Nuclear weapon

A nuclear weapon (or nuke, nuclear warhead, nuclear bomb) is an explosive device that uses nuclear reactions, either fission (fission bomb) or from a combination of fission and fusion reactions (thermonuclear bomb). Both bomb types release large quantities of energy from relatively small amounts of matter.

Nuclear bombs have had yields between 10 tons and 50 megatons of TNT. Its weight to energy yield ratio is more than 1:1000. Potential gigaton yield devices are "doomsday bombs." One detonated about 16 kilometers up would start fires over an area of more than 700,000 square kilometers. A few 1000 gigatons would be enough to kill all humans.

Nuclear devices are weapons of mass destruction (WMD) or doomsday devices and can devastate entire cities by blast, fire, and radiation. Nuclear non-proliferation treaties have to be signed by Type 0 civilizations in order to prevent MAD (mutually assured destruction) in a futile nuclear war.