Science and Technology

Up south!

| Updated on October 24, 2021

Lost your bearings? The last polar flip took place 780,000 years ago, so another is perhaps overdue   -  ISTOCK.COM

What would a flip in the Earth’s magnetic poles mean for the future of satellite launches?

Imagine navigating a ship north with nothing more than a compass and finding yourself beached in Antartica! Impossible? Not quite.

Compasses point to the magnetic North, where the lines of the earth’s magnetic field meet. This point does not coincide with the geographic North, which is the northern point of the earth’s axis. The magnetic North, which drifts, lies some 500 km south of the geographic North, in the Ellesmere island, northern Canada.

Recent discoveries show that the drift is speeding up — about 50 km a year. And, the shift doesn’t have to be gradual, because the magnetic field itself is due to the convection (movement) of molten iron in Earth’s core, some 3,000 km below the surface. The superhot liquid metal generates electric currents, which in turn throw up magnetic fields. As imagined in Jules Verne’s Journey to the Centre of the Earth, the magnetic poles could just flip — it happens frequently in the Sun, whose magnetic field reverses every 11 years. A recent article in the Discover magazine notes that “computer simulations of planetary dynamics show that the reversals arise spontaneously”. The last polar flip took place 780,000 years ago, so another is perhaps overdue.

Now, this is a problem, especially at a time when thousands of satellites are set to be launched for various purposes, from telecommunications to broadband to earth observation and scientific research, most of which would lie protected in the earth’s magnetosphere (which bulges 60,000 km sunwards and 300,000 km away from the sun). No one quite knows how a change in earth’s magnetic field might affect these satellites.

Also, as the Discover article notes, a flip in magnetic poles could confuse animal migration — avian, terrestrial and aquatic — because they are known to use magnetic signals to navigate.

None of us were around when the last polar flip happened. If another happens now, there could be any number of unforeseen consequences. Who knows?

Published on October 24, 2021

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