@I_Has_A_Hat You’re mostly correct, but it’s a bit more than that. ‘Radiation’ is a lot of things (heat, light, etc.), but what we mean in cases like this is IONIZING radiation. And our world is filled with that. Bananas are radioactive, for example. Your own body is, too, only because it also contains some potassium-40. Anything granite you encounter is slightly radioactive, and so on. This does not require us to ingest waste from bombs, but that’s also a factor.
@I_Has_A_Hat You’re mostly correct, but it’s a bit more than that. ‘Radiation’ is a lot of things (heat, light, etc.), but what we mean in cases like this is IONIZING radiation. And our world is filled with that. Bananas are radioactive, for example. Your own body is, too, only because it also contains some potassium-40. Anything granite you encounter is slightly radioactive, and so on. This does not require us to ingest waste from bombs, but that’s also a factor.