would be cool if inertia wasn't a thing
this post was submitted on 04 Feb 2024
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People have a terrible understanding of orbital mechanics and apparent weightlessness. It's not like gravity just stops affecting you after you get out of the atmosphere. Getting out of the atmosphere is the easy part of getting to orbit. Going sideways fast enough is the hard part.
I feel like everyone should play KSP, just to get a taste of it
I used to baby sit a friend's kid when he was a wee lad, frankly we spent most time playing KSP. Used to give him challenges like if he could build a ship using x amount of parts and make orbit would let him order out pizza instead of food his mom prepared for us. He rarely succeeded at first but apparently kept at it long after I stopped mentoring him and apparently is now going to school to be an aerospace engineer. And before all that his mom could never get him to do his math homework as a tyke.
Pizza has a strange powers over humans. Good job friend.
The real friends is the pizza we make along the way.
Definitely not all those kerbals stranded on Duna. He never did figure out how to properly make it there and back
What a great origin story
Nothing got me working on math quite like trying to figure out my ship's ∆v back in 2014 before I installed Kerbal Engineer
That's where I learned about it.
Watching the trajectory change as you accelerate is so satisfying...
what? are you telling me I couldn't reach the other side of the planet by jumping for 12h ?
Also, wind.
Anon's airship has inertial dampeners. Checkmate, atheists.
That's easy, instead of accelerating towards your destination you just have to brake and stop moving to let the earth move under you, checkmate physics
Doesn't inertia fuel our magnetosphere?
This is dumb as shit. Hot air balloons only go so high, less than 70k feet according to records. They only stay aloft if the heat is continually applied, if not, air cools and they sink. They move with the air, and the air moves with the planet.
This doesn’t work for the same reason jumping in an airplane doesn’t slam you into the back wall.
I don't think it was posted because it was brilliant…
70k ft: 21,336m
Sig figs!!
70k ft = 21 km
Ok but they're going really really high up
Yeah, but anon smart, u dumb. Checkmate.
Balloons using hydrogen can reach 33 miles. But even then the atmosphere still moves with the ground.
I hope troll logic makes a comeback
ikr they forgor to say "Problem?"
I hope so too, given how many people are taking this seriously.
This is just playing into the hands of big basket.
I’m not a rocket surgeon, but I think the amount of energy required to reach orbit is higher than what a jet would use.
Nah, weather balloons can get really really high. The problem here is, the atmosphere doesn’t “end” it just gets thinner and thinner. You would still spin with the earth, just a bit slower.
Okay so then like, 14 hours.
I think it would probably be more like several days.
Op homie invented space travel
The problem here has almost nothing to do with the atmosphere and nearly everything to do with the massive amount of energy required to cancel out the inertia of already moving at about 1000MPH radially relative to the center of the earth, assuming anon launches his magic balloon from the equator. The kind of energy that takes, oh IDK, a fucking rocket.
In other words, if you could actually float above the atmosphere somehow, you wouldn't just stop relative to the surface of the planet because it's not the air current that carries you along, but the fact that you started off moving along with the earth's rotation and did nothing to slow down.
Well that's why they're going really high up, so the earth rotates beneath them
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And winds aloft are often going much much faster than on the ground.
And temps, youd have to do a lot to keep warm.
And pressurization, at ~60k ft your blood boils.
That’s how you make your money! Sell them suits!
The suits don’t have to work. The customer won’t complain either way.
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Not exactly brain science is it.
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Your move, globe heads.
Randall Munroe answered that in detail - https://what-if.xkcd.com/58/
That does not answer the question. The balloon is not going to orbit, high atmospheric balloons exist and do not require propulsion.
The reason it won't work is because the atmosphere is coupled to the ground and rotates with the ground.
I think you have some terms mixed up. Orbit would refer to a body moving around another body is some type of elliptical revolution. High atmosphere balloons do require propulsion to get to altitude. The atmosphere coupled with the ground makes no sense. (think of a constant spinning marble in a gold fish bowl, the surrounding water doesn't stay perfectly in line with the marble)
The cartoon above does answer the question to some degree though. Essentially in order for the balloon to be stationary while the earth rotates below you would need a propulsion system to maintain its height (fight gravity) as well as combat high winds (that would prevent it from staying "stationary" relative to the earth below). I would imagine the benefit of getting outside of the earth atmosphere completely (which is what I believe you meant by orbit) is there would be no wind to fight against. The problem then is that the balloon would've popped by then.
I think that's right but someone could correct me.
EDIT: Realizing we're talking about high altitude balloons which wouldn't need a propulsion system to achieve altitude, but would not be able to maintain altitude before popping. I think the rest of my statement stands true.
Balloons go to 12 miles all the time, they stay at whatever altitude they are neutrally buoyant at. The OP says hot air balloons, but if you ignore that requirement you can get a non propulsed balloon to 30 miles up. It doesn't just pop, it does leak slowly bc no bag is perfect.
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Going from the US to Japan or China by hot air balloon would mean going the long way over Europe due to the jet stream, this would take more than 12h.
If they don't understand gravity, I suspect the jet stream will be harder to grasp
I think he'd run out of oxygen that high up wouldn't he? Or it would get too cold for the balloon to stay inflated if he didn't freeze to death first? Also, is a hot air balloon even capable of lifting a 500lb man-child that high? Would there even be room for his mobility scooter, his snacks and his high performance gaming PC?
The density of the air becomes so thin that I don't think you could have a container for enough hot air that wouldn't weigh more than the lift provided. Helium weather balloons end up getting so large because of the pressure difference that they end up bursting at those altitudes.
The lift of the balloon depends on on the temperature difference and the air inside the envelope, and the air outside, and that part would actually work.
As far as oxygen goes, you'd need to have a pressurised capsule suspended under the balloon, which has been done before.
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