The Sunspot Cycle Explained

An anonymous reader writes "After the recent spate of auroras visible as far south as Florida and Greece, and radio amateurs having lots of fun bouncing their signals off the auroral curtain, maybe some explanation was needed. It has been known for a while that the peak of solar activity trail trails the sunspot cycle peak by a couple of years, but this BBC article appears to explain why. As you may expect most of the data came from the SOHO satellite and the theory has been put together by some scientists using what appears to be data mining."