this post was submitted on 03 Aug 2024
1141 points (100.0% liked)

196

16226 readers
2445 users here now

Be sure to follow the rule before you head out.

Rule: You must post before you leave.

^other^ ^rules^

founded 1 year ago
MODERATORS
 
you are viewing a single comment's thread
view the rest of the comments
[–] mossy_@lemmy.world 2 points 1 month 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@programming.dev 10 points 1 month ago

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

[–] StormWalker@lemmy.zip 1 points 1 month 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.

[–] PythagreousTitties@lemm.ee 7 points 1 month ago (1 children)

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

[–] Klear@sh.itjust.works 5 points 1 month ago (1 children)

Also numerous tests in space.

[–] PythagreousTitties@lemm.ee 4 points 1 month ago* (last edited 1 month 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.

[–] Quatlicopatlix 5 points 1 month ago (1 children)

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

[–] TheOakTree@lemm.ee 5 points 1 month ago

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

[–] StormWalker@lemmy.zip 1 points 1 month ago* (last edited 1 month 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

[–] lud@lemm.ee 3 points 1 month ago* (last edited 1 month 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.