sciencetech-blog

comments

The Earth's magnetic field, which protects the planet from cosmic radiation, has grown weaker over the past six months.

Data collected by the European Space Agency's Swarm satellites has indicated weak spots in the magnetic field.

The first set of high-resolution images generated from the constellation reveals dramatic declines over the Western Hemisphere.

Enlarge  

The Earth's magnetic field, which protects the planet from solar radiation, has grown weaker over the past six months, according to satellite data. This map shows the filed from January to June. Shades of red represent areas of strengthening, while blues show areas of weakening over the 6-month period

However, the field has strengthened in other areas since January, including over the southern Indian Ocean.

Scientists are unsure why the magnetic field is weakening, but one reason could be that the magnetic poles are preparing to flip, Swarm mission manager Rune Floberghagen told Live Science.

The latest measurements, made by magnetometers on board the three Swarm satellites confirm the movement of magnetic North towards Siberia.

'Such a flip is not instantaneous, it would take many hundreds if not a few thousand years.

'They have happened many times in the past,' he said.

Swarm (pictured) is Esa's first Earth observation constellation of satellites. Two satellites orbit almost side-by-side at the same altitude - initially at about 460km - while the third satellite is in a higher orbit of 530km

Changes in the strength of the Earth's magnetic field are normal, but satellites have shown that it is weakening more rapidly than in the past.

Scientists have previously estimated that the Earth's magnetic field is weakening at five per cent every century, but now they believe it could be diminishing 10 times as fast.

This means that the flip could occur sooner than the 2,000 years already predicted, according to experts who presented their findings at the Third Swarm Science Meeting in Denmark.

Scientists are not sure why the magnetic field is weakening, but one reason could be that the magnetic poles are about to flip. The magnetic field and electric currents near Earth (pictured) generate complex forces, but exactly how it is generated and why it changes is not yet fully understood

Esa's satellites pick up signals from the magnetic field as well as other sources, which could help scientists solve the mystery of why the planet's magnetic field behaves as it does.

'Over the coming months, scientists will analyse the data to unravel the magnetic contributions from other sources, namely the mantle, crust, oceans, ionosphere and magnetosphere,' ESA said.

'This will provide new insight into many natural processes, from those occurring deep inside our planet to space weather triggered by solar activity. In turn, this information will yield a better understanding of why the magnetic field is weakening.'

There is no evidence to suggest that a weakened magnetic field will mark the end of life on Earth as we know it.

During previous flips, there are no records of mass extinctions or evidence of radiation damage.

But as with the threat of space weather, scientists think that power grids and modern communication systems would be most at risk.

This is a snapshot of the main magnetic field at Earth's surface as of June 2014, based on Swarm data. The measurements are dominated by the magnetic contribution from Earth's core (about 95%) while the contributions from other sources (the mantle, crust, oceans, ionosphere and magnetosphere) make up the rest. Red represents areas where the magnetic field is stronger, while blues show areas where it is weaker