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space on earth

build mountains and stop the atmosphere with them
 (+6, -1) [vote for, against]

This ring of 1300 kilometer high mountains would entirely separate part of earth's atmosphere from the rest of it. Air would then be pumped out of the middle and airlocks installed.

Useful for launches, observation, science, and many other things. You'll need to install several fail- safes along the way.

BONUS: install a powerful rocket engine to change earth's orbit. The mountains will keep this from disturbing the rest of the atmosphere. you need only assure most of the particles you're shooting out are at escape velocity and the rest land outside the barrier or are pumped out.

BONUS2: build tunnels and rooms into the mountains for a giant arcology

BONUS3: mine minerals from the mountain material as you go.

BONUS4: you'll need to build several nuclear power plants to provide sufficient energy to accomplish this. When you're finished you'll be able to sell lots of excess energy.

 — Voice, Nov 07 2012

This guy thinks small http://www.archdail...ntain-in-the-world/
[Voice, Nov 07 2012]

Angle of repose http://en.wikipedia...iki/Angle_of_repose
the position material will naturally stay (assuming the bottom doesn't melt from the pressure) [Voice, Nov 07 2012]

 // You'll need to install several fail-safes along the way. //

Why, to keep the vacuum from escaping?
 — Alterother, Nov 07 2012

Yes, how would you stop your artificial vacuum mixing with the vacuum of space? You would need a roof I think.
 — pocmloc, Nov 07 2012

 If you build your mountain ring of loose gravel, it can only handle a slope of ~45 degrees, so your 1300km high mountains are going to be 2600km thick at the base. Since you'll need (effectively)two of them on any given line (assuming you want the center at base level), you'll need a site 5200km in diameter.

 On that site, you will be placing 3x10^19 Tonnes of gravel. Producing that much gravel would require re-carving Mount Rushmore approximately 8x10^13 times.

 The weight on the site would be so significant that the entire tectonic plate it was sitting on would sink catostrophically.

In summary: Go ahead, just let me move to Mars first.
 — MechE, Nov 07 2012

Better yet, build the installation on Mars, and all of us can stay here.
 — Alterother, Nov 07 2012

 I was about to ask what the minimum slope would be if we made the mountain range out of reinforced concrete, but then I realized that this idea is rather halfbaked [+] and not worth that much analysis.

If you have the ability to create a mountain that tall, why not just build a single tall mountain and haul your rockets, and observation equipment to the top? Doing this, you could get most of the benefits without building it nearly as high. An atmostpheric dam as proposed would be completely worthless if it wasn't built high enough. For example if it is built high enough that the atmosphere was 1/100th as dense at the top, air would still be spilling over the top so fast that it couldn't possibly be pumped out. However an observatory at an altitude with 1/100th the air density, would probably have 99% or more of the benefit.
 — scad mientist, Nov 07 2012

 //If you build your mountain ring of loose gravel, it can only handle a slope of ~45 degrees// If only it were possible to mix some sort of "cement" with the gravel to create something a little more stable.

//you'll need a site 5200km in diameter.// If only we could think of a largish continent of this size, preferably one where American know-how is readily available. If it already had a cultural vacuum in its centre, the job of pumping out would be simpler.
 — MaxwellBuchanan, Nov 07 2012

1300 km high... 5200 km across... Hey! We could suspend a sensitive microphone right in the middle, and make a huge American Football grunt-detector - and listen to space rock!
(Sorry, I deleted the comment about Dyson being the guy making "Cultural vacuums")
 — lurch, Nov 07 2012

No, he's only into really big spheres now. If you asked him to build this, he'd roof it over on all sides and try to stick a fusion reactor in the center. It would totally spoil the ring aesthetic.
 — Alterother, Nov 07 2012

Let's just buy Sudan. It's large, flatish, near the equator, has a small population, and most importantly is poor. I bet we could persuade the population to move to neighboring nations for the low price of 500 billion dollars. or an average of 14,000 dollars each.
 — Voice, Nov 07 2012

Really nice thought! We'll definitely need one in the near future.
 — Inyuki, Nov 07 2012

 //idea is rather halfbaked ... and not worth that much analysis.//

Isn't ridiculously excessive analysis of completely pointless ideas the purpose of the halfbakery?
 — MechE, Nov 07 2012

 As far as doing it with reinforced concrete, it's surprisingly hard to finder the taper angle for self supporting concrete. Obviously, since you aren't limited by the angle of repose, it could be much narrower.

However, since 3km of glacier was enough to press down tectonic plates, I'm going to modify that prediction. If it's possible to make the structure significantly thin to not sink the plate, it will punch through it.
 — MechE, Nov 07 2012

Ah, but you're forgetting the buoyancy of all that vacuum. You'll need to tether it down so it doesn't float off into space!
 — spidermother, Nov 07 2012

More seriously, an L or inverted T cross section, or a complete bowl, would prevent sinkage (but would require unobtanium).
 — spidermother, Nov 07 2012

[spider] you may have something there. What if we make a wall leaning out partially supported by air pressure?
 — Voice, Nov 08 2012

 I like this for a scifi detail. I would mill an asteroid in space into the ring then gently land it. More fun than a made thing would be a found thing: a planet set up as described.

 Maybe the center has the original atmosphere of the planet and the original horrific denizens, with the ring placed by preservation minded alien colonists who did not want to mingle but did not fancy wholesale genocide either.

Maybe the center has developed vacuum over the eons because of a fusion-powered laser pointed into space which has consumed all the local atmosphere for fuel. The exhalations of visiting explorers are captured by the fusion engine and to their surprise something sputters to life. Realizing there is an intake valve one of the explorers blows into it. The laser powers up in earnest and burns a hole in their orbiting ship, destroying their billiards table.
 — bungston, Nov 08 2012

 Ooo! Ooo! How about this: The ring is not built from a single asteroid or raised somehow out of the subtrate, but assembled from space junk in orbit. The space junk is assorted asteroids, held together by fused metallic spacecraft. The spacecraft used as cement are a combination of colony ships together with a number of warships of various types. Some warships are of the swords-to-plowshares variety and belonged to the conquering colonists. Some are those which belonged to the original inhabitants and which were wrecked in space battle. Ingress to the circle interior is accomplished through the hull of one of the latter. It would be better if this ingress is made in hot blood, with the explorers fleeing some menace encountered on the outside. Better still if some working ship mounted weaponry was found on the wrecked warship, and used to slow the pursuing outring menace.

The chapter 9 revelation would be that although there are plenty of alien monsters inside the circle, both the now - stone age technology original inhabitants (in Kong Kong-like fortified villages) dwelling within the circle as well as the now-vanished colonists are human. That makes casting a lot easier too. Those CGI cast members get the casting couch all pixelly.
 — bungston, Nov 08 2012

Why would you let them rub their members on the couch anyway?
 — 2 fries shy of a happy meal, Nov 08 2012

[bungston], have you been at the C.J. Cherryh again?
 — normzone, Nov 08 2012

 //Am I the only one not taking hallucinogenic drugs today ?//

Trying to kick the habit? Or did you just forget this morning?
 — ytk, Nov 08 2012

 — Inyuki, Jan 11 2013

I only want organic vacuum. None of that synthetic crap.
 — Ling, Jan 11 2013

 I'm surprised there were any comments after MechE's. His comment has inspired me to add this to my list of fav's.

I don't know if MechE is a man, but if he is, then I have a man crush on him.
 — Brian the Painter, Jan 12 2013

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