I'm pretty sure aerographite is porous, and the numbers you're quoting don't count the mass of the air permeating the aerographite. You could wrap it in something like mylar, but it'd be less safe than helium. Any break in the skin would be like a hole in a space capsule. This could be ameliorated with smaller cells, but that cuts into your lift. It's also not clear if aerographite is strong enough for the job.
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.
This is a great idea except for this tricky bit (which they even mention in the article)
"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.
Can someone explain why the material isn't floating in the air? I watched the video and it just sits here?
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?
Physics doesn't work that way. The "6x lighter than air" doesn't include the air inside the material.
I'm not sure that "if law of physics X were repealed, we could..."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.
Other than giant airships: how about just novelty/party balloons that never out-gas & sink? Re-positionable ceiling decorations? Indoor microblimps?
If such things escape into the atmosphere, you've got a floating-garbage problem... as described in Stephenson's Snow Crash.
> You might ask yourself, how are you going to come back down to earth if you cannot release some of the hydrogen/helium?
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 )
The article somehow seems to have a misconception that if you bring material lighter than air aboard, you will float up... Then you could as well just take some vacuum with you.
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 :)
Helium 0.1786 g/L
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?
There's also a greater potential health risk posed by carbon nanotubes. I am completely guessing, but I feel as though the risk of dispersed airborne nanotubes (in this model) would be greater than dispersed helium (from a current blimp.)
The article mentions this would be safer than flammable hydrogen, but wouldn't this stuff burn really well being carbon with a whole lot of surface area?
how are you going to come back down to earth if you cannot release some of the
hydrogen/helium?
You have to take into account two things:
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.
Imagine having a landfill of this stuff, blanketing the Earth at 10,000 feet.
Hmmm. :|
How about flying cars?
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.
I'm not too sure if I interpret these right, but wouldn't this material be tailor-made for a weightless sail that can compress itself 20 times?
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.
Cover this new stuff with a balloon and then fill it with helium. Is there any difference to a balloon filled with helium?
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.
> You might ask yourself, how are you going to come back down to earth if you cannot release some of the hydrogen/helium?
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.
I've wondered if we could fill a sealed ballon with thin wires. Then put a large electric charge on all the wires so they repel each other and expand the balloon with vacuum.
Why do you guys think?
Actually, I would be more excited about it replacing the non-biodegradable styrofoam. Since it's a simple carbon composite it should be more environmental friendly, no?
What about the effect of 15nm carbon fibres entering your lungs? Are we setting ourselves up for another asbestos-like scenario? Or is this stuff somehow safer?
seems to me like a good styrofoam alternative/competitor, but for floating like properties, it to have vacuums in the tubes right? That is certainly the difficult problem to make this truly be better than helium for some applications. On the other hand, maybe with the structure each small tube is under or is a vacuum.
Idea: how about super-heated air in a balloon lined with aerogels to act as an insulator.
Air at 1000f is a third as dense as air at 200f.
How did this get voted up this high? What? WHAT?
Aerographite is NOT lighter than air. What they mean is that a vacuum-filled cubic cm of aerographite is lighter than a cubic cm of air.
A piece of that material will NOT float up on its own, because it's heavier than air.
The author doesn't understand the concept of a blimp. The only reason for filling it with helium (or hydrogen) is to counter the atmospheric pressure. Since aerographite doesn't do that (it would just collapse under the pressure) there is absolutely no point in filling a blimp with aerographite.
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!