# Will engines not work at the approach of a nuclear bomb? **URL:** \ **Category:** Factual Questions\ **Created:** [January 30, 2008, 1:28am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540 "2008-01-30T01:28:56Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![monstro](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@monstro](https://boards.straightdope.com/u/monstro)\ **Post date:** [January 30, 2008, 1:28am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/1 "2008-01-30T01:28:56Z")
I’m sitting here watching _The Day After_. Right before the bomb dropped down, the movie shows a bunch of panicked people trying to get their stalled vehicles to work. The cars just stopped working and then KA-BLOOEY!! Would this really happen? If so, what would cause it? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 30, 2008, 1:34am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/2 "2008-01-30T01:34:32Z")
Engines (or rather, the electronics and electrical systems needed to run them) can be disabled by an EMP (electromagnetic pulse) generated by an airbusrt nuclear explosion. Basically, the EMP induces large surge currents in circuitry which burns it out. However, this happens _after_ the explosion, not before. And it only happens to any significant degree in an airburst detonation. Ground bursts and subterranean explosions don’t cause EMP, despite what the film _Broken Arrow_ would have you believe. ---
**Author:** ![treis](https://avatars.discourse-cdn.com/v4/letter/t/bc79bd/32.png) [@treis](https://boards.straightdope.com/u/treis)\ **Post date:** [January 30, 2008, 1:36am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/3 "2008-01-30T01:36:12Z")
Isn’t the metal body of the car going to act as a sort of Faraday cage? ---
**Author:** ![VunderBob](https://avatars.discourse-cdn.com/v4/letter/v/839c29/32.png) [@VunderBob](https://boards.straightdope.com/u/VunderBob)\ **Post date:** [January 30, 2008, 1:42am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/4 "2008-01-30T01:42:15Z")
[QUOTE=monstro] I’m sitting here watching _The Day After_. Right before the bomb dropped down, the movie shows a bunch of panicked people trying to get their stalled vehicles to work. The cars just stopped working and then KA-BLOOEY!! Would this really happen? If so, what would cause it? [/QUOTE] In _The Day After_, the Sovs lobbed a couple of orbital bursts for EMP before the rest started hitting targets. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 30, 2008, 1:44am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/5 "2008-01-30T01:44:27Z")
[QUOTE=treis] Isn’t the metal body of the car going to act as a sort of Faraday cage? [/QUOTE] Nope. Unlike an electric field, a magnetic field cannot be entirely blocked by a proper Faraday cage. Cars are far from an effective cage, in any case. The best you can do is attenuate it, and even then only if the shield is a good “conductor” of magnetism (in magnetics, we say it has a high permeability, aslo called mu), and has no large gaps in it. Cars with all-steel bodies would have a fairly high mu, but these are becoming increasingly rare in these days of lightweight nonmetallic composites, and besides, with the large windows, you’re pretty boned anyhow. Replace all the solid-state electronics with tubes and you might have a shot. Just ask the Russians. ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [January 30, 2008, 1:51am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/6 "2008-01-30T01:51:12Z")
[QUOTE=VunderBob] In _The Day After_, the Sovs lobbed a couple of orbital bursts for EMP before the rest started hitting targets. [/QUOTE] **Monstro** , without hijacking your thread, can I ask **VunderBob** for an explanation of why they’d do this? It sounds pretty brilliant really… is it to halt the sequences in place by the military for bunkering and, then, retaliation? EMPs to halt everything from blast doors shutting to the launch of strike aircraft, minuteman missles, etc? I’m assuming the EMP would be strategically feasible since it would have a much farther reaching effect than simple nuke blast dynamics? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [January 30, 2008, 1:53am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/7 "2008-01-30T01:53:28Z")
