Scientists Dig Deep to Detect Earth's Hidden Layer, But No One Knows What it is

The world may possess more layer than researchers imagined. Recent research discovers that there might be an unknown layer inside the Earth's thick inner core - an inside-inside core, if you will. The accurate nature of this layer is unusual, but it could have few things to do with shifts in the pattern of iron under intense pressure and temperature.

Australian National University in Canberra's doctoral student in seismology Jo Stephenson explained that the research indicates that there is more sophistication to the inner core than formerly appreciated, it's not only a thick ball of iron.

The Solid Core

The Earth's core reaches into two portions. The liquid outside the core begins about 2,897 kilometers (1,800 miles) from the Earth's surface and is composed of liquid metals at a temperature between 9,000 to 4,000 degrees Fahrenheit which is 2,204 to 4,982 degrees Celsius. At around 5,150 km (3,200 miles) below the surface of the Earth, the core changes to a fraction of a nickel (solid iron)

The initial inklings that there might be something fascinating hiding at the heart of the inner core came since the 1980s. Because there is no means to get to the inner core, where temperatures reaches those at the sun's surface, researchers use earthquake waves to create pictures of the core.

The wave coming from an earthquake noticed on the other path of the planet has subtle changes that researchers uses to remake photos of what they have gone through.

Remarkably, when waves go through the core from north to south, the journey is quicker than waves going through the core parallel to the Earth's equator. Nobody understands why this is, Jo explained, but it's a constant finding. The specialized word for this exception is anisotropy.

100,000 Earthquake Waves

But at the very heart of the inner core, something appears to be distinct, researchers noted in the early 2000s. At this depth, the anisotropy appeared not to match that of the remaining inner core. "For the recent two decades, it has been extremely, extremely blurred what this clue at the heart of the Earth in the data is and why we notice it," Jo discloses

Jo and her colleagues brought together a dataset of around 100,000 earthquake waves that went through this stage of the core and connected an algorithm that scans for the best physical justification of what's happening to clarify the data.

Prototypes of the Earth's Solid Inner core

What they discovered was that in the inside-inside core, beginning around 650 km (400 miles) from the middle of the Earth, the anisotropy in the slow direction is not that equal with the equator anymore, but 54 degrees off.

Jo said, "This is not just a sound in the data, this is surely something that's there." But it's never simple to say what that something is.

The scientists are presently working with mineral geodynamics and physicists so they will try coming up with prototypes of the inside-inside core that would explain this change. As the Earth cools, the inner core is also expanding and cooling Jo explained.

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