Space Flight

Gas has mass but is not a solid like lead shot or a bowling ball or whatever else.
This is the bullshit that scientists give out to explain why a rocket will work in a vacuum.

Solid, liquid, gas, plasma, it doesn't matter, it's still made of the same particles, and it's those particles that give it mass.

Anyway, no response on the try-it-out-yourself thing? Is there a reason why you don't want to answer that?

I think it might be time for this diagram.

Gas has mass but is not a solid like lead shot or a bowling ball or whatever else.

Doesn't matter, the mass is the important part.

This is the science that scientists give out to explain why a rocket will work in a vacuum.

Fixed that for you.

Do you realise how much mass you would need to throw away from you to propel yourself on a chair with any meaning on a level floor.

Yes, I do.

Do you realise how much mass you would have to throw below you to make you raise off the floor just one foot.

Yes, I do.

Transfer that your your rocket that simply supposedly just uses mass to propel it upwards, especially something like the shuttle and you will quickly realise that not only would it blow up but it wouldn't even get off the ground...and if it did...it's fuel would be spend before it had time to get a few thousand feet into the sky...let alone anywhere near space.

There's a lot of careful design, which I do understand by the way, that goes into making sure they don't just explode on takeoff. It took a lot of trial and error to learn what was needed too. Oh, and have you seen the size of the fuel tanks these things use? They're freakin huge!

In space if it was ever able to...which is wasn't...it would be a dud.

No, it wouldn't. If you actually took the trouble to understand physics, instead of dismissing it simply because you don't understand it, all this would make a lot more sense.

Quote from: icanbeanything on June 04, 2013, 04:30:47 AM

Quote from: sceptimatic on June 04, 2013, 04:23:47 AM

Gas has mass but is not a solid like lead shot or a bowling ball or whatever else.
This is the bullshit that scientists give out to explain why a rocket will work in a vacuum.

Solid, liquid, gas, plasma, it doesn't matter, it's still made of the same particles, and it's those particles that give it mass.

Anyway, no response on the try-it-out-yourself thing? Is there a reason why you don't want to answer that?

I know what would happen but firstly..tell me how to put a blown up , open ended balloon inside a vacuum chamber.

You blow it up a bit (not as much as you would normally), tie a spring-release or a specific pull-to-untie knot on the mouth. They you put it in the chamber, it sucks the air out, and they usually have ways of manipulating objects in the chamber. Of course, it depends on what kind of chamber it is, but it should be doable with a little tinkering in any chamber.

Once the balloon is in, and vacuum is attained, it will grow in size a lot, this is why it shouldn't be very inflated beforehand, or it will pop at this stage. Once there's a vacuum, you just press the spring release or pull the string or whatever you have to do, to open up the balloon. If you can't think of a way to do this, the people there will probably help you out.

That's it! Don't forget to film it with something!

That's akin to blowing your own sail on a boat.
You should know this is absolutely impossible and if not...go and get into your car...don't start it..just sit in the drivers seat and push your car by slamming your face off of the windscreen, see how far you get on a level surface.

Oh, i you want to, you can have a friend in as well and he/she can throw heavy bowling ball out of the back window as you are doing this...see how far this gets you.

If you want to be extreme, then get your friend to get a bazooka and fire it out of the back window....this may get you slightly moving but will probably wreck your car after 1 minutes worth of firing it.

I'm not trying to be funny here by the way...this is what you are telling me that a rocket does.

If someone is throwing heavy balls out of the back of the car then yes it would give it some energy in the opposite direction. Probably not enough to overcome the friction with the ground but it should be measurable.

As for the diagram it's just about as simple a rocket as you can get, imagine a balloon that you have blown up. There is air inside the balloon at a higher pressure than the air outside it. While you hold the end shut the air is pressing on all "sides" of the balloon equally and this is why it is bigger than if it's just open to the air, the pressure inside the balloon  pressing out is stretching it.
Now if you let go of the blown up balloon it doesn't immediately revert to it's original size, rather it shrinks at a rate equal to how fast the air can come out. While the balloon is shrinking there is still pressure being exerted on the sides of the balloon and the pressures all cancel each other out except for the one opposite the nozzle where the air is coming out.

