Scientists Discover Evidence of a Hidden Structure Deep Inside the Earth's Core

 


While most of us take the ground under our feet for granted, Earth's past is written within its intricate layers, just like the pages of a novel. This is the story of our lives.

Researchers have discovered new evidence for a whole new chapter of Earth's history: Earth's inner core appears to contain a second, much more inner core.

According to Joanne Stephenson of Australia, we've all been told that the Earth has four primary layers: the crust, the mantle, the outer core, and the inner core.

What we know about what lies under the Earth's crust is largely based on what volcanoes have revealed and seismic waves have whispered. Scientists also determined that the scorching hot inner center, with temperatures exceeding 5,000 degrees Celsius (9,000 degrees Fahrenheit), makes up just 1% of Earth's total volume based on these indirect observations.

Now, Stephenson and colleagues have discovered new evidence that the Earth's inner core can be divided into two layers.

It's very exciting - and it can necessitate rewriting textbooks! She continued.

The researchers used a search algorithm to sift through thousands of inner core models and compare them to data gathered by the International Seismological Centre over decades on how long seismic waves take to travel through Earth.

Differences in the paths of seismic waves as they travel across the Earth's layers. (Journal of Geophysical Research: Solid Earth, 2021, Stephenson et al.)


So, what's going on down there? The researchers looked at various models of the inner core's anisotropy, or how variations in the make-up of its material affect seismic wave properties, and discovered that some were more likely than others.

Although some models claim that the inner core's material channels seismic waves faster parallel to the equator, others argue that the combination of materials allows for faster waves parallel to the rotational axis of the Earth. Even then, there are disagreements about the precise degree of difference at different angles.

The inner core did not display much difference with depth, but there was a shift in the slow direction to a 54 degree angle, with the faster direction of waves running parallel to the axis, according to this analysis.

According to Stephenson, we discovered evidence of a change in the composition of iron, which suggests two separate cooling events in Earth's history.

The specifics of this major occurrence remain a mystery, but we've gained another piece of the puzzle in our understanding of the Earth's inner heart.

These new results may explain why some experimental evidence has been incongruent with current Earth structure models.

For quite some time, the existence of an innermost layer has been suspected, with suggestions that the iron crystals that make up the inner core have different structural alignments.

The team wrote in their paper that the distribution of global earthquakes and receivers limits them, particularly at the polar antipodes, and that the missing data reduces the certainty of their conclusions. However, their findings are consistent with other recent research on the anisotropy of the innermost inner heart.

A new method in progress could soon fill in some of these data gaps, allowing scientists to confirm or refute their findings and, possibly, translate more stories written in this early layer of Earth's history.

Reactions

Post a Comment

0 Comments