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Very sobering.

This reminds me of a story back from 2003 called "Villages in Germany are three kilotons apart." It puts an even more sobering perspective on the bombs.

http://everything2.com/title/Villages+in+Germany+are+three+k...

Nice read, but I must say: Having every second word be a link is really distracting. Ended up pasting it in a text editor.

It's really interesting that the "Davy Crockett" (smallest bomb) will only level three city blocks and spread radiation for six. Not sure why you would not just use conventional weapons if you need a blast that small?

On the opposite end, it's really scary to see the effects of a Tsar Bomba 100mt Bomb. It basically takes out the entire New York metropolitan area :(

You need the blast that small because the Davy Crockett was to be fired by a human on the ground, not dropped from an airplane.

A small blast can be strategically preferable if you want to fire a bunch in a line in order to stop troops from advancing over a border for several days due to radiation hazards.

It seems that using the weapon posed massive risk for the operator, so it might have been in the maker's interest to make the bomb even smaller.

http://en.wikipedia.org/wiki/Davy_Crockett_(nuclear_device)

Are you sure the Davy Crocket has any lingering radiation worth worrying about? Fallout ought to be a function of radiation flux over volume, plus the unconsumed portion of the bomb, and for three stage devices the unconsumed portion of the uranium tamper as well. I seem to recall that most fallout from your typical nuclear weapons comes from the tamper - replacing the uranium with lead reduces yield by around 50%, but reduces fallout by a much larger fraction. I'd expect that after three days the blast site would be almost safe for habitation, and that you could safely travel through the site of the explosion immediately if you're in a tank or APC.

Wikipedia says that the area would be uninhabitable for up to 48 hours. The intent was not to make the border region permanently unavailable, but simply stall for time to mobilize other defensive forces.

A conventional weapon capable of doing that much damage would need to be delivered by a large truck or aircraft. The Oklahoma City bomb weighed 7,000 pounds, for example, and didn't even destroy one city block. The Davy Crockett weapon, on the other hand, was small enough to be transported in a single jeep and fired by one person.

Additionally, since it was designed as a tactical weapon of war, the quarter-mile lethal radiation dose is what really matters. I believe this was particularly important for tanks, which are robust against nearby explosions but whose armor provides only poor shielding against radiation, meaning that you'd likely end up killing the crew even though the tank itself would still be mostly intact.

The fact that you could set these up ahead of time and have them manned around the clock would have made them an incredibly effective defense in Europe in the event of war with the USSR. Over two thousand were produced, and many positioned around the countryside. Delivering the equivalent in conventional explosives would have required hundreds or thousands of aircraft, vulnerable to getting shot down, and needing much more advance notice and planning, while making those aircraft unavailable for other uses.

I'm not saying that deploying a couple thousand man-portable nukes around the border areas of West Germany was necessarily a good idea, but it did make sense given the situation at the time.

... needing much more advance notice and planning

Without disagreeing with your point ...

The Army being the Army - while the weapons were issued, the troops trained on the system with dummy warheads, I suspect that issuing live atomic warheads to the troops would have required just as much confusion, hurly-burly, and wacky improvisation as getting a wing of airplanes aloft.

Or more? The Air Force does fly airplanes around all the time. One suspects the guys in charge of atomic warheads did not actually issue their toys to the battle groups very often.

It's a complex subject, certainly. One additional subtlety that's worth considering is that, while they may not have had warheads on the border all the time (although things were more lax in the 60s), war was unlikely to break out with absolutely no warning, and they could be stationed at the border if tensions rose, potentially days or weeks in advance of war breaking out. Whereas with airplanes, you can't launch your bombers days before you expect the enemy to cross the border.

However, probably the more pertinent point was that, even if the warheads would have been troubled by administrative confusion as you propose, they probably looked much more effective to the guys in charge of procuring items like this, where such problems often get abstracted away or simply forgotten about.

war was unlikely to break out with absolutely no warning, and they could be stationed at the border if tensions rose

I have recalled where I first heard about the Davy Crockett a - from Hackworth's memoir 'About Face'. Looked it up in google books to verify.

Per Hackworth, while the Crockett platoon leader in his battlegroup did not know where to obtain live rounds, they would have been procured in about two hours. (pg 413).

This seems like an amazingly short time to issue anything, even with Russian tanks coming over the border. But perhaps they expected to move a little faster in West Germany in the 60s.

I wonder if "did not know where to obtain live rounds" might have been a convenient fiction to placate people, like how the launch codes on ICBMs were set to 00000000 for decades so there wouldn't be any chance of them getting in the way of nuking the Russkies. Something like, "The live rounds for your weapons are definitely NOT housed in room 404 of the local armory, wink wink nudge nudge."