I know exactly what would happen with it and one thing it won't do is fly about.

Well, I know exactly that it would fly about. I've done this - well, not with balloons, but with other things that work just like a rocket - and it definitely will fly about. Why don't you try it? This one seriously doesn't require anything else, just a balloon, IF there's a university nearby. I'm sure they'll help you do it, just ask if they have the time and say you want to film it for YouTube.

Do not ask the secretaries or the dean... Just ask where the laboratories are and approach a lab practicant, ask them for the experiment itself.

Quote from: Manarq on June 04, 2013, 04:41:50 AM

I think it might be time for this diagram.

That's akin to blowing your own sail on a boat.
You should know this is absolutely impossible and if not...go and get into your car...don't start it..just sit in the drivers seat and push your car by slamming your face off of the windscreen, see how far you get on a level surface.

Oh, if you want to, you can have a friend in as well and he/she can throw heavy bowling ball out of the back window as you are doing this...see how far this gets you.

If you want to be extreme, then get your friend to get a bazooka and fire it out of the back window....this may get you slightly moving but will probably wreck your car after 1 minutes worth of firing it.

I'm not trying to be funny here by the way...this is what you are telling me that a rocket does.

Lol!  Are you saying that throwing a bowling ball or breathing generates as much continuous force as a jet engine?  Analogies are supposed to be good comparisons, not intentionally trivializing of the original situation. Your analogy is basically a lie Pinocchio...

Quote from: icanbeanything on June 04, 2013, 05:14:50 AM

Quote from: sceptimatic on June 04, 2013, 05:08:43 AM

I know exactly what would happen with it and one thing it won't do is fly about.

Well, I know exactly that it would fly out. I've done this - well, not with balloons, but with other things that work just like a rocket - and it definitely will fly about. Why don't you try it? This one seriously doesn't require anything else, just a balloon, IF there's a university nearby. I'm sure they'll help you do it, just ask if they have the time and say you want to film it for YouTube.

Do not ask the secretaries or the dean... Just ask where the laboratories are and approach a lab practicant, ask them for the experiment itself.

So what have you experimented with with the things that work just like a rocket?

One example would be measuring the thrust generated by a special laser, testing for laser propulsion. Experiment done in a vacuum. You turn on the laser, the beam comes out one end, and it pushes the device the other way, with a very small force that I had to measure.

Don't mind all this, just try what I suggested. If they're willing to help you, all you need is a balloon, they'll take care of the rest.

Quote from: Manarq on June 04, 2013, 05:04:13 AM

Quote from: sceptimatic on June 04, 2013, 04:49:51 AM

That's akin to blowing your own sail on a boat.
You should know this is absolutely impossible and if not...go and get into your car...don't start it..just sit in the drivers seat and push your car by slamming your face off of the windscreen, see how far you get on a level surface.

Oh, i you want to, you can have a friend in as well and he/she can throw heavy bowling ball out of the back window as you are doing this...see how far this gets you.

If you want to be extreme, then get your friend to get a bazooka and fire it out of the back window....this may get you slightly moving but will probably wreck your car after 1 minutes worth of firing it.

I'm not trying to be funny here by the way...this is what you are telling me that a rocket does.

If someone is throwing heavy balls out of the back of the car then yes it would give it some energy in the opposite direction. Probably not enough to overcome the friction with the ground but it should be measurable.

As for the diagram it's just about as simple a rocket as you can get, imagine a balloon that you have blown up. There is air inside the balloon at a higher pressure than the air outside it. While you hold the end shut the air is pressing on all "sides" of the balloon equally and this is why it is bigger than if it's just open to the air, the pressure inside the balloon  pressing out is stretching it.
Now if you let go of the blown up balloon it doesn't immediately revert to it's original size, rather it shrinks at a rate equal to how fast the air can come out. While the balloon is shrinking there is still pressure being exerted on the sides of the balloon and the pressures all cancel each other out except for the one opposite the nozzle where the air is coming out.

This just proves that the balloon is pushing against the air under it by use of the force of the elasticated shell of it forcing it out.
If this is your rocket, then this is proof that your rocket needs an atmosphere.
The only difference here is, the balloon is expelling the air by elasticated means and a rocket does it by pressure of oxygen in a fuel mix.

