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But hydrogen is not that readily reactive, not that "hungry" persay. It will combine naturally, but not quickly, so that is not a sufficent explanation. I don't see how my kenetic model, which accuratly describes the translational motion of hydrogen on the molecular level, will permit the CNT straw pipeline.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
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Does your model show how H2 makes it to space?
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Yes, it does. The upper limit for the velocity of hydrogen molecules at a reasonable temperature is above escape velocity, or at least high enough to reach an altitude where solar wind can bake it off. However, very little gas moves in this way per time, almost but not quite zero.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
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Errorist
[http://www.physics.usyd.edu.au/~cairns/ … node2.html]This may be of some use in seeing how molecules escape into space, I studied the subject a couple of years ago and seem to remember looking at a similar website then to get the process fixed in my head. We are talking *tiny* amounts over a year though.
There was a young lady named Bright.
Whose speed was far faster than light;
She set out one day
in a relative way
And returned on the previous night.
--Arthur Buller--
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I agree about the tiny amount. What if you added extra tons & tons of H2 or He in the atmosphere in your model. would the net amount be more that escapes the atmosphere??
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Yes, but the total amount would still be extremely small. A thousand times .0000000000001g/hr would still be a useless quantity. Many times almost nothing is still almost nothing. Plus, you can't raise the pressure indefinatly, and will eventually burst the tube.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
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So what you are saying is the gas would have to be compressed so much it would have to become a liquid before it would have any chance of coming out the end of the tube in space, and the tube would break before that would happen. I ain't bying that idea because the H2, and He make it out of the atmosphere in a gas state and not the liquid state to begin with.
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This is beginning to become a broken reccord response... please relate your statements to the theory behind compressable fluid motion, and not the upteenth repeat of statement that "the gas escapes from earth;" of course it does, that is not at issue nor am I trying to refute that, only the quantity of the gas that does.
Provided the temperature stays reasonable and constant, the only way to increase the number of molecules leaving the tube is to increase the number of molecules in the tube to begin with. Since you are dealing with volume that is constrained by gravity, this would in turn increase the pressure. Obviously if it is a liquid it won't leave the tube, so you are correct that this would be an effective upper limit on the pressure syntheticly applied by a pump.
The natural quantities of Hydrogen and Helium gas in the atmosphere stay a gas from surface to space, no liquification required. And and any concieveable gas pressure/temperature combination, the total flow of gas will still be negligible over such a small area.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
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Simply put, if it escapes Earths gravity then it will also escape the tube. If the pecentage of H2 is near 100% entering the tube then it will be near 100% as it exits the tube. The differential of pressure is more than enough to overcome the gravity effect on H2 or He. If it was not then no H2 or He would never escape the atmosphere at all. How about giving the Earth 100% H2 in the atmosphere in your model with no solar energy, and see what happens to it?
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For almost literally the tenth time, YES some gas will escape the tube. HOWEVER the vast majority of the gas will not escape even with a very high pressure. This is well explained in the kenetic model for gasses as previously stated.
The pressure (or pressure differential) of a gas has little to do with if a column of gas or mixture of gasses can reach geosynchronous orbit from the ground.
1: Pressure does not effectively determine the speed of any individual gas molecule, only temperature does this. Pressure is simply the the density of a gas in a given volume, not how fast the individual molecules travel, only their number.
2: Unless a gas molecule can reach speeds at aproximatly 11,000m/s, then the molecule will not reach the top of the tube. Hydrogen, the "fastest" gas there is, the majority does not signifigantly top 3,000m/s at reasonable temperatures. However, a VERY small number of molecules do gain this velocity due to momentum transferred from other molecules, but this number is so small that it will accomplish nothing.
This same principle governs how high H2/He will rise in Earth's atmosphere, and since it only has to reach ~100km to enter space and not 36,000km against the force of gravity to the geostationary tube end, much more gas per-area can escape. Even then, the amount of gas that escapes is quite small by area things considerd. Furthermore, our atmosphere has a HUGE surface area, so even the tiny loss of gas over a small area is magnified orders of magnetude... since the tube will be pretty small, it will not have this luxury either since its cross-section is small.
