Will Compasses Point South?

The collapse of the Earth's magnetic field, which both guards the planet and guides many of its creatures, appears to have started in earnest about 150 years ago. The field's strength has waned 10 to 15 percent, and the deterioration has accelerated of late, increasing debate over whether it portends a reversal of the lines of magnetic force that normally envelop the Earth.

This computer simulation shows the Earth's interior as its magnetic field reverses, perhaps because of changes in the flow of molten iron in the core.


From New York Times