Okay, pretend you had a REALLY tall pipe, tall enough to reach out of our atmosphere. Then support the pipe on struts above the ground so that it's bottom is completely open, not on the ground. Would all of our air be sucked through it out into space?
that's an interesting idea... perhaps, since the whole "system" will try to bring it self into equ... and since there's an infinite space... heh.
No, you'd need to start a suction reaction. Sorry I don't the exact term, but hopefully you know what I mean. Our gravity holds our atmosphere to the planet's surface, so you can't suck air out of it into space really anyway. If possible, whats to stop our air from already being sucked into space? There would be no barrier for you to break with a tube...
I don't think so.
Like was already said, gravity holds the atmosphere to the Earth. If you stretch a tube out to space, it'll be no different, for the tube isn't superceding any tangible "bubble-like" boundary in which our air is contained. It's just something sticking out there - the gravity of the Earth will hold the air (in the tube) near the Earth.
So no, I don't think it would be like a straw.
See, air escapes ruptured cells (or spacecraft) in space for two reasons. The first and major one is air pressure. It's a term called 'diffusion' - substances will flow from an area of high concentration to an area of low concentration until an equilibrium is found. Because space has a SEVERE lack of oxygen, it diffuses from inside the capsule to outside it.
Reason 2 being that there's nothing to hold the air in. Say, you had a big sphere in space, like a bathysphere. Then you had a gravity well in the middle. So, stick this thing out in the Andromeda galaxy with air in it. If you puncture the sphere, the air will rush out. Now, theoretically, I THINK that if you turn this gravity well on to the proper setting (which would squash us all to the middle), it could keep the air inside - the gravometric attraction would overcome the force of diffusion, and keep it inside.
This is what Earth does - the force of gravity overcomes the force of diffusion.
Now, inside a small tube, the affects of gravity wouldn't be avoided or deterred. Perhaps, if you could offer some gravometric shielding, so as to eliminate the force of gravity from the region around the tube (and block it radiating from the Earth), theoretically, you might be able to make a giant straw.
That might kinda suck, though.
Like was already said, gravity holds the atmosphere to the Earth. If you stretch a tube out to space, it'll be no different, for the tube isn't superceding any tangible "bubble-like" boundary in which our air is contained. It's just something sticking out there - the gravity of the Earth will hold the air (in the tube) near the Earth.
So no, I don't think it would be like a straw.
See, air escapes ruptured cells (or spacecraft) in space for two reasons. The first and major one is air pressure. It's a term called 'diffusion' - substances will flow from an area of high concentration to an area of low concentration until an equilibrium is found. Because space has a SEVERE lack of oxygen, it diffuses from inside the capsule to outside it.
Reason 2 being that there's nothing to hold the air in. Say, you had a big sphere in space, like a bathysphere. Then you had a gravity well in the middle. So, stick this thing out in the Andromeda galaxy with air in it. If you puncture the sphere, the air will rush out. Now, theoretically, I THINK that if you turn this gravity well on to the proper setting (which would squash us all to the middle), it could keep the air inside - the gravometric attraction would overcome the force of diffusion, and keep it inside.
This is what Earth does - the force of gravity overcomes the force of diffusion.
Now, inside a small tube, the affects of gravity wouldn't be avoided or deterred. Perhaps, if you could offer some gravometric shielding, so as to eliminate the force of gravity from the region around the tube (and block it radiating from the Earth), theoretically, you might be able to make a giant straw.
That might kinda suck, though.
I think it depends on the lenth and position of the pole.
If more of the pole is in space than in atmospheare and you were able to fill the pole with gas, wouldnt the gas in the space seaction of pole be sucked out in to space and pull the gas in the atmosphere section of the pipe along with it, then it would continually keep refilling and never stop.
Just like a siphoning hose.
If more of the pole is in space than in atmospheare and you were able to fill the pole with gas, wouldnt the gas in the space seaction of pole be sucked out in to space and pull the gas in the atmosphere section of the pipe along with it, then it would continually keep refilling and never stop.
