Does Rocketry Work beyond Earth's atmosphere?

[Flabbergasted]

The big question is this: Is this a valid experiment?

It´s a simple and clever experiment and I am not surprised it shows that the "opposite reaction" is insufficient to move the balloon cart. In any case, the experiment is not valid in the sense that the wheels are in contact with a surface to which energy (if any) can be transferred. The drawing above shows equally distributed vectors hitting the inside of the "combustion chamber", but the wheels of the balloon cart will only allow forward movement.

[hoi.polloi]

A slightly more ideal version could involve pseudo-frictionless ball bearings as a conveyance. However, yes, the point is interesting.

[ICfreely]

We know that cold water boils in a near perfect vacuum chamber:

Boiling cold water In a Vacuum Chamber

full link: http://www.youtube.com/watch?v=glLPMXq6yc0
https://www.youtube.com/watch?v=glLPMXq6yc0

It’s a foregone conclusion that Earth is suspended in the vacuum of space. At the risk of sounding too simplistic, I just can’t seem to figure out what sort of barrier between Earth’s atmosphere and the vacuum of space (which is penetrable by rockets) prevents the water on Earth’s surface from boiling.

[hoi.polloi]

Well, air thins as we go higher, that's true enough. As for anything up there or beyond where we've been being a foregone conclusion, I think we are having that discussion in another thread or two — and will likely discuss for centuries to come, or until we actually get there.

Still, that's a pretty profound inquiry. Boiling ... hmm.

[pov603]

Boiling is only the change of 'water' into 'water vapour'?
If so, is it safe to assume then there is plenty of water vapour at higher altitudes due to lower temperatures but lower pressures?

Edited higher to lower...

[I, Gestalta]

I do not recall as to whether or not I actually voiced this curiosity of mine, but since the early days of this thread, I'd always humored the idea that one could devise an experiment on combustion within a vacuum by using a Magdeburg sphere.

Forgive any oversimplification on my part---and I am certainly open to being corrected on any misunderstanding(s) I might have---but:

If you placed some sort of remote-controlled or automatic camera inside the sphere (one which would not collapse after vacuum or near-vacuum is achieved), and took several instances of video footage of various, NASA-styled combustion examples, (remote-controlled or automated), wouldn't we at least learn something?

I'd try two things, basically:

1.) Try to ignite several types of lighters (possibly even matches with some sort of rigged up self-striking system) within the sphere at gradually-reduced degrees of atmospheric pressure. Is combustion achieved? For how long?

2a.) Suspend a sort of makeshift rocket from a string attached to the inner ceiling of the sphere, and set its engine(s) to ignite (or attempt to ignite), and see what happens. Does it rock back and forth? If so, why? Is it because the string is attached to the sphere and there's a vibrational interaction taking place?

2b.) Try it without the string. Place the "rocket" inside the sphere unattached, and see what happens when you attempt to ignite whatever engine you've fashioned. Perhaps it would clank around on the inner surface due to internal vibration, I don't know.

To take it a step further, perhaps all of this would be moot, and would need to be tested in some sort of "zero G" environment, such as extremely high-altitude and/or one of those fancy chambers.

[Flabbergasted]

I am sure the experiment would be exciting to watch, but...

1) unlike "interplanetary space", chambers and spheres have inner walls against which the rocket exhaust will push, much like a launch pad. I would surprised if the rocket didn´t move.

Place the "rocket" inside the sphere unattached

2) unless you can replicate conditions of perfect weightlessness, the rocket won´t be able to float or otherwise "remain unattached" inside the sphere but will be in contact with some structure or surface with which it will interact the moment force is applied.

Also:
http://cluesforum.info/viewtopic.php?f= ... 5#p2393845

[I, Gestalta]

Well, a primary aspect of the experiment would be to determine whether or not a flame would actually be possible to create within these conditions. It would be an attempt at creating a combustion reaction with lesser and lesser degrees of oxygen.

The attachment-to-matter aspect of the experiment would be secondary, and would require separate observations. For instance, what if the experiment determined that, no matter what degree of oxygen were present at a particular stage of air/oxygen reduction, a flame could not be produced?

Finally, what would be the harm in seeing if a flame could be created in an environment which has been entirely relieved of oxygen?

Depending upon the results, the rest of my conditions could be tested (and expanded upon) fairly easily. The primary objective of my supposition is to test the possibility of combustion even occurring in vacuum, let alone creating "work".

[brianv]

Well, a primary aspect of the experiment would be to determine whether or not a flame would actually be possible to create within these conditions. It would be an attempt at creating a combustion reaction with lesser and lesser degrees of oxygen.

The attachment-to-matter aspect of the experiment would be secondary, and would require separate observations. For instance, what if the experiment determined that, no matter what degree of oxygen were present at a particular stage of air/oxygen reduction, a flame could not be produced?

Finally, what would be the harm in seeing if a flame could be created in an environment which has been entirely relieved of oxygen?

