How’s this for the plot of a new disaster movie – the earth’s magnetic field begins to weaken, and then flips completely. The result? Flash floods, earthquakes, meteor showers and other natural and cosmic calamities, none of which prevent Tom Cruise from getting his family to safety. Title: Field of Screams. The idea is less far-fetched than most epic blockbusters – in fact, it may be actually happening right now. However, unlike our special effects-laden Hollywood version, there is no cause for alarm. The earth’s magnetic field has flipped before and it will flip again.