What would happen if a nuke went off in the stratosphere?

[ruthiechan]

Seriously, I want to know what sort of repercussions would there be if a nuke or some other high explosive or serious EMP blast went off in the atmosphere/stratosphere. Would the weather change? Would the people on the surface be able to notice something had happened beyond the noise? Would it muck with any frequencies or power lines or anything?

[skippy740]

My guess would be that people would actually start talking to other people wondering why they can't access Facebook or Twitter to find out what's going on.

[Moksha]

When exploded one mile or less above the earth's surface, it is projected that circuits could be damaged within a forty mile radius.

We certainly would not want to do anything to damage the ozone layer.

[Traveler]

When exploded one mile or less above the earth's surface, it is projected that circuits could be damaged within a forty mile radius.

We certainly would not want to do anything to damage the ozone layer.

Damaged circuit is an understatement. The electromagnetic pulse (EMP) would fry every electric circuit within so many miles depending of the size of the blast - everything including watches, microwaves, cell phones, automobiles and house wiring even if they are turned off. The electrical grid in the area would be shut down and would not come back on line without major replacement – usually taking weeks.

In addition a giant heat column igniting anything flammable in the atmosphere would quickly raise creating winds well over 100 mph in the area. Finally there would be nuclear fallout that would be spread according to weather patterns

The Traveler

[ruthiechan]

That's interesting. So theoretically a terrorist doesn't have to hurt us from the ground.

[Traveler]

That's interesting. So theoretically a terrorist doesn't have to hurt us from the ground.

There are many ways a terrorist could hurt us. A single terrorist could kill 20 million Americans (if they knew what to do) with little more than that which could be found in an average garage. This has been a concern to me that I have discussed with the FBI because I am concerned that if I can figure this out so can a terrorist. It is because we are so vulnerable that I am concerned that so many in this country want to limit those that protect us and give rights and privilege to our enemies whenever and in all cases and circumstances when terrorists are questioned for vital information necessary to keep us safe.

The Traveler

[NeuroTypical]

That's interesting. So theoretically a terrorist doesn't have to hurt us from the ground.

I'm sure we haven't forgotten 9/11 that quickly...

[DigitalShadow]

True security and safety are illusions that in reality are never possible. If someone is intelligent and very determined to do harm to others, they will find a way no matter what security measures are in place.

While I believe it is reasonable to put in place measures that will deter the vast majority of attackers, I don't believe it is a good idea to completely disregard the rights and property of others in the name of enhanced security (for example, giving airport security the right to pretty much destroy any of your property because they are on a power trip and there is no legal recourse.)

[DigitalShadow]

There are many ways a terrorist could hurt us. A single terrorist could kill 20 million Americans (if they knew what to do) with little more than that which could be found in an average garage. This has been a concern to me that I have discussed with the FBI because I am concerned that if I can figure this out so can a terrorist. It is because we are so vulnerable that I am concerned that so many in this country want to limit those that protect us and give rights and privilege to our enemies whenever and in all cases and circumstances when terrorists are questioned for vital information necessary to keep us safe.

The Traveler

And when the the department of homeland security detains you for an indefinite amount of time accusing you of formulating a terrorist plot when you were only trying to warn them, I hope you are still just as pleased with all the power they have been given in the name of safety :)

[Traveler]

And when the the department of homeland security detains you for an indefinite amount of time accusing you of formulating a terrorist plot when you were only trying to warn them, I hope you are still just as pleased with all the power they have been given in the name of safety :)

Having served in the military had having been exposed to military intelligence in combat situations – I am very concerned that current policy dictates we must follow Miranda in dealing with enemy combatants and any intelligence they may have. It is my honest impression that many do not realize or think that we are at war. However, I am sure that we will all learn, in time.

The Traveler

[threepercent]

Damaged circuit is an understatement. The electromagnetic pulse (EMP) would fry every electric circuit within so many miles depending of the size of the blast - everything including watches, microwaves, cell phones, automobiles and house wiring even if they are turned off. The electrical grid in the area would be shut down and would not come back on line without major replacement – usually taking weeks.

