What does a rocket push against in space?

50 yrs since even manned round trips to the moon, yet no video of propellant ignition resulting in propulsion and thrust velocity/acceleration in action.. whatta shame.

Seeing is believing, NASA.

(Faking it doesn't count, Musk)

Is space even really a vacuum?

The whole arena of space videos seems peculiarly shrouded in layers of edits and cuts, for decades now, yet they're planning commercial tours to mars and so on.

Maybe in another 50 years.

a reply to: oldcarpy

Claim that those are fake/CGI in 3...2...1.....

looks like you got that one right.

a reply to: NicSign

Why do you think a rocket will not work?

Think about it this way. The gas exiting from the rocket is basically a controlled explosion. If the reacting gasses were not in a nozzle, the exit gasses would want to expand in all directions. Is that false. In a rocket, the gas release is forced out in one direction. Is that false. So the gas is required to push against the combustion chamber. Is that false. The expanding gasses by contact and collisions is forced out the nozzle opening. Is that false. So by Newton’s third law, the expanding gasses forced out of the nozzle by contact will result in thrust for the rocket. Is this false. Using Newton’s third law to move the rocket has nothing to to with the atmosphere. Is that false.

originally posted by: Artesia
50 yrs since even manned round trips to the moon, yet no video of propellant ignition resulting in propulsion and thrust velocity/acceleration in action.. whatta shame.

Seeing is believing, NASA.

(Faking it doesn't count, Musk)

Is space even really a vacuum?

The whole arena of space videos seems peculiarly shrouded in layers of edits and cuts, for decades now, yet they're planning commercial tours to mars and so on.

Maybe in another 50 years.

I bet you don’t understand why you can’t here the rockets? Or you don’t understand they don’t fire rockets near the international space station? Or spaceships don’t always use fired rockets to maneuver, but do use hard to see high pressure bottled gas. And if there is no external camera near to capture anything, it’s not going to be be filmed.

To bad there is third party verification and radar tracking of space flights to the moon. You can actually find the landing sites from lunar mapping by the Chinese. The international space station is the third brightest object in earth’s sky. To bad the distance to the moon is measured with lasers by using mirrors placed on the moon by moon missions. Never mind GPS satellites, satellite phones, telecommunications satellites, images from Hubble space telescope, missions to planets, and missions to comets.

Docking of Soyuz MS-12 To International Space Station
m.youtube.com...

Soyuz undocking, reentry and landing explained
m.youtube.com...

originally posted by: NicSign
a reply to: moebius

Pgf= 1/density*difference in pressure.

So if you can give me a figure of how much pressure is built up in the rocket chamber, I can calculate it for you.

According to Wikipedia the NK-33 chamber pressure is:

"Chamber pressure 14.83 MPa (2,151 psi)"

At earth's surface the pressure of one atmosphere is about 0.1 MPa or about 14.7 psi.
In space the outside pressure is about zero so the pressure gradient in space (the full 14.83 MPa - 0 MPa) is actually a little higher than near Earth's surface (14.83 MPa - 0.1 MPa).

As I told you in the other thread though, you can't overlook conservation of momentum. This describes the correct way to calculate thrust as far as I know:

www.braeunig.us...

The chamber pressure is Pc in that diagram, but the thrust formula uses the pressure at the exit of the nozzle instead, Pe.
The formula also uses the conservation of momentum parameters moebius mentioned.

I also don't know what you plan to use for density since the density in the nozzle changes a lot from from the entrance end to the exit end.

originally posted by: NicSign
a reply to: wmd_2008

Are you sure it’s just not an aerial photograph form a plane or helicopter?

YES I'm sure its not from a plane did you even look at the web site link look at the perspective of the Mecca video.

a reply to: tinymind

You take your 'scientz' and your 'fizzix' and get stuffed.

This is a place for insane theories and fringe dwellers, not facts.

a reply to: Artesia

Uh-huh....

originally posted by: OneBigMonkeyToo
a reply to: Artesia

Uh-huh....

Stop using facts and documentation to destroy a ludicrous conspiracy fantasy based entirely on innuendo and prideful self delusion.

a reply to: Arbitrageur

Thrust equation thoroughly debunked
www.youtube.com...

a reply to: OneBigMonkeyToo

Why does it look so fake?

originally posted by: NicSign
a reply to: Arbitrageur

Thrust equation thoroughly debunked
www.youtube.com...

How. How does it debunk Newton’s third law. Care to develop an actual argument. I know it’s hard when you referenced a blatant falsehood.