To me, re-reading that chapter, it's clear that the neither the platoon leader nor his immediate chain of command knew how to obtain atomic warheads at the time. Years later, the author met a key responsible for implementing the weapon who assured him of the two-hour metric.

Of course ... the author is biased, it's a memoir, and at time a very selective one. Take it with a grain of salt.

Hackworth was a lot of things but one thing he was above all else was very opinionated and sure of himself.

The 100 megaton version of Tsar Bomba was only a design. The biggest one tested was 50 megatons, because anything more powerful would have been too large and/or too heavy to carry, and the pilots would not have had enough time to get to a safe distance before detonation.

"The bomb, weighing 27 tonnes, was so large (8 metres (26 ft) long by 2 metres (6.6 ft) in diameter) that the Tu-95V had to have its bomb bay doors and fuselage fuel tanks removed. The bomb was attached to an 800 kilogram parachute, which gave the release and observer planes time to fly about 45 kilometres (28 mi) away from ground zero. The fireball reached nearly as high as the altitude of the release plane and was seen almost 1,000 kilometres (620 mi) from ground zero. The subsequent mushroom cloud was about 64 kilometres (40 mi) high (nearly eight times the height of Mount Everest). The base of the cloud was 40 kilometres (25 mi) wide. All buildings in the village of Severny (both wooden and brick), located 55 kilometres (34 mi) from ground zero within the Sukhoy Nos test range, were completely destroyed."

http://en.wikipedia.org/wiki/Tsar_Bomba

Just to add a little on to what you wrote, seems like there's also a part where anything much over 50 MT just blows the rest of the energy out into space, so there seems to be a cap on how big one can be?

I'm not an expert here, but my opinion is that there is no limit on the megatons, or if there is, it's substantially higher than 50. The reason I believe this comes partly from one sentence in the Wikipedia article: "Atmospheric focusing caused blast damage at even greater distances, breaking windows in Norway and Finland." That focusing reminds me of the practice of shaping conventional explosives. The focusing from the Tsar Bomba test was accidental, meaning that they did not design it into the bomb, but if you were to, for example, design a nuclear explosion to work in conjunction with techniques which allow for precise, large-scale control of weather, you could effectively create a nuclear shaped charge which would focus the explosion downwards or outwards, thereby allowing you to increase the expected yield, as delivered to the target, whereby dissipation into space would not be a real concern. This is just off the top of my head, and I'm guessing that no one's tried it, mostly either due to lack of need, or lack of ability to do grand nuclear experiments.

http://en.wikipedia.org/wiki/Atmospheric_focusing

Big bombs are extremely inefficient at directing damage at targets. Their main benefit is that they don't have to be aimed accurately. If you lob a 10 MT bomb at a capital city, metropolis, or military base and you miss by a mile you will still almost certainly destroy it.

The advent of accurately targeted MIRVed weapons makes big bombs obsolete. Instead of lobbing one 10 MT bomb near a target you attack a lot of smaller targets with smaller bombs.

Sorry, but this is flat out wrong.

The Tsar Bomba was a 100 MT bomb, period. It was capable of being used in 50 MT configurations but there was absolutely, positively zero chance that the 100 MT configuration would not work. Additionally, the 100 MT version would not have been a significantly different weight or size.

The reason for the 50 MT / 100 MT difference is that such weapons use a mix of fission and fusion reactions. In a thermonuclear weapon you can use natural Uranium (U-238) as a jacket around the fusion fuel capsule. While U-238 doesn't normally participate in a fission chain reaction it will fission when under high neutron flux and as it turns out fusion bombs generate enormous amounts of neutrons. Thus typical thermonuclear weapons leverage the fusion reactions to drive fission reactions and boost yield enormously, resulting in most of the energy from a "thermonuclear" weapon ultimately coming from fission reactions.

The downside of this is that fission reactions are very dirty. And in the case of the Tsar Bomba design that meant that testing the design at a full 100 MT yield would result in 50 MT worth of nuclear fission fallout being spread across the Soviet Union (and ultimately the world of course). Which is rather quite a lot of fallout. By replacing the jackets around the 3rd stage fusion fuel capsules with different materials that do not undergo fission the result is that the fusion reactions still proceed, and the bomb still releases 50 MT of energy, but very little energy comes from fission (the primary, parts of the secondary and the spark plugs in the tertiary stages), massively reducing fallout.

The part about the pilots not having enough time to get to a safe distance from a 100 MT explosion is true, but aside from that had the Soviets wanted to they could have done a 100 MT test of Tsar Bomba quite readily.

