How quickly can exposure to nuclear radiation kill a human?
Radiation sickness, which invloves the break-down of the human cells by bombardment with high energy photons, or particles, can cause death in a matter of a few days. Ionization, caused by high intensity radiation, say at the center of ground zero of an atomic bomb impact, will kill on impact. Every day radiation, such as the radiation we absorb from microwave ovens, cell-phones, electrical appliances or in the worst case radiation we get from medical treatment does not, as far as studies have shown, cause any sugnificant damage to the body. However if one is exposed to this kind of radiation (especially x-ray) for a long period of time the chances of developing cancerous growths increase.