5 ms·

Since learning about gravitational waves I was always curious if a type III civilization could potentially use them as a weapon.

cde-v 3y ago
Anything can be used as a weapon.
- HansHamster 3y ago
  First thing that comes to mind is a lethal dose of neutrino radiation: https://what-if.xkcd.com/73/ https://what-if.xkcd.com/73/ Now the tricky part is probably to build a neutrino / gravitational wave / whatever source that is intense enough to be useful as a weapon without just evaporating everything in a supernova scale explosion before...
  - causality0 3y ago
    One of the most interesting yet sadly least rigorous What-Ifs. He relies on simply scaling up a calculation in absorbed dose at the distance of one parsec. Neutrinos do not interact with nuclei the same way gamma rays do, and the effects of a particular amount of neutrino radiation on living tissue is unstudied and unknown. The paper he cites explicitly points this out but he ignored it.
    - raverbashing 3y ago
      Of course it doesn't, I think that was given by the relationship between neutrino count and sieverts But make no mistake, there is such a thing as a fatal amount of neutrinos. It's just that's a supernova mind boggling amount, but it exists. They do interact due to the weak force, which is more than neutrons do (and a lethal dose of those is well known)
  - mhh__ 3y ago
    See also neutrino HFT
  - ridgeguy 3y ago
    In the sci-fi novel Iron Sunrise by Charles Stross, death by neutrino flux from a weaponized star figures into the plot. (edit - spelling)
- bsder 3y ago
  Any sufficiently advanced propulsion also qualifies as a weapon.
sparker72678 3y ago
Maybe? There would be far less energy-intensive ways to wipe other civilizations out of the universe, though.
dekhn 3y ago
step 1: arrange two black holes near your enemies step 2: wait 2 billion years
- groestl 3y ago
  Depending on your preferred solution to the Fermi Paradox, you might be able to just skip Step 1.
saiya-jin 3y ago
I dont think so, they go in all directions as a shockwave, pass through everything including black holes (even though it would warp it a bit), so its dark forest signalling basically to whole universe. Since we came to exist so early in the overall age of universe, there is absolutely no chance we are the only sentient civ across hundreds of billions x hundreds of billions/trillions x nr of planets realm. Super focused super dense ray of very hard gamma rays/cosmic rays should do any trick required for anything made out of matter. Or just swipe left with a black hole or two.
- MaxikCZ 3y ago
  Correct me if I am wrong, but since not even spacetime can escape blackholes, even gravitational wave would get swallowed, wouldn't it? Of course, since we can't "point" gravitational waves in a certain direction, because of the rest of the wave traveling around the hole would basically propagate it even directly behind blackhole (from perspective of source), but that's because the wave goes around, not trough. Or do grav waves really pass ~trough~ black holes?
  - borissk 3y ago
    Hmmm, gravity does escape black holes, so maybe gravitational waves do too.
- jakear 3y ago
  > there is absolutely no chance If you hold Faith in the axiom "the universe was initialized homogeneously and propagated untampered thereafter", perhaps. Plenty of axioms for which "there is absolutely no chance we are not the only sentient civ across..." is just as true though. And everything in between.
kadoban 3y ago
Seems orders of magnitude too difficult to be worth it. If you can approach that level of energy, pointing a gamma ray burst sounds more fun. Or just throw some rocks at fractions of c.
abecedarius 3y ago
Pretty hard to direct. If you've set up a close-orbiting neutron star binary and you're in a military frame of mind, one thing you could do is accelerate missiles to a good fraction of lightspeed. (Same principle as the gravity assists used by planetary probes like Voyager.) The tides would limit the practical size of the missile, though I haven't tried to compute this limit. (I don't consider this comment to be aiding the interstellar enemy, it's too obvious.)

cde-v 3y ago

Anything can be used as a weapon.

HansHamster 3y ago
First thing that comes to mind is a lethal dose of neutrino radiation: https://what-if.xkcd.com/73/ https://what-if.xkcd.com/73/ Now the tricky part is probably to build a neutrino / gravitational wave / whatever source that is intense enough to be useful as a weapon without just evaporating everything in a supernova scale explosion before...
- causality0 3y ago
  One of the most interesting yet sadly least rigorous What-Ifs. He relies on simply scaling up a calculation in absorbed dose at the distance of one parsec. Neutrinos do not interact with nuclei the same way gamma rays do, and the effects of a particular amount of neutrino radiation on living tissue is unstudied and unknown. The paper he cites explicitly points this out but he ignored it.
  - raverbashing 3y ago
    Of course it doesn't, I think that was given by the relationship between neutrino count and sieverts But make no mistake, there is such a thing as a fatal amount of neutrinos. It's just that's a supernova mind boggling amount, but it exists. They do interact due to the weak force, which is more than neutrons do (and a lethal dose of those is well known)
- mhh__ 3y ago
  See also neutrino HFT
- ridgeguy 3y ago
  In the sci-fi novel Iron Sunrise by Charles Stross, death by neutrino flux from a weaponized star figures into the plot. (edit - spelling)
bsder 3y ago
Any sufficiently advanced propulsion also qualifies as a weapon.

sparker72678 3y ago

Maybe? There would be far less energy-intensive ways to wipe other civilizations out of the universe, though.

dekhn 3y ago

step 1: arrange two black holes near your enemies step 2: wait 2 billion years

groestl 3y ago
Depending on your preferred solution to the Fermi Paradox, you might be able to just skip Step 1.

saiya-jin 3y ago

I dont think so, they go in all directions as a shockwave, pass through everything including black holes (even though it would warp it a bit), so its dark forest signalling basically to whole universe. Since we came to exist so early in the overall age of universe, there is absolutely no chance we are the only sentient civ across hundreds of billions x hundreds of billions/trillions x nr of planets realm. Super focused super dense ray of very hard gamma rays/cosmic rays should do any trick required for anything made out of matter. Or just swipe left with a black hole or two.

MaxikCZ 3y ago
Correct me if I am wrong, but since not even spacetime can escape blackholes, even gravitational wave would get swallowed, wouldn't it? Of course, since we can't "point" gravitational waves in a certain direction, because of the rest of the wave traveling around the hole would basically propagate it even directly behind blackhole (from perspective of source), but that's because the wave goes around, not trough. Or do grav waves really pass ~trough~ black holes?
- borissk 3y ago
  Hmmm, gravity does escape black holes, so maybe gravitational waves do too.
jakear 3y ago
> there is absolutely no chance If you hold Faith in the axiom "the universe was initialized homogeneously and propagated untampered thereafter", perhaps. Plenty of axioms for which "there is absolutely no chance we are not the only sentient civ across..." is just as true though. And everything in between.

kadoban 3y ago

Seems orders of magnitude too difficult to be worth it. If you can approach that level of energy, pointing a gamma ray burst sounds more fun. Or just throw some rocks at fractions of c.

abecedarius 3y ago

Pretty hard to direct. If you've set up a close-orbiting neutron star binary and you're in a military frame of mind, one thing you could do is accelerate missiles to a good fraction of lightspeed. (Same principle as the gravity assists used by planetary probes like Voyager.) The tides would limit the practical size of the missile, though I haven't tried to compute this limit. (I don't consider this comment to be aiding the interstellar enemy, it's too obvious.)