End result...fine on earth...no good for space.

Please draw me (or reference if you've already done one) one of your famous diagrams to show how the force is being applied to the balloon to push it forwards.

The physics you are being taught is Pinocchio physics. I'm not saying you are a liar though, all you have done is what many have done and bought into it.

Unlike you scepti, I have actually done numerous experiments which demonstrate the laws of physics that you deny exist.

This just proves that the balloon is pushing against the air under it by use of the force of the elasticated shell of it forcing it out.

The elasticity of the balloon is actually expelling the air you used to fill the balloon, not pushing on the atmosphere outside it. There doesn't need to be an atmosphere outside the balloon for this to work, as it already contains its propellant.

Just go and do ican's experiment, you might actually learn something. And don't keep saying "I know what will happen", because you haven't seen what will happen, so go do it so you can actually see for yourself!

Quote from: icanbeanything on June 04, 2013, 05:23:09 AM

Quote from: sceptimatic on June 04, 2013, 05:16:06 AM

Quote from: icanbeanything on June 04, 2013, 05:14:50 AM

Quote from: sceptimatic on June 04, 2013, 05:08:43 AM

I know exactly what would happen with it and one thing it won't do is fly about.

Well, I know exactly that it would fly out. I've done this - well, not with balloons, but with other things that work just like a rocket - and it definitely will fly about. Why don't you try it? This one seriously doesn't require anything else, just a balloon, IF there's a university nearby. I'm sure they'll help you do it, just ask if they have the time and say you want to film it for YouTube.

Do not ask the secretaries or the dean... Just ask where the laboratories are and approach a lab practicant, ask them for the experiment itself.

So what have you experimented with with the things that work just like a rocket?

One example would be measuring the thrust generated by a special laser, testing for laser propulsion. Experiment done in a vacuum. You turn on the laser, the beam comes out one end, and it pushes the device the other way, with a very small force that I had to measure.

Don't mind all this, just try what I suggested. If they're willing to help you, all you need is a balloon, they'll take care of the rest.

So what's this laser experiment and why does it work and what does it prove about rockets in a vacuum.
Who has these laser fuel rockets?

Nobody uses these for propulsion yet. It's research only for now. But it works just like a classical rocket. Have you ever seen or used a laser pointer? That's basically it. You turn on the laser, and it's pushed the opposite way by the exiting beam. Of course, you can't feel this when using a laser pointer. But you can if you construct an experiment around it.

What happens is, the photons act as the propulsion, just like the exiting gas would in a rocket. The photons carry energy, and thus, momentum with themselves, and as we've said before, that causes the laser to be pushed the opposite way. Exactly like a rocket.

It proves rockets work in a vacuum because it too worked in a vacuum. Can you not draw the parallel yourself?

Anyway, go do the balloon experiment, you won't regret it.

I thought Photons don't have any mass.

They don't. But they have energy and momentum.

Quote from: icanbeanything on June 04, 2013, 06:14:49 AM

Quote from: sceptimatic on June 04, 2013, 06:11:46 AM

I thought Photons don't have any mass.

They don't. But they have energy and momentum.

Wait a minute...you can't have it both ways...it's either mass that's doing the amazing rocket trick or it's not...which is it?

You have to realize, in physics, things are related. There is an order.

It's momentum doing it. The conservation of momentum is what makes a rocket work.

But since any mass, that isn't at rest, has momentum, it's also true that any mass does the trick. It means the same thing.

In my initial explanation I said mass, because I didn't want to invoke laws like the conservation of momentum, since you have an aversion to those.

Quote from: icanbeanything on June 04, 2013, 06:21:10 AM

Quote from: sceptimatic on June 04, 2013, 06:17:20 AM

Quote from: icanbeanything on June 04, 2013, 06:14:49 AM

Quote from: sceptimatic on June 04, 2013, 06:11:46 AM

I thought Photons don't have any mass.

They don't. But they have energy and momentum.

Wait a minute...you can't have it both ways...it's either mass that's doing the amazing rocket trick or it's not...which is it?

You have to realize, in physics, things are related. There is an order.

It's momentum doing it. The conservation of momentum is what makes a rocket work.

