According to a European Space Agency statement, an ESA mission has revealed recent fluctuations in Earth’s magnetic field. The Earth’s magnetic field which protects us from radiation from space is getting weaker. We don’t yet know why this is but new evidence confirms it is happening unevenly across the planet with some areas getting more protection.
Evidence of weakening of the magnetic field and it’s geographically inconsistent nature has been tracked for decades but the November 2013 launch of the European Space Agency’s three satellite Swarm constellation has allowed unprecedented precision in measuring these changes.
Swarm actually consists of a constellation of three satellites that all launched in November 2013 to study our planet’s magnetic field which blocks cosmic rays and charged particles that otherwise would make Earth unlivable. The high-resolution measurements by Swarm were make over the last six months.
Magnetic field is in a permanent state of flux. Magnetic north wanders, and every few hundred thousand years the polarity flips so that a compass would point south instead of north. Moreover, the strength of the magnetic field constantly changes and it is currently showing signs of significant weakening.
Measurements made by Swarm over the past six months confirm the general trend of the field’s weakening with the most dramatic declines over the Western Hemisphere. But in other areas, such as the southern Indian Ocean, the magnetic field has strengthened since January. The field is particularly weak over the South Atlantic Ocean known as the South Atlantic Anomaly and the latest measurements confirm the movement of magnetic North towards Siberia.
The weak field has indirectly caused many temporary satellite ‘hiccups’ (called Single Event Upsets) as the satellites are exposed to strong radiation over this area.
The different orbits along with satellites’ various instruments optimize the sampling in space and time distinguishing between the effects of different sources and strengths of magnetism.
A polarity flip or drastic weakening would not be lethal as demonstrated by the fact that past changes have not been associated with mass extinctions but could expose power lines and communication systems to much greater danger. On the positive side, auroras should become more spectacular and widespread. Should such an event occur most scientists anticipate the timescale will be of the order of millennia, rather than decades, making the Daily Mail’s call to ‘forget global warming and start worrying about the Earth’s magnetic field’
The changes are driven by a complex set of sources from the core, mantle and crust of the Earth and influences in space. The largest influence is thought to be the convection currents in the molten iron of the core causing expansion at some points and contraction at others. These convection currents may sometimes lead to domains where the magnetic field runs in the opposite direction to the main field, canceling part of it out.
The results were presented at the Third Swarm Science Meeting held in Copenhagen on Thursday. The Swarm Mission Manager Dr Rune Floberghagen said, “These initial results demonstrate the excellent performance of Swarm. With unprecedented resolution, the data also exhibit Swarm’s capability to map fine-scale features of the magnetic field.”
“I’m extremely happy to see that Swarm has materialized,” said Kristian Pedersen, Director of DTU Space.
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