Earth’s weakening magnetic field ‘could pose risk to satellites’
THE earth’s magnetic field has weakened by nearly 10 per cent in the past 200 years, scientists say, leaving satellites at increased risk of malfunction.
Generated by an ocean of liquid iron that constitutes Earth’s outer core, the magnetic field is essential in protecting our planet from solar radiation. Over the past two centuries, it has lost nine per cent of its strength on average.
Now, researchers studying the growth of a weak patch in the field, known as the South Atlantic Anomaly (SAA), between Africa and South America, have warned of the growing risks to spacecraft flying above the region.
Jürgen Matzka, from the GFZ German
Research Centre for Geosciences, said: “If the magnetic field in the SAA gets weaker, then the particles from the inner radiation belt can penetrate deeper down towards the earth and hit low-flying spacecraft like the International Space Station or low-earth-orbiting satellites – typically at 400-1,000km in height.”
“The worst case scenario is that their computer systems stop working, meaning the satellite or parts of it are no longer operational or permanently damaged.
“To protect the satellite from damage, they could be equipped more with metal foils to act like a sticker shell around it. Thicker materials will help block radiation from going through the satellites within this radiation belt which is only getting larger.”
A second centre of minimum intensity has recently developed south-west of Africa, raising the prospect of the anomaly splitting into two distinct cells.
Scientists from the European Space Agency’s Swarm Data, Innovation and Science Cluster are using “swarm satellites” – designed to precisely measure differing magnetic signals – to closely monitor the SAA to see if this happens.
It has been speculated whether the weakening of the magnetic field indicates that Earth is heading for a pole reversal, in which the north and south magnetic poles switch places. This last occurred about 780,000 years ago.