Why does the rocket fly Veeky Forums

>you are wrong about jet engines. you are thinking of trubo fans. i am talking about turbo jets.
wat?

Those are two types of airplane engines. He's still retarded. Rocket engine =/= jet engine.

Turbo jets use a combination of expelled propellent and ducted propellers for thrust.

Rocket engines are 100% propellent, no propellers.

I didn't say anything to the contrary...

Yeah I read too quickly.

stand on ice holding a 10kg rock, now throw it away from you. You slide the other way.

Let the air out of a balloon, the air rushes out and the balloon flies in the opposite direction.

Rocket fuel ignites, the explosion(s) propel it out of the nozzle. The spacecraft flies in the opposite direction.

its trivial

propeller blades actually gets lift from the air it passes through. Exactly as a plane's wing works.
It's not just a fucking fan.

Maybe you believe the pressure must be the same because the air volume going in equals the air volume going out.
While it's true that all the air going in the front goes out the rear, fuel is added between and ignited. This expands the air and creates the pressure differential. Since the plane rolls on the static ground and floats through air with little resistance, the plane can move against the immovable ground whether it's on the ground or thousands of feet above the ground.

Yeah, no. You see all those blades in there? Those are pretty much propellers. They compress the air by pushing back into the ignition chamber, where fuel is added and combusted. The result is the velocity of the gas coming out the back of the turbine (thats what educated people call it) is the combined effect of the velocity the turbine blades intaking the air added to the expansion rate of the fuel combusting. If you are referring to a ramjet (see bladeless turbine, like on the SR-71A blackbird) its the exact same principle as a regular turbine except instead of blades intaking the air, you just burn the fuck out of your fuel until you get to a speed where your relative velocity to the air is enough to compress the air, increasing fuel efficiency and thrust.

I dont think OP knows how a jet engine/gas turbine works, desu.

volume of exhausts > volume of fuel
that creates pressure diference
youtube.com/watch?v=t_hqEHYh12M

>why does the barrel rise?
because guns aren't symetrical and the barrel is a offset from gun's center of mass

can someone explain what that really bright white cone in the thrust jet actually is?

you know what im talking about

what the fuck is it?

Jew magic

OP is either a troll or in high school and knows nothing about the field he's trying to explain

>i mean the air escaping is not pushing against any thing at all
Therein lies your misunderstanding. The gas does push on something, it pushes on the walls of the nozzle.
en.m.wikipedia.org/wiki/De_Laval_nozzle

Shock diamond. They're cause when the gas expands below ambient pressure and collapses back in on itself, heating up again. They only form inside an atmosphere so if you ever see it in a scifi flick it will now be ruined for you.
en.m.wikipedia.org/wiki/Shock_diamond

Plenty of common misunderstandings when it comes to jets and rocketry, and turns out Veeky Forums is full of cunts who don't want to explain this stuff to people in an easy to understand way.

OP, read about the conservation of momentum and stop wondering about what pushes what

And then fail completely at actually designing anything that works, ever. OP posed a legitimate question that has a legitimate answer, you dolt.

Sometimes people just need time to think about things before doing them or opening their mouth or fucking posting.

Mods should ban you for this shit, OP. GTFO

Sure, but it's obvious that he is lacking in even understanding the basics

And? It's as good a question as any. I remember wondering about this myself a long time ago.

>And?

He needs to fuck off to &

The answer to this question is literally 'conservation of momentum'. It has been a long time, but if you draw a FBD on the fluid flow being expelled from the rocket nozzle, you can clearly identify a force propelling the rocket forward.

This would be a good place to start: grc.nasa.gov/www/k-12/airplane/thrsteq.html

you guys are all faggots. i do not think that you are understanding what i am asking.

first of all, i know about compressors in a turbo jet. they are not propellers. they do the opposite. they slow down the air coming in instead of pushing it back to move faster.

lets forget about turbo jets and stick to rockets. the speed of the exhaust gasses and their mass determines the force pushing the rocket. is the combustion occurs and the giant exhaust nozzle is not there the gas will escape the rocket but with slower speed. therefore, the rocket will produce less thrust. in other words it is not the combustion alone that determines the thrust but also the length and shape of the nozzle.

for those claiming that the gasses are pushing on the walls of the nozzle, they are not pushing in the direction opposite to the direction the rocket is travelling. so why do you keep bringing that up. the pressure on the walls of the nozzle is perpendicular to the direction of thrust and exhaust.

