edit: I understand that air is in the space between the nanotube fibers. But I still don't understand why the material doesn't float. Why doesn't the air inside the material average out with the material itself to result in a space with lower density (thus causing it to float) then the surrounding air?
Why isn't anyone discussing the one obviously useful application of this, the supercapacitors?
Letting the air flow in fills in those gaps, raising the interstitial density enough that the average is greater than air.
Yet apparently it collapses at that point. Unless that's solved we might as well be talking about birthday balloons here.
If you found a way to create a hull that withstand the pressure, and prevents the aerographite from being compressed, why fill it with that stuff in the first place? Just use a vacuum inside your superstrong hull!
To make something as safe and reliable as you describe, you'd have to build an evacuated closed-cell foam. That material would have to be extremely light while also being able to withstand being crushed by the atmosphere. It's not clear if anything is up to the task.
Sorry to dash your hopes.
But this stuff is open-cell, so perhaps seal it into manageable-size beads? Looks like it might hold up to temperature pretty well.
Alternatively, this stuff could be used to produce a lighter-than-air structure in a process that somehow consumes it.
"One other limitation will be creating aerographites that can support themselves with the air inside the material “pumped" out of it."
I really can't complain too much though as I too was pretty taken with the idea after reading Diamond Age (which has a variant of this). At some point we might be able to assemble dodecahedrons out of small diamond pentagon sheets while in a vacuum and thus create small, lighter than air, "bubbles". But that time is still quite a ways off. After researching a bit the forces on the materials relative to the amount of air they would have to displace in order to achieve a net density lower than air, at volume. It doesn't look particularly doable yet (perhaps ever but I'm not willing to completely rule it out.)
The idea though is very alluring.
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I've often wondered if a balloon-based system might be the way that this ("permanent" points of presence in the air) is eventually achieved. As solar energy becomes more and more efficient every year (apparently it's on an exponential price/performance growth curve), you coat the balloon with a light-weight, flexible solar array, and either heat the air like a hot air balloon, or as it becomes cheaper and more efficient to extract hydrogen from water, fill the balloon with hydrogen, and constantly replace the hydrogen that leaks out with hydrogen extracted from water vapor in the air: http://www.technologyreview.com/view/512996/a-cheaper-way-to....
You could use low powered propellers (like a blimp), and take advantage of weather patterns (like Google's Loon project) in order to maintain position or to slowly travel.
Google's balloon system [1] is apparently using quantity to cover holes that appear when winds blow them down range. Also if they get caught in the jet stream the can leave the area in a hurry.
Granted winds are a challenge for any aerial platform but actively flying shapes, seem to out perform lighter than air ideas when staying on station is required [2]. So solving the station keeping question would be a big part of the equation.
That said, the company that proposed the blimp to the Army is continuing to develop it as far as I can tell from their web site [3]. Perhaps it will get additional engineering work on those issues.
[1] http://www.google.com/loon/#utm_source=google&utm_medium=cpc...
[2] http://www.popsci.com/technology/article/2013-02/army-cancel...
> The two slowly revolving gondola sections slid gradually to a halt, preparatory to docking. People in both segments congregated on the sides nearest the island, for the view.
> The airship's system registered the imbalance building up and pumped bubblecarbon spheres full of vacuum from one lot of tanks to another, so maintaining a suitably even keel.
-- Iain M. Banks, Excession.I'm not sure that "if law of physics X were repealed, we could..." stuff is anything more than science fiction: see the multiple comparisons to Diamond Age in this thread.
>One other limitation will be creating aerographites that can support themselves with the air inside the material “pumped" out of it (to truly achieve being lighter than air). In practice, getting a real blimp to work will probably be made out of a future version of aerographite or another aerogel that is super strong and light, one that could self support itself without collapsing in on itself if the air between the meshes of nanotubes is pumped out. A partial vacuum will have to be created inside the aerographite structure without crushing the aerogel. This may be the fatal flaw to the idea or at least the next problem to solve (i.e. given that the material is superhydrophobic, maybe a thin shell of water could be put around the aerogel or some similar exotic solution).
Ionize the air?
I've always thought a great idea for a flying car was a van-like vehicle that is either filled with helium or a vacuum, maybe a combination.
A blimp-like vehicle that won't deflate or leak would be even better since it won't need lift to stay up and wouldn't require much power to propel.
So if the aircraft loses power, or loses its hydraulics, the failure results in the aircraft getting stuck in the air? I can see that being promoted as a feature.
Extracting water from the air or weather to use as ballast as your airship becomes lighter and lighter (by consuming fuel for instance) is a particularly clever idea I think.
http://en.wikipedia.org/wiki/Buoyancy_compensator_(aviation)
If the material can be compressed to 95% it's size and reexpands, you just compress your tanks and lower back down, expand tanks to rise. ( all concerns of other comments having been solved with the standard wave of the hand )
Hydrogen 0.08988 g/L
Air 1.275 g/L
This stuff is six times lighter than air so 0.2 g/L or there about. Both Helium and Hydrogen are lighter than this stuff. Considering the explosive reintroduction of air thing being pretty equivalent to the other two what makes this theoretically better?
how are you going to come back down to earth if you cannot release some of the
hydrogen/helium?
Hmmm. :|
A piece of that material will NOT float up on its own, because it's heavier than air.
If such things escape into the atmosphere, you've got a floating-garbage problem... as described in Stephenson's Snow Crash.
Maybe that would be even more useful than this material: a balloon filled with vacuum! And some support structure to make it keep its shape :)
1. the porosity, meaning air fills the cavities. Can you really talk about open structures and say they're really light? Make an aluminum balloon filled with air and it's probably lighter than air as well.
2. the buoyancy, meaning that the fibers displace air. If a light material is weighed in air, the result does not give the mass of the object.
With normal solids, this does not matter since they are heavy compared to air.
For example, you can weigh wood with a volume of 1 liter in normal air pressure, and get a mass result of 0.500 kg. Then weigh it in a vacuum, you should get a 1 gram difference (air density is about 1 gram per liter) - a weight of 0.499 kg. In practice this is in the noise for normal materials.
Cloced cell extruded foam is about 30 kg per cubic meter. So here the air mass 1 kg per cubic meter already has a 3% effect. I don't know if the weights are usually quoted with buoyancy or not. But this is closed cell, I don't know how well it stands up to a vacuum.
One example of structures that can have a lot of mass but little weight is inflated ones. There have been some human powered aircraft that are really big but light on the scale. Yet they take a lot of time and energy to accelerate since all the air mass inside must be brought up to speed.
Wouldn't this be a revolution for boats, lifebuoys or seaplanes?
Also, wouldn't this allow human-size people to carry around weightless wings on their back that expand 20 times from 50cm to 10 meters in span, letting them fly like birds?
Edit: I know these ideas have no scientific basis. I'm just surprised that the only mentioned applications of this material are lithium batteries, waterproof clothing and the likes. Surely there would be a lot of things to create out of an essentially weightless solid.
I suppose it could keep its shape, which would be a benefit.
When the shape doesn't change there is less wear and tear and tension on the "skin". It could be made of a light, inflexible but strong material, because the shape of "Beyond Helium" unlike with a balloon would not continuously change due to altitude and weather.
Why do you guys think?
Air at 1000f is a third as dense as air at 200f.