Scientists say poles might flip

December 15, 2003 | Source: Mercury News

The Earth’s protective magnetic field has fallen about 10 percent since 1845 and if that continues, the field could flip.

These flips happen every 200,000 years, on average, scientists say. The last one was 780,000 years ago.

Whether the field flips or merely continues to weaken, more harmful particles would flow in from the sun, resulting in an estimated extra 100,000 cancer cases a year; and solar particles would set off reactions that destroy ozone high in the atmosphere, lowering protection from harmful ultraviolet radiation.