Ripley: I say we take off and nuke the entire site from orbit. It's the only way to be sure.
Aliens
"Now I am become Death: the destroyer of worlds"
J. Robert Oppenheimer, quoting from the Bhagavad Gita during the Trinity test detonation.
Basic Information
The atomic bomb, also known as the A-bomb, Nuclear Bomb, or simply The Bomb, is a device that converts a small amount of uranium into energy, thereby creating an explosion capable of reducing a large metropolitan area to a smoldering crater. Furthermore, residual radiation can contaminate the target and surrounding areas for decades or even centuries to come. When combined with suitable delivery systems, The Bomb is arguably the only real-world doomsday device. As such, it has dominated geopolitics ever since its power was first demonstrated.
Atomic devices come in two main types: the fission bomb, which works by unleashing the energy resulting from the nuclear fission of Uranium or Plutonium, and the more powerful fission-fusion bomb (AKA. the thermonuclear bomb) in which the fission explosion is used to kick-start a hot-fusion reaction.
A bomb may be air-burst (detonated so that the fireball doesn't touch the ground) or ground burst (detonated on or near the ground). An air burst weapon will inflict superficial damage over a wide area and generate substantial electromagnetic pulse impact but is unlikely to breach hardened targets or create significant fallout. Ground bursters, by contrast, inflict more intense damage on a smaller area and are more likely to penetrate fortifications - but will vaporise and project a large plume of radiated fallout. Only a ground-bursting device generates the infamous mushroom cloud - which can actually result from any large explosion. The mushroom shape is created by air pressure. The blast extends out in all directions, but the heated air rises fast and then colder air from outside the blast collapses in on the sides. If a nuke goes off in space (or any place without a heavy atmosphere and/or earthlike gravity) the explosion and its immediately visible after-effects will be more spherical in shape.
Recent advances have also developed the sub-surface bursting atomic device, in which the warhead penetrates deeply enough into the earth that the blast is completely contained. This form of explosion is expected to shock-liquefy the ground generating earthquake like effects on the surface and destroy underground installations without creating airborne fallout. It is also possible to detonate a nuclear device under water - indeed, this was at one stage regarded as a viable way of destroying SSBNs before they were able to launch their warload - these generate an impressive shockwave and surface wave (and if the water is shallow enough can propagate their shockwave into the air) but apart from generating quantities of radioactive salt their fallout pattern is typically limited. Ecological damage - especially fish-kill - from the blast will still likely be large.
Detonated in a vacuum, an atomic device will be unable to generate a blast wave and will be substantially less effective - although the third or so of its output that is released as thermal energy, light, and fast neutrons will be unattenuated and effective over vast distances.
There are several other variations, including the neutron bomb (which releases an increased proportion of its energy as fast neutrons rather than blast or radioactive fallout) and the cobalt bomb which is designed to increase the level of radioactive fallout contamination which it creates.
For reference, the demonstrated outputs of non-specialised atomic devices (specified in the tonnage of TNT required to generate an equivalent explosion) range from 57 megatons (the Soviet Tsar Bomba) to ten tons (the American Davy Crockett). For comparison, the only two nuclear devices so far used in anger were Little Boy (Hiroshima, 15 kilotons) and Fat Man (Nagasaki, 21 kt). The Trinity device, detonated as the first ever live nuclear test, was logged at 20 kt.
History
After the theoretical possibility became clear during the 1930s, the ground work for the production of a viable atomic bomb was performed by the Anglo-French Tube Alloy project during World War II, which was then taken over and brought to fruition by the United States, in what has become known as the Manhattan Project. The first usable devices were delivered too late for the war in Europe, but served to being an end to the Pacific Conflict when Japan capitulated after the US used them against the Japanese cities of Hiroshima and Nagasaki. These remain the only two times the bomb has been used offensively.
There were also even less sane plans to use atomics for civil engineering purposes - peaceful nuclear explosions in fact. A more advanced understanding of the realities of nuclear radiation and fallout put a stop to this sort of thing quite swiftly.
Effects of Detonation
The size and scope of an Atomic detonation depend on the size and power of the bomb, but here's a few guidelines of what sort of special effects you might throw in to your game or story should the worst come to pass.