so once again lets say that the exhasut nozzle was so huge that the gasses slowed down before they exited the outward oppening of the nozzle. would that produce less thrust because the gasses got colder and slowed down and therefore mass times velocity equals less force for less speed? that is how i understand this. if this understanding is true then i cannot explain what is really happening. it cannot be the combustion pressure pushing against the rocket. since combustion pressure is the same no matter the length of the exhaust nozzle or the speed of the exhaust at the time it exits the outward opening of the nozzle.

and i am not a kid faggots. i just do not give a fuck about terms like conservation of momentum. i like to understand things on an intuitive level.

the same thing happens with a bullet fired from a rifle. now i know that all kinds of other recoil and shit is happening as soon as the trigger is pulled. but i also know that the exit of the bullet from the barrel causes

...and said force interacts with the surface of the nozzle, yes. That's what OP was asking.

continued.

the same thing happens with a bullet fired from a rifle. now i know that all kinds of other recoil and shit is happening as soon as the trigger is pulled. but i also know that the exit of the bullet from the barrel causes the whole rifle to jolt backwards as well. what is the reason for that? and dont tell me that it is the conservation of momentum. tell me in plain english what is happening. dont tell me that when a mass exits a barrel of the gun at high speed it will have an opposite reaction due to newtons law. i want to know why this happens. i can observe it happening my self. i do not need fucking newton to tell me that.

you people are not unerstanding the question at all. so i think it is better to use the example of the bullet leaving the barrel of the gun. i know it is not the only thing causing recoil in the rifle. but it does cause a jolt of the rifle back to the shooter's shoulder. why does this happen?

i think we can all relate to the example of the gun better than the example of the rocket.

>take heavy object
>throw it away from you as fast as you can
>feel the recoil
Congratulations you know how rockets work

>recoil
Happens instantly. The gas is expanding with a constant force in all directions. Acceleration is Force/mass, so the bullet gets accelerated much faster. It leaves the barrel long before the shooter can even perceive the gun moving backwards. The barrel rises only if the gun is off-center to the support (the shooter's shoulder). If you rest a barrel straight up against the wall with no off-line it will just push straight back.
>for those claiming that the gasses are pushing on the walls of the nozzle, they are not pushing in the direction opposite to the direction the rocket is travelling. so why do you keep bringing that up
See user right above your post,
The fluid is pushing against other fluid and the nozzle walls. Have you taken any physics, user?

incorrect. that would mean that only the force of the combustion matters and not the speed of the exhaust. remember, in a rocket the speed of the exhaust escaping the nozzle mouth is affected by the shape and size of the nozzle and not just the force of the combustion.

In a rocket with no nozzle then only the force of the reaction matters. Adding a nozzle however allows the rocket to convert the temperature of the exhaust into the speed of the exhaust and thus be more efficient, getting more of the energy of the reaction converted into kinetic energy.

but the gun also moves backwards because of the exit of mass from the barrel at high speeds. does it not ? then dont talk about the other stuff. there is no need to complicate things. my main question was about this phenomenon when a mass leaves the barrel at high speed it moves the rifle backwards. why does that happen at that time?

and i do not need to take any physics to learn about formulas and terminologies. i am just looking at this from my personal experience. too much is happening in the example of the rocket but the rifle and the bullet are easier to explain.

also that lavel nozzle.. it speeds up the exhaust gasses before they exit the mouth of the nozzle. so why would this speeding up of the gasses cause the frekin rocket to speed up. if i use the same engine and not havea lavel nozzle, isnt the force of combustion still the same. why would not have the lavel nozzle make the rocket go slower/ less thrust?

in the xample of throwing a rock the rock pushes back on me in the same direction as the original throw. and the push on me does not increase if the rock speeds up after leaving my hands. which is what the lavel nozzle does to gasses after they leave the combustion chamber.

and you have just pin pointed my problem for which i created this thread. why would increasing the speed of the exhaust by the lavel nozzle cause the rocket to have more thrust. shouldnt the force of the reaction be the only thing that matters in all cases ?

>dont tell me that when a mass exits a barrel of the gun at high speed it will have an opposite reaction due to newtons law. i want to know why this happens. i can observe it happening my self. i do not need fucking newton to tell me that.

The problem is that now you've left science and entered philosophical territory.

