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I’ve never understood this fear over EMP attacks. Is there a viable EMP attack? Wouldn’t a blast strong enough to damage lots of infrastructure also damage the

I’ve never understood this fear over EMP attacks. Is there a viable EMP attack? Wouldn’t a blast strong enough to damage lots of infrastructure also damage the contents of human skulls?

NotSammyHagar 9y ago
no, a high altitude emp burst of a nuke over a big city like nyc would be devestating to electronics but kill no one other than people dieing from the loss of power.
- mcculley 9y ago
  Do you have any citation for that? I would like to learn more about how that works.
  - mikeash 9y ago
    Wikipedia has a pretty good article: https://en.m.wikipedia.org/wiki/Nuclear_electromagnetic_pulse https://en.m.wikipedia.org/wiki/Nuclear_electromagnetic_puls... Note that this is not just theoretical. The American Starfish Prime nuclear test did significant damage to electrical systems in Hawaii, and the Soviets destroyed a power plant in Almaty with one of theirs.
dredmorbius 9y ago
In any energy-transfer weapon, from a club to a bullet to a grenade to a nuke, the critical elements are: 1. How much energy is released? 2. Over what time period? 3. In what forms? 4. At what distance from the target / victim? A bullet which misses you by a millimeter might as well be 1,000 km away. It requires direct contact with tisue to transact damage. Where it hits you also matters, and in many cases, a light interaction with an extremity (hand, foot) may do little damage, whilst a trunk or head shot will be critical or instantly lethal. Much of that comes from the transmission of fluid shock through the body. (Watching super-slow-motion video of bullets impacting various targets on YouTube is ... interesting and informative.) A nuclear bomb delivers energy to the target in four major forms: 1. Prompt ionizing radiation. This is a pulse which lasts for a tiny fraction of a second, and is rapidly absorbed even by the atmosphere. It can be lethal or disabling at relatively close range. 2. Thermal pulse. Depending on the size of the weapon, this will ignite directly exposed flammable materials at ranges from a few hundreds of meters to a hundred km or so. This can be mitigated with white or reflective paint, or intervening structures. 3. Blast wave. This is the physical shockwave of the weapon (as well as any material picked up by it) which causes much of the direct damage. 4. Radioactive fallout. This is long-term radiation delivered generally downwind of the blast site. Exposure follows the seven-ten rule. For each increase by a factor of seven in time, the radiation falls by a factor of ten. A 1,000 rad dose 1 hour after the blast is 100 rads 7 hours after, 10 rads 2 days (49 hours) later, and 1 rad after two weeks. The detonations of nuclear weapons are fast, on the order of a microsecond (on one-millionth of a second). In large part it's the ability to deliver all its energy virtually instantly which gives a bomb its power. An alternative understanding comes from the idea of "generations" of nuclear interactions and their timescale -- a typical nuclear blast occurs over about 50 generations, after which the core has generally spontaneously disassembled past the point of sustainable reactions. (There's a pretty good Quora article on that point here: https://www.quora.com/How-long-does-a-nuclear-explosion-take