In addition a giant heat column igniting anything flammable in the atmosphere would quickly raise creating winds well over 100 mph in the area. Finally there would be nuclear fallout that would be spread according to weather patterns

The Traveler

this is incorrect

think of an emp as a streetlamp. the area that would experience massive electronic damage is the small area under the lamp that is well lit. most electronics with a circuit board will not work after an EMP in this area of effect. but things like flashlights will.

transmission lines are a diffrent story. now think of yourself way away from the streetlamp, but within line of sight so you can see it. of course you can see the lamp from much much further away that you could use the lamp to read by.... any transmission lines in this area of effect are toast.

so a relatively small area will experience total electronic deviation, and a huge area will experience loss of the power grid. a few (perhaps 4) well placed bombs could take out the entire us grid for perhaps 4 months to a year. yet those same bombs would take out only the electronics of the city proper of 4 large cities.

also, due to the nature of deployment of an EMP (optimal altitude) you don't really have fallout issues, as most fallout is from debris sucked up from the initial blast, and that doesn't happen with a high altitude burst.

EMP also is a tactical stepchild as well. it has limited uses.

[Traveler]

this is incorrect

think of an emp as a streetlamp. the area that would experience massive electronic damage is the small area under the lamp that is well lit. most electronics with a circuit board will not work after an EMP in this area of effect. but things like flashlights will.

transmission lines are a diffrent story. now think of yourself way away from the streetlamp, but within line of sight so you can see it. of course you can see the lamp from much much further away that you could use the lamp to read by.... any transmission lines in this area of effect are toast.

so a relatively small area will experience total electronic deviation, and a huge area will experience loss of the power grid. a few (perhaps 4) well placed bombs could take out the entire us grid for perhaps 4 months to a year. yet those same bombs would take out only the electronics of the city proper of 4 large cities.

also, due to the nature of deployment of an EMP (optimal altitude) you don't really have fallout issues, as most fallout is from debris sucked up from the initial blast, and that doesn't happen with a high altitude burst.

EMP also is a tactical stepchild as well. it has limited uses.

There are two kinds of nuclear devices, fission and fusion. A fission reaction is far less sophisticated but much more “dirty”. Also the EMP is in essence twice (per megaton) that of a fusion reaction. All unshielded or unhardened devices will be affected by an EMP that will act in essence the same as a very powerful radio transmission across a spectrum of frequencies. Anything with a plug in cord or wires (like head phones) could pick up enough energy to melt the wiring or connections or in many cases alter semiconductor operations especially if they involve low voltage switching. Some devices – like flashlights may still operate but I doubt anything like the family car would.

I am basing this on requirements I worked with directly while working as a consultant for the Department of Defense.

The Traveler

[threepercent]

yes, and that is because of mil-spec, anything required to be hardened has to be able to withstand the very rigorous tests associated with being right under the "street lamp."

most all electronics in this area will be toast unless hardened.

the emp's loss of power (amplitude) when generated by a bomb is crazy high.

of course the sun also produces EMP's that can make all this theory go to pot.

and as you say, the spectrum of a HEMP is very wide, so not all protected circuits will withstand the wave, but many circuits with lightning or surge protection will.

here is the waveform:

kEpkea(t-ts)

E(t) = --------------(kV/m)

l+e(a+b)(t-ts)

where the coefficients are given by--

Epk = 50 kVtm, the peak electric field (kV/meter)

k = 1.2, a normalization constant

a = 5 x 108 sec-1, the exponential rise rate (sec-1)

b = 2.3 x 107 sec-1, the exponential decay rate (sec-1)

Ts = 10-8 sec, the time shift parameter (sec)

t = the time of interest (sec).

[Moksha]

There are two kinds of nuclear devices, fission and fusion. A fission reaction is far less sophisticated but much more “dirty”. Also the EMP is in essence twice (per megaton) that of a fusion reaction.

