h a l f b a k e r yMake mine a double.
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Recently, several space satellites have been experimenting with lowering a line towards earth... I say, lower a vacuum cleaner hose to earth from a geosychronous satellite and 'clean house'. The surface side of the hose can be capped off until ready to use. Tow the surface side of the hose to the
job site, uncap it, and stand way way back. That baby will suck everything and anything into it - shoot it up the vacuum cleaner hose and eject it into outer space - way out where the geosychronous satellite is parked. It won't use ANY power or electricity. It won't cost a thing to operate, once in place, and it will be the most perfect vacuum we could achieve on earth. No bags to change, no worries about what we suck up... water, food, dirt... doesn't matter - it's GONE! It could double as a weapon... suck the enemy country into space. It could also act as a launching device for small projectiles. You could literally change weather patterns with it. You could run a 'wind generator' from it - free electrical power (at least until the earth runs out of air). No end of things you could do... and I have a list of more ideas you could use this for. Remember, you saw it here first...
collaberative web fiction
http://www.halfbake...ive_20web_20fiction
[RobertKidney, Aug 19 2001, last modified Oct 17 2004]
watertube
http://www.halfbakery.com/idea/watertube
[RobertKidney, Aug 19 2001, last modified Oct 17 2004]
Closable giant chimney vacuum cleaner to space
Closable_20giant_20...leaner_20to_20space
Making it a chimney [caspian, Oct 29 2018]
[link]
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um .... there is no way this would work. Even if you could
make tube that long there would be no suction because
the earth's atmosphere would simply push up into the
tube as you lowered it. |
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It would work for a space ship-- but it'd suck out more
precious air than trash.. (and there's be no way to get
the air back-- unlike in a normal vacuum where the air
simply passes through the filter.) |
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read the coments on my water tube idea and the link on vacuum cleaners from colaberative web fiction... |
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Like all such ideas, one should try to figure out from where the energy is coming. |
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Here, there are two sources: the energy required to lift the tube, and the energy required to overcome its buoyancy on the way down. Try submerging an air-filled straw in your drink; it takes force to hold it down. And while some of that force is provided by the weight of the tube, that weight must be overcome when lifiting it in the first place. |
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Also, you won't eject it into outer space; you'll just fill the tube until the pressures equalize. Then you have to figure out what to do with the tube and its contents. |
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If you shove a straw down into a glass of water - the straw fills up. Sure, and that is the end of that. But there, the comparison ends - because you must remember liquid is pulled up through the straw by the vacuum you create in your mouth. As long as you suck, the liquid gooes up. The vacuum in space will never fill up and hence will always be a vacuum - and therefore, this would work like a CHAMP, Chump! |
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jim_brain: then what holds us and our atmosphere down? |
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//'liquid is pulled up through the straw by the vacuum you create in your mouth'//
Sorry, wrong. The liquid is *pushed* up by atmospheric pressure on the surface of the liquid *outside* of the straw. It rises in the straw because that pressure is not present in your mouth. Stuff would rise up [gorn]'s hose only if the pressure inside were lower than that outside at the same altitude, which is not the case. |
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still just because it doesnt work properly doesn't mean we should vote against it (I want more votes for my water tube - please take the hint)... there must be a way to work around these small technical problems... |
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you could put something resembling a real vacuum cleaner at the top of the tube for example... |
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Using what Angel said, restated in a different way: Stuff is *pushed* up by atmospheric pressure on the air at and around the bottom of the sky-tube. Stuff and air then rises in the tube because that pressure is not present in outer space. Stuff would rise up tube because the pressure inside is lower than that outside the end of the tube in space. So, this would work! |
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gravity stops it getting into space... some sort of energy must be used... the "antigravity vacuum vacuum" is born... |
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[jim_brain]: You're right, stuff *would* rise up the tube, but only as far as it extends *outside* the tube.
<Einstein-type thought experiment>You have a bucket of water with a hose in it. Apply a vacuum-cleaner to the open end of the hose. Water is sucked up the hose into the vacuum-cleaner. So far, so good, but what you want to do is to apply the vacuum-cleaner to the entire bucket. Either everything is sucked up or nothing is sucked up. Guess which.</Einstein-type thought experiment> |
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Gurggh! If you have a perfectly rigid tube without no leaks and a perfect vacuum inside it then water will rise in the tube only 10.5 meters or 34 feet whichever it pleases! Not a penny more! If you wish to eject trash into space you will have to pay to catapult it! You cannot suck it! Oooooh my brain hurts... |
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Imagine a bucket of water. Tiny little people live at the bottom of the bucket, struggling to move under the high water pressure. To clean the bottom of the bucket they have little "Air Cleaners" which work by generating a little pocket of air which sucks water in through a dirt filter etc.