The natural loss of H2/He from the Earth's ~100km high atmosphere, however small, is for intents and purposes an entirely different set of circumstances from a tiny tube 36,000km long against this same gravity force... they are not even worth trying to compare.
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1: Pressure does not effectively determine the speed of any individual gas molecule, only temperature does this. Pressure is simply the the density of a gas in a given volume, not how fast the individual molecules travel, only their number.
Not according to Bernulli's principle. If one increases the pressure of a gas on one side of a venturi then the molecules will accelerate through the narrow passage way.
2: Unless a gas molecule can reach speeds at aproximatly 11,000m/s, then the molecule will not reach the top of the tube. Hydrogen, the "fastest" gas there is, the majority does not signifigantly top 3,000m/s at reasonable temperatures. However, a VERY small number of molecules do gain this velocity due to momentum transferred from other molecules, but this number is so small that it will accomplish nothing.
This same principle governs how high H2/He will rise in Earth's atmosphere, and since it only has to reach ~100km and not 36,000km against the force of gravity to the geostationary tube end, much more gas per-area can escape. Even then, the amount of gas that escapes is quite small by area things considerd. Furthermore, our atmosphere has a HUGE surface area, so even the tiny loss of gas over a small area is magnified orders of magnetude... since the tube will be pretty small, it will not have this luxury either since its cross-section is small.
Since the gas only has to reach ~400km this is where the end of the tube will be placed in space about as high as the shuttles orbit.The counter balance for the structure can be further away. If it even needs one since it will be filled with lighter gasses.
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You are not making the transition from the macro-scale world where things are "fudged" to the micro-scale world that actually governs things. In the "big" world, many effects are so small, they can be ignored... Venturi's model is also subject to gravity, but it is ignored because of the near-zero height change.
The jumbled, roiling mass of molecules will move according to Venturi now that they are not as constrained, but this does not mean the INDIVIDUAL MOLECULES will go faster than the ~3000m/s limit (they infact may slow down), so the effect of gravity will still hold you back even at an elevated pressure. Case in point, that molecules of higher mass (not volume) will diffuse slower thru a pinhole than ones of less mass at comperable conditions. Venturi does not take this into account either, nor do most macro-scale world physics calculations.
Even cutting down the tubes height from 36,000km to 400km is only a tiny improvement, given that gravity will cause the vast majority of the gas to "pool" at lower altitudes. Again, an order of magnetude improvement of an extremely small value is still useless.
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No matter how you look at it if you change the pressure you change the velocity no matter how big or small the molecule is.
Even cutting down the tubes height from 36,000km to 400km is only a tiny improvement, given that gravity will cause the vast majority of the gas to "pool" at lower altitudes. Again, an order of magnetude improvement of an extremely small value is still useless.
Did you run the model on the 100% H2 or He in the Earths atmosphere without solar heat added? Since H2 is the universes greatest element in mass you would think there would be more of it here. Look at Jupiter its gravity is so great that H2 is collected there in great masses.
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No, increasing the pressure does not increase the velocity of the molecules, which quite simply get in eachothers' way most of the time, it only permits the velocity there already was to manifest. In fact, if you had a system that was perfect and the molecules did not get in eachothers' way, then the velocity of the gas would be on the average a little above 1,500m/s. The fact that gas molecules can get in eachothers' way explains the sound barrier.
Adding small amounts of energy in an attempt to raise the molecules speed only produces a small increase over the temperature regieme that a carbon nanotube can exsist. Further temperature increase raises a number of problems...
1: The tube will disintigrate
2: Even if it didn't, it would take a huge amount of energy
3: If you get it hot enough, the hydrogen may become monoatomic (and eat the tube) or a plasma, which throws a number of issues into the kenetics... No, making it hot won't work.
The Earth has very little hydrogen because we didn't start with that much to begin with where most has collected in the Sun and the outter planets, and that it has been a very long time since the Earth had much of a gravity well.
