4 ms·

the US Air Force's Plan to Stop the Earth Rotating

26 points by deadbunny 3y ago

tgv 3y ago
That was probably just written as an "out of the box" idea, not as a serious proposal. How much energy would it cost to stop the rotation of the Earth? And that should be spent in a matter of minutes. There's no source on Earth that can provid that power. And where would these "engines" be hooked? All over the globe, I suppose, because otherwise it wouldn't be very effective. So no. To suggest "the US Air Force" had such a plan is most likely click-bait.
- mcbutterbunz 3y ago
  This feels like a brainstorming exercise where you come up with a few bizarre ideas to open your mind a little. And you’re right, just because someone had an idea doesn’t make it a “plan”.
- anaganisk 3y ago
  Even if it was serious, anyone who could achieve that can thanos snap the humanity off earth, that's interesting.
  - tgv 3y ago
    Not just humanity, practically all higher life, and a whole bunch of single cell organisms too.
- aerio 3y ago
  >How much energy would it cost to stop the rotation of the earth? it would require 2.6 x 1021 kilograms (5.7 x 1021 pounds) of propellant, which is "about 500 times the mass of the Earth’s atmosphere". According to the article.
  - tgv 3y ago
    According to the Encyclopedia Brittanica, the Earth's atmosphere weighs one millionth of the Earth's mass. 0.5% can't be enough to stop rotating it, or it needs a lot more explanation than "propellant."
    - aerio 3y ago
      Sorry, some of the superscript got stripped out when copy/pasting to HN. The actual calculation is below: >2.6 x 1021²¹ kilograms (5.7 x 1021²¹ pounds) of propellant They don't say what propellant though, but I assume whatever kind of jet fuel they used at the time.
mabbo 3y ago
I think they chose a terrible means to stop the earth, but the plan itself may still be salvageable (no, I'm not seriously suggesting it would be a good idea). Consider angular momentum. It must be conserved. And a cool fact about that is that if you spin around and gain angular momentum, you steal it from the earth until you stop. So all we need is a large number of very large and very fast spinning devices that we can turn on, spin up over say 5 minutes, and then stop afterwards. They'd probably need to spin at speeds that would shatter the atoms they're made of, of course, and the entire continent would need to be covered in them, I imagine. But at least the atmosphere would be saved, and it wouldn't be a sudden stop and start.
- ekaryotic 3y ago
  Isaac arthur's channel on youtube covers changing the rotation speed of venus in one of the terraforming episodes. He envisoned a belt of spacecraft in a rough orbit for that purpose.
credit_guy 3y ago
Common. This was clearly some type of April's fools joke. You can't stop the Earth's rotation, no matter how many nuclear bombs you use. You can't slow it down. This is an extraordinarily blatant bluff. Of course, the US military is not exactly known for its great sense of humor. Why would they release such an idea? To overwhelm the opponent's intelligence agencies. They need to dedicate some time to analyze even silly ideas like this. If you send too much noise their way, you tie their hands down. To some extent. If you look for patents filed by the US Navy, you'll find all sorts of even more ridiculous ideas (see [1], [2]). I'm pretty sure the US Air Force is ok to play the same type of games. [1] https://www.vice.com/en/article/4adpv9/us-navy-has-patents-on-tech-it-says-will-engineer-the-fabric-of-reality https://www.vice.com/en/article/4adpv9/us-navy-has-patents-o... [2] https://nationalinterest.org/blog/reboot/navy-just-filed-patents-new-unbelievable-superweapons-177310 https://nationalinterest.org/blog/reboot/navy-just-filed-pat...
- amanj41 3y ago
  Can someone explain like I'm 5 why, in theory, the earth's rotation about its own axis could not be stopped?
  - mensetmanusman 3y ago
    It could be stopped but it would require a majority fraction of the earths crust and shell to be thrown off into space. The only source of such huge amounts of energy would probably require converting more mass to energy than is easily obtainable in a few millennia of continuous mining and filtering for nukes etc.
    - speedylight 3y ago
      Could you in theory counter the earths rotation by exerting force in the opposite direction? I always think about this every time I see one those videos of SpaceX where they test fire a rocket engine while it’s bolted down to the ground. I don’t see why you can’t build scaled up versions of those engines, strategically place them around the globe so that when they’re fired up the force they create would counter the Earths rotation. I’m really curious if the idea is feasible no matter how ridiculous it is.
fwlr 3y ago
Sounds like some Air Force guy got paid to spitball ideas, seems fine to me. This kind of brainstorming is often effective at generating good ideas. Something like “Stopping the Earth’s rotation would cause ballistic missiles to miss due to their inertia, it’s just impractical to stop the whole Earth’s rotation. What if we move the just thd target instead?” could very well give rise to sensible operating procedures like “once a hostile missile launch is detected, every mobile launch platform must change its course”. I would not be surprised if that is literally a real operating procedure on nuclear launch subs, for instance. This Ellsberg guy from RAND and this Zimbleman guy from Smithsonian then both engaged in a bit of fun XKCD-style “what if” / “do the math” speculation, that also seems fine. I don’t know what happened at the final step here that has this writer reporting on it like it’s a real proposal.
CmdrLoskene 3y ago
[flagged]
Avlin67 3y ago
on planet scale the earth is like a liquid. the rock is solid but on large scale it acts as a solid. sou cannot stop a ball of liquid easily
PM_me_your_math 3y ago
Sounds about right for a government 'thought' experiment.
ChainOfFools 3y ago
This was 11 year old me's mad scientist movie plot idea. I imagined a Lex Luthor type of character who had quietly bought a majority of the world's clock, watch and calendar manufacturers, and was going to use hundreds of enormous rocket engines buried in the Himalayas and rockies to slow the Earth down, not stop it, by only one second a day. Just enough to throw off all of the time keeping devices on Earth and require everyone to buy brand new ones. from him.

