Vacuum Balloons (2020)
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The book is about much more than that though.
His characters are non-tech but have a "Djinn of Technology" who can conjure things for them, but they haven't the understanding to ask for the right things or use them, at first. He has fun with it. Once they get a balloon in the air they ask for a rudder to steer it; and get the wrong kind.
First proposed by Italian Jesuit priest Francesco Lana de Terzi in 1670...
One method is to go bigger: because of things like the square-cube law, the lift provided by a vacuum container increases faster than the demand on structural integrity, so a sufficiently large container lets you use more conventional materials. It’s been a long time since I did the math and I wasn’t very confident of my calculations even then, but I vaguely recall if you used steel you’d be looking at containers with multiple cubic kilometers of volume or something - highly impractical.
Another approach is only using vacuum in the upper atmosphere. The pressure on the vacuum container is much lower up there so you would have less of a structural integrity challenge. You don’t gain as much as you’d think from this approach, however, because the positive structural integrity provided by the expansion of lifting gasses allows for containers that expand, increasing their volume in response to lower air pressure (we call these containers “balloons”). In fact, because of this property, to a first approximation altitude has NO effect on the lift provided by a set amount of lifting gas (counter-intuitive, I know), and getting a helium balloon to STOP rising is a real challenge. Getting the vacuum chamber up high enough to make it safe to pull a vacuum is obviously a bit of a chicken-and-egg problem too, not to mention you’d have to bring the extra weight of a vacuum pump with you. Where this idea might work is if you’re coming in from space in the first place. Assembling the container in space means you don’t need a vacuum pump, and since you’re descending from above you don’t need a container strong enough to withstand containing a vacuum at sea level pressure. So this might have some use for putting floating structures into Venus’s upper atmosphere.
The noise about a shortage is because the US gov't decided to stop subsidizing storage and delivery of helium, and scientists untrained in economics see "losing a subsidy" as similar to "a shortage" since the net effect is the same - prices are rising.
Culling recreational use would add 10-20 years of supply, which is unlikely to be the 'make or break' bridge to fusion or space mining.
Let people have fun, it's arguably the meaning of life.
Humans had thousands of years experience having fun w/o wasting non-renewable resources.
Genuinely curious, are you speaking of pre-Bronze Age civilizations?
Honestly, if my niece's quinceanera balloons stop the world from being saved, there's something deeply wrong beyond my scope of helping.
Fun at parties? Bad idea most likely.
Oh, and on the color of aerogels.
This technique has promise.
In short, you construct a shape made of inflatable cells which, when pressurized, contort in such a way that a vacuum is formed in the space within the collection of cells.
The problem, though, is that the additional air needed to make the cells stretch away from the center (and thus make a vacuum) is greater than than the air ‘missing’ from the vacuum part.
In any case, it’s been tried before:
“Vacuum/heat formed cushion with pyramidal, inflatable cells”:
14 pounds per square inch is a lot of force. A reference example, when planing a nuclear detonation(a grim task to be sure) the 5 pounds per square inch isoline covers the area where all non hardened structures(houses) are assumed destroyed.
I also have an idea for active vacuum isolation for housig, much better lifetime than passive vacuum panels. Too bad no known takes my vacuum engineering serious.
Also, modern VIPs have decades of life if installed properly.
It just seems like if a substitute for party balloons is needed then exploring alternate gas mixtures might be low-hanging fruit compared to engineering lightweight yet low-cost vacuum structures.
For those wondering about "the math", the simple version is to find the nominal density of atmosphere at the altitude you want to sit, take your material of choice and it's density. And then use (material_volume x material_density) < (atmosphere_volume x atmosphere_density), the amount of vacuum you need is then (atmosphere_volume - material_volume). You can plot it out, for every gram of material you need x cubic centimeters of vacuum. If you can find a solution where the material properties allow it to withstand the pressure differential, then you can, in theory, demonstrate a vacuum balloon if you can build it.
Note that it will almost always be a spherical balloon as pressure on a sphere becomes compression strength of the material you're using.
The wildcard is what has to change for the thickness of the shell as it scales. That either makes it work, or be infeasible. More research required.
A drone or other flying object could float by pulling a vacuum (also not really feasible with today’s pumps) and control it’s density, without the need for any kind of reservoir. Maybe just enough buoyancy to massively reduce the power and noise needed on propellers. Add some form of wireless energy transmission (laser?) to remove the battery weight and voilà. UFOs!
Train car imploding: https://youtu.be/Zz95_VvTxZM
Vacuum chamber imploding: https://youtu.be/qs6p8tPaur4
These people have not achieved it because it’s impossible to do in the real world. You need a material with almost no weight and infinite strength.
And after all that, the meme balloon only has slightly more lift then hydrogen. Could have just made a hydrogen balloon.
I’m seeing serious safety issues. No sign that they are.
Perhaps the toy would consist of bags of inch-diameter vacuum balls, the rupture of any one creating just a pop.
The fragile vacuum part of a thermos has far fewer cc's of vaccuum (vs. a ~30cm "balloon"), is inside a pretty tough shell, and kids usually aren't allowed to play with 'em. CRT's hold more vacuum, but certainly aren't something that kids get to play around with.
Vs. have you ever watched younger kids play with balloons? Consider the potential for ear injury, if Kid_1 breaks a 30cm vacuum balloon in close proximity to Kid_2's eardrum. Or how similar the broken pieces of a vacuum balloon might be to broken glass.
Further, given that the vacuum balloons are rigid, I think it’s far more likely to take on a leak that fills the balloon rather quickly but not instantly. For argument’s sake, suppose one does fail suddenly- do we even know what that sounds like? I don’t think it could possibly be worse than a (thick enough) mylar balloon pumped up to two atmospheres and exploding. It’s not like suddenly there’s vacuum in the room.
Party balloons don’t need replacing - they need banning. They use irreplaceable resources frivolously, and cause harm to wildlife and livestock, who almost inevitably end up eating the things.
You could even do instant balloons, which come pre-sealed and just require snapping a vessel within to generate hydrogen.
The only thing that's dangerous about them is how boring they are. You'll be graduating to more interesting forms of pyromancy (like trying to make a flame thrower out of a punching balloon) in no time.
I cannot believe these things are encouraged and cheap to buy. What a waste for almost zero actual value
- dead poets society
"But Beaux noted that these small-scale prototypes were not air buoyant.
"We've demonstrated that we can build them, we can pull vacuum, but in order to make them flow to air, we just need to make them bigger," he said."
So, step two: profit.
A larger balloon would have larger compressive stress over its entire surface. I'm very skeptical that could ever be made to float.