June 23, 2015

How Many Nuclear Bombs WOULD it Take

...to effectively knock most of the world back into the 7th century?


Well, to physically devastate the planet through blast and heat would take thousands upon thousands of bombs, probably more than existed at the height of the cold war. 

However, all we have to do is bring down the thing that (philosophical advances notwithstanding) makes the modern world modern...our technology.

One could go a long way to doing that with an Electro Magnetic Pulse. There are a few ways to get these, but we're talking about nukes, so one can obtain the effect by detonating a nuclear weapon at high altitude. The sweet spot seems to be an area with a lower limit between 18 and 31 miles up (depending on latitude and other factors) and an upper limit around 300 miles into space. The effects are caused by interaction with the earth's atmosphere and magnetic field and extends to the visible horizon. The effects radii for various altitudes can be seen here...



The actual effects are fairly consistent throughout the area with a horseshoe shaped area containing a zone of very high effects and a small area just north (or south in the southern hemisphere) of ground zero with minimal effects.



Most of the area has between 50 and 80% of the maximum intensity of effects. The effects can be...impressive.


  The electromagnetic pulse (EMP) fused all of the 570-kilometer monitored overhead telephone line with measured currents of 1500 to 3400 amperes during the 22 October 1962 test. The monitored telephone line was divided into sub-lines of 40 to 80 kilometres (25 to 50 mi) in length, separated by repeaters. Each sub-line was protected by fuses and by gas-filled overvoltage protectors. The EMP from the 22 October (K-3) nuclear test caused all of the fuses to blow and all of the overvoltage protectors to fire in all of the sub-lines of the 570 km (350 mi) telephone line.The EMP from the same test caused the destruction of the Karaganda power plant, and shut down 1,000 km (620 mi) of shallow-buried power cables between Astana (then called Aqmola) and Almaty.  

Even assuming these were maximum effects and most areas would receive 30-80% of this effect this messes everything up. 

Back to the question at hand. How many bombs would it take for a not entirely rational government to apply those effects to the entire world?

Well, using the 1470 mile radius of the affected area we get an area of 6,788,670 square miles. The earth has a total surface area  of 196,939,900 square miles (rounded after conversion from km) and 196,939,900 / 6,788,670 = 29.010 so one would need less than 29 of these to send the whole Earth back into the dark ages (less because the nefarious individuals doing his would not need to hit most of the 70% of the surface area that's oceans, Antarctica, or themselves.

Now a small crazy country that wants to do this and had the capability to make 25 bombs a year and a transportable ballistic missile, and a modest merchant marine might discreetly disperse these missiles to where they could be simultaneously launched for global coverage... like so...


Iranian Shabab 4? missiles and their TELs on small container shiip.

Now to what end would they do this?

Well a conquering, convert or die army is kind of like a zombie apocalypse, with fast, tool-using, gun shooting zombies (except they don't often bite) and we've seen some of what can happen when a group like that moves into an area that's demoralized and destabilized...



Of course if this outfit ever encounters a proper modern military, they'll get curb-stomped. 

Note though that if you have the same goal and can demoralize and destabilize the entire world, by say, knocking a good chunk of it back to the 7th century, even if only for a few years...well., these people have a sense of history...



Imagine this transpiring while the whole world is knocked on their behinds by a power failure, starving and desperate, and assume to that kept aside a few nukes for military bases and tactical usage.

That would probably be quite a powerful motive for those who consider modernity itself to be an abomination.

Is this likely? Would it work?....probably not.

But, if you're crazy enough to roll the dice with nukes you're crazy enough to try really crazy crap especially since the EMP doesn't require particularly challenging targeting capability and could conceivably do far more damage than the same nuke could via blast and heat.  

Anyway, I was surprised that you could do it with 20-30 midsize nukes.

UPDATE: Corrected some typos, fixed a hyperling and. umm, removed the picture of Mum-Ra. 

Posted by: The Brickmuppet at 12:26 PM | Comments (9) | Add Comment
Post contains 813 words, total size 7 kb.

1 Fiber optic cables are immune to EMP, so there's that, at least.

Posted by: Pixy Misa at Tue Jun 23 23:09:29 2015 (PiXy!)

2 I can imagine the telephone lines can't handle that kind of induced current, but I'm not so sure about power lines.

But I think part of the voltage induction is related to them being long segments of conductor. being able to induct damaging current in handheld electronics might not be so easy, there's not enough distance to induce much of an electrical gradient.

The big problem with trying to knock ISIS back to the stone age is that's their goal.