[Cecil on Faraday cages:](http://www.straightdope.com/columns/000609.html) > [@](#): > > . In a dynamic electromagnetic environment (radio waves), things are a little more complicated, but you do have something called the “skin effect,” in which a Faraday cage will cause significant attenuation of an incoming signal, depending on the cage’s construction and the signal’s frequency. To work properly, however, the cage must fully enclose the shieldee. If, like a dork (excuse me, Ms. Starfire, but one must call a spade a spade), you cover only a portion of yourself with the helmet, not only will the cage not shield you,… Cars are faraday cages with holes in them. It doesn’t take much to shut them down: > [@](#): > > [With $500 and a trip to the hardware store](http://news.zdnet.com/2100-9595_22-515644.html) , saboteurs can build a device capable of remotely disrupting computers, automobiles, medical equipment and nearly anything else dependent on electronics, according to a California engineer who demonstrated a homebrew computer death-ray at the InfowarCon '99 conference here Wednesday. ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [January 30, 2008, 2:00am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/8 "2008-01-30T02:00:00Z")
[QUOTE=lieu] **Monstro** , without hijacking your thread, can I ask **VunderBob** for an explanation of why they’d do this? It sounds pretty brilliant really… is it to halt the sequences in place by the military for bunkering and, then, retaliation? EMPs to halt everything from blast doors shutting to the launch of strike aircraft, minuteman missles, etc? I’m assuming the EMP would be strategically feasible since it would have a much farther reaching effect than simple nuke blast dynamics? [/QUOTE] Not so much military, which is hardened against EMP (somewhat) as much as civilian electronics. A couple of high-altitude air bursts would set all communications and electronics in the US on “burble.” No communication+no co-ordination= Bad Things for the Good Guys. It would also turn every civilian airliner into a multimillion dollar brick. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [January 30, 2008, 2:05am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/9 "2008-01-30T02:05:30Z")
[QUOTE=lieu] can I ask **VunderBob** for an explanation of why they’d do this? [/QUOTE] This document gives a good description of what you can accomplish with a single nuke in space: [Achilles’ Heel: Space and Information Power in the 21st Century](http://64.233.167.104/search?q=cache:KbgoT76WP8UJ:www.schriever.af.mil/shared/media/document/AFD-070906-082.pdf+emp+%22space+pearl+harbor%22&hl=en&ct=clnk&cd=4&gl=us&client=firefox-a) > [@](#): > > How could such a Space Pearl Harbor take place? There are several possibilities. The first is a nuclear > detonation in space. In 2004, the Commission to Assess the Threat to the United States from > Electromagnetic Pulse outlined the serious and little-advertised danger to national security that would result > from a nuclear explosion in space. > > “A single nuclear weapon carried by a ballistic missile and detonated a > few hundred miles over the United States would cause ‘catastrophe for the nation’ by damaging electricity- > based networks and infrastructure, including computers and telecommunications.” > > The effects of such an > incident would be wide ranging for information systems in space and air, as well as on land and sea. As an > example of the threat to space, “just one such detonation holds the potential to disable all non-hardened low- > Earth orbit (LEO) satellites.” > > X-rays produced from a nuclear detonation in space would immediately > degrade or destroy the electronics of those unhardened space systems within the line of sight of the blast ---
**Author:** ![Mongo\_Ponton](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@Mongo\_Ponton](https://boards.straightdope.com/u/Mongo_Ponton)\ **Post date:** [January 30, 2008, 4:38am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/10 "2008-01-30T04:38:48Z")
So is it true the Soviets had redundant electronics systems made with vacuum tubes in they’re bombers? Did we have that? ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [January 30, 2008, 10:05am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/11 "2008-01-30T10:05:50Z")
[QUOTE=Q.E.D.] Ground bursts and subterranean explosions don’t cause EMP, despite what the film _Broken Arrow_ would have you believe. [/QUOTE] You sure about that? Surely they do generate an EMP but the EMP is absorbed by the surrounding material? ---
**Author:** ![Pushkin](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@Pushkin](https://boards.straightdope.com/u/Pushkin)\ **Post date:** [January 30, 2008, 10:42am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/12 "2008-01-30T10:42:27Z")
[QUOTE=Mongo Ponton] So is it true the Soviets had redundant electronics systems made with vacuum tubes in they’re bombers? [/QUOTE] The [MiG-25](http://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-25) a defector brought to Japan was equipped with vacuum tubes. ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [January 30, 2008, 10:58am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/13 "2008-01-30T10:58:34Z")