Just like a siphoning hose.
Well, but siphoning works here on Earth under a uniform attraction of gravity. In fact, a factor contributing to siphoning IS gravity.
So, if we were to try to siphon out the air from Earth... and the gravity is different, I don't think it'd work under the same principle.
Like I said, the force of gravity overcomes diffusion (the basic principle that makes siphoning work).
So, if we were to try to siphon out the air from Earth... and the gravity is different, I don't think it'd work under the same principle.
Like I said, the force of gravity overcomes diffusion (the basic principle that makes siphoning work).
QUOTE (Toucan+Jun 4 2005, 01:42 AM)
I think it depends on the lenth and position of the pole.
If more of the pole is in space than in atmospheare and you were able to fill the pole with gas, wouldnt the gas in the space seaction of pole be sucked out in to space and pull the gas in the atmosphere section of the pipe along with it, then it would continually keep refilling and never stop.
Just like a siphoning hose.
Hi Toucan,
I draft water on a regular basis using a fire truck. There is one truth:
The largest vaccuum you can create is *exactly* one atmosphere of pressure.
Earth's grav pull, by definition, defines that pressure. You can stick tubes, create venturies (that's the term someone was looking for, earlier), whatever you want - the most you'll get is one atmosphere. That atmosphere of pressure is, by definition, not adequate to beat gravity, since gravity is what causes it. Note that you *can* cheat by putting a venturi on the source end of the pipe; but it requires active energy to make it function, and it functions at a net loss.
It's demonstrated best with a firetruck, obviously - at sea level, the best draft you'll get is about 30 feet of height if everything is perfect. Note that it doesn't matter what size pump you use - a little 500 GPM PTO deal, or the big 2500 GPMs found on a real truck - 30 feet, max, assuming no leaks *anywhere*.
Note that you can draft horizontally for hundreds of feet, depending on the diameter of the hose (which dictates friction loss).
I had a big argument with a fire instructor about this very concept. He believed that a 4 inch hard-suction hose could feed a 2500 GPM pump at capacity. Clearly, he believed, that a 4 inch soft-hose can do it (from a pressurized hydrant), a hard-suction hose can do it from draft. He was clearly mistaken, however, and here's why:
To get water out, you need to get water in. Water-in is measured in Gallons Per Minute, GPM. GPM is easily calculated: Diameter of the pipe gives you quantity, and pressure gives you rate. A soft-hose from a hydrant at 60 pounds can give a lotta water. Tell me... how many pounds of pressure is one atmosphere? Because that's the max "pressure" you can get in a draft. If you think you can max-out a 2500 GPM pump from a 4" under draft at one atmosphere, you (Mr. Instructor) need to show me where this additional water is coming from - because it sure as hell isn't the suction feed.
So, hopefully the above anecdote will show some nature of the tools you've got to work with, regarding pipes, pressures, vaccuums, and venturies. Our perception of "suction" only exists due to atmospheric pressure; the air in the end of your pipe would not "suck" anything, since there is no pressure there (because there's no gravity to cause it).
Enjoy,
- Steve
If more of the pole is in space than in atmospheare and you were able to fill the pole with gas, wouldnt the gas in the space seaction of pole be sucked out in to space and pull the gas in the atmosphere section of the pipe along with it, then it would continually keep refilling and never stop.
Just like a siphoning hose.
Hi Toucan,
I draft water on a regular basis using a fire truck. There is one truth:
The largest vaccuum you can create is *exactly* one atmosphere of pressure.
Earth's grav pull, by definition, defines that pressure. You can stick tubes, create venturies (that's the term someone was looking for, earlier), whatever you want - the most you'll get is one atmosphere. That atmosphere of pressure is, by definition, not adequate to beat gravity, since gravity is what causes it. Note that you *can* cheat by putting a venturi on the source end of the pipe; but it requires active energy to make it function, and it functions at a net loss.