But since any mass, that isn't at rest, has momentum, it's also true that any mass does the trick. It means the same thing.

In my initial explanation I said mass, because I didn't want to invoke laws like the conservation of momentum, since you have an aversion to those.

So the bowling ball and wheeled chair is a fabrication for the explanation of how rockets work. Well ok, at least that's one sack of crap out of the way..it's just a case of destroying the rest..which I will.

That's the conclusion you drew? I don't see how. I haven't been bowling for a while, but do bowling balls not have mass now?

Quote from: Manarq on June 04, 2013, 05:24:07 AM

Please draw me (or reference if you've already done one) one of your famous diagrams to show how the force is being applied to the balloon to push it forwards.

Air pressure which is higher than the air pressure outside of it, so wants to get out and equalize with it.
The only two ways it can do this is to burst the balloon or come out of the bottom where the higher pressure air tries to push through the air under the balloon and the air under it creates resistance creating a push on push...a push of war rather than a tug of war.


To put it into another context, it's like the Roman army against the Spartans, with Kirk Douglas and Tony Curtis in their mini dresses and snazzy sandals, (copied by millions of females today)...

Ok, what happens is...the Spartans...(balloon air pressure)..attack the Romans...(wider atmosphere) and try to drive right through them but as the Roman front gets breached, the back line crowd in and force themselves against the rampant Spartans and because the Roman army is inexhaustible it keeps pushing the Spartans further back... and as much as the Spartans push against the Romans, the Romans push back more , resulting in the Spartans getting weaker and weaker as they are pushed all the way back up the hill until they finally run out of fight and all tumble back down through the masses of Romans who part their way for the tumbling Spartans.

I'm spartacus. 

The film you're mis-referencing here had nothing to do with the Spartans, for a start Spartacus was Thracian, trained as a gladiator and led a slave uprising.

As for how the balloon moves please draw a diagram showing where the force is acting upon the balloon in order to move it forwards. A force has to be acting upon the balloon to move it, you're saying that the air escaping the balloon meeting the air outside the balloon creates the force but how is this transferred to the balloon?

Quote from: Manarq on June 04, 2013, 06:52:12 AM

The film you're mis-referencing here had nothing to do with the Spartans, for a start Spartacus was Thracian, trained as a gladiator and led a slave uprising.

As for how the balloon moves please draw a diagram showing where the force is acting upon the balloon in order to move it forwards. A force has to be acting upon the balloon to move it, you're saying that the air escaping the balloon meeting the air outside the balloon creates the force but how is this transferred to the balloon?

Think of being in a swimming pool with a blown up balloon. Rest it on the water  and it floats right?

Start to drag that balloon under the water  and the balloon wants to release from your grip, right?
The reason it does this, is because the water is denser than it and is squashing it and the balloon doesn't appreciate it, so it struggles free and shoots up.

This only happens because you forced that balloon into this situation but the reality is... the water does not like the balloon and decided to push him out of his space by crowding around it and bullying it, yet you holding that balloon, forced that balloon to struggle against the bullies.

Your force....your hand= fuel against the force of the water pushing back= the atmosphere.

You didn't answer the question, where is the force acting on the balloon? In your very poor example my hand would be in physical contact with the balloon, so where is the "fighting" air pushing on the balloon?

Quote from: Manarq on June 04, 2013, 07:22:43 AM

Quote from: sceptimatic on June 04, 2013, 07:06:16 AM

Quote from: Manarq on June 04, 2013, 06:52:12 AM

The film you're mis-referencing here had nothing to do with the Spartans, for a start Spartacus was Thracian, trained as a gladiator and led a slave uprising.

As for how the balloon moves please draw a diagram showing where the force is acting upon the balloon in order to move it forwards. A force has to be acting upon the balloon to move it, you're saying that the air escaping the balloon meeting the air outside the balloon creates the force but how is this transferred to the balloon?

Think of being in a swimming pool with a blown up balloon. Rest it on the water  and it floats right?

Start to drag that balloon under the water  and the balloon wants to release from your grip, right?
The reason it does this, is because the water is denser than it and is squashing it and the balloon doesn't appreciate it, so it struggles free and shoots up.

