The core of the Earth has stopped, but everything remains (almost) the same

Recently, a study was published stating that earth’s core there was a break and that this event affects various aspects of the planet, such as the magnetic field or climate.

As a result of this publication, some voices suggesting exaggerated and disastrous consequences. It is important to analyze this news from a critical point of view. Without detracting from the huge impact of scientific discoveries on the functioning of our planet – even with so many mysteries – do not fall into simplicity or drama.

To understand this news, we must first know the internal structure of our planet, which is made up of different layers. In the center is earth’s inner core, a solid sphere of iron and nickel with a radius of 1220 km. It is surrounded by a layer of similar composition 2260 km thick, but in a molten state. outer core.

Convection movements in this layer of fluid, together with the earth’s rotation, create a magnetic field that protects our planet from particles arriving from the Sun and from space. Around the nucleus we find mantlewith a capacity of about 2900 km, and above it bark the earth layer on which we live is only 10 to 50 km thick.

The first thing to be clear is that the kernel has not stopped. The earth with all its layers rotates in such a way that it takes about 24 hours to complete one revolution.

Until now, it was believed that the inner core rotates somewhat faster than the mantle and crust – this is called superrotation— so that every year it added about one-tenth of a degree.

According to this new study, Earth’s core would slow down until reaching the same rotation speed as the outermost layers, or even a slightly slower speed. These relative speed differences are very small.

Example of a car on a highway

Imagine, for example, that we are driving along a highway at a speed of 120 km/h, and another car passes us at a speed of 121 km/h. Through the window we will see that he is gradually catching up with us. If now another car brakes and accelerates to 120 km / h, we will see it “stationary” next to our car. However, he continues to move, as do we.

To conclude that the core is now spinning more slowly, the researchers chose earthquakes originated in the South Sandwich Islands, in the South Atlantic Ocean. And they studied the signal registered at the observatory in Alaska, practically on the other side of the planet.

In the same way, the core would slow down, and now, rotating at the same speed as the mantle and crust, from the surface of the Earth we would see it stopped.

Thus, they were able to analyze the time it took for waves passing through the earth’s core always on the same paths. They noticed that the waves take different times to cross the core at different times.

Different regions of the core can have different properties, meaning that waves take longer to cross some regions than others. Therefore, they concluded that if the travel times of the waves varied over the years, it was because the inner core was ahead of the Earth’s crust.

In other words, if for waves emitted and recorded at the same points on the surface, we get different results depending on time. This means that the waves pass through different regions of the core, meaning it rotates at a different speed than the Earth’s surface.

Nevertheless, since 2009 waves always take the same time to cross the core. This means that the core is now stationary relative to the surface (it is rotating at the same speed). The same results were obtained when the study was extended to earthquakes that originated in other parts of the planet, confirming previous findings.

This slight shift in core rotation is not the first time. The data shows another similar event in the 1970s, which suggests that the phenomenon repeats itself at a frequency of about seven decades.

Relationship with geophysical phenomena

Curiously, this same frequency also appears in other geophysical observables such as geomagnetic field, day length or the weather. Which suggests they may be related.

This phenomenon is currently believed to be periodic change in the rotation of the nucleus should be:

1. To the electromagnetic interaction between the inner and outer core, tending to accelerate the inner core.
2. To a gravitational connection with the mantle, forcing it back to rhythm.

Does the study say the Earth’s core froze in place in 2009 and is about to start spinning in the opposite direction? No, he just changed his speed relative to the earth’s crust.

It has happened so many times before

Throughout history, the magnetic field has reversed many times. Does this core slowdown imply another imminent pole reversal, or could the magnetic field disappear? No, the core continues to rotate and the magnetic field will continue to be generated.

Will this phenomenon have implications for the climate? The article suggests that there may be some connection, but that the origin multidecadal variations climate is not yet fully understood. Moreover, it is unlikely that such small changes in the rotation of the nucleus could have really noticeable consequences.

As we can see, the dynamics of the Earth is a system of great complexity and there are many interrelated factors that determine the characteristics and evolution of our planet.

The long history of the Earth compared to our research makes understanding its evolution a big challenge. Discoveries like this are an example of science’s efforts to understand more and more how the planet we live on works.

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