As you may or may not know, the Newton's law you are talking about is a scientific law, i.e. it's just an assertion made by countless observations. What you're asking is equivalent to asking 'why do forces work like they do'. If you can answer that question in a satisfactory manner, it will undoubtedly be the pinnacle of human achievement for the lifespan of our race, and you will forever be hailed as the greatest genius that ever lived.

To increase the speed there has to be more pushing happening, otherwise it wouldn't go faster.

The gas wants to expand sideways as it exist the nozzle, which causes it to push up against the walls. However, since the walls are at an angle, the gas can push sideways and down, making it move faster and the nozzle to feel a force. Now that the gasses are moving faster but expanding sideways at the same speed you need to make the nozzle wall angled differently to get the force out of the expansion. That's why rocket nozzles follow that specific curve shape.

It actually acts kinda like a sail on a boat, with constant wind. By changing the angle of the sail as you go faster, you can continue to gain momentum by cutting across the wind even though you're technically moving faster than the wind at that point. Obviously the comparison isn't perfect but it's the same basic principal of deflecting a compressed moving gas to gain momentum.

this is the problem with western thinking. just tell me exactly which of the """"why"""" questions are called scientific question and which of the """"why"""" question are called philosophy. why the hell would my question be philosophy and not science. does science not deal with understanding how shit is working. is the atomic model and quantum physics philosophy or physics?

your response is strange. i am asking the why question because this is how new knowledge is discovered. imagine if the answer has something to do with how gravity works. is this not the domain of science ? is discovering all the fundamental laws governing the universe not the domain of science. i can see that questioning why the fundamental laws are the way they are is a question of philosophy but discovering them is science.

lets take your logic and apply it to beginning of human curiosity about the material laws. a caveman sees ice turn into water then turn into air. the cave man asks the other caveman why does this happen. the other caveman replies that is a question of philosophy and science does not concern itself with such questions. and no one ever tries to find any answer to any questions from that point onward.

>the force of the reaction be the only thing that matters in all cases ?

go read a gas dynamics books and learn whats actually happening in the combustion chamber.

i see that explanation and it does make some sense. although, i would think that the gasses would take the path of least resistance and escape the exhaust nozzle without too much pressure on the walls. i do not see how the sideways pressure on the walls on the nozzle could cause the gas to exert so much pressure upwards. since the gas is moving mostly downwards due to the reaction and the shape of the nozzle. i just do not see how the sideways force applied to the walls on the nozzle would be strong enough to push the rocket in the upwards direction in any significant way. the intesting thing is that the afterburner in jet engines relies in the exhaust air to escape at very high velocity. now how would the after burner cause the jet engine to be pushed forward? you cant tell me that the sideways pressure on the small area of the engine walls in enough to produce that much more thrust by the afterburner?

The exhaust speed is only relevant in relation to the amount of matter being pushed out. Yes the nuzzle increases the exhaust speed which means more matter can be pushed out in a specific time frame, how this works has to do with how combustion works in a rocket. The nuzzle also makes sure all of the matter is actually pushed into the direction in which you want to push.

> you cant tell me that the sideways pressure on the small area of the engine walls in enough to produce that much more thrust by the afterburner?

Yes I can though. When gasses heat up quickly they try to expand quickly. That expansion IS the path of least resistance for the gasses, despite the fact that it applies a force to anything trying to contain it. It has no choice but to expand, and the force of the expansion is greater the higher the temperature.

In a jet engine the gasses cannot be allowed to reach temperatures higher than the melting point of the materials that make up the engine, but since a rocket engine can have regenerative cooling and doesn't have any fans or other components directly immersed in the gasses, temperatures can easily reach beyond the boiling point of iron. That's why a big nozzle is so effective on a rocket engine, the huge temperatures cause the gasses to exert a huge force once they exit the combustion chamber and apply that force to the engine nozzle as they expand. That expansion causes acceleration, making the gasses move very quickly while the engine bell rebounds off of the diverted gasses producing thrust.

The gasses in a nozzle are moving mostly downwards, yes. However, they're trying to expand so quickly that as long as your nozzle follows a certain 'bell' shape they will strike it and remain in contact as they are diverted from trying to flow in all directions to mostly trying to flow downwards. That acceleration of the gasses only happens because they directly exert pressure on the walls of the nozzle, pressure that results in thrust.

