Earth 'overdue' for pole swop

2011-04-18 12:30

Duncan Alfreds

Cape Town - The world is overdue for a pole change, and the South Atlantic Anomaly is evidence that the pole will change, albeit slowly, an expert studying the phenomenon has said.

"The Earth's magnetic field isn't uniformly smooth, it has wobbles and the South Atlantic Anomaly the most significant of these wobbles," the Space Weather Warning Centre's Kobus Olckers told News24.

The Earth's magnetic field has changed several times in the past and experts can measure this as lava takes on the magnetic field when it cools. By measuring this change in volcanic rock, scientists can build a history of magnetic field changes.

"Eventually the field will change, but it will take hundreds or thousands of years. We've measured many magnetic changes in the past, and we've been overdue for a very long time," said Olckers.

The South Atlantic Anomaly (SAA) lies over the South Atlantic ocean between Brazil and SA. Part of the reason it is ideal to place the Hermanus Magnetic Observatory at its location is that it lies at the edge of the SAA.

Radiation belts

The SAA influences the radiation belts around the Earth and forms an integral part of its geo-magnetic structure. High energy particles from the sun are trapped in these geo-magnetic "mouse traps", said Olckers.

"There are much higher particles in those radiation belts and there's a slight dip in polarity at the South Atlantic Anomaly. The compass bearings are slightly different."

Even though the errors in the magnetic field do not directly affect people, Olckers said that airlines often have to re-route flights if there are high activity particles.

"There's a constant solar wind blowing against the sphere and if you've got low-earth satellites orbiting over the South Atlantic Anomaly, they're liable to have slightly more errors in their circuitry."

Many have suggested that a change in the Earth’s magnetic field would result in global catastrophe, but Olckers rejected this, saying that technology such as Global Positioning Systems would provide direction and bearing requirements.

Transition

"There will be no side effects. Mechanically, there will be nothing to be concerned about - no Earth shaking. If you are in this area, you will see more auroras, though. There's nothing to be scared about."

The magnetic field is currently in transition, and down the line, it will affect airlines, Olckers said.

The radiation can affect people and airlines operating transpolar flights usually have crews wear radiation tags to guard against increased radiation levels. Ultra violet radiation would increase in the SAA as the magnetic field became more unstable.

"In 500 years, we're going to have to travel from Cape Town to Rio via London because of the anomaly. The business for making compasses will go out the window."


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