26 points by deadbunny 3y ago

tgv 3y ago

That was probably just written as an "out of the box" idea, not as a serious proposal. How much energy would it cost to stop the rotation of the Earth? And that should be spent in a matter of minutes. There's no source on Earth that can provid that power. And where would these "engines" be hooked? All over the globe, I suppose, because otherwise it wouldn't be very effective. So no. To suggest "the US Air Force" had such a plan is most likely click-bait.

mcbutterbunz 3y ago
This feels like a brainstorming exercise where you come up with a few bizarre ideas to open your mind a little. And you’re right, just because someone had an idea doesn’t make it a “plan”.
anaganisk 3y ago
Even if it was serious, anyone who could achieve that can thanos snap the humanity off earth, that's interesting.
- tgv 3y ago
  Not just humanity, practically all higher life, and a whole bunch of single cell organisms too.
aerio 3y ago
>How much energy would it cost to stop the rotation of the earth? it would require 2.6 x 1021 kilograms (5.7 x 1021 pounds) of propellant, which is "about 500 times the mass of the Earth’s atmosphere". According to the article.
- tgv 3y ago
  According to the Encyclopedia Brittanica, the Earth's atmosphere weighs one millionth of the Earth's mass. 0.5% can't be enough to stop rotating it, or it needs a lot more explanation than "propellant."
  - aerio 3y ago
    Sorry, some of the superscript got stripped out when copy/pasting to HN. The actual calculation is below: >2.6 x 1021²¹ kilograms (5.7 x 1021²¹ pounds) of propellant They don't say what propellant though, but I assume whatever kind of jet fuel they used at the time.

