What Happens When The Earth's Magnetic Field reverses It's Polarity?

From time to time, one reads about new signs that we are currently in the middle of a reversal period of the magnetic poles of our earth. Every new message about it immediately calls the catastrophe theorists and end-time prophets on the scene. Scientists, who deny the topic any explosiveness, are speaking out against these. So where's the truth now? Do we have to worry, or may we sit back and relax?

A short introduction to the earth's magnetic field - Where it comes from and what it does - the magnetic field of our earth

To anticipate: There is no conclusively recognized theory of the origin of the earth's magnetic field. Instead, several hypotheses compete with each other. Nevertheless, one of these theories is widely preferred in science. The main features of this are briefly outlined here.

The process that generates the magnetic field is also known as geodynamo. Similar to a dynamo, an electric field is induced inside the earth by movement.

The earth's magnetic field takes its starting point in the earth's core. This consists of a solid, inner core of iron and a liquid, outer core of molten iron to which silicon, oxygen, and sulfur are presumably added.

According to estimates, the temperatures in the earth's core are roughly the same as those that prevail on the surface of the sun and are thus around 5,000 degrees Celsius. The fact that the inner core of the earth is still not liquid could be explained by the enormous pressure prevailing there.

The idea of the liquid, outer core of the earth must also be corrected somewhat. What we generally call the liquid state does not quite apply in the case of the earth's core. The flow velocity there is a few meters a year.

The term "liquid" is used here analogously to the technical term of viscosity. If one knows that even glass has a certain degree of viscosity, one can perhaps better illustrate the term "liquid" concerning the outer core of the earth.

To explain: The fact that glass actually has a flow velocity can be seen on ancient church windows. The panes are noticeably thicker there at the lower edge than further up. This is explained by the fact that the glass has flowed downwards in the centuries following gravity.

The exact process leading to the formation of the magnetic field is highly complicated. I would like to confine myself to an abridged version of the explanation for reasons of the consumability of the article.

Roughly speaking, hot material rises up from the earth's core, and cooler material sinks down. This constant circulation of material is called convection. The hot, rising material carries a certain electrical charge, and the circulation process generates an electromagnetic field.

This is further amplified in a complicated way by deflecting and twisting the convection currents by the rotation of the earth and probably also some other forces.

Sometimes the poles wander - What geologists know about past polarity reversals

It is a fact little known to the public that the magnetic poles do not constantly remain in the same place.

Just 100 million years ago, we would have had severe orientation problems with today's compass.

The fact that magnetic poles have often been replaced in the past is well documented scientifically. One speaks with such an exchange of magnetic north and south pole also of a pole jump. The word jump, however, suggests a suddenness that is usually not given. In fact, such a process usually takes up to 10,000 years.

The past pole jumps can be proven by analyzing the magnetic polarization of old volcanic rock. If ferrous rock melts and then cools down again, it preserves the polarization prevailing at that time. Based on numerous studies, we now know that in the past, there was an average pole jump every 250,000 years.

Interestingly, the last polarity reversal took place 780,000 years ago. That would mean that another pole jump would be long overdue.

In fact, there are numerous indications that we are currently in precisely such a phase. It has been proven that the strength of the magnetic field is currently decreasing, which is interpreted as a sign of an imminent pole jump. It is estimated that this scenario will occur in 3,000 - 4,000 years. The exact time of the pole jump cannot be predicted, of course.

Pros and cons of the disaster scenario - How threatening is a Pole Jump for mankind?

Disaster scenarios about the time during a pole jump usually refer to the assumption that a dramatic weakening of the magnetic field in the course of this change exposes the earth to the solar wind without protection.

The consequences would then be the failure of the worldwide communication systems, the disorientation of animal species oriented to the magnetic field (bats, migratory birds, etc.) and bad influences on our DNA by cosmic radiation.

Opponents of these doom scenarios, however, quite rightly put forward some arguments against it. It is criticized that the catastrophe theory starts from a very sudden event, but the known facts have so far always proven a phase of 4,000 to 10,000 years for a Pole Jump.

Harmful effects, such as on the sense of orientation of animals, could thus be prevented by gradual evolutionary adaptation to changing conditions. The transitions of sediment layers from times of earlier pole jumps also showed that species changes took place in the microorganism area, but not in larger organisms. Significant extinction events at least do not coincide with periods in which pole jumps took place.

However, the disaster scenarios receive new food as a result of new scientific findings. At least two American scientists believe they have found evidence that pole jumps can happen much faster than previously known.

According to this, a change of polarity would even be possible within only a few years. Such a short period would, of course, make any natural adjustment impossible.

Reason for this assumption are investigations of 16 million years old, cooled lava flows in the US federal state of Nevada. Since the rock there melted twice in one year, the magnetic field between the two events had rotated by 53 degrees.

While many peers believe that this may also be a local phenomenon, they have yet to prove this claim. In contrast, the scientists in question have since been searching for evidence that this was a global event. The result of this search is still open.

As early as 1995, similar studies even found indications of a field reversal within only one month. But since this result completely deviated from the doctrine of the time, it was simply ignored. In the light of the investigations in Nevada, however, this trail has now also been resumed.

Let us hope that these measurement results will not be confirmed in the end, because if they do, we would probably have to deal with the theoretical possibility of a global catastrophe caused by a Pole Jump.

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