[vmurthy]

Sorry to hear about your partner :-( The first part of the last paragraph makes sense. Multi-cellular -> more cells dividing -> more chances of mutations -> more chances of cancer. The second half of your last para implies that cosmic radiation / something similar causes cancer. I’m genuinely curious : is there some link between cosmic microwave radiation and cancer ? Any sources ?

[smueller1234]

There's no known link between cosmic microwave background and cancer. Would do for one hell of a difficult thing to study, too.

There's perfectly ample evidence for cosmic rays (ie. high energy radiation from astronomical sources) increasing risk of cancer as does any ionizing radiation. Maybe GP conflated the two?