The Earth's magnetic field is weakening, and that could lead to a flip in the planet's poles making compasses point south instead of north for the first time in almost a million years, say scientists. Experts at the American Geophysical Union in San Francisco say the field has declined 10 percent in the last 150 years, and suggest a reversal could lead to problems in navigation and a jump in cancer rates with a diminished ozone layer. "Is a reversal coming? Yeah, it's coming for sure – sometime,'' said geologist Robert Coe of the University of California-Santa Cruz, according to...