A Nuclear Weapon is a hugely powerful explosive device that generates its destructive force from nuclear reactions within. There are two types of Nuclear Weapon: the nuclear fission weapon or the more powerful nuclear fission/ nuclear fusion combination – both types release vast quantities of energy from small amounts of matter. Fission bombs are also known as Atomic Bombs while fission/fusion bombs are sometimes known as Hydrogen Bombs or Thermonuclear Bombs.

To give an impression of the destructive power of these weapons of mass destruction, a thermonuclear weapon weighing little more than 1,000 kg can produce an explosive force comparable to the detonation of more than 1 million tons of TNT (traditional explosive material). Thus, even a small nuclear device no larger than a traditional bomb could devastate an entire city from the combination of its blast, fire, and radiation fallout.

Nuclear Weapons have been aggressively used twice in human history: Atomic Bombs were invented and developed as part of the Allied Powers’ Manhattan Project during World War 2 and used by the United States against Japan to end the war. On 6 August 1945, a uranium fission bomb (code-named “Little Boy”) was detonated over the Japanese city of Hiroshima. Three days later, on 9 August, a plutonium fission bomb (code-named “Fat Man”) was exploded over Nagasaki. These bombings resulted in the deaths of approximately 200,000 people, mostly civilians.

During the ideological ‘Cold War’ following World War 2, the US and USSR engaged in an arms race to build up huge stockpiles of Nuclear Weapons to position themselves as the most dominant global super-power. Other countries followed suit. The threat of complete annihilation on both sides became known as Mutually Assured Destruction (M.A.D.). The devastating potential consequences of full-on Nuclear War is sometimes said to have prevented World War 3 taking place. Indeed, the M.A.D. defence is used to this day by those who argue against making possession of Nuclear Weapons by countries illegal.

Although the Cold War has since thawed, the use and control of Nuclear Weapons remains a major focus of international relations. The first countries to develop possession of Nuclear Weapons were the US, the USSR/Russia, the UK, France and China – the five permanent members of the United Nations Security Council. India, Pakistan and North Korea have since followed suit. Israel is also widely believed to possess Nuclear Weapons (though it does not acknowledge having them), while Iran and Syria have in recent years been suspected of developing Nuclear Weapons programmes too.

While they have only been used in warfare twice, thousands of Nuclear Weapon tests and demonstrations have taken place since World War 2, and during that time more complex and lethal types of Nuclear Weapon have been developed. For example, one particular version of the Thermonuclear Bomb is the Neutron Bomb, designed to yield a relatively small explosion but release large amounts of radiation to cause massive human casualties while leaving infrastructure relatively intact. Nuclear Weapons can also now be dropped from aircraft, carried by intercontinental ballistic missiles or launched from submarines. As of 2012, it was estimated that there were more than 17,000 nuclear warheads in the world, with around 4,000 of them considered “operational” and ready for use.

Any new World War – a Nuclear War – could destroy humanity as we know it. But we obviously can’t ‘un-invent’ the Nuclear Weapon now that we’ve invented it, so what do we do with them now that we have them? Couldn’t we put them all under the control of the United Nations? Couldn’t we use them as propulsion mechanisms for interplanetary space travel (as the Cold War ‘Project Orion’ study proposed)? Couldn’t we agree to just destroy them all?

Various safeguards have been developed to protect humans against their own misuse of Nuclear Weapons since their invention: the International Atomic Energy Agency was established by the U.N. in the late 1950s to encourage development of peaceful applications of nuclear technology, and various attempts at test ban treaties or disarmament deals have been instigated – but never seen through to full conclusion. US President Barack Obama stated a goal in 2009 of “a world without nuclear weapons”, so the political will is still there.

The debate on nuclear weapons and nuclear disarmament has, however, been complicated in recent years by the threat of terrorism. Mutually Assured Destruction, for example, would not deter an enemy who expected – or even welcomed – death. Equally, if a terrorist organisation were to attack a sovereign state with a Nuclear Weapon, who would the state retaliate against with a further nuclear strike? And why?

To learn more about Nuclear Disarmament, jump to Chapter 38: Nuclear Disarmament – content to follow

To learn more about the development and use of Nuclear Technology, jump to Chapter 39: Nuclear Technology – content to follow

To learn more about the threat and consequences of Nuclear War, jump to Chapter 40: Nuclear War – content to follow

And, just for fun, to learn more about the proposed Project Orion spacecraft, jump to Chapter 41: Project Orion – content to follow