>first of all, i know about compressors in a turbo jet.
Turbojets have a turbine after the combustion chambers to propel the exhaust. I was not talking about the compressors.

>for those claiming that the gasses are pushing on the walls of the nozzle, they are not pushing in the direction opposite to the direction the rocket is travelling.
Yes they are. The choke point turns fluid pressure of the gas into velocity in the direction of flow. If I'm shooting gas out in a certain direction, it doesn't really matter how I created that velocity, whether by combustion or conversion in some other manner, I'm still pushing gas out and thus the gas is pushing on me. Did you look up the Venturi effect like I told you or are you just refusing to learn?

Think about what happens when you press on a balloon and let the nozzle go. It doesn't matter in what direction you push, the gas is only going to escape in the direction of exit out of the nozzle, and the balloon is going to experience thrust opposite that direction.

>so once again lets say that the exhasut nozzle was so huge that the gasses slowed down before they exited the outward oppening of the nozzle. would that produce less thrust because the gasses got colder and slowed down and therefore mass times velocity equals less force for less speed?
Well you are going to have to be a little more specific, since making the nozzle "bigger" would not necessarily make the propellant slow down. In fact it is optimal to have as long a nozzle as possible, but things like weight and material strength limit that. But yes, slowing down the propellant is bad, because that means you are being pushed on less.

>it cannot be the combustion pressure pushing against the rocket.
The combustion pressure is only one source of thrust. Once the propellant is out of the combustion chamber we want to convert as much pressure as possible into kinetic energy of the escaping propellant.

I'm not saying there's anything bad with asking such questions, but I think you're fundamentally misunderstanding my statement.

No field of science has ever answered why [something happens], they only explain how something happens (you can insert any question in the brackets).

Science is based upon observation and mathematical modeling of reality. Therefore, by definition, you cannot use science to answer questions outside the scope of observation and mathematical modeling.

>does science not deal with understanding how shit is working
That's exactly it, how shit is working, not why.

>is the atomic model and quantum physics philosophy or physics?
They're based purely on observation and mathematical modeling of reality, so of course they are physics.

>i can see that questioning why the fundamental laws are the way they are is a question of philosophy but discovering them is science.
I think this is your fundamental misunderstanding. Any why question will eventually boil down to questioning why a fundamental property of our universe is the way it is, a question that is impossible to answer from a scientific framework.

>a caveman sees ice turn into water then turn into air. the cave man asks the other caveman why does this happen
Only by asking how does this happen can they learn something about reality. Asking why it happens means that even if they discover e.g. the atomic model, they're not one iota closer to an answer, they've just moved the question. They could live infinitely long lives and there would still be a 0 % chance of answering the question, at least from a scientific framework.

>but i also know that the exit of the bullet from the barrel causes the whole rifle to jolt backwards as well.
Nope, the reason it is hard for you to observe the recoil before the bullet leaves the barrel is because obviously you don't want to design a gun that can't be aimed properly due to recoil pushing the gun up and sending the bullet off in a direction you weren't aiming at. So bullet propellant and the barrel and the recoil mechanism of the gun are all designed to send the bullet out before recoil seriously effects anything. If you took a bunch of propellant out of the bullet you would see the recoil happening before the bullet comes out of the barrel.

When a bullet is fired, it has essentially stopped interacting with the gun even before it leaves the barrel (ignoring the rotation of the bullet in the barrel, which slightly decreases the speed of the bullet and the recoil). Not so with a rocket, which is designed to derive thrust from both the combustion chamber and the gas leaving the nozzle.

>but the gun also moves backwards because of the exit of mass from the barrel at high speeds. does it not ?
No. All the recoil was derived from the combustion propelling the bullet while it was in the gun. Leaving the barrel is irrelevant.

>so why would this speeding up of the gasses cause the frekin rocket to speed up
Because faster gas = more kinetic energy = more push against the nozzle.

>if i use the same engine and not havea lavel nozzle, isnt the force of combustion still the same.
Yes, but much of that force is wasted in the form of heat and pressure in the escaped propellant. The entire point of modern rockets and jets is to more efficiently convert that energy into kinetic energy.

>in the xample of throwing a rock the rock pushes back on me in the same direction as the original throw. and the push on me does not increase if the rock speeds up after leaving my hands. which is what the lavel nozzle does to gasses after they leave the combustion chamber.
Nope, the speed up happens before it leaves the nozzle, at the choke point. The gas then pushes against the nozzle as it flows out.

