How radiation causes cancer
Roughly 15 per cent of the energy released in the initial blast and fallout of an atomic bomb is high-frequency ionising radiation. Unlike other forms of radiation, such as visible light and microwaves, ionising radiation is fast and energetic enough to strip electrons from molecules, including the ones that make up the cells in your body. That radiation randomly damages the DNA in your cells – as if you’ve been shot with millions of tiny pins. (UV rays are borderline ionising, which is why you can get skin cancer from tanning.) If ionising radiation strips enough electrons from your DNA, or if you’re unlucky and it hits the wrong places in your genome, the genes that control cell growth can start to function abnormally. Certain cells divide out of control, causing tumours, leukemias, or other cancers. The risk is particularly high for children, whose cells have divided less often and are more likely to run amok if damaged.