I am basing this on requirements I worked with directly while working as a consultant for the Department of Defense.

The Traveler

So theoretically, a cold fusion bomb accidentally exploded at Brigham Young University, would leave the west side of Provo as well as Orem unscathed? That sounds like good news.

:)

[bcguy]

read this.

In essance, todays discrete componets that fry with less then 20 volts would be destroyed. Even under this test, high current and high voltage devices back then! fried! So yes, the US could be sent back to the pre industrial age. In other words, keep that old high voltage tube radio handy..it may be the only radio operating within a thousand miles!

Starfish Prime

Main article: Starfish Prime

In July 1962, a 1.44 megaton United States nuclear test in space, 400 km above the mid-Pacific Ocean, called the Starfish Prime test, demonstrated to nuclear scientists that the magnitude and effects of a high altitude nuclear explosion were much larger than had been previously calculated. Starfish Prime also made those effects known to the public by causing electrical damage in Hawaii, more than 800 miles away from the detonation point, knocking out about 300 streetlights, setting off numerous burglar alarms and damaging a telephone company microwave link.[6]

The EMP damage of the Starfish Prime test was quickly repaired because of the ruggedness (compared to today) of the electrical and electronic infrastructure of Hawaii in 1962. Realization of the potential impacts of EMP became more apparent to some scientists and engineers during the 1970s as more sensitive solid-state electronics began to come into widespread use.

The relatively small magnitude of the Starfish Prime EMP in Hawaii (about 5,600 volts/meter) and the relatively small amount of damage done (for example, only 1 to 3 percent of streetlights extinguished)[7] led some scientists to believe, in the early days of EMP research, that the problem might not be as significant as was later realized. Newer calculations[8] showed that if the Starfish Prime warhead had been detonated over the northern continental United States, the magnitude of the EMP would have been much larger (22,000 to 30,000 volts/meter) because of the greater strength of the Earth's magnetic field over the United States, as well as the different orientation of the Earth's magnetic field at high latitudes. These new calculations, combined with the accelerating reliance on EMP-sensitive microelectronics, heightened awareness that the EMP threat could be a very significant problem.

[edit] Soviet Test 184

In 1962, the Soviet Union also performed a series of three EMP-producing nuclear tests in space over Kazakhstan, which were the last in the series called "The K Project".[9] Although these weapons were much smaller (300 kilotons) than the Starfish Prime test, since those tests were done over a populated large land mass (and also at a location where the Earth's magnetic field was greater), the damage caused by the resulting EMP was reportedly much greater than in the Starfish Prime nuclear test. The geomagnetic storm-like E3 pulse (from the test designated as "Test 184") even induced an electrical current surge in a long underground power line that caused a fire in the power plant in the city of Karagandy. After the collapse of the Soviet Union, the level of this damage was communicated informally to scientists in the United States.[10] Formal documentation of some of the EMP damage in Kazakhstan exists[11][12] but is still sparse in the open scientific literature.

[ruthiechan]

I'm sure we haven't forgotten 9/11 that quickly...

No, of course not. But that required running the airplanes into the ground, therefore I see 9/11 as bombs being dropped from the air and exploding on impact as opposed to exploding in the air which is what I am essentially asking about.

bcguy, was that from wikipedia?

threepercent, can you explain the wave form in English? I am still learning the mathematical language (actively working on it right now) and you lost me a bit there.

traveler, think you could explain this, "or in many cases alter semiconductor operations especially if they involve low voltage switching," in more detail?

[NeuroTypical]

No, of course not. But that required running the airplanes into the ground, therefore I see 9/11 as bombs being dropped from the air and exploding on impact as opposed to exploding in the air which is what I am essentially asking about.

That makes sense - thanks for clarifying. Yes, an EMP is a way of attacking a group of people without touching the ground. There are a lot of ways to wage war without doing anything to people directly. Wars are fought by economics, in the media, by proxies, in the UN, etc.

LM