*250 words please!*

Sometimes our planet's magnetic field completely flips. The north and the south magnetic poles swap places. Such reversals, recorded in the magnetism of ancient rocks, are unpredictable. They come at irregular intervals averaging about 300,000 years; the last one was 780,000 years ago. Could we be heading for a geomagnetic reversal that would leave us defenseless against the lethal effects of solar wind and cosmic rays