Posted by: Mauser at Wed Jun 24 05:36:19 2015 (TJ7ih)

3 I do wonder about that. I keep hearing about how vulnerable integrated circuits are in comparison to vacuum tubes/valves but is that really so? Don't we at least have better surge protection than we used to? (though that would only be of limited effect against what the Russians described at Kasputin Yar). Is a modern semi-conductor really more likely to suffer an induction induced overload than the Cathode & anode in a tube?
(Obviously integrated circuits are a good thing, my i-Mac would be se size of the U.S. national mall or larger and have frequent bit errors if it was tube based)

Posted by: The Brickmuppet at Wed Jun 24 10:30:50 2015 (ohzj1)

4 Mauser is right, it's about the length of the wires.  An EMP that would induce tens of kilovolts in a long run of telephone or power lines would be barely measurable on a circuit board and not even that within an integrated circuit.  Integrated circuits are vulnerable to direct radiation, but then, so are people.  Anything that kills your iMac will be bad news for you too...

The vulnerable things are the electricity grid and local telephone / internet services.  The big worry is the grid; if a lot of large transformers are damaged, it could take years to replace them all.

Posted by: Pixy Misa at Wed Jun 24 12:37:51 2015 (PiXy!)

5 The problem is, you don't need to have much of electric gradient to fry electronics. I met a guy once in a local pilot's club, who described an early EMP weapon they built while working in the Sandia lab. They too two aluminized balloons and tied them to two quartz plates, then smeared the plates with C4 and built a sandwich. They hoisted that contraption at the base and blew it up. When they did it, they fried a bunch of rados in town and knocked a local AM station off the air.

A nuke is going to induce a ton of low-gigahertz and wreck a bunch of Ethernet switches and computers, despite most being in metal cases. Cellphones, too.

Posted by: Pete Zaitcev at Wed Jun 24 15:02:41 2015 (RqRa5)

6 That's very peculiar, Pete.  So a Nuke isn't necessary for causing EMP?  Something THAT low-tech is easily within the reach of ISIS.

And now Fred the Fed is reading....

Posted by: Mauser at Wed Jun 24 19:34:47 2015 (TJ7ih)

7 Well you have to have some kind of physical that converts some other energy (such as temperature, or mechanical energy of the shockwave) into the EM radiation. I do not quite understand how nuclear explosion produces its EMP. If it were just the tail of the glow as it cools down, its power would not be that great, I imagine. But its available power is absolutely immense and perhaps there are massive currents in its plasma ball. In contrast, using quartz plates is a more efficient way to generate the electric tension from the shockwave, and balloons were chosen to be effective antennas, so a pound of C4 makes, say, 1/100th EMP of a 100kt nuke while using 1/1,000,000th of energy. It wasn't an imaginative way to generate EMP either. I heard of more intricate designs that, for instance, blow up coils and such. A number was intended to fry satellites for the Soviet anti-SDE program.

Posted by: Pete Zaitcev at Wed Jun 24 19:46:58 2015 (RqRa5)

8 Another funny story I heard from that lab is they once were tasked to build a weapon to combat tunnels. So they went and bought a bunch of toy tanks. They used the tank chassis and put some C4, about 1/4 of a pound on it, a detonator, and an electric circuit. The tank would crawl forward, until it hit an obstacle. Then, the curcut made it turn 45 degrees and try to crawl again. If it could not proceed after a 360 degree turn, it blew up. It also blew up after crawling about 100 ft. The idea was to cave tunnels in at a distance from the well that they drilled to lower the tank. You could also lower two or three if you were lucky and the first blew up far enough away.

I thought it could be easier to pump some propane into the tunnel, then ignite it. Unfortunately, the Rodenator didn't exist in the 1970s and the thought didn't occur to those boffins.

Posted by: Pete Zaitcev at Wed Jun 24 19:55:52 2015 (RqRa5)

9 Generating a small-scale EMP is easy enough.  Anything that generates an electromagnetic field in normal operation can do the trick if you pump a whole lot of energy into it all at once.  

Coils are good for this, as Pete mentioned.  Wrap a coil around an explosive core, run a current through the coil, and blow it up.  Voila, EMP.  But the total energy is much much less than a nuclear blast, so the effects fall off sharply with distance (inverse square law).

On a really small scale, you can just set up a working coil, put it on the floor, and stamp it flat.  Something that simple will still generate a measurable EMP.

Posted by: Pixy Misa at Wed Jun 24 22:59:31 2015 (PiXy!)

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