SCEINCE

How the reversal of the Earth’s magnetic field will affect life on our planet


The reversal of the planet’s magnetic pole sounds like the plot of a disaster movie, but it seems to happen cyclically and at somewhat predictable intervals. In fact, over the last 20 million years, the Earth’s magnetic field has changed every 200,000 to 300,000 years – although more than twice as long as the last one has passed.

But what does that mean? Can the next geomagnetic inversion occur at any time? And if so, should we worry?

What is the Earth’s magnetic field?

The Earth’s magnetic field is a magnetic field that arises in its core. The reason the Earth has a magnetic field is due to its solid iron core, which is surrounded by an ocean of hot liquid metal that generates an electric current as it moves.

The molten, conducting liquid in the Earth is constantly moving. The Earth’s core is extremely hot, above 9000 ° F (5000 ° C), even hotter than the outer layer of the Sun., and this heat drives convective currents in the outer core. The constant motion of the molten outer core around the inner core of solid iron generates a magnetic field by dynamo effect, which extends into space around the Earth.

The magnetic field protects the planet from the effects of the solar wind and this allows life to exist on Earth.

The solar wind is full of charged particles, magnetic clouds and radiation that would be heavy. damage any life that can exist. The Earth’s magnetic field, or magnetosphere, serves as a shield, diversion and redirection of the solar wind.

In fact, when the solar wind hits the magnetosphere, it produces aurora borealis, northern and southern aurora borealis in the polar regions. When charged particles from the sun hit atoms in the Earth’s atmosphere, electrons move to higher-energy orbits. When electrons move back to a lower energy orbit, it releases a particle of light or photon.

Aurora Australis from space. Source: NASA

The Earth’s magnetic field continued to create magnetic poles that are close to the geographic poles, but not exactly “on” them. For example, in 2015, the geomagnetic north pole was located on Ellsmere Island, Canada, while the geographic north pole remained at the “center” of the globe, about 310 miles (500 kilometers) apart.

This is because geographic poles do not actually move over time, but geomagnetic poles do. The Earth’s magnetic field is not 100% stable, and due to variations in field strength, the poles can migrate until they eventually “swap places” – the North Pole becomes the South and vice versa. This is called magnetic inversion and according to some sources, the process can take up to 28,000 years.

The effects of geomagnetic inversion

The last reversal of the Earth’s magnetic poles has occurred about 42,000 years ago and is accompanied by a weakening of the magnetic field, which is thought to have caused a global environmental crisis towards the end of the ice age. This short magnetic reversal is known as the Laschamp excursion, as the first evidence of the event was found in Lachamp flows lava, Central French Massif, in the 60s of last century.

Ozone depletion caused by the strong weakening of the Earth’s magnetic field during The Laschamp event may have led to drastic changes in weather patterns. These changes, in turn, could lead to the extinction of most species of megafauna and perhaps even Neanderthals.

However, other cases of reversal of the magnetic field do not appear to have been accompanied by any drastic changes in plant or animal life. In fact, given the frequency with which the field has rolled over time (estimated at least hundreds of times over the last three billion years), the event is unlikely to have affected life’s ability to exist on Earth.

Magnetosphere
Source: Image Editor / Flickr

During the trip to Lashamp, The North Pole roams North America and then quickly descends across the Pacific Ocean to Antarctica. The North Pole remained in Antarctica for about 400 years and then quickly moved back across the Indian Ocean to the North Pole. However, these changes were accompanied by a weakening of the magnetic field to about six percent of its strength today.

The ozone layer was badly damaged and living things were exposed to harmful ultraviolet light more directly than ever. Extreme climate change and natural disasters are also believed to have occurred during this period.

As scary as it sounds, many scholars believe that this doomsday scenario is extremely exceptional. Although no one can guarantee that such a thing will not happen again in the history of the Earth, when magnetic inversions occur for thousands of years, as they almost always do, the effects on the Earth are less dramatic.

But, as NASA points out, on The Earth’s magnetic field is weakening and increasing all the time, but there is no indication that it has ever completely disappeared. A weaker field would certainly increase the Earth’s solar radiation, but the Earth’s dense atmosphere also offers protection against the solar wind. The field would have to weaken considerably, as during the Laschamps excursion, to have such a devastating effect. In this case wThere will be a higher risk of developing cancer due to the greater amount of radiation entering the Earth.

According to space explorer Daniel Baker, some parts of the planet may become uninhabited due to radiation. In terms of human health, cancer is not the only side effect of unfiltered radiation. There are also several degrees of radiation poisoning and radiation-induced mutations that can cause other diseases.

In addition, navigation systems based on the Earth’s magnetic field will have to be recalibrated, or those that rely on them will be lost. Compasses, airplanes and migrating animals would be disoriented as the magnetic field readjusted. If the readjustment is slow, they may have time to adapt. If there is a sudden reorganization, it can lead to mass extinction.

It is also known that a weaker magnetic field can affect energy networks and communications. Satellites and spacecraft currently have problems passing through the South Atlantic Anomaly (SAA), an area between South America and South Africa where the Earth’s magnetic field is weaker than anywhere else on the planet.

South Atlantic anomaly 2020
The strength of the Earth’s magnetic field by 2020, measured by the ESA satellite constellation SWARM. Source: Christopher K. Finley, Clemens Kloss, Nils Olsen, Magnus D. Hammer, Lars Töfner-Clausen, Alexander Graver and Alexei Kuvshinov / Wikimedia Commons

Although some people believe the SAA evidence incoming magnetic reversal, scientists really weren’t able to predict when the next one would happen, as magnetometer records show that The Earth’s magnetic field can suffer from severe fluctuations in intensity without causing them to reverse..

The sun also reverses its magnetic field

One of the most important pieces of evidence for rotation affecting the magnetic fields of celestial bodies is the sun. The rotation of the sun causes the magnetic field to reverse every 11 years.

In 2017, researchers from the University of Montreal, the Harvard-Smithsonian Center for Astrophysics, the Federal University of Rio Grande do Norte and others created 3D simulations of several stars to confirm relationship between rotation and inversion of the magnetic field.

The Earth and the Sun.
Source: NASA Johnson / Flickr

They concluded that the slower a star rotates, the faster its magnetic cycle repeats. And while the Earth rotates every 24 hours, the sun rotates at the equator every 25 days and even longer at higher latitudes. That is why the magnetic cycle of the Sun is extremely short compared to the Earth.

Movements in the sun’s magnetic field near sunspots cause solar flares – explosions that often release coronal mass ejections (CMEs). These are eruptions that can cause geomagnetic storms in the Earth’s magnetosphere, affect the Earth’s magnetic field and therefore cripple energy networks and at least interfere with communications.

Depending on the scale of the event, the impact on Earth may be even more intense. For example, Daniel Baker of the University of Colorado noted in 2014 that if the solar superstorm in 2012 hit Earth, “we would still be collecting the pieces“, With massive radio and power outages and GPS navigation malfunctions.





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