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Physics says,H2 or He will transfer inside the carbon nano tube because of the following reasons:
1.) Physics says,any pressure differential = flow.
A differential of pressure of -30" of mercury in space and 15psig at sea level. Will cause the flow of molecules.
2.) Physics says, heat always flows from warm to cold.Temperature differentail between space, and sea level. Average temperature is 0 degrees in space,and 80 degrees at sea level. The temperature in space near earths orbit in sunlight is +250 degrees. In the shade it is -250 degrees. Thus, the average temperature is around 0 degrees.
3.) Physics says, rotational velocity increases as distance increases from Earths axis increases. Thus, as the molecules flow outwards their velocity increases.Wow, this reminds me of the Earth as being a big pump thowing the molecules outward like the vanes in a pump. Earth the giant pump!!!
4.) Physics says, energy will be conserved in a closed tube.
5.) Physics says, H2 and He make it to space every day and it is not even in a tube it is just floating around freely. It is constantly escaping Earths gravity.
ANY THOUGHTS OUT THERE???????
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Again, just as with the other identical thread previously, gravity is the devil in the details... the pressure --> flow concept does not take into account gravity, since in the narrow kilometer or two layer of human life on Earth's surface, gravity has a small enough effect on gasses to ignore in most cases. However, when dealing with a height difference of dozens of thousands of kilometers then gravity will have a nontrivial effect. In fact, it will stop the flow entirely.
Kenetics says some miniscule quantity of hydrogen molecules will eventually reach escape velocity and rise to the top of the tube, this is a given, but it also says that no signifigant quantity will rise... we would be lucky to detect it.
Now, say you want to add velocity on a tangent to improve the flow? Such as the nanotube hose "pulling" the gas up to orbital velocity to help counter gravity? Unfortunatly, the distance the gas will travel will not get it high enough to take signifigant advantage of this, the speed gulf between the highest practical hydrogen velocity and the speed needed to reach the height of hundreds or thousands of miles is too great.
Futhermore, the system will NOT conserve energy in this case as the kenetic motion of the gas will not automaticly add its own "free" velocity to the horizontal orbital motion, you have to add some sort of energy to push it... I am wondering if it will induce a drag the tube, thus making the top of the tube unstable and requiring stationkeeping.
If you need hydrogen cheap that bad, it would be more practical to go grab a comet with a Nuclear Salt Water Rocket and haul it into Earth orbit... the easiest way is to build a giant DC-X rocket or a X-30 NASP that works, hauling up tons of liquid hydrogen at a go once a week.
[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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Have you calculated how much energy would be required to get say hydrogen to escape velocity?
If we say the mass of an hydrogen atom is around 1.6735 x 10exp-24 g
And it needs to reach 11200 meters per second, what is the amount of energy required, and furthermore is that amount of energy provided?
Remember that helium would require twice as much energy.
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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ERRORIST is wanting to use the natural thermal motion of gas molecules to get into space, so the question is not quite how much energy is needed, but how hot you would need to get the gas to at least aproach escape velocity.
Since you are talking about increasing the velocity by a factor of 5 at least in order to get a nonzero flow, I estimate the temperature would be very high into the hundreds of degrees celsius, which would destroy the carbon 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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The gas naturally escaping earths atmosphere is not heated that much nor is it traveling that fast.
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Yes it is traveling that fast, or at least it was, until gravity slowed it down. As mentioned elsewhere, solar wind may skew the equilibrium to speed this, but solar wind isn't going to help in a closed tube. Furthermore, the quantity of that gas escaping is very, very small given the area of the Earth's outter atmophere.
I'd like to reffer back to the Boltzmann distribution, which is the speed of molecules of gas (X axis) versus the fraction of the total number of molecules at that speed (Y axis) at a given temperature. It is a bell curve, which is slightly truncated on the slow end since it is impossible molecules will slow to a stop, and slightly stretched on the fast end to make up for it.
Now, the two features of this plot that I want to point out:
1: There is no signifigant quantity of hydrogen that moves faster than 3,000 meters per second at 0C/273K temperatures. It is essentially the upper limit that hydrogen moves. This is about one quarter the speed you would need to reach orbit, obviously far too low.
2: The plot then flattens out beyond 3,000m/s and goes to zero; that is the number of molecules reaching beyond this speed in a given quantity of hydrogen is effectivly zero. Although the distribution does not actually reach zero until much higher velocity regions, it is such a small fraction of the whole that is may as well be zero in the 11,000-12,000m/s region.
Injecting hydrogen molecules up the tube with a particle accelerator in the hopes that it will carry bulk quantities of hydrogen gas with it to the top also will not work, because the momentum of the injected molecules will inevitibly transfer to the bulk hydrogen, slowing it down and heating the gas as a whole until it frys the tube. The only way to circumvent this is to reduce the pressure in the tube nearly to a vacuum, which defeats the purpose.
[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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I would suspect that more 3/4 the tube is under a vaccum since one open end is in space.
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But you want the whole length of the tube filled with hydrogen or helium, so you can have substantial (multi-kilogram) quantities of gas over a few hours or a day... Anyway, if 1/4th of a 24,000mi long tube is filled with gas, that would be more than enough to impede a particle accelerator.