By the way.
Think about it this way. The gas exiting from the rocket is basically a controlled explosion. If the reacting gassed were not in a nozzle, the exit gasses would want to expand in all directions. Is that false. In a rocket, the gas release is forced out in one direction. Is that false. So the gas is required to push against the combustion chamber. Is that false. The expanding gasses by contact and collisions is forced out the nozzle opening. Is that false. So by Newton’s third law, the expanding gasses forced out of the nozzle by contact will result in thrust for the rocket. Is this false. Using Newton’s third law to move the rocket has nothing to to with the atmosphere. Is that false.

a reply to: neutronflux

It doesn’t debunk Newton’s law. It just show how it is misapplied. Where is your proof of an equal and opposite force from gas movement due to pressure gradient force.

originally posted by: NicSign
a reply to: neutronflux

It doesn’t debunk Newton’s law. It just show how it is misapplied. Where is your proof of an equal and opposite force from gas movement due to pressure gradient force.

Ok, and your video is wrong.

Below is how a rocket works regardless of vacuum.

Think about it this way. The gas exiting from the rocket is basically a controlled explosion. If the reacting gasses were not in a nozzle, the exit gasses would want to expand in all directions. Is that false. In a rocket, the gas release is forced out in one direction. Is that false. So the gas is required to push against the combustion chamber. Is that false. The expanding gasses by contact and collisions is forced out the nozzle opening. Is that false. So by Newton’s third law, the expanding gasses forced out of the nozzle by contact will result in thrust for the rocket. Is this false. Using Newton’s third law to move the rocket has nothing to to with the atmosphere. Is that false.

Again, Newton’s third law can be expressed without terms of pressure gradient force.

Unless you want to mathematically show how the only deciding factor for Newton’s third law is “ pressure gradient force.“

a reply to: neutronflux

So then when wind blows on the back of your head why doesn’t the air in front of you push off off your face as it moves away from you?

originally posted by: NicSign
a reply to: neutronflux

It doesn’t debunk Newton’s law. It just show how it is misapplied. Where is your proof of an equal and opposite force from gas movement due to pressure gradient force.

This is how ridiculous your argument is. Are you saying a powerful explosive placed on an asteroid and detonated will not result in hurling pieces of asteroid in to space because of pressure gradient force? How is the detonation hurling pieces of asteroid in to space any different then the controlled detonation from a rocket engine.

originally posted by: NicSign
a reply to: neutronflux

So then when wind blows on the back of your head why doesn’t the air in front of you push off off your face as it moves away from you?

What does you response have to do with

Think about it this way. The gas exiting from the rocket is basically a controlled explosion. If the reacting gasses were not in a nozzle, the exit gasses would want to expand in all directions. Is that false. In a rocket, the gas release is forced out in one direction. Is that false. So the gas is required to push against the combustion chamber. Is that false. The expanding gasses by contact and collisions is forced out the nozzle opening. Is that false. So by Newton’s third law, the expanding gasses forced out of the nozzle by contact will result in thrust for the rocket. Is this false. Using Newton’s third law to move the rocket has nothing to to with the atmosphere. Is that false.

Again, Newton’s third law can be expressed without terms of pressure gradient force.

Unless you want to mathematically show how the only deciding factor for Newton’s third law is “ pressure gradient force.“

originally posted by: NicSign
a reply to: Arbitrageur

Thrust equation thoroughly debunked
www.youtube.com...

I gave you the chamber pressure you asked for which you said you could use to calculate the thrust using your method, so I'm still waiting to see your promised calculations, since as I said I don't know what you're going to use for density.

As far as I can tell neither you more the video maker (if different) understand conservation of momentum which is a basic principle of science that we have consistently observed.

originally posted by: NicSign
a reply to: neutronflux

So then when wind blows on the back of your head why doesn’t the air in front of you push off off your face as it moves away from you?

This question is more evidence that you have no concept of conservation of momentum, and until you understand that you should go back to studying and quit embarrassing yourself. You don't debunk conservation of momentum, and you don't even mention it and you don't seem to understand it.

The fuel inside the rocket and the rocket are all part of a more or less isolated system before the burned fuel exhaust gases leave the rocket, so when the gases go one direction, the only way for momentum to be conserved is for the rocket to go the other direction. That situation is not analogous to wind blowing on the back of your head, because there is no isolated system in that example like the rocket and it's fuel and exhaust gas where you can observe the conservation of momentum.

Momentum is conserved on a larger planetary scale for meteorological phenomena like wind, but you can't demonstrate that by analyzing wind blowing on the back of your head, because unlike the rocket it's not an isolated system.

originally posted by: NicSign
a reply to: neutronflux

So then when wind blows on the back of your head why doesn’t the air in front of you push off off your face as it moves away from you?

I think your arguments are running dry, do you think all the wind on the earth is connected as one entity across oceans and vast mountains, so when you fart all other wind should have an equal and opposite reaction, I did not think you could play this troll game anymore but I was clearly wrong.

If what you believe above was applied to the rocket in question YOU are then asking for every gas in the universe to have an equal and opposite reaction to the gas because its the same gas.

The people answering you in this thread are genuine geniuses with way more actual knowledge and in some cases have/do worked in actual science labs, this is not NASA or the guberment explaining it to you, I do nto wish to belittle you but you are giving your self no chance to learn with the approach you are currently taking, proven by your last analogy regarding air pushing of your face.

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