Re illogical Supervening influences on half life of samples   I understand that the halflife of a radioisotope is unaffected by temerature pressure etc But dont other radiological sources have an effect eg the atomic fallout from a meteorite or a supernova in a nearby star system It seems such events could trigger substantial nonspontaneous decay that would cause is discontinuity in the typical halflife curve and set dates off by an order of magnitude Also the level of C in the atmosphere could increase significantly in response to such events too making a sample appear younger than it really is   No Are there any reliable sources research on this