Reading the EMP and cars thread below, I remembered something I’d always wondered about:
Simple circuits are immune to EMI, from what I understand, (although I don’t get why vacuum tubes are unaffected while copper wire is destroyed), right?
Now- the human body is full of electrical impulses at any given time- does that make us complex electrical systems, and thus, vulnerable to EMI?
I remember the scene in 007: Goldeneye where the MiGs are hit by the satellite- the pilots seemed to be getting fried too, although it looked like they were being electrocuted by their cockpit systems rather than fried by the blast.
I know, I know, Bond movies are not exactly chock-full of realism. I was just pointing out why I wondered. So back to the question- will an EMP just stop my watch, or my heart too?
According to the military folks, EMP weapons result in no casualties, although I did read once where whoever wrote the article said something along the lines of “we might get a general with a pacemaker.” It will stop your watch but not your heart.
A military aircraft is shielded against such things. If for some reason you did manage to weasel an electromagnetic pulse into the cockpit controls, I seriously doubt you’d see hollywood type sparks fly. More than likely you’d see weird readings on the instruments or maybe they’d go completely dead, and if all of the controls were knocked out the pilot would use the ejection seat, which I think is purely mechanical and wouldn’t be affected by an EMP.
Newer electronics with small wires and especially semiconductors are very sensitive to having too much current flow through all the wrong places. You’ll end up with semiconductor parts destroyed and the itty bitty wires inside the chips melted. Copper wire like in a car’s coil will melt from having too much current flow, and may break down as the higher voltage punches holes through the wire insulation (ruining the coil).
Vacuum tubes just by their very nature run on much higher voltages and currents and hence are much more immune to this sort of thing. 50 volts shoved onto something that is designed for 3 volts is going to cause some damage. 50 volts on something designed for 500 isn’t going to do squat.
AFAIK, (and despite what some people echewing cell-phones say) the human body is fairly immune to magnetic fields (a la EMP). You might want to check out how neurons function. I seem to recall that most of it was by changing the surface charge of nerve cells. This seems unlikely to me to be affected by magnetic fields. OTOH, I’m not a doctor or an engineer, so who knows.
Hijack: Since I wanted to know what EMP does, I posted to a survivalist message board about it hoping to get an answer to some EMP questions. I figured people preparing for a nuclear war will know what EMP does. Well, so far, one person is claiming that Russia will use 150 megaton, megaton, not kiloton, weapons on cities so I doubt I will get an good inormation from there. He also said the US has defense systems in orbit which will shoot down 70% of enemy missles.
Now that I realize how bad some of the nutcases in my country are, I figure EMP is no longer a worry. We in fact may need a good dose of EMP to get them off the net.
ok, end of Hijack, the seatbelt sign has been turned off. Please feel free to move about the nutcase ridden net.
AFAIK, humans do not experience particularly significant effects from EMP. As evidence, I offer the results of the atom bomb tests on human subjects (uninformed US soldiers). Of course, it’s possible that the effect is small and was swamped by the exposure to radioactivity (gamma, high energy charged and uncharged particles, etc. There was also significant analysis of then-existing data in the 70’s, when the ERW [Enhanced Radiation Weapon, aka Neutron bomb] was considered for deployment in the 70s.
As I recall, no significant EMP effects stood out at that time, despite significant human EMP exposure.
EMPs induce current through metal objects. To oversimplify it, nerves are made of carbon and water and work by secreting inorganic ions at the tips (axons). The next nerve reads the very small charge of the ions. It’s not the same as an electrical current.
No metal wires - no induced current - no electrical overload.
To nitpick: EMPs induce voltage across a conductor. The human body has very little inductance, and so only a small voltage will be induced, plus the resistance of the body is relatively high, so the current will be small too. On the other hand, an ignition coil has very high inductance, so a large voltage will be induced across it, and if the circuit is closed, a correspondingly large current will flow, buring out the wire.
EMP just means Electro-Magnetic Pulse. While nukes do generate EMPs, there are other ways to generate them. I think you are probably right that we don’t have to worry so much about the nuke versions any more, but there has been a lot of talk about the military using non-nuke generated EMP weapons (i.e. microwave generators). I read a couple of articles that they might be used in IRAQ, but after the hostilities started I never heard anything about it again.
Assuming our hypothetical pulse is generated by a nuke, rather than anything which produces the EMP without fission (a safe assumption, given the AIP’s take on “pinches”, etc.- http://www.aip.org/isns/reports/2001/033.html ) would the EMP radius be larger than the blast radius of the nuke in any case?
I mean, even if your car didn’t work anymore, would you be around to notice?
The EMP radius depends on the burst altitude of the nuke. It is a common assumption in military planning that any first strike will start with a nuclear weapon exploded over the Nebraska area, bathing the lower 48 and most of Canada in EMP.
So yes, it is very possible to have everything done in by EMP and not be hurt by the blast or even see the blast I would suspect.
while I am posting here and notice that my other post didn’t work, I’ll make a short comment
geek, what I meant was that I worry about the nutcases more than the EMP now. I know an EMP style attack is very possible.
