h a l f b a k e r yNaturally, seismology provides the answer.
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At some point in space air is released until it forms a suitable environment for humans and other animals to be in.
Obviously there are many problems to overcome.
Perhaps it should be done near a heatsource to prevent freezing.
Maybe it could be made large enough to have some internal pressure.
I
wonder if all the problems could be overcome at least theoretically.
Then we could fly about here, perhaps accompanied by birds.
We could look around and see wonderful sights.
A silly idea, perhaps not as far fetched as it seems.
Would certainly be fun. And entertaining to think about, at least to me.
If all else fails perhaps a small center of gravity, small enough as to not be seen from any distance could be added.
Or a giant fishbowl moving through space, but I digress.
Virga
http://inthearmchai...-by-karl-schroeder/
This Idea has been described elsewhere, and more thoroughly as more Virga books get written. [Vernon, Oct 29 2011]
Atmospheric warfare
Atmospheric_20Warfare
Similar scheme to pump atmosphere into space, but this one in the "I'll show them! I'll show them all!" mode. [bungston, Oct 31 2011]
[link]
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it does have a haiku feel to it... |
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I have a sneaky suspicion I know what inspired this little
orbital waltz. |
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Niven, "Integral Trees" ? |
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Niv... what [normzone] said. |
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Far fetched? Au, contraire! I myself have launched many, many, many air biscuits into space. These biscuits circle the globe just above the **doodysphere (**a brazenly gratuitous reference to my "Helium Charged Dog Food" idea) until such time as they can be launched into space. Ironically, I would recommend avoiding flying in it if you are at all troubled by the concept of complete respiratory collapse. Nevertheless, to this idea I heartily bun! [+] |
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What holds the air there? |
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What's the minimum mass of air which will exert
enough gravitational pull to hold itself together
and provide a habitable zone? Clearly a sun-mass
would be more than adequate, while a moon-mass
would be very underadequate. |
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Since Earth's atmosphere has a mass of something
like 10^15 tonnes, whilst the moon has a mass of
about 10^20 tonnes, I suspect we''re going to need
to buy in a lot of air. |
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On the assumption that this is just a really dumb
idea proposed without the use of envelope-backs,
[-]. However, if some line of reasoning can be
evidenced, it's negotiable. |
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If you know whether the gas giants have a rocky core, you can narrow the requirements further. Regardless, the core of the "air" is not in any sense gaseous, as at the pressures involved, the core is solid. |
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The inspiration was those boxes filled with vacuum that were proposed not long ago. |
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I don't understand much about what happens to air when it is vented into space, what with the instant boiling and freezing at the same time. But I imagined a lot of air being vented, maybe enough to create an air pocket several light hours in diameter. Or even bigger. There must be some point where there forms a sort of habitable space in the middle. |
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If a center of gravity is needed after all, I would want it to be small, like pea-sized but with immense mass like a planet. |
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We would indeed need to buy a lot of air from somebody, fortunately air is cheap. |
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Whatever the amount of air required (smaller version of Jupiter, I assume), there will only be a small portion of it that is habitable: the small part that is equivalent to +4,000m or so, and let's say -10,000m (actually, I have no idea under what maximum air pressure humans can permanently live). |
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Since a smaller version of Jupiter would perhaps be multiples of 10,000kms across, the livable portion would be the smallest fraction.* |
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* None of these numbers have been verified - it's just guess work. |
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Alterother: my guess would be the Silfen homeworld from the
commonwealth saga by Peter F Hamilton |
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You don't have to add a center of gravity, you know. You have one automatically. |
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Interesting exercise. Design a "cottage" planet, with as small a surface area as possible. Say at the surface the gravity must be 1g and air-pressure 1bar, and surface altitude variation of no more than 500 ft. Since it should be self-sustaining we're probably stuck with the atmosphere mix we (and all plants and animals) grew up with. |
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Maybe what we need to do is find some very dense
gaseous compound of oxygen which will
spontaneously decompose in the lungs, releasing
molecular oxygen. |
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There are plenty of enzymes in the mucosa of the
lung; we ought to be able to come up with some
oxygen-releasing reaction which will work there. |
