Would a hot air balloon take off in a vacuum?

[richaron]

Could you help me out and describe what you think would happen if gravity didn't exist, because it's something greater than which I can conceive. You seem quite patient, having not overtly made fun of me for my ignorance thus far. What happens when gravity ceases to be a thing? According to wikipedia:

A thought experiment considers some hypothesis, theory,[4] or principle for the purpose of thinking through its consequences.

So think through the consequences, but only the ones you're interested in, or what? Can't quite put my finger on it, but this just seems weird to me.

A thought experiment is about a closed imaginary system. With these types of systems "ideal" ideas are often imposed. Like an apple falling from a tree we often ignore air resistance. Or with basic spacecraft we ignore the fact space isn't a complete vacuum and other stuff like solar particles.

An environment with real zero gravity is impossible in reality as we know it. But it's often used as a basic approximation. As far as we currently know all matter produces some gravitational effect, so an environment with zero gravity must also have zero matter. But there is some speculation even space with no matter has some sort of zero point energy and maybe gravity fluctuations so even a "reality" with no matter may have gravity of some sort. Zero gravity is only an idea in people's heads.

 

[William Gaatjes]

Could you help me out and describe what you think would happen if gravity didn't exist, because it's something greater than which I can conceive. You seem quite patient, having not overtly made fun of me for my ignorance thus far. What happens when gravity ceases to be a thing? According to wikipedia:

A thought experiment considers some hypothesis, theory,[4] or principle for the purpose of thinking through its consequences.

So think through the consequences, but only the ones you're interested in, or what? Can't quite put my finger on it, but this just seems weird to me.

Well, Gravity is a force all around us but it weakens with distance.

I had to look this up to verify it :
The force of magnetism is inversely proportional to the distance squared.
So two times the distance is 4 times weaker force.
The force of electricity (Coulombs law) is the same.
Gravity is exactly the same. Two times the distance is 4 times less attraction.

I think the problem you are facing is that we take something for common in our thought experiment.
If the Earth did not have a gravitational pull on the balloon, then the moon would, as would the sun, as would all planets in our solar system but inversely squared to the distance weaker and by the mass they have which we ignore. And that is what we assume to be at 0.

Also, the Earth rotates , so there should be a coriolis effect inside the fully closed balloon with air.

If you want to go head on in a thought experiment. Here is one :

What happens to an electron when it accelerates or decelerates ?
What happens to an electron moving in a circular orbit, not around an atom but let say a circle of 12000 meters. Does it emit radiation ?
When it is forced around by electric and magnetic forces in that circle ?

What happens when that same electron is moving in a circular orbit (~12000 meters diameter) about 465 meters per second.

Hint (Larmor formula and circular motion).

 

[justoh]

I think the problem you are facing is that we take something for common in our thought experiment.
If the Earth did not have a gravitational pull on the balloon, then the moon would, as would the sun, as would all planets in our solar system but inversely squared to the distance weaker and by the mass they have which we ignore. And that is what we assume to be at 0.

Also, the Earth rotates , so there should be a coriolis effect inside the fully closed balloon with air.
.

If no gravity, then the moon wouldn't exert any gravitational influence on the balloon, not just because neither would continue to exist, but also because no gravity. Alright, so, it's clear none of us can conceive of a universe without gravity. Only suggesting more coherent thought experiments.

 

[richaron]

If no gravity, then the moon wouldn't exert any gravitational influence on the balloon, not just because neither would continue to exist, but also because no gravity. Alright, so, it's clear none of us can conceive of a universe without gravity. I suggest more realistic thought experiments.

Lol I suggest you get over your fixation on gravity. You could have been just as righteous (and correct) arguing the concept of a total vacuum, but you completely missed that point as well.

You may think your opinion matters, but I doubt it should affect the rest of us with our thought experiments.

 

[William Gaatjes]

If no gravity, then the moon wouldn't exert any gravitational influence on the balloon, not just because neither would continue to exist, but also because no gravity. Alright, so, it's clear none of us can conceive of a universe without gravity. Only suggesting more coherent thought experiments.

