Hold on Tight! Earth's Magnetic Field May Be Preparing to Flip!
News story originally written on May 20, 2003

The Earth's magnetic field may not be something you think about everyday, but it is very important! It shields us from dangerous solar particles, some of which collect near the poles and glow in the night sky as the aurora. Also, people have found the magnetic field very useful for exploring the world. For centuries, people have been navigating up high mountains, across the sea, and through the sky, guided by compass needles that always point to the magnetic North Pole.

However, strange things have been happening to Earth's magnetic field. This might be a sign that a magnetic field reversal is starting to get underway, meaning that the magnetic North and South Poles will flip!

The magnetic field does not just flip overnight. It takes thousands of years. The magnetic field strength decreases and then returns a few thousand years later with the North and South magnetic poles reversed. Scientists have never seen this happening before because magnetic reversals take so long and only happen, on average, every 250,000 years. In fact, it has been 750,000 years since the last reversal!

Motions in the Earth's molten iron core create electrical currents that cause the magnetic field. When the motions of the molten iron change, so does the magnetic field. Researchers have identified that the Earth's magnetic field is decreasing by about 5% each century. Also, they have found a part of the Earth's core that seems to have a different polarity than the rest of the core. The spot may grow and be the start of a magnetic reversal, or it may die down.

While the magnetic field is very important, there is no evidence in the fossil record that past magnetic reversals caused any harm to the animals and plants that lived on the planet. So, there is no need for worry, but you might keep an eye on your compass needle!

Last modified May 22, 2003 by Lisa Gardiner.

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