Earth’s magnetic poles are due for a reversal in the near future.
Artwork by Rachel Wilson
Most like stability in their lives, especially when it comes to planet-wide phenomena, such as the daily appearance of the sun or the periodic change of season. So, it can be unsettling to learn of global phenomena that are inherently unpredictable, such as the Earth’s magnetic field. Every so often, our planet’s magnetic poles reverse polarity. Compass needles have always pointed to geographic north, or magnetic south; in a reversal, they will point to geographic south.
These reversals happen very infrequently, on average every 250,000 years. However, it’s been over 700,000 years since the last reversal, and the next one may be currently underway. TJ Science Teacher, Sharon Colbath, said, “The Earth’s magnetic pole is moving a few inches every year. The current theory is the ‘convection cells’ in our planet are moving and transferring heat. This movement is what is creating the magnetic field. Since the material in the Earth is changing, the magnetic field is changing also. I think the current theory is that the reversals are slow and not abrupt. “
In the Earth, the liquid metal that makes up the outer core passes through a magnetic field, which causes an electric current to flow within the liquid metal. The electric current, in turn, creates its own magnetic field—one that is stronger than the field that created the current in the first place. As liquid metal passes through the stronger field, more current flows, which increases the field still further. This self-sustaining loop is known as the geomagnetic dynamo. Earth’s magnetic field protects the planet from deadly radiation and “space weather,” which deals with phenomena involving ambient plasma, magnetic fields, radiation and other matter in space.
Every time the Earth’s magnetic poles go through a reversal, the magnetic field weakens. Today, the field is about 10 percent weaker than it was when German mathematician Carl Friedrich Gauss first began measuring it in 1845. Scientists are still unsure about what exactly drives the poles to reverse, but are studying it extremely in depth, as it is suspected that we are currently undergoing one of these mysterious reversals.
Some radicals with less of a science background believe that this reversal will happen in 2012, when it is predicted by the Mayans that the world will end. These people say that the reversal will cause Earth’s magnetic field to disappear and end the world. Although this probably will happen eventually, it is extremely unlikely – based on scientific studies – that this will happen anytime in the near future. “The reversal will not lead to the end of the world since it has occurred hundreds of times already,” said Colbath.
