The earth's inner core is a sphere composed of pure iron that is 5,000 kilometers deep and much hotter compared to the sun. The Washington Post reports that a recent study discovered how this planetary core is getting slower as part of its 70-year cycle. Other than that, it could also be rotating in the opposite direction from the surface of the planet.
This was according to a study published in Nature Geoscience. Such a slower sleep may impact the entire planet. For one, it may make days shorter by less than a second or affect sea levels and climate change.
According to EL PAíS, the study authors tried to look into the enigma that has left specialists puzzled ever since it was confirmed tens of years ago that there is a fifth layer within the earth's planetary core. This was specifically pursued by Yi Yang and Xiaodong Song, who are both from the Institute of Theoretical and Applied Geophysics at Peking University in China.
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How Deep Is Earth's Inner Core?
The inner core is a strong sphere that has a diameter of around 1,200 kilometers. It freely spins within a sea of iron, among other metals, which is called the outer core. El Pais notes how the huge sphere's rotation is similar to a dynamo that creates the magnetic field of the earth, which safeguards the planet against space radiation and enables the existence of life.
The mantle of the planet extends to surround such a nucleus. It is close to 3,000 kilometers thick. Finally, there is also the earth's outer crust, which has an average thickness of around 40 kilometers.
Reaching the earth's center is an impossible feat. During the late 1970s, scientists from the Soviet Union tried digging and creating a deep well within the Kola Peninsula of northern Russia. After working for years, they were able to go 12 kilometers deep, which is the deepest that has ever been dug. EL PAíS notes how it seems impossible to go deeper without the hole's walls collapsing due to the strong pressure.
Rotation of Earth's Inner Core
To know more about what could be happening at such depths, specialists usually study earthquakes. The seismic wave variation, as such waves route through the planet, shows the core's internal composition as well as its rotation rate.
In 1996, Xiaodong Song was among a team of researchers who discovered that the inner core of the earth rotates much faster compared to its crust. The scientist verified these observations in 2005 and explained how the core spins an additional one time every 900 years compared to the other parts of the planet.
In the new study, Song looked at almost 200 earthquakes within the South Sandwich Islands that happened from the 1960s up until the present.
Analyzing the tremors revealed that in 2009, the inner core of the earth slowed down its rotation. Ever since then, its rotation has been quite slow compared to the crust. Song also notes how, if viewed from space, the core looks like it is rotating at a close rate to other parts of the planet. However, seeing it from the surface, where seismic stations are situated, the core has also been spinning in the opposite direction, which is west.
EL PAíS reports that a similar difference was also detected by specialists during the mid-1970s. Song notes how there may be an oscillation cycle that takes place for around seven decades. Song also expresses how such findings suggest a resonance that links the earth's layers and that takes place within such a rhythm.
Implications of Slower Rotation
Such findings have various global implications. Song notes how recent shortened days could be attributed to the earth's inner core. Other than this, the inner core's rotation inside the outer core also changes the gravitational field. It also leads to surface deformations that can affect sea levels. Such alterations may also impact the earth's global temperatures.
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