months ago (1 children)

It could be tested to a degree with a vacuum chamber here on earth. Put a little rocket inside horizontally and see if it moves when fired in a partial vacuum.

[–] [email protected] 7 points 4 months ago (1 children)

It might surprise you, but there have been numerous tests in vacuums on earth.

[–] [email protected] 5 points 4 months ago (1 children)

Also numerous tests in space.

[–] [email protected] 4 points 4 months ago* (last edited 4 months ago) (1 children)

Yup. You'd also have to discount satellites as fake if you choose to not believe in rockets. And also everything that satellites provide for us.

Plus, you know... basic physics.

[–] [email protected] 5 points 4 months ago (1 children)

Pff gps is a hoax, in reality there is a little goblin with a perfect sense of direction in your phone.

[–] [email protected] 5 points 4 months ago

GPS: Goblin's Perfect Sense (but in the phone)