RADIOACTIVE materials decay at a predictable rate—so
predictable, in fact, that scientists widely use them to date artefacts and
geological objects. That, at least, is the received wisdom, which Jere Jenkins
and Ephraim Fischbach, from Purdue University in Indiana, think may need
revising. In 2006 Dr Jenkins noticed that the decay rate of the radioactive
isotope manganese-54 dipped 39 hours before a solar flare came crashing into
Earth's protective magnetic field. Now it seems that the sun might affect other
types of decay, too.