[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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"But you want the whole length of the tube filled with hydrogen or helium, so you can have substantial (multi-kilogram) quantities of gas over a few hours or a day."
Elaborate futher on this? please???
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If you WANT to move gas up the entire length of tube, won't it then not be under vacuum?
[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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That is correct. It must fill the entire tube. If the tube is full then it can't be under the full vacuum of space.
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As stated above, the tube will not fill as long as you try and put gas into it from below. The only way it will fill is if you inject gas from the TOP, which defeats the purpose.
[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 lets evacuate the tube first by pulling a vacuum on it with a vacuum pump, then lets pump the H2 into the tube all the out to space. Possible?????
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No, it will just collect at the bottom and the pressure will rise. You would have to apply a huge amount of pressure to ever get anywhere near the top, more than enough to destroy the system... Look at Venus, aproximatly the same gravity, but its atmosphere is a hundred times the pressure, not a hundred times as HIGH.
[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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Field Marshal Mathers doesn't think so nor do I. Why is that?
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As on the other thread:
"Unfortunatly, your key assumption - density remains that at 1atm pressure over the average, is incorrect. Hydrogen is a compressable gas, not an incompressable liquid. Hence, the gas will be at a considerably higher pressure at the base, and further injection by pump will only serve to increase the pressure there, not to eject the gas out of the end of the tube. A gas does not behave like a liquid does in pressure calculations because it is mostly empty space.
Further, simply raising the pressure does not circumvent the kenetics of the molecules: gravity will still confine the gas molecules that do not reach escape velocity to Earth's gravity, simply increasing the pressure only increases the number of molecules per volume, it does not increase their velocity."
[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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Any increase at the bottom should send H2 out the top. Gravity does not confine H2 to our atmosphere.So why would it inside the tube?
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No, that is not quite accurate. Any addition of gas at the bottom will only cause a pressure rise at the bottom, it will not force any signifigant quantity of gas out of the top. Again, a gas does not behave like a true liquid because it is mostly empty space. It is not like a garden hose where you can push water in one end and it comes out the other, the gas molecules will simply be compressed tighter together.
Back to my last post, about how gas molecule velocity determines if it can reach end of the tube or not. This does not change with pressure, this only changes with temperature. Simply adding more slow-moving molecules at the bottom with a pump will not change the miniscule average fraction that leave the tube; the vast majority will collapse back down and occupy some of the excess empty space of the original gas, hence raising pressure - not altitude.
[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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I agree if it was an enclosed system. However, it has a place to escape out the other end.The more molecules you add to the system the more the system pressure will increase. Thus, since it is open at the end, and that end is near a perfect vacuum in space, it will flow.
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No, it will not. You may get some miniscule detectable quantity, but never enough to be useful. Gravity will hold the gas back almost like a solid wall with a tiny pinprick, and essentially none of it will escape. The conventional highschool physics textbooks ignore the force of gravity on gasses, since the effect is so small over short distances.
[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 if the effect of gravity is so small over low altitudes, why would the effect be so great over high altitudes?
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It is not the level of the altitude the matters so much, it is the total verticle distance the tube covers, which is about 24,000 miles. The effect of gravity on free gasses is negligible here in the mile or two of height that >90% of humanity lives in, so it isn't a problem and why it is ignored in simple physics textbooks.
Lets have another look at Earth's evil twin, Venus... It has extremely high pressures of gas, but the molecules of the gas are far below escape velocity. Even though Venus has similar gravity to the Earth, its atmosphere has a hundred times the pressure but does not spontainiously blow out and vanish into space, nor is its atmosphere a hundred time higher than ours. This example is directly applicable to hydrogen or any gas escaping from a strong gravity field, including the hydrogen in 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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Then how is it that H2 or He escapes the Gravity of Earth?
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It does escape the Earth, it just doesn't do it very fast. In fact, its really REALLY slow overall, even with the solar wind to bake part of it off. Considering the surface area of the Earth's atmosphere and its still really slow, and you want to only capture square inches of that effect - even if magnified a thousand times by using pure Hydrogen under modest pressure, the flow would be essentially 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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Here is what I think is happening:
For the case of H2 it is constanly being made in certain amounts by the Earths Oceans,Polar caps, and fresh water lakes. Now as the H2 rises up through all the turbulent layers of the atmospere it is readly combining with O2 and other elements because it is a hungry molecule. What doesn't get a chance to combine with other elements eventually makes it to space. It is a small amount. It reaches a balance so to say.
If a very very large pocket of natural gas were to bubble up from the ocean floor, I would expect to see an increase of the H2 leaving the atmosphere and going into space. There is nothing for it to combine with anymore. The O2 in the atmosphere has become saturated with the H2, and what is left escapes to space. It is not bound to Earth by gravity.It is bound to Earth by chemical reaction making heavier elements.
For the case of Helium there isn't that much of it. It doesn't combine so eventually it makes it out also to space. But, it takes twice as long because it is twice as heavy as H2.
So, by adding close to 100% H2 in the tube I would also expect to see it rise up through the tube and into space.
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