https://www.quora.com/How-long-does-a-nuclear-explosion-take) Chemical explosives are far slower -- I believe closer to milisecond (thousandth-of-a-second) range. Or: a nuclear explosion is as much faster than a chemical explosion as a chemical explosion is to change taking a full second. A table of chemical reaction velocities peaks at 10,000 m/s, or 1 km/s, or 1m / 0.001s, suggesting a typical deonation period of 0.001ms - 1ms. https://en.wikipedia.org/wiki/Table_of_explosive_detonation_velocities https://en.wikipedia.org/wiki/Table_of_explosive_detonation_... Meteor and meteorite impacts are often described in terms of megatons or Hiroshima-bomb equivalents. The Chelyabinsk meteorite is estimated to have released the energy of 20 - 30 Hiroshima-sized bombs, approximately 400 - 500 kilotons of TNT. However: 1. It did so primarily at an elevation of ~30 km, 2. over a period of 5 - 10 seconds, 3. in the form of light, heat, and sonic blast Much the same as you experience the same total change in kinetic energy whether you decelerate from 100 kph in 10 seconds or 0.01s, the difference is in the total shock and stress, as well as the energy delivered. TL;DR: a modest-sized nuclear blast high in the atmosphere or above it could have relatively modest ground impacts whilst delivering a strong EMP effect.
- B1FF_PSUVM 9y ago
  You teach, don't you? (That last line was a pretty good answer and did not really need the rest of the post above it, informative as it was ;-)
  - dredmorbius 9y ago
    I study, moreso. Explaining things (or trying to do so) is a check on my own understanding, both directly ("does this make sense?") and through responses ("no, actually, in X the truth is ..."). But the general case of such events is one element I've reflected on.
- escherplex 9y ago
  Good technical exposition but of course these would be somewhat localized consequences of human lunacy. Imagine a replay of the 1859 Carrington Event (equatorial disturbance – storm time estimate = -800 nT to -1750 nT) which fried telegraph networks worldwide. Wonder what would still work?
  - dredmorbius 9y ago
    That gets to the point of how is it specifically that disruptive events manage to disrupt. Sometimes it's physical disruption or damage. Very often though it's interference with energy cycles or communications and control. See various neurotoxins or the effects of cyanide (it blocks ATP cycling in mitochondria -- directly affecting the cellular energy cycle). EMP is an energy signal that causes direct physical damage to long-length or fragile conductors, disabling both energy transmission and processing equipment, and communications systems. Optical comms systems are unaffected, however. And systems based on microwave repeaters don't have the long-length conductors that telegraph systems did in the case of Carrington.
- mcculley 9y ago
  I understand why we fear nukes being exploded over our heads. What I don’t understand is the recurring notion of a weapon designed only for EMP attack. If an attacker can get a nuke over my head, I fear the nuke.
sliverstorm 9y ago
Whether or not it is viable, it also seems like life would continue. Like, power outages happen, even very long ones, and people mysteriously continue living their lives. Granted, it would suck for a while.
- 21 9y ago
  Life would continue, but not necessarily with the same head count. How long do you thing NY could sustain it's population numbers with a long power outage?