This only happens because you forced that balloon into this situation but the reality is... the water does not like the balloon and decided to push him out of his space by crowding around it and bullying it, yet you holding that balloon, forced that balloon to struggle against the bullies.

Your force....your hand= fuel against the force of the water pushing back= the atmosphere.

You didn't answer the question, where is the force acting on the balloon? In your very poor example my hand would be in physical contact with the balloon, so where is the "fighting" air pushing on the balloon?

The fight is your hand forcing the balloon to fight against the water...once you release your hand, the balloon lays on top of the water just as a spent rocket would after expending all of it's fuel , meaning the pull of your hand.

Look at what I wrote very carefully and you will understand what I'm saying if you convert it to what the balloon is doing.

I've started the picture for you, just draw an arrow on showing me where the force is acting on the balloon.


Uploaded with ImageShack.us

That's cool, but you forgot the air on the inside also pushing on the balloon's wall, opposing the force from outside.

In order for air to be exiting the balloon, inside pressure must be greater than outside pressure. So the inside arrows would be "stronger" than the outside arrows.



Like this.

Now, since the inside pressure is greater, the force pushing from inside is greater. So the blue arrows are "stronger" and if you add the blue arrows to the black arrows, you get the red arrows:

Now if you look at the red arrows, they're everywhere on the balloon except for the back, where the mouth is, since there's no wall to push against there (and consequently, it's where the air inside is leaving.)

The arrows pushing opposite sides of the balloon cancel out, since they're the same strength.
Here, green and green, respectively black and black cancel.
But there's nothing to cancel out the top part where force is pushing, since the opposite side has no wall, thus no arrow.


That single red arrow left gives you the overall resultant force. That force gives you the direction your balloon will accelerate.

Finally, consider what happens with all this if there's a vacuum outside.

If there's a vacuum outside, it means there are no black arrows to begin with, right? But the blue arrows are still there. So ultimately, the red arrows will just be "stronger", since there's no outside opposition. The reds cancel out just the same way, except for the top one, because there's no arrow on the opposite side.

The final arrow will still be there on the top, and will cause your balloon to accelerate even in a vacuum.

The reason a balloon works this way is due to the elasticity acting on the air, so your analogy in the vacuum is wrong.

Okay, look at the image, and now imagine it's not a balloon, it's a steel sphere. What's different about the action of the arrows?

Nothing. The elasticity of the balloon isn't even accounted for in this diagram.

Quote from: icanbeanything on June 04, 2013, 11:54:55 AM

Quote from: sceptimatic on June 04, 2013, 11:50:39 AM

The reason a balloon works this way is due to the elasticity acting on the air, so your analogy in the vacuum is wrong.

Okay, look at the image, and now imagine it's not a balloon, it's a steel sphere. What's different about the action of the arrows?

I know what you are getting at but that is not how rockets work.
Can you imagine if that was employed in a big fuel tank like that on the fake shuttle.
By your analogy, the fuel coming from that tank would also push that tank upwards but the tank is external from the fake shuttle.
Seriously they have filled you full of crap about how a rocket works, that is why it's not easy to explain it to rational thinking people the way they do...because it simply does not work in how they say it does.

The shuttle is moored to the solid rocket boosters.

Quote from: icanbeanything on June 04, 2013, 11:54:55 AM

Quote from: sceptimatic on June 04, 2013, 11:50:39 AM

The reason a balloon works this way is due to the elasticity acting on the air, so your analogy in the vacuum is wrong.

Okay, look at the image, and now imagine it's not a balloon, it's a steel sphere. What's different about the action of the arrows?

I know what you are getting at but that is not how rockets work.
Can you imagine if that was employed in a big fuel tank like that on the fake shuttle.
By your analogy, the fuel coming from that tank would also push that tank upwards but the tank is external from the fake shuttle.
Seriously they have filled you full of crap about how a rocket works, that is why it's not easy to explain it to rational thinking people the way they do...because it simply does not work in how they say it does.

The fuel tank is external, but the diagram is for the engine itself, where the fuel is ignited. That is on the bottom of the rocket/shuttle.

So, with a fuel tank, imagine the same diagram, but with a small feeding nozzle coming from somewhere, constantly replenishing the gas that leaves the bottom (into space).