>OP BTFO
Veeky Forums outski

>No. All the recoil was derived from the combustion propelling the bullet while it was in the gun. Leaving the barrel is irrelevant.

so what you are saying is that if i fired a blank bullet with the same amount of propellant it would have the same recoil? that is simply not true. the mass of the bullet has a huge impact on the recoil even when there is not a big difference in propellant.

lets keep this discussion to rifles. since it is easier to talk about.

>Turbojets have a turbine after the combustion chambers to propel the exhaust. I was not talking about the compressors.

the turbine after comsution does not propel the exhaust it slows it down. the turbine is used to run the compressors. the compressors also slow down the incoming air, just as the turine takes energy away from the outgoing air to generate force for the compressor to function. were you the one saying that i have no idea how jet engines work?

coming back to reheat/afterburning. it seems to me that the effect of mass leaving at high speed causes the engine to move forawrd. i mean the reheat/afterburner is only causing the air to speed up and expand and escape quickly at the end there. but sometimes that is enough to raise the thrust of an engine by 50%.

RAIL GUNS. MOTHER FUCKING RAIL GUNS.

would rail gun produce any recoil.? here is what one link has to say.

>The answer is that it has exactly the same recoil. Take a projectile of the same mass and push it out of a barrel at the same muzzle velocity and it will push back on the breech with the same recoil force. ... I'll cover more about railgun recoil in part2.

now lets stop talking about everything else and start talking about rail guns and why they produce recoil. i do not understand the explanation that the recoil is caused by the bullet exerting force on the breech. that makes no sense. why would a bullet traveling in the direction away from the breech exert and a force on breech to push it backwards

sit in a roller chair and throw something heavy. you will move backwards. Same principle.

i understand. but is that the same as a rail gun firing bullets and still getting recoil. i believe the roller chair can be explaind by saying that the weight of the thing i am trowing is pushing back onto me. but the same effet should not happen in space where there is no gravity.

The bullet has trapped pressurized gasses behind ti which expand pressing against both the bullet and the interior of the rifle.

>where there is no gravity.

It's the mass, not the weight. Mass resists acceleration which is why it requires energy to push. Weight is actually a result of mass in a gravity field, whereas mass is an independent property.

can you answer why RAIL GUNS also produce recoil when mass is ejected from the breech end.

also the reason why mass resists acceleration and why rail guns have recoil seems to be related. and i believe that all of this is related to whatever causes gravity to occur.

Yup. This is sad but true. For instance, we know that there are 4 fundamental forces through observation and experiment. What science can't answer is *why* there are 4. Why not 7 or 2? The best you can say is that these 4 shape the universe as we know it, and without it shit wouldn't be the way it is.

Same thing with the conservation of momentum.

because its' exerting a force on the bullet

The way a rail gun accelerates its projectile is by steadily speeding it up as it travels the length of the rails. A force is applied to both the projectile and the rails, the projectile goes one way while at the exact same time the rails go the other. The reason the projectile ends up moving faster is that it has a lot less mass than the big heavy railgun that is likely also attached to something that is even bigger and heavier.

here are the links talking about rail gun recoil

humanlegion.com/authors-notes/railgun-recoil-pt1/

humanlegion.com/authors-notes/railgun-recoil-newton-wont-be-denied-pt2/

they say that momentum of the projectile exerts a backwards force on the rail gun. that was my initial question for which i opened this thread. what would cause the projectile escaping the barrel to push the barrel backwards? conservation of momentum is a phrase that describes an observation, like the melting of ice into water is an observation. if we can explain why ice metls to water then we can also explaun why projectile exerts an equal force according to its momentum on the breech of the rail gun.

i believe the answere has to do with something fundamental that is wrong with physics itself. i suspect that the projectile is part of the gun by some unseen connection that we cannot see. the gun does not want to let go of the projectile and the force moving the projectile is pushing the gun in the opposite directions. like two people pushing playing tug of war when one guy lets go of the rope.

how this thing would work is probably related to my idea that there are no atoms at all and that gravity is not a curve in space time but a thing found in matter that is passed through space by a similar mechanism that causes the projectile to push the barrel of the rail gun backwards.

you people were calling me dumb, when you did not even understand the question. i think i am 2deep4u.

you have simply described what is happening. i am looking for more something like this.