- Flash Blindness: People outside and within tens of miles are likely to be temporarily blinded for several minutes - and permanent blindness is highly likely. Fishermen looking in the direction of the Bikini tests without eye protection were permanently blinded at a great distance and, allegedly, found to have the shape of the mushroom cloud bleached into their retinae by the flash. The flash will also contain a wave of intense nuclear radiation in the form of beta and gamma rays and fast neutrons which can be fatal in their own right, and an intense pulse of thermal and electromagnetic energy.
- Thermal Radiation Burns: These can be very severe and often fatal even out to several miles. People in dark clothing suffer more damage than those in white or light clothing because more of the thermal energy is absorbed by their surface, but within the immediate area of the detonation temperatures can climb to over 30,000'C, which is more than sufficient to evaporate human tissue.
- Electromagnetic Pulse: Will destroy nearby electronics, and may affect devices hundreds of miles away.
- Blast Wave: Tremendous amounts of force issue out from the center of the blast, generating winds over 150 mph, collapsing buildings and hurling debris into the air. The blast wave expands outward at roughly a mile every 5 seconds carrying a cloud of debris ahead of it. This is generally followed by a fire storm as everything that can burn does, heated to its ignition point and beyond already by the flash.
- Fallout and Lingering Radiation: After the blast, you've got about half an hour to get into shelter before the radioactive fallout is expected to coat the landscape. For a couple weeks after the explosion, the surrounding environment is deadly toxic, and the fallout can spread great distances carried by the weather. Cancer and mutation are likely eventual results for many of those who survived the immediate effects of the blast.
The dynamics of the radiation and explosive blast are governed by the Inverse-Square Law, so if your character knows there's going to be a blast you want to put as much distance as possible between them and ground zero. Also, don't forget to take cover, preferably behind thick layers of concrete or something else dense and sturdy that will absorb or reflect some of the radiation and survive the shockwave. The flash travels in a straight line, so getting below ground level can help, but the blast wave is quite capable of blowing out an underground bunker if it touches it, and will need some pretty impressive pressure tight doors to resist.
Sources
And here's an interesting video on the immediate damage and lingering effects of an atomic bomb detonation:
…for reference, the wierd vertical smoke trails seen in the detonation footage around 3:23 are nothing to do with the bomb itself - they are marker rockets set off by the explosion and designed to allow the observing scientists to judge the blast radius.
See Also
Game and Story Use
- An espionage plot can revolve around stopping people planning to acquire or sell atomic bombs or the capability to produce them.
- For a time travel or alternate history plot, changing which country develops the bomb at which moment in history will have a dramatic impact on the course of events.
- For those that like it Hollywood style, note that you can outrun the blastwave from a nuclear device - if you can move faster than about 720mph. The problem is doing that after you've dealt with the flash and EMP blast travelling at the speed of light that preceded it.
- The number of authors that have dropped characters into the Trinity test site at the time of the detonation would have the place looking like Picadilly Circus in the rush-hour. No reason for your PCs not to get in on the action though…
- Alternative drop ins could include Hiroshima, Nagasaki, Bikini Atoll (where the first post-war tests were carried out) … Sukhoy Nos (where the Tsar Bomba was fired) would be less appropriate given that it air-burst, but might still be a possibility.
- A pulp-era adventure could involve scientists —evil or otherwise — who are trying to invent an Atomic Bomb.
- "After the Bomb" is a common premise (if not THE standard premise) for Post-Apocalyptic settings. See After The End.
- You can even have a cult of mutants who worship an unexploded bomb. That's always fun!
- Trying to salvage an unexploded nuclear device could be a useful plot in its own right - especially if the parts are required to make your own nuclear device.
- This could work well "after the bomb" if a faction wants to resurrect one of the super weapons of the past, in a WW2 like scenario where one power is slightly ahead of the other and has rushed out the first ever nuclear attack only for it not to detonate, or, as per Clancy's Sum of All Fears1, on behalf of a non-state actor or non-nuclear power eager to salvage a device lost by one of the "nuclear club".