This changes every five minutes.
Now which is it...Is it the fuel in the tank that pushes the rocket... or the fuel at the bottom of the rocket which has nothing to do with the tank.

Be clear here, otherwise we will have to conclude that rockets do not work in space and you have been told lies and believed them for no apparent reason.

Nothing is changing, it's just you seeing it wrong. In case of a simple balloon, the fuel tank, rocket, and engine are the same thing, the balloon itself. This is where your confusion comes from. A modern rocket isn't just a big chamber.

There's a tank to hold the fuel. This is just to hold the fuel, it's not where the propulsion is generated. This fuel is fed into the engine, which has a fuel burning chamber. This chamber is essentially what you see on the diagram. It is in this chamber that the thrust is generated by expanding gas, the same way it is in the diagram. The expanding gas is pushing on the top of the burning chamber's wall. The chamber is attached to the rocket, so all the rocket is pushed therefore.

The fuel tank of a rocket is just to keep the engine chamber constantly fed with more gas to expand. It's like you attached a CO2 tank to the side of the balloon through a valve and nozzle, to keep feeding the balloon more gas as it is constantly being expelled from it.

Scepti, what is propelling the rocket is that those expanding gases are pushing the TOP of the inner chamber from where they're coming from. Like in the diagram. Think of the diagram. The gas inside is expanding every way, but there's only one way it can exit, and that's below. There's no wall below, there's the open neck of the chamber, so the force of the expanding gas doesn't cancel out the top component. The top component remains, pushing the rocket.

Thanks for the diagram Scepti, I still can't see where the upward force is being applied as air pressure acts on the balloon equally from all directions.

Anyway maybe if we look at a mechanical application of the forces involved, do you know how the internal combustion engine works?

Scepti, are there any others espousing that rockets do not work in a vacuum? I must say, I somewhat believe you. Although I am not totally convinced. Perhaps another's explanation may help me and others to comprehend the futility of rocket propulsion in space.

Here is someone else who seems to have thought the whole "rockets can't work in a vacuum" through a little better than Sceptimatic.  He's still wrong, but at least he tries to give specific reasons.
http://cluesforum.info/viewtopic.php?f=23&t=1632&sid=859ccbe6e2bec4c0fa4419addac7bd92

Here is someone else who seems to have thought the whole "rockets can't work in a vacuum" through a little better than Sceptimatic.  He's still wrong, but at least he tries to give specific reasons.
http://cluesforum.info/viewtopic.php?f=23&t=1632&sid=859ccbe6e2bec4c0fa4419addac7bd92

Interesting read Markjo, the persons statement of "I'm not going to use equations" is very Sceptimaticy.

A simple explanation is alright up to a certain point. The point of the equations is that they act as a proof for the explanation and provide a predictive element, without them it becomes a game of "my explanation makes more sense to me".

I like to keep things simple. I'd rather someone explain a theory is simple terms rather than a thread full of equations for two reasons.

1. It is much more interesting to read simple explanations to theories.
2. People viewing the forum will not feel intimidated if they have a theory but can only explain it in simple terms and they will feel more inclined to join up and get involved, which as we all know can lead to many on here at least evaluating their thought process or even expanding their knowledge.
The more that take part in a topic, for or against or on the fence, it can bring up more questions and potential answers, which at the end of the day we are all trying to find aren't we.

I know that equations are part of science, so I don't need anyone to tell me this.

The problem is, when you read and think up simple explanations, you're using assumptions and philosophy to imagine how something happens, like this:

If you wanted to jump up, you know you cannot do it unless you produce a downward force to spring you up...so naturally you bend your knees and launch off of?....the floor, right?
The reason you spring up, is because your energy in your legs... (fuel)... meets resistance.. (floor)... and allows you to use that energy to propel you up.

You assume a rocket works similarly. You make assumptions based on your creative mind, and not theories.

This is the problem with simple explanations given without the understanding of the fundamental theories: you can get things wrong.
It may be harder to understand the theory, but without it, you can get things wrong. With the theory, you know you get things right.

This is how I know that my understanding of rocket theory confirms me that they work in space.

I did try explaining the theory as simply as I could, but as you can see, it's not that simple.