Solar flares affect radioactive decay? ( Via. ) In fact, not just solar flares, but any solar activity seems to have an effect on how quickly radioactive isotopes decay. ... "All of the evidence points toward a conclusion that the sun is 'communicating' with radioactive isotopes on Earth." But they don't know how , and learning the answer to that question will be very, VERY interesting. Their current thinking is "neutrinos" but considering that a neutrino can pass through a light year of lead without being absorbed it doesn't make a lot of sense. This might be a way to check the neutrino theory. For damn sure, solving this riddle will mean some new additions to our understanding of physics. That's always good.