[QUOTE=Quartz] You sure about that? Surely they do generate an EMP but the EMP is absorbed by the surrounding material? [/QUOTE] No. The EMP isn’t generated by the nuke directly, but by its gamma rays interacting with the atmosphere. Subterranean nukes have all their gamma absorbed before it gets out into the air. There’s a nice essay here: [Yahoo | Mail, Weather, Search, Politics, News, Finance, Sports & Videos](http://www.geocities.com/capecanaveral/5971/emp.html) ---
**Author:** ![si\_blakely](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@si\_blakely](https://boards.straightdope.com/u/si_blakely)\ **Post date:** [January 30, 2008, 11:06am UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/14 "2008-01-30T11:06:35Z")
[QUOTE=Quartz] You sure about that? Surely they do generate an EMP but the EMP is absorbed by the surrounding material? [/QUOTE] No. The EMP is generated by high energy particles from the blast ionising a huge area of the upper atmosphere. The free electrons start oscillating in the earths magnetic field. It is this oscillation that produces the EMP over a wide area. In the lower atmosphere/ground burst those high energy particles are busy actually heating up material to ionise it, and the density is higher so the volume of ionisation is smaller. There is an effect from direct high energy particles from a nuclear blast on electronics, but if you are that close to the blast, EMP is the least of your worries. ETA: What matt said. The [wikipedia](http://en.wikipedia.org/wiki/Electromagnetic_pulse) article covers this as well. Si ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [January 30, 2008, 7:57pm UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/15 "2008-01-30T19:57:34Z")
[QUOTE=matt] No. The EMP isn’t generated by the nuke directly, but by its gamma rays interacting with the atmosphere. Subterranean nukes have all their gamma absorbed before it gets out into the air. There’s a nice essay here: [Yahoo | Mail, Weather, Search, Politics, News, Finance, Sports & Videos](http://www.geocities.com/capecanaveral/5971/emp.html) [/QUOTE] With the gamma rays, there is also a significant risk of Hulkism. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [January 30, 2008, 8:12pm UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/16 "2008-01-30T20:12:24Z")
[QUOTE=Mongo Ponton] So is it true the Soviets had redundant electronics systems made with vacuum tubes in they’re bombers? [/QUOTE] Not exactly. The vacuum tubes weren’t redundant systems, they were the airframe’s main systems. The initial reaction of Western observers after they inspected Belenko’s plane was scorn - “they’re still using _vacuum tubes_?!?”- the West having long since moved on to solid-state electronics. Then they thought about it a little bit, and said “Wait… you don’t think they’re planning for EMP… do you?”, which as it turned out, they were. ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [January 30, 2008, 8:58pm UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/17 "2008-01-30T20:58:31Z")
Older, mechanically injected, Diesel engines are immune to EMP. An old car with a carburetor and Kettering ignition (mechanical points) would probably be fine as well. Modern engines, most diesels included, have electronic controls that would not survive. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [January 30, 2008, 9:03pm UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/18 "2008-01-30T21:03:57Z")
In Russia, electronics burst YOU! ---
**Author:** ![Mr.Slant](https://avatars.discourse-cdn.com/v4/letter/m/c57346/32.png) [@Mr.Slant](https://boards.straightdope.com/u/Mr.Slant)\ **Post date:** [January 30, 2008, 9:22pm UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/19 "2008-01-30T21:22:48Z")
In the book War Day, the STARTERS on most cars built since around 1965 wouldn’t work after EMP hits, despite the fact that the engines would by and large have worked on many cars built prior to the 1980s. ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [January 30, 2008, 9:46pm UTC](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540/20 "2008-01-30T21:46:08Z")
[QUOTE=Mr. Slant] In the book War Day, the STARTERS on most cars built since around 1965 wouldn’t work after EMP hits, despite the fact that the engines would by and large have worked on many cars built prior to the 1980s. [/QUOTE] Nah, starters have excellent magnetic shielding, and fields sufficient to saturate the iron they contain won’t overvoltage the windings. (that is pretty much thier normal operating condition) What DOES approximately fit that vintage, though, is the change from generators, to alternators. Alternators have diodes that could well be susceptible to EMP. [Next page](https://boards.straightdope.com/t/will-engines-not-work-at-the-approach-of-a-nuclear-bomb/435540.md?page=2)