EMP Explanation
Jul 08
Posted: under General, Technology.
I’ve read through quite a few reviews for War of the Worlds and I’ve noticed more than one person confused about how after the lightning most things with batteries didn’t work but some things did…..it has nothing to do with batteries.
To make obvious exactly what was going on, the movie makes mention of an EMP, or Electromagnetic Pulse, associated with these storms. They don’t really explain what exactly that means very well though. Not that I’ll do a great job myself, but here’s the gist:
an EMP is radiation that can disable/destroy electronics while causing no harm to biological life. The radiation will travel through metal and cause a power spike. If the spike is high enough, the wire will heat up sufficiently to burn through the insulation surrounding it and the circuit will short out, destroying it. Lower powered EMP’s can temporarily disable electronic devices. I’m not really sure exactly how this works, but I would imagine that what happens is that the circuits heat up sufficiently to cause them to not operate but not enough to actually cause a short.
The failure of electronics after an EMP has nothing to do with batteries. In fact, right off hand, I’m not even sure how much an EMP would effect batteries. The problem is with the electronic equipment itself. To relate this to the movie, everything that quit working was electronic in nature. Everything had circuitry that would have been susceptible to the EMP. To be fair, we’re not exactly sure how an EMP effects a large area due to lack of testing (go figure), so it is somewhat possible that most things would be fried while some things would continue to work. I’ll stick to my diagnosis that the van wouldn’t have worked though….. Even the radio worked, which is extremely unlikely. The radio’s antenna would act like…an antena… and it would have gotten more of a jolt because of it. Yet it was fine?
EMP’s are usually associate with nuclear weapons as a nuclear blast will cause an EMP. There’s a theory going around that if you set off a nuclear warhead a couple of hundred miles above the center of the US we’d black out from coast to coast. Fun, eh?
How do you protect yourself? There’s a concept of EMP hardening that can give some hope I suppose. You can put things inside of a faraday cage, which is basically a wire-mesh surround that will absorb the radiation. Unfortunately, the “perfect” Faraday cage doesn’t really exist as any stray wire (read power line, phone line, antenna, etc) that exits the cage will act as a conduit and bring the radiation inside.