mabbo 3y ago

I think they chose a terrible means to stop the earth, but the plan itself may still be salvageable (no, I'm not seriously suggesting it would be a good idea). Consider angular momentum. It must be conserved. And a cool fact about that is that if you spin around and gain angular momentum, you steal it from the earth until you stop. So all we need is a large number of very large and very fast spinning devices that we can turn on, spin up over say 5 minutes, and then stop afterwards. They'd probably need to spin at speeds that would shatter the atoms they're made of, of course, and the entire continent would need to be covered in them, I imagine. But at least the atmosphere would be saved, and it wouldn't be a sudden stop and start.

ekaryotic 3y ago
Isaac arthur's channel on youtube covers changing the rotation speed of venus in one of the terraforming episodes. He envisoned a belt of spacecraft in a rough orbit for that purpose.

credit_guy 3y ago

Common. This was clearly some type of April's fools joke. You can't stop the Earth's rotation, no matter how many nuclear bombs you use. You can't slow it down. This is an extraordinarily blatant bluff. Of course, the US military is not exactly known for its great sense of humor. Why would they release such an idea? To overwhelm the opponent's intelligence agencies. They need to dedicate some time to analyze even silly ideas like this. If you send too much noise their way, you tie their hands down. To some extent. If you look for patents filed by the US Navy, you'll find all sorts of even more ridiculous ideas (see [1], [2]). I'm pretty sure the US Air Force is ok to play the same type of games. [1] https://www.vice.com/en/article/4adpv9/us-navy-has-patents-on-tech-it-says-will-engineer-the-fabric-of-reality https://www.vice.com/en/article/4adpv9/us-navy-has-patents-o... [2] https://nationalinterest.org/blog/reboot/navy-just-filed-patents-new-unbelievable-superweapons-177310 https://nationalinterest.org/blog/reboot/navy-just-filed-pat...

amanj41 3y ago
Can someone explain like I'm 5 why, in theory, the earth's rotation about its own axis could not be stopped?
- mensetmanusman 3y ago
  It could be stopped but it would require a majority fraction of the earths crust and shell to be thrown off into space. The only source of such huge amounts of energy would probably require converting more mass to energy than is easily obtainable in a few millennia of continuous mining and filtering for nukes etc.
  - speedylight 3y ago
    Could you in theory counter the earths rotation by exerting force in the opposite direction? I always think about this every time I see one those videos of SpaceX where they test fire a rocket engine while it’s bolted down to the ground. I don’t see why you can’t build scaled up versions of those engines, strategically place them around the globe so that when they’re fired up the force they create would counter the Earths rotation. I’m really curious if the idea is feasible no matter how ridiculous it is.

fwlr 3y ago

Sounds like some Air Force guy got paid to spitball ideas, seems fine to me. This kind of brainstorming is often effective at generating good ideas. Something like “Stopping the Earth’s rotation would cause ballistic missiles to miss due to their inertia, it’s just impractical to stop the whole Earth’s rotation. What if we move the just thd target instead?” could very well give rise to sensible operating procedures like “once a hostile missile launch is detected, every mobile launch platform must change its course”. I would not be surprised if that is literally a real operating procedure on nuclear launch subs, for instance. This Ellsberg guy from RAND and this Zimbleman guy from Smithsonian then both engaged in a bit of fun XKCD-style “what if” / “do the math” speculation, that also seems fine. I don’t know what happened at the final step here that has this writer reporting on it like it’s a real proposal.

CmdrLoskene 3y ago

[flagged]

Avlin67 3y ago

on planet scale the earth is like a liquid. the rock is solid but on large scale it acts as a solid. sou cannot stop a ball of liquid easily

PM_me_your_math 3y ago

Sounds about right for a government 'thought' experiment.

ChainOfFools 3y ago

This was 11 year old me's mad scientist movie plot idea. I imagined a Lex Luthor type of character who had quietly bought a majority of the world's clock, watch and calendar manufacturers, and was going to use hundreds of enormous rocket engines buried in the Himalayas and rockies to slow the Earth down, not stop it, by only one second a day. Just enough to throw off all of the time keeping devices on Earth and require everyone to buy brand new ones. from him.