Nuclear radiation and automobiles

Remember the movie “The Day After” when the cars on K-10 all stalled out right before the blast? I’m wondering, what exactly would have caused that. I’d guess radiation playing heck with the OBD systems, but this movie was made before OBD was invented.

Note: I chose 2000 Honda Odyssey for this post, as that’s what I drive. That part doesn’t have anything to do with my question, though.

Never saw the movie, but assume there would be a detonation high in the atmosphere which created an electro-magnetic pulse (EMP) which induced currents which burned out sensitive circuits in the vehicles.

Older vehicles would still start and run.

Yep, the one time it would really pay to drive a Stanley Steamer with carbide headlights. :wink:

I think that if you are close enough to a nuclear explosion for the EMP to fry your car’s electrics, your non-functional car will be the least of your problems.

It doesn’t happen before the blast, but after it. The electromagnetic emissions move at the speed of light (light is an electromagnetic emission). The shock wave moves much slower; it is air moving at may hundreds of miles per hour. It’s like thunder and lightning.

Yes, the EMP from a high-altitude explostion of an H-bomb. This would be combined with low/ground level blasts.

The cut-off for most cars would be the advent of electronic ignition. This happened roughly around 1973-75 in most domestic cars and a little later in some of the imports. Before this, they used breaker points which were electromechanical and wouldn’t be affected.

You did not buy the EMP hardening option offerded on your Odyssey? now your going to pay the price for not thinking ahead,stock up on thoses MRE’s,the times a coming.

I try not to infuse fiction and reality. It is important to keep them separate.

The same thing happened in the movie Broken Arrow, but that doesn’t mean it will happen in a real life nuclear explosion like that. Movie makers often deviate from reality with details like that for dramatic effect.

If you want to speculate about what will happen in a nuclear explosion, look to science, not fiction.

I’m really glad my lawnmower has electronic ignition instead of the old magneto points. In the event of a nuclear explosion, my lawnmower will stop and I can go in and wait the problem out with a cold beer.

I agree, if the electronics of a car are that fragile, the repair shops would be snowed under everytime there was a lightning storm.

I think you’re underestimating an EMP. Not science fiction at all. Read more about it here:

Google on ‘Starfish Prime’ to read about the US tests to gauge the effectiveness of EMP from a high altitude thermonuclear detonation. It has to be done in near space, outside of the atmosphere, for it to be effective. The strategy of both the US and Soviets during the cold war was to detonate a number of nuclear devices just above the atmosphere to knock out satellites and any other communications equipment they could prior to the second wave of near-ground burst weapons.

“…if the electronics of a car are that fragile, the repair shops would be snowed under everytime there was a lightning storm.”

The lightning would have to be right next to your car for it to make a difference. We had a lightning strike between my neighbor’s garage and mine a few years ago. How do I know? Our garage door motor electronics were fried the next morning.

Now, consider that an electromagnetic pulse from the Sun can wipe out satellites orbiting Earth and can even shut down power facilities. All from a distance of 93 million miles. A nuclear explosion is the same type of event that causes the EMPs from the Sun that play havoc with us on Earth. Not nearly as large, but many orders of magnitude greater than one lightning bolt.

Gamma radiation can fry any electrical system. Electromagnetic radiation is the monster and will get the system anywhere that isn’t protected by metal.

There are actually three components to the EMP, only one of them similar to a lightning strike. They are labeled E1, E2 and E3. The E2 component is similar to lightning. The E1 and E3 components are much more damaging, especially in light of the fact that we already provide protection from lightning in most electronics since it is a common threat. The E1 component is produced by gamma rays and the E3 component is the result of the temporary shift in magnetic field- neither of which is present in lightning and a solar flare does not affect the magnetic lines of the earth.

EMP effects carry out to a much greater distance than the other main effects (blast, heat) of a nuclear weapon.

Here’s an excerpt about the effects of the 1.4 megaton Starfish Prime device from

“The Thor missile carried the test instrumentation and the W-49 warhead/Mk-4 RV payload to 248 miles. The test appeared quite spectacular from Hawaii (800 miles away) and at Kwajalein (1600 miles away), with impressive light displays from an artifical aurora lasting up to seven minutes. The electromagnetic pulse (EMP) from this test sent power line surges throughout Oahu, knocking out street lighting, blowing fuzes and circuit breakers, and triggering burglar alarms.”

According to a Nuclear Weapon Effects Calculator the blast of a device of that power can cause widespread destruction out to 8 kilometers, thermal radiation causing 3rd degree burns out to 13 kilometers and immediate fatal radiation out to 3 kilometers. Compare that to EMP at roughly 1500 kilometers.

Gamma radiation can fry any electrical system.

[i]…and turn you into a giant green monster![/i]

Most operational weapons today are in the 5 to 15 megaton range. Movie scenarios are mostly the daydreams of screenplay writers. A 10 megaton airburst creates a 20 mile circle of death inside which there are no survivors. The EMP is the LEAST of your worries.

20 miles is nothing compared to the area affected by an EMP:

The flare does not effect the Earth’s magnetic field, but the ejecta does. The increase in solar wind pushes the magnetosphere away. It doesn’t remove it, but does compress it on all sides but anti-sun, where it stretches it.