It's demonstrated best with a firetruck, obviously - at sea level, the best draft you'll get is about 30 feet of height if everything is perfect. Note that it doesn't matter what size pump you use - a little 500 GPM PTO deal, or the big 2500 GPMs found on a real truck - 30 feet, max, assuming no leaks *anywhere*.
Note that you can draft horizontally for hundreds of feet, depending on the diameter of the hose (which dictates friction loss).
I had a big argument with a fire instructor about this very concept. He believed that a 4 inch hard-suction hose could feed a 2500 GPM pump at capacity. Clearly, he believed, that a 4 inch soft-hose can do it (from a pressurized hydrant), a hard-suction hose can do it from draft. He was clearly mistaken, however, and here's why:
To get water out, you need to get water in. Water-in is measured in Gallons Per Minute, GPM. GPM is easily calculated: Diameter of the pipe gives you quantity, and pressure gives you rate. A soft-hose from a hydrant at 60 pounds can give a lotta water. Tell me... how many pounds of pressure is one atmosphere? Because that's the max "pressure" you can get in a draft. If you think you can max-out a 2500 GPM pump from a 4" under draft at one atmosphere, you (Mr. Instructor) need to show me where this additional water is coming from - because it sure as hell isn't the suction feed.
So, hopefully the above anecdote will show some nature of the tools you've got to work with, regarding pipes, pressures, vaccuums, and venturies. Our perception of "suction" only exists due to atmospheric pressure; the air in the end of your pipe would not "suck" anything, since there is no pressure there (because there's no gravity to cause it).
Enjoy,
- Steve
QUOTE (Steve+Jun 4 2005, 06:45 PM)
Tell me... how many pounds of pressure is one atmosphere?
If I'm not mistaken, around 14.7 pounds per square inch (PSI).
If I'm not mistaken, around 14.7 pounds per square inch (PSI).
drat
my evil plan to take over the world won't work!
my evil plan to take over the world won't work!
You could of course stick a giant compressor at the base of your really tall pipe. (it would have to extend at least as high as the altitude for geostationary orbit, 35,000 km, give or take. It would need to be even taller than this for really efficient atmospheric evacuation) You could then push as much air as you like into that tube, which would begin to fill the tube with air higher and higher, until the air finally reached the top of the tube, and escape forever into space. Note - the tube would have to be located exactly at the equator. The continuous acceleration the tube would experience from the earth's rotational force at its apex at any other place (other than at the true north or south pole) would certainly knock it over. (Ok, so it could be shaped hyperbolically, but that sort of construction seems inefficient and from an engineering standpoint, a nightmare even beyond the otherwise "easy" task of constructing a 35,000 km hollow tube to outer space. capable of withstanding the incredible amount of air pressure we're talking about producing here...) At the poles, you don't get the benefit of the earth's rotational speed, and the air at the top of the tube would not achieve escape velocity. It would fall right back down to earth with a big "whoosh."
Does anyone want to take up the question of how many atmospheres would be required at the base of this tube to fill it to the top? oh, wow I just remembered something - your air would be compressed to a liquid at room temperature far before you achieved enough atmospheres to push it into orbit. Heck, it might even be a solid with that much pressure. Here's an alternative - every couple of miles or so, you have a repeater compressor, so that the atmospheres never exceed a certain fixed level in any given part of your air tube.
-jeff
Does anyone want to take up the question of how many atmospheres would be required at the base of this tube to fill it to the top? oh, wow I just remembered something - your air would be compressed to a liquid at room temperature far before you achieved enough atmospheres to push it into orbit. Heck, it might even be a solid with that much pressure. Here's an alternative - every couple of miles or so, you have a repeater compressor, so that the atmospheres never exceed a certain fixed level in any given part of your air tube.