They make a tube, filled with air and raise it through the water in the bucket until it reaches the air above the bucket. By remote control, they take the lid off the top of the tube. Water from the bottom of the bucket quickly rushes into the tube. What happens next?
(a) Water carries on being sucked into the tube, fountaining out the top until the bucket is drained?
(b) Water rushes into the tube and stops when the level in the tube is the same as the level of the water in the bucket? (ignoring the tiny capillary effects). |
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I think we're well on the way to establishing that this idea might have one or two tiny flaws. |
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What about momentum? If the velocity of water in the pipe is great enough initially, then perhaps a little bit of water will spurt out the top, or at least rise a little further, before it settles at a level. To remove an object from the surface of the earth into space will require the object to be set in motion by a rush of air up the pipe greater than or equal to the object's escape velocity. If you could get a capped, vacuum-filled space pipe in place (the tricky bit), it might be possible to use it to hurl something into space, maybe. Probably not though. |
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How about a variation on the *siphoning* principle to make this idea feasible? [angel]'s bucket of water demonstrates the intrinsic flaw in this idea, but with a tiny additional suction, and by extending the exit of the tube below the bottom level of water, gravity will act to empty the bucket as long as the tube is kept open. So <scratches chin, pondering>, I'm no physicist but what we need is surely a way to make the other end of the tube *further down* than the end inside the atmosphere - perhaps attach it to one of our handy neighbourhood gas giants like Saturn or Jupiter with a heavier gravity. We'd still have to provide an initial suck to get the air from the bottom past the top of the atmosphere, far enough for the heavier gravity to take over - just like getting the water over the top curve of the siphoning hose - but how hard could this be? <blinks, wide-eyed and innocent> And once we get it started it'll just keep going till we close the tube. All seems perfectly reasonable to me. ;) |
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Now we're talking about using the gravity of Saturn to move stuff, not the vacuum of space. You'll need to push your stuff beyond the 'thingy'-point (LeGrange? Something like that. The 'equal-gravitational-pull-from-two-bodies' point.) so that Saturn's gravity takes over, and once again you're talking big rockets. |
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Hmm. I can think of a minor logistical point here. The earth travels round the sun much quicker than Saturn, and the distances between them vary tremendously, so not only would the tube have to be very flexible, but we'd have to work out a method to stop it wrapping itself several times around the sun. |
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I'm getting a picture of the hose Klein-bottling in on itself so the inside becomes the outside. Not sure what's supposed to happen after that though. |
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Maybe we could get some of those tiny people at the bottom of the bucket to help prevent the hose from getting tangled up with other heavenly bodies. |
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Why, Lemon, you're a genius. Forget Saturn; we use the sun itself. That's heavier still, so the thingy point that angel's talking about should be closer to Earth, plus we don't have to worry about out-of-phase orbits. All we have to do then is have the hose curve slightly out of the plane of the planet's orbits so Venus and Mercury don't slam into it. Am I wrong? |
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"The heat-sink had a mass of some two thousand billion tons and was contained within a black hole mounted in an electromagnetic field situated half-way along the length of the ship, and this heat-sink enabled the craft to be manoeuvred to within a few miles of a yellow sun, there to catch and ride the solar flares that burst out from its surface." |
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One of these might come in handy.... |
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I'm voting for this simply on the basis that it could result in all the air being sucked out of the atmosphere. If someone left the end off of the tube we could all suffocate in days. |
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You obviously have different criteria from me as to what makes a good idea... |
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And if it does get pulled into the Sun, we'd better let go
of our end pretty quickly... |
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the hose would not be pulled into the sun becaused it is atatched to the earth which is in orbit around the sun... after reading the siphon anotation I wanted to vote for this idea but then realised that I already had... not fair, I want another vote... |
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This wouldn't work. Why does the earth's atmosphere stay with us? Gravity!! |
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//You're right, stuff *would* rise up the tube, but
only as far as it extends *outside* the tube.// |
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Unless the air in the tube was lighter, because it
was warmer. Options: electrically heat the tube.
Make the tube black to absorb solar energy. Use
tube as a chimney for a fire. Heat the air as it goes
into the tube. It may help to insulate the tube, but
the air inside will cool as it expands so I'm not
sure. |
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It's a closable giant chimney as vacuum cleaner. I'm
posting this as it's own idea, there's probably
plenty of problems with it to point out. |
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