We do not know that the optimal level isn’t 3 times average background. Or that the body does not adapt to constant low exposures in a way it does not to acute ones. Both of which are theoretical possibilities. - Earth has been getting less radioactive over geological time, and the mechanisms of cell repair are of very ancient origin. LNT isnt just an unconfirmed theory at levels below background. It is a line which is extrapolated from data derived from people who had doses much higher than that. “Hiroshima survivors”. “Ill advised handling of multiple naked near-critical masses”. sort of doses. The correlation is rock solid as we go from 90% mortality to 50, to 25, and it points at “Zero exposure, zero morbidity” more or less.. but once you get to doses within an order of magnitude of background, the expected morbidity is a very small percentage, and detecting it among all the other things that cause similar damage is just impractical. So we assume. It’s a solid assumption, but it is an assumption. It could be wrong.
We do not know that the optimal level isn’t 3 times average background. Or that the body does not adapt to constant low exposures in a way it does not to acute ones. Both of which are theoretical possibilities. - Earth has been getting less radioactive over geological time, and the mechanisms of cell repair are of very ancient origin. LNT isnt just an unconfirmed theory at levels below background. It is a line which is extrapolated from data derived from people who had doses much higher than that. “Hiroshima survivors”. “Ill advised handling of multiple naked near-critical masses”. sort of doses. The correlation is rock solid as we go from 90% mortality to 50, to 25, and it points at “Zero exposure, zero morbidity” more or less.. but once you get to doses within an order of magnitude of background, the expected morbidity is a very small percentage, and detecting it among all the other things that cause similar damage is just impractical. So we assume. It’s a solid assumption, but it is an assumption. It could be wrong.
OK, I think I misunderstood what you meant by “in the vicinity of” in the ancestor.