>what would cause the projectile escaping the barrel to push the barrel backwards?
The force isn't applied when the projectile escapes the barrel, it is applied as the projectile travels along the rails.

Rails push projectile one way, projectile pushes the rails the other. The force applied to both is not instantaneous at the exit, but over the period of time where the two are in contact.

What a stupid thread.
Why ask when you can read it up in wikipedia.

>so what you are saying is that if i fired a blank bullet with the same amount of propellant it would have the same recoil?
No, where did you get that idea from what I said? When you throw something heavy and something light, you will feel more recoil from the heavy object, since kinetic energy is based on both mass and velocity. The "throw" is the propellant sending the bullet down the barrel, not the bullet leaving the barrel.

>the turbine after comsution does not propel the exhaust it slows it down. the turbine is used to run the compressors.
No, that is only the first stage of the turbine. The second stage accelerates the exhaust.

> i do not understand the explanation that the recoil is caused by the bullet exerting force on the breech.
Take two repelling magnets and push them together.

> that guy needs to drop his phone and run the fuck off

i have read everywhere. and the question i was asking was not about what the current science is on this. i was wondering if someone has any theories.

it is clear that the force is applied on the exit side. for example if i vector the exhaust gasses of my rocket to change direction when they exit at the end the direction the rocket travels will also change. even if the gasses had to travel straight down first. similar to how f-35 engine vectors the thrust or and f-22 engine. some air-to-air missiles also have this thrust vectoring. it seems that the direction the projectile comes out determines the direction in which force is applied and that the force is measured by the mass X velocity of the projectile at the exit.

Propellers work by creating a pressure gradient, not by pushing air and getting forward like an action-reaction pair

Turbofans are turbojets with a variable bypass of cool not compressed gas. The inner compression and combustion chamber stages are pretty much the same

Finding recoil in magnetic force systems is sometimes not easy, but in normal railguns it's distributed on the breech like a regular gun.

some people say that the recoil happens all along the length of the barrel. now you say that it is distributed in the breech. that is how i understand it as well. why would it happen at the breech?

I am an idiot when it comes to this but this seems really really simple. Bullet fires, explosion of gunpowder creates expansion, that expansion pushes the bullet forward towards path of least resistance, and pushes shell and by proxy the gun itself as well as the shooter the other direction. I imagine this is why a clogged barrel will cause the gun to "explode" at the weakest structural point the explosion can find to exit. So in a rocket, which is a controlled explosion, the gasses leave the rocket by path of least resistance, the nozzle, which is there to focus the explosion in the direction you want.

It seems pretty simple. Like how a machine gun continuously wants to creep up under sustained fire.

i understand that. i am simply asking why does mass escaping at high velocity cause the thing expelling the mass to pass back in the direction opposite to the direction of the ejection. the thing is that the force applied on the ejector by the mass is determined by the mass times the velocity at the POINT OF EXIT. that is what makes it so interesting. i believe this says something about the fundamental nature of all matter in the universe.

Because the universe came to existence in such a way.

That's why.

but if we say the same thing about everything else then we might as well not do any "science" at all. btw, i am no supporter of science. i only search for understanding.

OP it seems like you ignore every practical explanation you're given (I haven't seen you reply to a single one of the 'good' answers that replies to you on your terms). You cherry-pick the dense or confrontational answers to further an argument that seems at complete odds with your original questions.

I think it's a good question, that at heart is asking "why is newton's 3rd law (or equivalently the conservation of momentum)" true.

Adding on, we know it's true experimentally. Is there some rigorous way to derive newton's third law though, or is it just taken as an axiom upon which we build classical mechanics.

Perhaps noether's theorem or something?

Some other good reading that might provide glimpses of insight:

physics.stackexchange.com/questions/12122/deriving-newtons-third-law-from-homogeneity-of-space

physics.stackexchange.com/questions/14526/where-does-the-reaction-to-action-come-from?noredirect=1&lq=1

physics.stackexchange.com/questions/93883/is-force-a-real-thing-or-a-tool-for-explaining-changes-in-measurable-phenomen?noredirect=1&lq=1

Except you're wrong and it has nothing to do with the point of exit you retarded nigger

so it is bait after all

-- "the rocket is not pushing against anything in space"

-- "Yes... it is."

>yeah it's pushing against the vacuum of space, and all that spooky dark matter