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// smaller version of Jupiter // Saturn, Neptune,
Uranus. |
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I would guess that any body of gas large enough to be useful and dense enough to be breathable would have sufficient gravitational attraction to form a liquid or solid core - maybe not as extreme as the "metallic hydrogen" core of Jupiter, but solid, nevertheless. |
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//// smaller version of Jupiter // Saturn, Neptune, Uranus// |
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OK, point taken. Can we agree on "Gas midget"? |
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"Planet of restricted size" is generally preferred to "midget" which has some history as a term of abuse. |
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A "peanut" won't work: gravity drops off with distance so the only way you'll get 1atm is by having >1g at the peanut (which would make walking difficult). Looks like you're stuck with a Zorb. |
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Of course if you don't mind getting really complicated, it might be possible to have a water world which spins... centripugal force might keep an air pocket in the middle. I haven't thought too hard about this though. |
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[fho]: Sorry, not what I had in mind, either. This is a fun
game. Keep guessing, people! |
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What Zeno is suggesting is impossible. Air released into
space will quickly dissipate until the effective pressure is 0.
If there is a large enough cloud gravity will eventually pull
it towards the center, creating a gasseous planet of
extremely high pressure in the middle, with no surface to
stand on. Either of those will kill you. |
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//the only way you'll get 1atm is by having >1g at
the peanut// |
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Hang on hang on hang on. No it's not. |
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I'm trying to get my head around the relationship
between surface gravity and the greatest possible
surface atmospheric pressure that could be
maintained. |
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Take Earth as an example. We have 1g at the
surface and 1atm, of course. The atmosphere
leaks away, but very very very slowly - it is
effectively permanent. |
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If we could magically import more air, to double
the mass of the Earth's atmosphere, what would
happen? The surface pressure would double
(2atm), since it's just the weight of the overlying
air. The height of the atmosphere would
increase, but not by 2-fold (since the lower
atmosphere is under more pressure). |
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But, the "extra" atmosphere would still not leak
away . Even though the atmosphere is "taller" (if
you choose an arbitrary pressure to define the
edge of the atmosphere), it's still not significantly
further from the Earth's centre, and hence
remains under the same 1g as always. |
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In other words, Earth would have 2atm surface
pressure if we added an extra load of air. |
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Obviously, if we keep adding more air to Earth's
atmosphere, things will eventually go funny.
Either the lower atmosphere will liquify (maybe),
or the top of the atmosphere will be so high
(thousands of miles) that gravity *does* become
significantly less, and air is lost to space to
balance that which is added. |
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Anyway, there's nothing that says "1g=1atm", and
hence it does not follow that you could not have
1atm surface pressure with less than 1g surface
gravity. |
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So, my question is this. Suppose we have a body
with a surface gravity of g' , and we keep adding
air to it (we'll stick to air - not start using denser
gases). What happens to the surface pressure?
How low can g' be before it is impossible to reach
1atm surface pressure? |
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(Again, I know that atmosphere will leak slowly
into space from any planet, including Earth and
even Jupiter, but the rates of leakage we see
today from Earth, Mars, Jupiter etc are, by
definition, extremely slow.) |
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//What Zeno is suggesting is impossible.// Naturally // Air released into space will quickly dissipate until the effective pressure is 0. If there is a large enough cloud gravity will eventually pull it towards the center, creating a gasseous planet of extremely high pressure in the middle, with no surface to stand on. Either of those will kill you.// |
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Well, yes, But we do not need to go as far as creating that planet, we would stop adding air as soon as there is enough to create some density that would allow us to breathe and then we would fly around in it. And even if we do need to go as far as having this planetoid you describe, we would not be so foolish to fly too near it. |
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So it would work, in theory. |
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Hmm... well if you want to get all sciencey I suppose. |
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But my point was that the denser the gravitational source, the smaller it is. Smaller it is the faster gravity drops off from its surface as you move away from it. |
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