Although most of us have taken the land under our feet for granted, written in its complex layers, like the pages of the book, is the history of the earth. Our story.
Studies show that there are little known chapters in that story, deep in the past of the earth. In fact, the inner core of the earth seems to have another inner core.
“Traditionally, we were taught that the Earth has four main layers: crust, mantle, outer nucleus and inner nucleus,” – 2021. Explained by Joanne Stephenson, a geophysicist at the Australian National University.
Related: The inner core of the earth is a mysteriously changing form, the study reveals
Our knowledge of what lies under the Earth’s crust was mostly done from what the volcanoes revealed and what seismic waves whispered.
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Based on these indirect observations, scientists estimate that the scandalously hot internal core, with temperatures above 5000 degrees Celsius (9000 Fahrenheit), is only 1 percent of the total volume of Earth.
However, a few years ago, Stephenson and colleagues found evidence that the Earth’s inner core could actually have two different layers.
“It’s very interesting-and can mean we have to rewrite the textbooks!” Stephenson explained at the time.
The team has used the search algorithm to move and reconcile thousands of internal core models, with observed data over many decades about how long seismic waves take to travel through the Earth, collected by the International Seismological Center.
Differences in seismic waves through the layers of earth. (Stephenson xxxxxx)
Differences in seismic waves through the layers of earth. (Stephenson et al.Geophysical Research Magazine: Solid Earth, 2021)
So what is there? The team looked at some models of anisotropy of the “inner nucleus”-as its material makeup differences change the properties of seismic waves-and found that some were more likely than others.
While some models show the seismic waves of the inner core channels faster parallel to the equator, others indicate that the mixture of materials makes faster waves more parallel to the axis of the Earth’s rotation. Even then, there are arguments about the degree of exact difference in certain angles.
The study here did not show large variations of the inner core, but it found that slowly changed at 54 degrees, and faster wave direction was parallel to the axis.
The inner core of the Earth can actually have two different layers. (Alexlmx/Canva Pro)
“We have found evidence that can mean a change in iron structure, which indicates that perhaps two separate cooling events in the Earth’s history,” Stephenson said.
“The details of this big event are still a little secret, but we have added another piece of puzzle when we need to know about the inner core of the earth.”
These findings may explain why some experimental evidence did not match our current Earth structure models.
The presence of an inner layer was suspected beforeWith hints that iron crystals forming an inner core have different structural alignments.
“We are limited by the distribution of global earthquakes and receivers, especially in polar antipodes,” the team writes in its document, explaining that the missing data reduces the certainty of their findings.
However, their findings are in line with other inner nuclear anisotropy studies.
Future research can complete some of the gaps in these data and allow scientists to confirm or contradict their conclusions and hopefully translate more stories written in this early layer of earth history.
This study has been published Geophysical Research Journal;
The previous version of this article was published in 2021. March