Thanks for the correction, and the explanation. I recalled reading the following in the Wikipedia article, but forgot about it as I was writing the comment, while trying to juggle several other things.

"The initial three-stage design was capable of yielding the power of approximately 100 Mt, but would have caused too much radioactive fallout. To limit fallout, the third stage and possibly the second stage had a lead tamper instead of a uranium-238 fusion tamper (which greatly amplifies the reaction by fissioning uranium atoms with fast neutrons from the fusion reaction). This eliminated fast fission by the fusion-stage neutrons, so that approximately 97% of the total energy resulted from fusion alone (as such, it was one of the "cleanest" nuclear bombs ever created, generating a very low amount of fallout relative to its yield). There was a strong incentive for this modification since most of the fallout from a test of the bomb would have ended up on populated Soviet territory."

Also, if you have the time, I'd like your opinion on what I said about atmospheric focusing.

http://news.ycombinator.com/item?id=3626601

Atmospheric focusing is a pretty inefficient process, on top of the existing inefficiencies of massive nuclear weapons it's probably not worthwhile to use as a weapon. It's a lot easier to send conventional bombs or bullets to Finland if you want to break windows there than to use multi-megaton bombs thousands of miles away.

The main reason you build big bombs is (aside from the arms race / show boating aspect) to destroy important targets with inaccurate delivery systems. The other reason to build big bombs is to intentionally create fallout, which could be used in a "doomsday" weapon, possibly as a MAD deterrent. If you exploded a 1,000 MT nuke on a containership in international waters off the coast of Europe or North America and you took advantage of the prevailing winds you could do devastating damage to the population, agriculture, etc.

a little bit farther is something much more disturbing, at least for me:

"The device was trillions of times more powerful per unit volume in comparison to the material in the sun's fusion core (about 25% of the sun's radius) and it would take about 10 million years for an equivalent volume of the sun's core to produce the same amount of energy as came from within the bomb's casing."

It's a confusing metric because stellar fusion is actually extremely slow. The power density of the sun's core is about 0.3 watts/liter, which wikipedia compares to the metabolic heat density of reptiles:

http://en.wikipedia.org/wiki/Sun#Core

Much more interesting is the fact that, during the few dozen nanoseconds the bomb spent exploding, it produced over 1% of the power output of the entire Sun.

I don't think you really appreciate how large destruction "only" three city blocks is.

I appreciated it when I put the marker on my home - I could then clearly imagine what the destruction range is.

It'd be really cool to add some "equivalences" to compare what an asteroid hitting Earth would do, in terms of Mt.

E.g.

* Annual impact -- 5-20 kt (~Hiroshima)

* Indonesia superbolide (2009) -- 50 kt

* Tunguska (Siberia 1908) -- 10-15 Mt (~large hydrogen bomb)

* K-T extinction (65 MYA) -- 10^14 t = 100,000,000 Mt (complete detonation of ~2 million tons fusion fuel)

I'm not sure how far you can compare these figures -- issues like (i) how much energy is released as an atmospheric shock wave vs. infrared radiation vs. heat; (ii) what altitude the explosion is at.

http://www.nature.com/news/2002/021121/full/news021118-7.htm...

http://www.nature.com/nature/journal/v420/n6913/full/nature0...

http://neo.jpl.nasa.gov/news/news165.html

http://en.wikipedia.org/wiki/Tunguska_event

http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Tertiary_ext...

When I first found one of these it changed nukes for me, properly permanently. Before that I had always assume that if terrorists gets their hands on nukes then it was goodbye world, maybe a few people survive the slaughter but you can kiss the city goodbye.

But the kind of yields they would get are so low that they wouldn't do much damage unless you were within a few blocks.

That's 2/3rd's the kilo tonnage of Hiroshima. I wouldn't call that 'low yield'. See: Hiroshima.

They're doing fine these days!

(we got Hiroshima and Nagasaki, they got Detroit and Pittsburgh... fair trade)

are you seriously afraid terrorists like Umar "underwear bomber" Farouk and such could get their hands on real nuclear weapons (not dirty bombs) or are you calling heads of states seeking nuclear capability terrorists?

This article introduced me to the term "Megadeath". I've never really thought of that in terms of SI units. The scale of destruction that we have the potential to cause is simply horrifying. When you see pictures of Hiroshima/Nagasaki and then scale up to an H bomb and realise that those were simply tiny in comparison it's really rather sobering.

How is this sobering? I find it fearmongering. Or is there any meaning behind this other than "The humankind has powerful weapons to destroy itself and you are not safe"?

....perhaps we shouldn't have these weapons...

You're right. Please put the cat back in the bag, and refill Pandora's box on your way out.

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