Depending upon the results, the rest of my conditions could be tested (and expanded upon) fairly easily. The primary objective of my supposition is to test the possibility of combustion even occurring in vacuum, let alone creating "work".

One of the first "Science" experiments we did as school-children was to put a candle inside a Bell Jar and extract the air. The candle went out.

[rusty]

Well, our rocket scientists tell us that space rockets have some sort of combustion chamber which is separated from the vacuum by some sort of nozzle with some sort of valve. They tell us that the combustion takes place in the combustion chamber and then, pffft, the hot combustion products press the valve open and push the rocket forward. Or something like that.

However, I think it's a valid question to ask, if there's a vacuum outside and some gaseous sort of oxygen/fuel mixture inside if this would not automatically lead to a pressure difference that opens the valve and pulls all our precious propellant gases out before they can be ignited.

I guess that's a purely speculative and theoretical question which can hardly be corroborated by any sort of experiment.

[Flabbergasted]

It would be an attempt at creating a combustion reaction with lesser and lesser degrees of oxygen.

I was going to answer, but rusty beat me to it

Rocket fuel requires no oxygen (or atmosphere) for "combustion". It does however require a combustion chamber sealed off from the environment (in this case, space vacuum), or else the fuel/gas will instantly expand into "infinity". I am an ignoramus in rocket science (whatever that is), but the question seems to hinge on how the nozzle/valve can keep the combustion chamber tightly sealed while hurling out the exhaust at many times supersonic speed AND producing an insane recoil effect in a specific direction.

[I, Gestalta]

Well, yeah, we've been over the absurd "nozzle" nonsense again and again, I feel. I hate even thinking about it, because it sounds like such a Deus-Ex-Machina copout, the likes of which would be employed by Tolkien, or old episodes of Star Trek: Voyager---"Oh, we cannot understand their language? Hmmm. Well, 'just remodulate the universal translators', Janeway said". I guess I digress.

The ultimate goal of what I am proposing is that, first, we establish the elementary/fundamental point that gas cannot perform work in a vacuum.

While I already believe that it makes absolutely no sense for an object to be able to propel itself by pushing against itself, the experiment(s) might greatly benefit from creating an engine (and environment) as close to what we are given by NASA as possible.

Perhaps I am mistaken, but it might seem that one way to deal with the problem of the thrust reacting with the internal shell of the sphere would be to make our makeshift rocket very small by comparison to the volume of the sphere, thus allowing us a wider berth to account for things like d=rt, etc.

Question is, how much actual sense does this "nozzle" malarkey actually make from an engineering perspective?

[omaxsteve]

I am just curious as to how, and why, we are certain that there even is a "vacuum" in (outer) space.

Is it simply taken for granted, or has there been any concrete evidence put forth of the lack of "earth like" atmosphere above the Karman line (100 km above sea level)?

regards,

Steve O.

"when everyone is thinking the same thing, chances are no one is thinking at all"

[brianv]

I am just curious as to how, and why, we are certain that there even is a "vacuum" in (outer) space.

Is it simply taken for granted, or has there been any concrete evidence put forth of the lack of "earth like" atmosphere above the Karman line (100 km above sea level)?

regards,

Steve O.

"when everyone is thinking the same thing, chances are no one is thinking at all"

Indeed Steve. It has even crossed my mind that "space" could be an abstraction - the product of our brains and some sort of collective consciousness that keeps us all on the same page. The clowns would have us looking trillions of miles away when all the answers lie within us, wouldn't they? Like has any one of their "missions" brought back a jar of "space"? They claim it has a "fabric" so it must be collectable.

[I, Gestalta]

I am of the same opinion, actually, and I do not accept at face-value that space is simply a vacuum. If it is, or something similar, fine. That's great. It really means nothing to me either way. Nevertheless, yes, it's kinda easier to take "vacuum" for granted, even though we all employ a certain level of skepticism toward what I would call the scientific establishment ::coughs:: dictatorship.

However, being that it is supposably (not supposedly) observable that oxygen levels and air pressure are significantly decreased to extreme levels even at an altitude as low as the peak of Mount Everest, I don't think it's wholly irrational to, for instance, infer that an exponential jump from that altitude will most likely result in a still more significant reduction. While I have not taken these readings, myself, they're reasonable to me.

If at any point it seems as though I am writing from a place of what appears to be foregone conclusions, I assure you that this is not the case (for most subjects, that is). If I've learned anything from the past 3 years of reading and interacting at Clues, it is that there is always room for doubt and self-debunking, so to speak.

So, all of that said (and perhaps quite unnecessarily so), I'm just trying to think of ways to replicate NASA-ish conditions to run NASA-ish simulations, instead of resigning myself to the idea that these people are super-intelligent geniuses whose scientific throne will be usurped by no peasant/goyim.

The curiosity is so...irksome that it almost burns, in a way.