3 ms·

Yeah who are we kidding. Any craft that can visit the Earth from outside the solar system is also capable of destroying civilization on Earth. Literally that

Yeah who are we kidding. Any craft that can visit the Earth from outside the solar system is also capable of destroying civilization on Earth. Literally that same craft. At relativistic speeds, any sizable piece of matter can become an extinction level event.

rolph 4y ago
just travelling close to the earth would hit it with a relativistic shockwave. no classical weapons required, like using jetwash, or transsonic shock to cause extremely prejudicial complications
- chii 4y ago
  > a relativistic shockwave This would assume that the spaceship is emitting matter as part of it's propulsion mechanism, or it's somehow able to push matter in it's way away (rather than obliterating it). otherwise, how does shockwave from relativistic speeds happen?
  - rolph 4y ago
    distortion of spacetime, as occurs when energetic content results in a disequilibrium energy-tensor metric. conceptual example, alcubierre warp. https://en.wikipedia.org/wiki/Alcubierre_drive https://en.wikipedia.org/wiki/Alcubierre_drive very much like a boats bow/stern waves, or a jets acoustic waves, except much higher energy in a different substance.
    - chii 4y ago
      > in a different substance but there's no such a substance in empty vacuum. If the speed was enough to generate gravitational waves somehow, and that gravitational wave is strong enough to disturb macro objects like the earth, we'd be a bit dead i suppose. The disturbances of spacetime like the alcubierre warp is still theoretical - requires things like negative energy?!
      - rolph 4y ago
        spacetime isnt empty vacuum. its a sea of 0 sums that periodically dissociate, into tangible matter. the negative energy requirement was probably a fast and lose statement, its looking more like ...negative for us, energy is required. casimir plate devices and soliton wave functions are the newest idea. https://en.wikipedia.org/wiki/Casimir_effect https://en.wikipedia.org/wiki/Casimir_effect https://en.wikipedia.org/wiki/Soliton https://en.wikipedia.org/wiki/Soliton

rolph 4y ago

just travelling close to the earth would hit it with a relativistic shockwave. no classical weapons required, like using jetwash, or transsonic shock to cause extremely prejudicial complications

chii 4y ago
> a relativistic shockwave This would assume that the spaceship is emitting matter as part of it's propulsion mechanism, or it's somehow able to push matter in it's way away (rather than obliterating it). otherwise, how does shockwave from relativistic speeds happen?
- rolph 4y ago
  distortion of spacetime, as occurs when energetic content results in a disequilibrium energy-tensor metric. conceptual example, alcubierre warp. https://en.wikipedia.org/wiki/Alcubierre_drive https://en.wikipedia.org/wiki/Alcubierre_drive very much like a boats bow/stern waves, or a jets acoustic waves, except much higher energy in a different substance.
  - chii 4y ago
    > in a different substance but there's no such a substance in empty vacuum. If the speed was enough to generate gravitational waves somehow, and that gravitational wave is strong enough to disturb macro objects like the earth, we'd be a bit dead i suppose. The disturbances of spacetime like the alcubierre warp is still theoretical - requires things like negative energy?!
    - rolph 4y ago
      spacetime isnt empty vacuum. its a sea of 0 sums that periodically dissociate, into tangible matter. the negative energy requirement was probably a fast and lose statement, its looking more like ...negative for us, energy is required. casimir plate devices and soliton wave functions are the newest idea. https://en.wikipedia.org/wiki/Casimir_effect https://en.wikipedia.org/wiki/Casimir_effect https://en.wikipedia.org/wiki/Soliton https://en.wikipedia.org/wiki/Soliton