BY ALPHONSE NDOLIA nuclear weapon is a weapon which delivers its destructive force from nuclear reactions of fission or fusion. Weapons which produce their explosive energy trough fission are known colloquially as atomic bombs, A-bombs, or fission bombs. The second basic type of nuclear weapon produces a large amount of its energy through nuclear fusion reactions and can be over a thousand times more powerful than fission bombs. These are known as hydrogen bombs, H-bombs, thermonuclear bombs or fusion bombs. A nuclear blast is so powerful that it can crush objects many miles away and it leads to extremely high temperatures, comparable to those that occur at the centre of the sun, causing massive and deadly fires. Nuclear weapons are still one of the dominant issues of our time, despite the ending of the cold war.Orgin of Nuclear warThese weapons not only produce large explosions but also produce hazardous radioactive by-products, they can be delivered by artillery, plane, ship, or ballistic missile (ICBM), some can also fit inside a suitcase. They are unique in their terrifying destructive potential. Their energy release is a million times larger than that of other explosives and mass destruction is inevitable if they are used in conflicts. Two primitive atomic bombs destroyed, literally wiped out, the Japanese cities of Hiroshima and Nagasaki at the end of the World War 11. The use of these weapons resulted in the immediate death of more than 200,000 and even more over time. Yet those weapons were no more than primitive versions of modern nuclear weapons, for now, a hydrogen bomb can release 1000 times or more destructive energy and there are several tens of thousands of them in the world today.The first nuclear weapons were created in the United States by an international team, including many displaced scientists from central Europe, with assistance from the United Kingdom and Canada during the World War 11 as part of the top –secret Manhattan project. They were developed primarily out of fear that Nazi Germany would develop them first. The only countries known to have developed such weapons are (chronologically) the United States, the former Soviet Union, United Kingdom, France, and People’s Republic of China, India, Pakistan and North Korea. Israel appears to have an extensive nuclear programme, although it officially maintains a policy of "ambiguity” with respect to its actual possession of nuclear weapons. Iran currently stands accused by the United Nations of attempting to develop nuclear weapons, although its government claims that its nuclear activities are for peaceful purposes. South Africa also secretly developed a small nuclear arsenal, but disassembled it in the early 1990’s. Threat of Nuclear warSoon after the Second World War, it was realised that the existence of nuclear weapons posed a new and fearsome threat to modern civilisation and that it was vital to treat them differently from "conventional” non nuclear weapons. Serious initiatives during the decade following the Second World War tried to bring these terrifying new weapons under international control, but these efforts failed as the cold war took hold. Land-based intercontinental ballistic missiles and long-range ballistic missiles on sub-marines moving about invisibly under the surface of the oceans brought the threat of nuclear annihilation very close indeed. It also became clear before long that there was no known or prospective technology that could provide a complete defence against a determined nuclear attack. In contrast to previous wars, essentially nothing would be left of a large urban "target”, its population and industry if just one, or at most a few, nuclear war heads exploded over them. A defence would have to be essentially perfect to provide protection against nuclear weapons, and that is neither a realistic standard of performance today, nor a prospective one for near future military systems. Recognition of the ineffectiveness of defences against the almost unimaginable destructive potential of a massive attack by nuclear bombs led the United States and the former Soviet Union to acknowledge that their very survival was based on mutual deterrence, ensuring that nuclear weapons were not used. The five "nuclear club” members, (the United States, the former Soviet Union, Britain, France, and the People’s Republic of China) agreed to attempt to limit the spread of nuclear weapons to other countries. In 1957, the International Atomic Energy Agency was established under the mandate of the United Nations in order to encourage the development of the peaceful applications of nuclear technology, provide international safeguards against its misuse and facilitate the application of safety measures in its use. The Nuclear non-Proliferation treaty (1968) attempted to place restrictions on the type of activities which signatories could participate in, with the goal of allowing the transference of non-military nuclear technology to member countries without fear of proliferation. However, other countries (India, South Africa, Pakistan and Israel) were able to develop or to acquire nuclear weapons.Nuclear prolification Nuclear proliferation has continued, in January 2005, Pakistan metallurgist Abdul Qadeer Khan confessed to selling nuclear technology and information of nuclear weapons to Iran, Libya and North Korea in a massive, international proliferating ring. On October 9, 2006, North Korea claimed it had conducted an underground nuclear test. During the cold war, the United States and the Soviet Union came close to nuclear warfare several times, most notably during the Cuban missile crisis. There have almost been accidental nuclear wars several times in the past and there can be an accidental nuclear war any time. As of 2006, there were estimated to be at least 27,000 nuclear weapons held at least by eight countries, 96 percent of them in the possession of the United States and Russia.In addition to the danger of radioactive fallout, in the 1970’s, scientists began investigating the potential impact of nuclear war on the environment. The collective effects of the environmental damage that could result from a large number of nuclear explosions has been termed "nuclear winter”. Treaties have been signed limiting certain aspects of nuclear testing and development and although the absolute numbers of nuclear warheads and delivery systems have declined since the end of the cold war, disarmament remains a distant goal.There is the threat to global security by nuclear weapons in the hands of North Korea’s dictator Kim Jong, following Pyongyang’s test of a nuclear bomb. The risk that North Korea may sell a nuclear weapon or material for a bomb is real, given Kim Jong’s record of selling arms to support his weak economy. While Iran has yet to produce nuclear weapons, it is on the path that will inevitably lead there, in defiance of the U.N. Security Council and the International Atomic Energy Agency. The two countries pose a danger to international peace if they are allowed to have nuclear weapons. There is an additional danger that terrorists could get hold of a nuclear weapons, this would indeed be very dangerous. It is important to realise that should there be a nuclear war, be that accidental or intentional, a "nuclear winter” would follow, and even if humanity was not wiped out, the living might well envy the dead.