According to geologic record in the minerals, Earth’s magnetic dipole polarity reversed many times during the planet’s 4.5 billion year history. The average time between reversals is 250 thousand years. There were no reversals in the last 780 thousand years. It seems that we are overdue for a reversal.
Earth’s magnetic field has weakened 10 times faster in the last 6 months
Earth’s magnetic field strength has been weakening in the last 2000 years. The trend accelerated in the past decades. There is news from the European Space Agency (ESA) that Earth’s magnetic field has weakened 10 times faster in the Western hemisphere in the last 6 months.
You can read the description of the results directly from the ESA article.
In the image above, shades of red show areas where the magnetic field is strengthening, and shades of blue show
areas that are weakening.
As a reminder, there is an overall dipole component to Earth’s magnetic field but the overall magnetic energy is non-uniformly distributed on the surface.
Image credit (Open Stax College)
Magnetic north pole drifting to Siberia
Another recent phenomenon is the drift of the magnetic north pole towards Siberia. The magnetic poles move daily. In the last 50 years the magnetic north pole has been drifting towards Siberia. If this drift continues the magnetic north pole will certainly be in Siberia in the next few decades. The measurements by ESA’s SWARM sattellite network also confirm the movement of magnetic North towards Siberia. On its way to Siberia the magnetic north pole will be very close to the rotational north pole. This is interesting!
North magnetic pole move (red dots)
South magnetic pole move (red dots)
ESA SWARM Animation
“This animation shows changes in Earth’s magnetic field from January to June 2014 as measured by ESA’s Swarm trio of satellites. The magnetic field protects us from cosmic radiation and charged particles that bombard Earth, but it 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. The field is particularly weak over the South Atlantic Ocean – known as the South Atlantic Anomaly. This weak field has indirectly caused many temporary satellite ‘hiccups’ (called Single Event Upsets) as the satellites are exposed to strong radiation over this area. ” [1]
Speculation
Earth’s magnetic field is created by the geodynamo in Earth’s core. We do not understand the details of the geodynamo.
I speculated in the “Past and Future Pole Shifts” about the possibility that the rotational north pole and the magnetic north pole will be aligned in Siberia due to coupling created by the geodynamo in Earth’s core leading to a polar shift of the TPW (true polar wander) kind.
[1] http://www.esa.int/spaceinvideos/Videos/2014/06/Earth_s_ever-changing_magnetic_field
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