-jeff
are you a fucking idiot? we don't have an oxygen shield, like planet druidia, but our atmosphere stays in place. know why? GRAVITY. gravity is so powerful, it can hold light gasses like oxygen and nitrogen (but not hydrogen or helium) at STP.
to move earth's atmosphere off of the planet, you'd have to have a powerful gravitational field pulling the atmosphere away from the planet, but not pulling earth itself. or maybe a series of compressors stacked up, reaching past geostationary orbit. either way, it's a really stupid idea.
to move earth's atmosphere off of the planet, you'd have to have a powerful gravitational field pulling the atmosphere away from the planet, but not pulling earth itself. or maybe a series of compressors stacked up, reaching past geostationary orbit. either way, it's a really stupid idea.
Space does not suck - Gravity does! The gas in the pipe (like the gas on earth) is held in place by gravity. If your idea was true then why does all of our atmosphere just not get pulled up and into space?
Ok, one more idea. To quote some random plastic surgeon , It's easier to dig a hole than to build a pole. to remove the air from the surface of the earth, you simply need to provide an easy way for to air to go the direction it wants to go, which is down, not up. drill a large-ish hole to the center of the earth, jules verne style. Create a cavity down there large enough to hold all the air in the atmosphere. gravity will do the work for you. For those of you astute enough to realize that g=0 at the center of the earth, realize that there are are 3,963 miles of tube leading to this cavity. At the surface of the earth, a single atmosphere of pressure can only support air up to about 60 miles. Our tube will act as a compressor, ensuring the air trapped in the center of the earth will be highly compressed (and stays that way). After you've dug your hole and your cavity, you only need to wait before the entire atmosphere gets sucked into the giant hole.
If you really wanted to remove the Earth's atmosphere all you would have to do is heat it up so that the kinetic energy of gas molecules would be enough that they could reach escape velocity. Escape velocity on Earth is about 11.2 km/s or 25,000 mi/hr. The kinetic energy of one molecule of Nitrogen gas would have to be 2.9*10-19 Joules. Not much right? Well that would be a temperature of about 141,680 Kelvin or 56,595 Fahrenheit. So we would all be long cooked before we suffocate. Good luck by the way! 
No, this entire idea has already been done. Your approaches toward atmospheric removal are all all wrong...
I think someone has watched "Spaceballs" too many times. You know... the part where they suck all of the oxygen away from earth with giant robot vacuum ship. = )
Besides, I think we'll all sufficate from pollution before you find a way to remove all of the air from Earth.
Besides, I think we'll all sufficate from pollution before you find a way to remove all of the air from Earth.
One could eliminate the atmosphere in other ways than removing it from the surface of the earth, with far less energy. Rather than heating the earth up to boil the atmosphere off the planet, or pump it into outer space, you could deploy a really, really large belt of aluminum foil into orbit around the planet (think rings orbiting saturn, only a single piece). Also, unlike saturn, instead of being flat with respect to the orbital plane, it will be flat at a ninty degree angle to that, so that the belt effectively reflects all sunlight away from the Earth at all times. immediately, the planet will cool dramatically. Under the relatively balmy temperature of -109F, the CO2 will rain out of the atmosphere as a superfine powdery snow. at -297, the oxygen will turn into LOX and rain out as well. The atmosphere is mostly nitrogen, as you know, and nitrogen has an evaporation temperature of -346F. Below that temperature, the remainder of the atmosphere will rain down out of the sky. The same effect could be achieved by moving the planet out of the solar system, but the energy requirments for the earth achieving escape velocity are significantly higher than lofting up some aluminum foil.
Incidentally, their is a major difficulty with the aluminum foil plan - it would be exceedingly difficult to keep such a belt in orbit long. the solar wind would push very strongly on the side of the belt facing the sun, immediately destabilizing its orbit. I feel this difficulty is still less than the difficulty of building a 35,000 Km air pipeline into geostationary orbit though.
Incidentally, their is a major difficulty with the aluminum foil plan - it would be exceedingly difficult to keep such a belt in orbit long. the solar wind would push very strongly on the side of the belt facing the sun, immediately destabilizing its orbit. I feel this difficulty is still less than the difficulty of building a 35,000 Km air pipeline into geostationary orbit though.
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