I’ve never understood this fear over EMP attacks. Is there a viable EMP attack? Wouldn’t a blast strong enough to damage lots of infrastructure also damage the contents of human skulls?

NotSammyHagar 9y ago

no, a high altitude emp burst of a nuke over a big city like nyc would be devestating to electronics but kill no one other than people dieing from the loss of power.

mcculley 9y ago
Do you have any citation for that? I would like to learn more about how that works.
- mikeash 9y ago
  Wikipedia has a pretty good article: https://en.m.wikipedia.org/wiki/Nuclear_electromagnetic_pulse https://en.m.wikipedia.org/wiki/Nuclear_electromagnetic_puls... Note that this is not just theoretical. The American Starfish Prime nuclear test did significant damage to electrical systems in Hawaii, and the Soviets destroyed a power plant in Almaty with one of theirs.

dredmorbius 9y ago

In any energy-transfer weapon, from a club to a bullet to a grenade to a nuke, the critical elements are: 1. How much energy is released? 2. Over what time period? 3. In what forms? 4. At what distance from the target / victim? A bullet which misses you by a millimeter might as well be 1,000 km away. It requires direct contact with tisue to transact damage. Where it hits you also matters, and in many cases, a light interaction with an extremity (hand, foot) may do little damage, whilst a trunk or head shot will be critical or instantly lethal. Much of that comes from the transmission of fluid shock through the body. (Watching super-slow-motion video of bullets impacting various targets on YouTube is ... interesting and informative.) A nuclear bomb delivers energy to the target in four major forms: 1. Prompt ionizing radiation. This is a pulse which lasts for a tiny fraction of a second, and is rapidly absorbed even by the atmosphere. It can be lethal or disabling at relatively close range. 2. Thermal pulse. Depending on the size of the weapon, this will ignite directly exposed flammable materials at ranges from a few hundreds of meters to a hundred km or so. This can be mitigated with white or reflective paint, or intervening structures. 3. Blast wave. This is the physical shockwave of the weapon (as well as any material picked up by it) which causes much of the direct damage. 4. Radioactive fallout. This is long-term radiation delivered generally downwind of the blast site. Exposure follows the seven-ten rule. For each increase by a factor of seven in time, the radiation falls by a factor of ten. A 1,000 rad dose 1 hour after the blast is 100 rads 7 hours after, 10 rads 2 days (49 hours) later, and 1 rad after two weeks. The detonations of nuclear weapons are fast, on the order of a microsecond (on one-millionth of a second). In large part it's the ability to deliver all its energy virtually instantly which gives a bomb its power. An alternative understanding comes from the idea of "generations" of nuclear interactions and their timescale -- a typical nuclear blast occurs over about 50 generations, after which the core has generally spontaneously disassembled past the point of sustainable reactions. (There's a pretty good Quora article on that point here: https://www.quora.com/How-long-does-a-nuclear-explosion-take https://www.quora.com/How-long-does-a-nuclear-explosion-take) Chemical explosives are far slower -- I believe closer to milisecond (thousandth-of-a-second) range. Or: a nuclear explosion is as much faster than a chemical explosion as a chemical explosion is to change taking a full second. A table of chemical reaction velocities peaks at 10,000 m/s, or 1 km/s, or 1m / 0.001s, suggesting a typical deonation period of 0.001ms - 1ms. https://en.wikipedia.org/wiki/Table_of_explosive_detonation_velocities https://en.wikipedia.org/wiki/Table_of_explosive_detonation_... Meteor and meteorite impacts are often described in terms of megatons or Hiroshima-bomb equivalents. The Chelyabinsk meteorite is estimated to have released the energy of 20 - 30 Hiroshima-sized bombs, approximately 400 - 500 kilotons of TNT. However: 1. It did so primarily at an elevation of ~30 km, 2. over a period of 5 - 10 seconds, 3. in the form of light, heat, and sonic blast Much the same as you experience the same total change in kinetic energy whether you decelerate from 100 kph in 10 seconds or 0.01s, the difference is in the total shock and stress, as well as the energy delivered. TL;DR: a modest-sized nuclear blast high in the atmosphere or above it could have relatively modest ground impacts whilst delivering a strong EMP effect.

B1FF_PSUVM 9y ago
You teach, don't you? (That last line was a pretty good answer and did not really need the rest of the post above it, informative as it was ;-)
- dredmorbius 9y ago
  I study, moreso. Explaining things (or trying to do so) is a check on my own understanding, both directly ("does this make sense?") and through responses ("no, actually, in X the truth is ..."). But the general case of such events is one element I've reflected on.
escherplex 9y ago
Good technical exposition but of course these would be somewhat localized consequences of human lunacy. Imagine a replay of the 1859 Carrington Event (equatorial disturbance – storm time estimate = -800 nT to -1750 nT) which fried telegraph networks worldwide. Wonder what would still work?
- dredmorbius 9y ago
  That gets to the point of how is it specifically that disruptive events manage to disrupt. Sometimes it's physical disruption or damage. Very often though it's interference with energy cycles or communications and control. See various neurotoxins or the effects of cyanide (it blocks ATP cycling in mitochondria -- directly affecting the cellular energy cycle). EMP is an energy signal that causes direct physical damage to long-length or fragile conductors, disabling both energy transmission and processing equipment, and communications systems. Optical comms systems are unaffected, however. And systems based on microwave repeaters don't have the long-length conductors that telegraph systems did in the case of Carrington.
mcculley 9y ago
I understand why we fear nukes being exploded over our heads. What I don’t understand is the recurring notion of a weapon designed only for EMP attack. If an attacker can get a nuke over my head, I fear the nuke.

sliverstorm 9y ago

Whether or not it is viable, it also seems like life would continue. Like, power outages happen, even very long ones, and people mysteriously continue living their lives. Granted, it would suck for a while.

21 9y ago
Life would continue, but not necessarily with the same head count. How long do you thing NY could sustain it's population numbers with a long power outage?