No Worries – Scientists Say Earth’s Poles Won’t Flip for 4,000 Years

Posted February 9th, 2017 at 3:55 pm (UTC-5)
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Illustration of Earth as its bombarded with high-energy particles from the Sun's coronal mass ejection. Our planet's magnetic field acts like a shield protecting the planet against harmful radiation. (NASA/Goddard Space Flight Center)

Illustration of Earth as its bombarded with high-energy particles from the Sun’s coronal mass ejection. Our planet’s magnetic field acts like a shield protecting the planet against harmful radiation. (NASA/Goddard Space Flight Center)

The Earth’s magnetic fields helps create a shield that protects us from the continuous onslaught of highly charged space particles and radiation, which are dangerous to creatures living on the Earth’s surface.

Without these protective fields, scientists say that the solar wind also would simply blow away our atmosphere in way similar to what scientists suspect happened to Mars billions of years ago.

Artist's illustration of the shape and function of the Earth's magnetic field that protects us from harmful cosmic radiation (NASA)

Artist’s illustration of the shape and function of the Earth’s magnetic field that protects us from harmful cosmic radiation (NASA)

So it’s natural that some people would get quite concerned over any news of a weakening or shifting of the magnetic fields.

Over the last several years there have been studies that suggest Earth’s magnetic field has been weakening at a rate around 10 times faster than originally thought or approximately 5 percent of its strength every decade.

Some scientists argue that the weakening of Earth’s magnetic fields is due to an upcoming flip in polarity.

In other words, the magnetic North Pole would become the South Pole and vice versa.

Earth’s magnetic fields have flipped seveal times throughout its 4.5 billion year history.

A study conducted in 2014 by an international team of scientists found that planet Earth is on the verge of magnetic field reversal.  They said the last time this happened was about 786,000 years ago, taking about 100 years to do so — a relatively short time.

Schematic representation of Earth's magnetic field lines after a polarization reversal (Zureks/Wikimedia Commons)

Schematic representation of Earth’s magnetic field lines after a polarization reversal (Zureks/Wikimedia Commons)

Scientists say, on average, the reversal of Earth’s magnetic fields take place roughly every 250,000 years, although the periods between periods field flips can vary.

Usually the magnetic fields remain steady and at the same intensity for thousands or millions of years, but for reasons that scientists can’t explain, the field weakens and then flips direction over a period of about a couple thousand years.

Scientists believe that magnetic field reversals are driven by changes in the Earth’s iron/nickel core.

Now, calculations made in a new study led by mathematician Matthias Morzfeld at the University of Arizona, suggests “with high confidence,” that we can relax for 4,000 years, which is when Morzfeld’s team predicts the next magnetic flip will take place.

The study, published in the journal Physics of Earth and Planetary Interiors, drew upon paleomagnetic data recorded in rocks over the past 2 million years, as well as other sources, such as several centuries’ worth of measurements taken by ships.

With the data, Morzfield and his colleagues created a mathematical framework and computer models that precisely forecast all the magnetic field reversals over that 2-million-year period.  Doing this, the researchers say, they were able to make accurate predictions of future reversals.

Illustration of Earth including its mantle and inner/outer core. (Kelvinsong/Wikimedia Commons)

Illustration of Earth including its mantle and inner/outer core. (Kelvinsong/Wikimedia Commons)

If we could be around in 4,000 years when the predicted magnetic field reversal occurs, Morzfield expects we’d see the field become very weak.

“But nobody knows what would happen next. It’s possible that the field just changes shape and goes from the dipole [two poles] into the quadrupole [four pole] configuration, said Morzfield in a University of Arizona press release.

He also warned that the magnetic fields could completely collapse, which would be really bad, since our planet would be exposed to the things the fields currently protect us from.

“On the other hand, field reversals have happened, and life on Earth has survived,” said Morzfield.

Rick Pantaleo
Rick Pantaleo maintains the Science World blog and writes stories for VOA’s web and radio on a variety of science, technology and health topics. He also occasionally appears on various VOA programs to talk about the latest scientific news. Rick joined VOA in 1992 after a 20 year career in commercial broadcasting.

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