Scientists Detected Signs of a Hidden Structure Inside Earth’s Core
While most of us don’t miss a thing about the earth beneath our feet, Earth’s history is written inside its many layers, just like those of an open book.
Our past. Scientists have found that deep inside Earth’s past are little-known chapters of its history.
Indeed, there appears to be an additional inner core to Earth’s inner core. Australian National University geophysicist Joanne Stephenson explains,
This was stated in 2021. Most of what we have learned about what’s beneats the crust of Earth has come from what seismic waves and volcanoes have spoken to us.
From indirect measurements, scientists have estimated that the intensely hot inner core covers only about 1% of the Earth’s volume. Such temperatures are more than 5,000 degrees Celsius or 9,000 Fahrenheit.
However, evidence that Earth’s inner core might be composed of two separate layers was discovered a few years ago by Stephenson and colleagues. “It’s very exciting — and might mean we have to re-write the textbooks!”
Then, Stephenson clarified. The scientists applied a search algorithm to sift through thousands of inner core models and analyze them with data gathered by the International Seismological Centre for decades on the transit time of seismic waves through Earth. So what does exist below?
The scientists examined thousands of anisotropic models of the inner core’s composition, how variations in material around that central core affect characteristics of seismic waves, and found some to be far more reasonable than others.
In fact, some models propose that the interaction of the materials allows waves to propagate faster parallel to Earth’s rotational axis, whereas others believe that the very composition of the inner core allows seismic waves to propagate much more rapidly parallel to the equator. But even with such ideas, there is still debate surrounding the precise degree of variation at any given angle.
While that study indicated a significant change in the slow direction of waves to a 54-degree angle, with the faster direction of waves flowing parallel to the axis, it did not display too much variation with depth in the inner core.
“We found evidence that may indicate a change in the structure of iron, which suggests perhaps two separate cooling events in Earth’s history,”
Stephenson said.
‘The details of this huge event remain somewhat mysterious, but we have added one more piece of the puzzle to our knowledge of the Earth’s inner core’.
These results may provide some explanation for why some experimental data were inconsistent with our existing Earth structural models, researchers say.
Previous studies have indicated that possibly there is an innermost core, looking at the indicators found from the different alignments of iron crystals forming the inner core in the earth.
The authors of this paper report that the researchers “are limited by the distribution of global earthquakes and receivers, especially at polar antipodes,” and that this reduces their confidence in the conclusions drawn.
Conclusions
Yet there conclusions dovetail with studies that previously studied the anisotropy of Earth’s innermost inner core. Of course, it would not be at all surprising if future research bridged some of these knowledge gaps to allow that researcher to confirm or refute his conclusions, and hopefully translate a few more narratives into this very early record of Earth’s past.