Well, i can imagine a local part of the universe without gravity if i try really hard but it is exhausting.
The magnetic forces and electric forces and strong /weak forces would dominate but it would be a mess. Some things would happen the same but on a much larger time scale.
It may sound strange but gravity is the reason why things happen fast but on an astronomic scale.

edit:
You think they do not set things to 0 with space simulations ?
How come it takes days if not weeks to simulate the folding of a complex protein which only consists of mostly a few hundred atoms but the simulation of the collapsing of a star is easily done in the same time ?


Have you thought of the electron ?

 

[justoh]

Well, i can imagine a local part of the universe without gravity if i try really hard but it is exhausting.

I did try look for an answer. BBC had something that also took for granted some localization, but Richaron specifically stated "no gravity," not no particular or specific gravitational influence. Even localized they're talking about the atmosphere floating away, making a balloon seem quite trivial. It's senseless localized or universal. Leave it on, imho.

 

[William Gaatjes]

I did try look for an answer. BBC had something that also took for granted some localization, but Richaron specifically stated "no gravity," not no particular or specific gravitational influence. Even localized they're talking about the atmosphere floating away, making a balloon seem quite trivial. It's senseless localized or universal. Leave it on, imho.

If gravity on, and the chamber is vacuum, the balloon will drop to the point where gravity is strongest. After that frictional forces are dominant. Some triboelectric effect might happen depending on the materials.

Sorry, i am a bit of a mood.

https://www.alphalabinc.com/content/tribo-electric-series/

 

[Thebobo]

no lol

 

[SKORPI0]

As posted by the OP. Not hot air balloon though.

in the real world....
NO, since there is no air in a vacuum to begin with to fill a balloon with hot air.

https://science.howstuffworks.com/transport/flight/modern/hot-air-balloon.htm


Ideal Gas Law..
http://www.atmo.arizona.edu/student...1s1/coming_up/week_2/lect6_ideal_gas_law.html

 

[DigDog]

you can just say "no".

 

[Red Squirrel]

There's a few important parts missing in that diagram.

 

[KillerCharlie]

Hot air balloons work because they have buoyancy. Without air surrounding the balloon, there'd be no buoyancy and no lifting force. Of course there's no air to fill the balloon in the first place... or light a burner with.

When you suck out the air in the vacuum chamber, the balloon would increase in size and eventually match the size of the vacuum chamber or just "pop"...

Assuming that the balloon could be filled with the non-existent air... that depends entirely on the strength of the balloon. If the material is strong and rigid, it wouldn't fill the whole jar and it wouldn't pop.

 

[sdifox]

It would simply seek out cbrunny, scoop him up, fly up into space and bust into flames. I call this the Final Destination Principle.

 

[William Gaatjes]

Hot air balloons work because they have buoyancy. Without air surrounding the balloon, there'd be no buoyancy and no lifting force. Of course there's no air to fill the balloon in the first place... or light a burner with.





Assuming that the balloon could be filled with the non-existent air... that depends entirely on the strength of the balloon. If the material is strong and rigid, it wouldn't fill the whole jar and it wouldn't pop.

When first reading the OP, i automatically assumed a given size to the vacuum chamber and i automatically assumed a closed balloon that has to be of light material given the size and bouyancy.
A normal balloon. Of course if it is rigid enough that would not be the case. But rigidness comes with weight.

 

[Paratus]

 

[Coalfax]

Guys, you are all thinking WAY too hard om this.

Hot air baloons are open to the envireonment. Hence in a vacuum, there would be no air in the balloon. Garvity takes effect and no floating.

Better question is why would a quetion like this even be asked...

 

[momeNt]

Nature abhors a vacuum.

Been saving that one for a while. Finally got to bust it out.

 

[IronWing]

Nature abhors a vacuum.

Been saving that one for a while. Finally got to bust it out.

I have the precedent here, Your Honour, Vogon lmperium versus Megabranlls Liposuction, Inc. Ruling: nature abhors a vacuum.

Whatever. Girlfriend. I'll just keep destroying the Earth till nature settles for a bloody vacuum.

 

[Red Squirrel]

Lol that's cool. Sulfur hexafluoride?