During a solar storm one flight over the poll can be the equivalent of 100 chest x-rays. The sun is capable of a whole lot worse than anyone now alive has ever seen. It can knock out power grids and pagers for millions of people. Sept 1, 1859 there was a solar flare that doubled the intensity of the sunlight. Aurora were seen as far south as Hawaii. Currents were induced on the surface of the earth. In 1859 the event caused several buildings to burn to the ground and people were shocked by touching conductors. It is just a matter of time before this happens again, but we are more vulnerable today.