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I guess Bernoulli was wrong then. Planes don't fly either.
H2 is not bound to this Earth as it is to Jupiter because Jupiter has a greater gravity well.
Did you run the model on the 100% H2 or He in the Earths atmosphere without solar heat added? What happens?
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What is this obcession with "running?" If a substantial portion of the gas does not aproach escape velocity, then the flow will be nil, its a simple if-then statement.
The Bernoulli principle applies only the average speed of the molecules - the macro world - and not to the speed of the individual molecules themselves - the micro. When you open the neck of a balloon full of hydrogen, tell me, does the bulk of the gas inside escape at a mile or two per second? The gas is constrained at least partially in this case by its own pressure front and low energy content.
Now, if you remove this constraint, add a little heat to make up for losses, and then enhance the Bernoulli effect to an absurdly high extent then the speed of the expanding gas would be equal to the speed of its molecules because there are no impediments to the motion of its constituents... which would hence be limited according to Boltzmann around 3,000m/s without raising the temperature to destructive levels.
Bernoulli's effect is a macro-world phenominon that operates just fine on the every day scale of things with our low speeds and such, but its errors grow as conditions become extreme and is hence no longer very accurate, even though it is almost exactly true for the birds and the airplanes. The micro world is where the base forces that govern the macroscopic are governed, and is accuratly explains behaviors over a much larger regieme of conditions.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
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Ok then, a micro world statement for you. If any free molecule of H2 escapes to space then all free molecules of H2 will escape to space.
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On the molecular level, the speed of a gas at a constant temperature is a statistical concern. A molecule will have to be struck by another molecule in roughly the right direction several times before it achieves the velocity needed to escape Earth's gravity, and it must do this without itself hitting another molecule going another direction.
Statisticly speaking, this can happen, and hence permits some gas to escape into space, HOWEVER this is a statististical unliklyhood: the chance of this occuring is so small that it cannot happen very often for a given mass of gas, which limits the amount that can escape over a given time.
Now, since the probability of reaching this velocity is so small, the total number of molecules of gas is pretty small, and the constraint that the molecules must move in almost exactly the right direction (up the tube), it is simply unlikly a given molecule will reach the top. Now, this is not to say that the probability is zero, it is infact a positive finite number, but it is so small that you have to wait a very long time for a signifigant number of molecules to randomly achieve the speed and direction nessesarry... So, the flow is essentially but not quite zero.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
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Wow Just got home. What if they are all going the same direction up the tube?
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There is no way to orient the random path of signifigant numbers of molecules. Particle accelerators of all types cannot move large quantities, making them useless.
Increasing the pressure will increase the number of molecules vying to win the "kenetic lottery," but as you have stated in earlier posts there is a limit where the gas will simply liquify, and then it won't go anywhere. Aproaching this pressure will not cause useful amounts of hydrogen to acend the tube either, even if this super-high pressure were practical.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
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Be back in a few minutes the wife says I have to go to the store.
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What kind of electrical charge will they have in the tube????
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You can, in theory, cause a hydrogen atom to assume either a positive or a negative charge, which requires a huge amount of electricity to do either one. In any event, you still can neither induce a charge nor move enough hydrogen atoms at the required velocity with a particle accelerator. Ion engines, which are simple particle accelerators, can move only small masses over time even though they are tailored to move a large mass as is practical. You also would have a problem with neuteralizing the charge when you get the hydrogen atoms to the other end of the tube.
Not gonna work.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
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How much energy is involved in giving the H2 or He a charge + or -?? Does it depend on the volume of H2 or He?
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A quick calculation of 0.5 x (H-H bond energy + 2 x ionization energy) comes out to be 365.122kcal per gram of hydrogen, assuming (which is never true) 100% energy efficency. Enough energy to heat a gallon of water to boiling, for a measly half a paperclip worth of propellant. Thats just to ionize it, not to accelerate it... to move a whole ton of hydrogen, the numbers start to get scarry real fast... Helium is extremely hard to ionize with its stable 1s2 electron configuration.
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