You may recall the summer sci-fi movie The Core; it sported some of the most howlingly awful science of any film in history. Nevertheless, life is now imitating bad art -- because apparently the Earth's magnetic field has weakened by 10 per cent in the last 150 years. Scientists wonder if this is the beginning of an inversion of the North and South poles, an event that has taken place several times in the planet's lifespan. As the New York Times reports:

The magnetic field last flipped 780,000 years ago, but the time between reversals has varied from a few thousand years to 35 million years.

At the current rate of decline, the field would disappear in 1,500 to 2,000 years. That is much faster than if the iron flows had somehow completely stopped, because then the electric currents generating the field would still persist for 15,000 additional years. This has led scientists to conclude that the changes in iron flow have produced kinks in the magnetic field that are weakening it.

"They're twisting the field the wrong way," said Dr. Peter L. Olson, a professor of earth and planetary sciences at Johns Hopkins University.