Earth's Wandering Poles

Timothy Birdnow

The Earth's magnetic pole is moving at a rapid rate, and nobody knows why.

According to this article we are witnessing a rabid move of the pole from Canada to Siberia. (I suppose this was the deal Trump made with the Russians, that they get the pole if he got elected.)

From the article:

Every year, geophysicists from the US National Oceanic and Atmospheric Administration (NOAA) and the British Geological Survey do a check on how the Earth’s magnetic field is varying.

This is necessary as the liquid iron churning in the Earth’s core does not move in a consistent manner.

"In 2016, for instance, part of the magnetic field temporarily accelerated deep under northern South America and the eastern Pacific Ocean,” Nature reports.

This shift was captured by satellites.
Earth has lines of magnetic force looping from North Pole to South Pole, creating Earth's protective magnetosphere. The straight line coming out of the North and South Poles represents Earth's axis of rotation.

End excerpts.

In fact, this has led to an emergency effort to rework models for geopositioning systems as the compass readings would now lead ships and planes astray.

The Earth's magnetic field is resonant with the Sun's, and it is critical for life as we know it; without the magnetic field we would be bombarded with cosmic rays, and worse, we would have no protection from solar flares. Solar flares are deadly. It is the Earth's magnetic field which blocks them, allowing us to live in the open. Without a magnetic field we would have to live underground. Land life would become extinct.

Why is this happening? Almost certainly something is going on inside the Sun.

Every planet with a magnetic field is tied by lines of magnetic force to the sun via long "ropes". (As a result, we get hit by coronal mass ejections more than planets like Venus or Mars, which don't have magnetic fields.) Our magnetic field is in resonance with the solar field, like a radio is in resonance with the transmitter. As the Earth's field is a result of molten iron inside the core, if it moves it means the iron is moving. If it was the planet itself moving we would see evidence of that, so it has to be the iron inside the core. Why would that suddenly move? Most likely because there is some shift in the solar magnetic field.

Changes in the Earth's magnetic field are not that unusual. According to researchers at Rochester:

The magnetic field that surrounds Earth not only dictates whether a compass needle points north or south, but also protects the planet from harmful radiation from space. Nearly 800,000 years ago, the poles were switched: north pointed south and vice versa. The poles have never completely reversed since, but for the past 160 years, the strength of the magnetic field has been decreasing at an alarming rate. The region where it is weakest, and continuing to weaken, is a large area stretching from Chile to Zimbabwe called the South Atlantic Anomaly.

In order to put these relatively recent changes into historical perspective, Rochester researchers—led by John Tarduno, a professor and chair of EES—gathered data from sites in southern Africa, which is within the South Atlantic Anomaly, to compile a record of Earth's magnetic field strength over many centuries. Data previously collected by Tarduno and Rory Cottrell, an EES research scientist, together with theoretical models developed by Eric Blackman, a professor of physics and astronomy at Rochester, suggest the core region beneath southern Africa may be the birthplace of recent and future pole reversals.

"We were looking for recurrent behavior of anomalies because we think that's what is happening today and causing the South Atlantic Anomaly," Tarduno says. "We found evidence that these anomalies have happened in the past, and this helps us contextualize the current changes in the magnetic field."

The researchers discovered that the magnetic field in the region fluctuated from 400-450 AD, from 700-750 AD, and again from 1225-1550 AD. This South Atlantic Anomaly, therefore, is the most recent display of a recurring phenomenon in Earth's core beneath Africa that then affects the entire globe.

"We're getting stronger evidence that there's something unusual about the core-mantel boundary under Africa that could be having an important impact on the global magnetic field," Tarduno says.

The magnetic field is generated by swirling, liquid iron in Earth's outer core. It is here, roughly 1800 miles beneath the African continent, that a special feature exists. Seismological data has revealed a denser region deep beneath southern Africa called the African Large Low Shear Velocity Province. The region is located right above the boundary between the hot liquid outer core and the stiffer, cooler mantle. Sitting on top of the liquid outer core, it may sink slightly, disturbing the flow of iron and ultimately affecting Earth's magnetic field.

A major change in the magnetic field would have wide-reaching ramifications; the magnetic field stimulates currents in anything with long wires, including the electrical grid. Changes in the magnetic field could therefore cause electrical grid failures, navigation system malfunctions, and satellite breakdowns. A weakening of the magnetic field might also mean more harmful radiation reaches Earth—and trigger an increase in the incidence of skin cancer.

Hare and Tarduno warn, however, that their data does not necessarily portend a complete pole reversal.

"We now know this unusual behavior has occurred at least a couple of times before the past 160 years, and is part of a bigger long-term pattern," Hare says. "However, it's simply too early to say for certain whether this behavior will lead to a full pole reversal."

End excerpt.

It should be pointed out the Sun has been very sluggish, with weak magnetic activity and sunspots. In fact, it is the weakest in 200 years.

Here is a dandy collection of articles on the current state of the Sun and how space weather affects the Earth.

Posted by: Timothy Birdnow at 10:29 AM | Comments (2) | Add Comment
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